Clinical predictors of low histopathologic risk features in unilateral

cT2b (Group D) retinoblastoma

Stephanie N. Kletke, MD1, Zhao Xun Feng, BSc2, Lili-Naz Hazrati, MD, PhD, FRCPC3, Brenda L. Gallie,

MD, FRCSC1,2,4, Sameh E. Soliman, MD2,5

Authors’ Affiliations

1 Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Canada;

2 Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Canada;

3 Department of Pediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Canada;

4 Departments of Molecular Genetics and Medical Biophysics, University of Toronto, Toronto, Canada;

5 Department of Ophthalmology, Faculty of Medicine, Alexandria University, Alexandria, Egypt.

Corresponding Author: Sameh E. Soliman, 555 University Avenue, Room 7265, Toronto, Canada,

M5G 1X8. samehelsayedsoliman@yahoo.com

Running Head: Histopathology in Unilateral cT2b Retinoblastoma

Word count: /3000 words

Number of Figures and Tables: /5

Keywords: unilateral retinoblastoma; Group D; histopathology; cancer; primary enucleation

Word Count for Original Clinical Science Research: (Excluding title page, abstract, tables, references,

acknowledgements, contributions) max 3000; Abstract max 250 words; References max 35

At a glance (/35)

Abstract (/250)

Background/Aims: Whether attempted eye salvage for unilateral cT2b (Group D) retinoblastoma

increases risk of tumor spread compared to primary enucleation is debated. Identification of clinical

features predictive of low histopathologic risk may guide potentially safe trial salvage.

Methods: A retrospective review of eyes primarily enucleated for unilateral cT2b retinoblastoma

(2008-2018) was conducted. Clinical features (intraocular pressure, optic nerve obscuration, macular

involvement, tumor seeding and serous retinal detachment >1 quadrant (RD)), histopathological findings,

metastasis and death were reviewed. Primary outcome was high-risk (HR) histopathology (pT3/pT4)

versus low-risk (LR) (pT1/pT2) (8th Edition American Joint Committee on Cancer). Clinico-pathologic

correlation was evaluated.

Results: Histopathology diagnosed 4/38–10.5% HR and 34/38–89.5% LR eyes. Clinical findings

included macular involvement (31/38–82%), optic nerve obscuration (27/38–71%), and RD (28/38–74%).

HR eyes demonstrated massive choroidal invasion (4/38–10.5%), and trans-scleral, extraocular and

retrolaminar optic nerve invasion (1/38–2.6%). The probability that an eye had HR histopathology was

13% with macular involvement, 11% with optic nerve obscuration, and 14% with RD. The probability

that an eye had LR histopathology was 100% with macular sparing, 91% with optic nerve visibility and

100% with <1 quadrant of RD. One child (with all 3 clinical HR predictive features) and HR

histopathology (pT3a) developed metastases and died; other children are alive and well (mean follow-up

65 months).

Conclusion: Macular sparing, optic nerve visibility and <1 quadrant of RD were highly predictive of

LR in unilateral cT2b eyes, enabling identification of eyes suitable for likely safe trial salvage.

Introduction

Unilateral retinoblastoma staged as Group D by the International Intraocular Retinoblastoma

Classification (IIRC)(1) and as cT2a or cT2b by the 8th Edition American Joint Committee on Cancer

(AJCC) TNMH (tumor, node, metastasis and heritable trait) staging,(2) poses a management challenge of

international debate. Attempted eye salvage using primary intra-arterial (IAC)(3-8) or systemic

chemotherapy(9) with focal consolidation has been suggested.(10) However, primary enucleation is an

effective and safe option to minimize risk of extraocular extension and metastasis. In Canada, the

National Retinoblastoma Strategy Guidelines for Care published in 2009 recommend enucleation of

affected unilateral Group D eyes.(11)

Recently, multiple treatment modalities have been suggested to improve success of eye salvage,

including intravitreal chemotherapy (IVC),(12-15) IAC,(3-8) periocular chemotherapy,(16) and tumor

endoresection via pars plana vitrectomy (PPV).(17) The primary concern with such modalities is whether

attempted eye salvage increases the risk of extraocular tumor dissemination. Our aim was to identify

potential clinical features of primarily enucleated unilateral cT2a/cT2b (Group D) eyes predictive of low

histopathologic risk, in an attempt to guide potentially safe trial salvage.

Methods

Study Design

A retrospective, non-comparative, single institutional observational study was conducted in

accordance with the guidelines of the Declaration of Helsinki. Institutional Research Ethics Board

approval was obtained.

Eligibility

Children diagnosed with unilateral Group D (cT2a or cT2b) retinoblastoma managed with primary

enucleation of the affected eye at the Hospital for Sick Children (SickKids), Toronto, Canada between

January 2008 (following submission and implementation of the Canadian guidelines(11)) through

February 2018 were evaluated. Exclusion criteria included unilateral retinoblastoma of any other staging,

primarily enucleated cT2a/cT2b eyes in bilateral cases, or cT2a/cT2b eyes that were secondarily

enucleated following trial salvage.

Data Collection

Clinical and Radiological Features

Medical records, including fundus photographs from examinations under anesthesia (EUA), were

reviewed for age at diagnosis and enucleation, laterality, clinical features at presentation (intraocular

pressure (IOP), optic nerve obscuration, macular involvement and >1 quadrant of serous retinal

detachment (RD)), parental agreement with the proposed treatment, molecular genetic analysis, follow-up

duration, adjuvant treatments received, metastasis and death. Eyes were retrospectively staged by the 8th

Ed. AJCC TNMH.(2) Baseline magnetic resonance imaging (MRI) or computed tomography (CT) of the

brain and orbit were reviewed.

Histopathologic Features

Histopathology reports and representative slides were reviewed for all children. Presence of choroidal

invasion was documented as “none”, “focal [<3 mm]” or “massive [>3 mm in maximum diameter]”,

based on consensus definitions from the International Retinoblastoma Staging Working Group.(18)

Invasion of the sub-retinal pigment epithelial (sub-RPE) space but not through Bruch’s membrane was

identified. Optic nerve invasion was categorized as “none”, “prelaminar”, “retrolaminar but not to the

optic nerve resection margin” and “tumor at the transected end”.(18) Scleral invasion, anterior segment

involvement and extraocular disease were also identified. Enucleated eyes were retrospectively staged by

the 8th Ed. AJCC pTNM.(2) Table 1 summarizes the 8th Ed. AJCC pathological staging.

Outcome Measures

The primary outcome was the presence of high-risk (HR) histopathology, defined as pT3 or pT4,

versus low-risk (LR) histopathology, defined as pT1 or pT2 (8th Ed. AJCC).(2) High-risk histopathologic

features included massive choroidal invasion, retrolaminar invasion of the optic nerve head, scleral

invasion and extraocular extension.

Clinico-pathologic correlation was evaluated. Positive predictive value was defined as the probability

that an eye with high-risk clinical features (macular involvement, optic nerve obscuration or RD) had HR

histopathology. Negative predictive value was defined as the probability that an eye with low-risk clinical

features (macular sparing, optic nerve visibility and <1 quadrant of RD) had LR histopathology.

Secondary outcomes included the proportion of eyes for which salvage therapy may have been

considered as an alternative to enucleation based on standard of care in 2018, as determined by senior

author review (B.L.G., S.E.S.).

Statistical Analysis

Results were summarized using frequency/percentage for categorical variables and mean, median and

standard deviation for continuous variables. Groups were compared using Fisher’s exact test for

categorical variables and Student’s t-test for continuous variables. All P-values reported were two-sided

and significance was judged at the 5% level. All analyses were performed using SPSS Version 25 (IBM

Corp).

Results

Demographic and Clinical Features

Thirty-eight primarily enucleated Group D eyes (63% right, 37% left) of 38 children (mean presenting

age 21 months, 2 – 48) with unilateral retinoblastoma were includedincluded (63% right, 37% left). All

eyes were staged cT2b (8th Edition AJCC).(2) Based on high-quality molecular genetic analysis, heritable

trait was HX (4/38–10.51%), H0 (27/38–71.1%) and H1 (7/38–18.4%). H1 children showed mosaicism

for the RB1 pathogenic variant (3/7), low penetrance RB1 pathogenic variant (3/7) and13-q deletion

syndrome (1/7).

At presentation, all eyes had normal IOP. Tumor involved the macula in 31/38–82%. Children with

macular involvement were diagnosed earlier than children with macular sparing (mean 20 vs 28 months,

respectively), though this difference was not significant (p=0.09). The optic nerve was obscured in

2728/38–7174% and RD was present in 28/38–74%. The presence of macular involvement, optic nerve

obscuration and RD were positively correlated [macula and optic nerve (p=0.01), macula and RD (p<

0.001), optic nerve and RD (p=0.002)]. Four eyes with optic nerve obscuration demonstrated possible

optic nerve enhancement on baseline imaging of the brain/orbit. There were no radiological cases of

extraocular or intracranial involvement.

The median interval from diagnosis to enucleation was 4 days (range, 0 – 14). Primary enucleation

occurred during the staging EUA for all children, with the exception of one child for whom enucleation

was delayed due to low partial thromboplastin time. All parents consented to enucleation as the primary

treatment.

Histopathologic Features

Choroidal involvement included “none” (26/38–68.4%), “focal” (8/38–21.1%), and “massive” (4/38–

10.5%). Six eyes (15.8%) demonstrated tumour cells in the sub-RPE space. Optic nerve involvement

included “none” (10/38–26.3%), “prelaminar invasion” (27/38–71.1%), and “retrolaminar invasion but

not to the optic nerve resection margin” (1/38–2.6%). There were no cases of tumor involvement of the

resected margin. One eye (2.6%) demonstrated histopathologic evidence of anterior segment involvement

(pT2b). There was one case (2.6%) of trans-scleral and extraocular extension (pT4).

Summary of High-Risk Eyes

Histopathology review identified 4/38–10.5% HR eyes and 34/38–89.5% LR eyes. HR eyes

demonstrated massive choroidal invasion (4/38–10.5%) and trans-scleral, extraocular and retrolaminar

optic nerve invasion (1/38–2.6%). Mean age at diagnosis was not significantly different for children with

HR versus LR eyes (p>0.05). Presenting signs included leukocoria (3/4–75%) and strabismus (1/4–25%).

Baseline MRI brain and orbits showed no evidence of optic nerve, extraocular or intracranial involvement

in children with HR eyes. There was no evidence of metastases at presentation. Figure 1 summarizes the

clinical and histopathologic features of children with HR eyes. A representative sample of children

with LR eyes are summarized in Figure 2.

Clinico-pathologic Correlation

Optic nerve obscuration was not significantly associated with retrolaminar optic nerve invasion in this

cohort (p=1.000). Macular involvement was not significantly associated with massive choroidal invasion

(p=0.557) or scleral invasion (p=1.000). Serous retinal detachment was not significantly associated with

massive choroidal invasion (p=0.287) or scleral invasion (p=1.000).

The probability that an eye had HR histopathology was 13% with macular involvement, 11% with

optic nerve obscuration, and 14% with RD. The probability that an eye had LR histopathology was 100%

with macular sparing, 91100% with optic nerve visibility and 100% with <1 quadrant of RD.

Follow-up, Metastasis and Death

At mean follow-up of 65 months, one child (2.6%) with all three clinical HR predictive features and

HR histopathology (pT3a) developed metastases and died. The child was diagnosed with bony metastases

1 year following retinoblastoma diagnosis.(19) He received six cycles of systemic chemotherapy,

autologous bone marrow transplant and focal radiation. While ocular pathology was initially interpreted

as LR, internal retrospective review identified an area of massive choroidal invasion. Metastatic

surveillance remained negative until 1 year later, when intracranial dural-based metastases were identified

on MRI. He died 18 months after metastasis diagnosis, despite focal radiotherapy. The other children in

this cohort are alive and well.

Discussion

The International Intraocular Retinoblastoma Classification (IIRC) introduced in 2005 staged

eyes clinically as Group A (very low risk) through E (very high risk) to predict outcomes following

systemic chemoreduction and focal therapy.(1) A modification was proposed in 2006 (International

Classification of Retinoblastoma, ICRB).(20) In 2010, the 7th Edition AJCC defined clinical and

pathological staging for overall prognosis.(21) The 8th Edition TNMH was recently updated based on

evidence-based data,(2) and serves as the current gold standard for retinoblastoma staging. IIRC Group E

eyes shows advanced intraocular tumors as phthisis bulbi (cT3a), anterior segment tumor invasion (cT3b),

rubeosis irides with neovascular glaucoma (cT3c), hyphema and/or massive vitreous hemorrhage (cT3d)

and or aseptic orbital cellulitis (cT3e). IIRC Group D eyes have intraocular tumor with significant RD

(cT2a) and/or any vitreous and/or subretinal seeding (cT2b). High-risk histopathologic features predictive

of increased metastatic risk are defined as pT3/pT4 following enucleation, and include massive choroidal

invasion,(22, 23) retrolaminar invasion of the optic nerve head with or without a positive margin,(22, 24)

scleral invasion and extraocular extension (8th Edition AJCC, Table 1).(2)

The main goal of treatment for advanced unilateral retinoblastoma is to save the child’s life and

prevent extraocular tumour dissemination followed by saving a seeing eye. The concept of salvage of a

blind eye for cosmesis is no longer justified, given the improved implant and prosthesis movement with

myoconjunctival enucleation.(39). Multiple modalities, including systemic chemotherapy, IAC, IVC,

periocular chemotherapy and PPV have been suggested for eye salvage. However, primary enucleation is

a safe option, allowing an early return to normal life,(28) less socioeconomic impacts, fewer interventions

and EUAs,(37) as well as histopathological review. This is the accepted practice in many centers for cT3

(IIRC Group E) eyes and probably most cT2b eyes (IIRC group D). The dilemma of parental refusal of

enucleation justifying treatment for these advanced eyes depend on the treating physician and how the

parents are counselled. In our cohort we did not face parental refusal in any of our enucleated eyes.

The success of intravitreal chemotherapy in controlling vitreous disease, a main clinical feature of

T2b (IIRC Group D) eyes, together with the availability of more published literature on IAC, that

previously posed a dilemma, as chemotherapy delivered focally that may not protect against tumor cells

that have escaped the affected eye(5) made the trial salvage attempt for a unilateral cT2b justified as long

as the tumor is less likely to spread beyond the eye. Clinical features at presentation predictive of HR

histopathology include older age, symptoms >6 months, hyphema, pseudohypopyon, orbital cellulitis,

secondary glaucoma and buphthalmos.(29, 40, 41) Furthermore, exophytic growth pattern, tumor

thickness >15 mm and vitreous hemorrhage predict optic nerve invasion,(24) and iris neovascularization

is associated with choroidal invasion.(23, 42) However, these characteristics predominantly describe cT3

(Group E) eyes and are not relevant when considering the treatment of cT2b eyes. As the decision of trial

salvage is at diagnosis, objective rather than subjective (presenting complain or duration) clinical findings

need to be evaluated. Yousef et al concluded that clinical staging alone (TNM 7th ed., IIRC or Reese

Elseworth classification) is insufficient to predict HR histopathology.

Approximately 2–33% of Group D eyes are expected to harbor HR histopathologic features

following primary enucleation.(25-31) However, the literature is heterogeneous and limited by non-

consensus in defining HR histopathology features, variable classifications, and inclusion of primarily and

secondarily enucleated eyes, children with unilateral and bilateral disease, as well as eyes with no

indication of staging. In our cohort of primarily enucleated unilateral cT2b eyes, 10.5% had HR

histopathology. Macular involvement, optic nerve obscuration and >1 quadrant of RD had low predictive

value for HR histopathology (13%, 11%, and 14%, respectively). However, macular sparing, visibility of

the optic nerve and <1 quadrant of RD had 100% predictive value for the presence of LR histopathology,

suggesting that an eye with these three clinical features may undergo cautious trial salvage.

.Fabian et al reported on 40 primarily enucleated IIRC Group D eyes (all cT2b, 37 unilateral). At

presentation, 75% had macular involvement, 91% had optic disc obscuration and 97% had RD, compared

to 82%, 74% and 74%, respectively in our cohort. They interpret absence of vitreous seeds as a sole

significant predictor of HR based on p=0.42.(30) Small sample sizes renders tests of significance

inaccurate as one extra entry can shift the p-value significantly which lead us to use the predictive values

rather than then tests of significance to interpret our data. When we applied predictive values to the data

reported by Fabian et al., we had the same results of 100% predictive of LR histopathology if the optic

nerve is seen and the fovea is not involved. Applying significance tests to our combined samples had a

lower p-value (p=0.3 and 0.59 respectively) but not yet significant (Table X). Jesse et al reported a

retrospective review of IIRC Group D/E eyes and found that 15% of eyes with optic nerve obscuration at

presentation (69/102) had postlaminar invasion, while 0% with visible optic nerve at diagnosis (33/102)

had postlaminar invasion following primary enucleation, suggesting a possible clinico-pathologic

association.(43)

Prolonged attempts at globe salvage could lead to delayed diagnosis of metastasis if HR features

are not identified timely. Systemic chemoreduction should also be considered cautiously, as pre-

enucleation chemotherapy may downstage pathological findings of extraocular disease.(38) With no

evidence from randomized controlled trials to guide management of cT2a/cT2b eyes, the clinician must

consider the impact of years of trial salvage for an eye with limited visual potential on quality of life for

the child and family.

Early detection of HR histopathologic features is important and when present, warrants metastatic

surveillance and adjuvant therapy. Postenucleation adjuvant treatments, including systemic

chemotherapy, significantly reduce metastatic events from 24% to 4%, particularly in the presence of

massive choroidal and retrolaminar invasion.(32) Furthermore, post-enucleation adjuvant VEC was

associated with no metastatic events for 51 high-risk ICRB(20) Group E eyes (mean 66 month follow-

up).(33) However, the specific indications for adjuvant therapy are debated,(34) with some groups

suggesting good prognosis for isolated choroidal or retrolaminar optic nerve invasion and negative

margins without adjuvant treatment.(35, 36) In our cohort, the child who developed metastasis did not

receive post-enucleation adjuvant therapy, as massive choroidal invasion was only identified following

retrospective review. The other three children with HR histopathology received adjuvant treatments and

are alive and well at last follow-up.

.

ADD: Paragraph on eyes that had a change in initial pathology staging based on review of representative slides

ADD: Paragraph addressing those eyes for which trial salvage may have been attempted based on current practice patterns in 2018. Reference Figure 2 (LR features)

ADD: Paragraph on the histopathologic finding of sub-RPE invasion and distinction from choroidal invasion

The limitations of this study include its retrospective design and relatively small sample size.

However, our inclusion criteria of only unilateral, primarily enucleated Group D eyes were stringent,

achieving a homogenous study population. Another limitation is the low rate of positive events, which

limits statistical analysis of associations between clinical findings and histopathological features of the

included eyes.

Conclusion

In summary, 10.5% of primarily enucleated unilateral cT2b (Group D) eyes had HR

histopathology. Macular sparing, optic nerve visibility and <1 quadrant of RD at presentation were highly

predictive of low-risk in unilateral cT2b eyes, and may predict which advanced eyes are suitable for trial

salvage. Given the widespread management debate of unilateral cT2a/cT2b eyes, there is a need for

robust, multicentre collaborative studies involving a larger group of children to further assess these

clinico-pathologic correlations.

References

1. Murphree AL. Intraocular retinoblastoma: the case for a new group classification. Ophthalmology

clinics of North America. 2005;18:41-53.

2. Mallipatna A, Gallie BL, Chévez-Barrios P, Lumbroso-Le Rouic L, Chantada GL, Doz F, et al.

Retinoblastoma. In: Amin MB, Edge SB, Greene FL, editors. AJCC Cancer Staging Manual. 8th Edition.

New York, NY: Springer; 2017. p. 819-31.

3. Munier FL, Mosimann P, Puccinelli F, Gaillard MC, Stathopoulos C, Houghton S, et al. First-line

intra-arterial versus intravenous chemotherapy in unilateral sporadic group D retinoblastoma: evidence of

better visual outcomes, ocular survival and shorter time to success with intra-arterial delivery from

retrospective review of 20 years of treatment. Br J Ophthalmol. 2016.

4. Shields CL, Manjandavida FP, Lally SE, Pieretti G, Arepalli SA, Caywood EH, et al. Intra-

arterial chemotherapy for retinoblastoma in 70 eyes: outcomes based on the international classification of

retinoblastoma. Ophthalmology. 2014;121(7):1453-60.

5. Yousef YA, Soliman SE, Astudillo PP, Durairaj P, Dimaras H, Chan HS, et al. Intra-arterial

Chemotherapy for Retinoblastoma: A Systematic Review. JAMA ophthalmology. 2016;134(6):584-91.

6. Ong SJ, Chao AN, Wong HF, Liou KL, Kao LY. Selective ophthalmic arterial injection of

melphalan for intraocular retinoblastoma: a 4-year review. Japanese Journal Of Ophthalmology.

2015;59(2):109-17.

7. Gobin YP, Dunkel IJ, Marr BP, Brodie SE, Abramson DH. Intra-arterial chemotherapy for the

management of retinoblastoma: four-year experience. Arch Ophthalmol. 2011;129(6):732-7.

8. Suzuki S, Yamane T, Mohri M, Kaneko A. Selective ophthalmic arterial injection therapy for

intraocular retinoblastoma: the long-term prognosis. Ophthalmology. 2011;118(10):2081-7.

9. Chan HS, Gallie BL, Munier FL, Beck Popovic M. Chemotherapy for retinoblastoma.

Ophthalmology clinics of North America. 2005;18(1):55-63, viii.

10. Shields CL, Kaliki S, Al-Dahmash S, Rojanaporn D, Leahey A, Griffin G, et al. Management of

advanced retinoblastoma with intravenous chemotherapy then intra-arterial chemotherapy as alternative

to enucleation. Retina. 2013;33(10):2103-9.

11. Canadian Retinoblastoma S. National Retinoblastoma Strategy Canadian Guidelines for Care:

Strategie therapeutique du retinoblastome guide clinique canadien. Can J Ophthalmol. 2009;44 Suppl

2:S1-88.

12. Munier FL, Gaillard MC, Balmer A, Soliman S, Podilsky G, Moulin AP, et al. Intravitreal

chemotherapy for vitreous disease in retinoblastoma revisited: from prohibition to conditional indications.

Br J Ophthalmol. 2012;96(8):1078-83.

13. Munier FL, Soliman S, Moulin AP, Gaillard MC, Balmer A, Beck-Popovic M. Profiling safety of

intravitreal injections for retinoblastoma using an anti-reflux procedure and sterilisation of the needle

track. Br J Ophthalmol. 2012;96(8):1084-7.

14. Berry JL, Shah S, Bechtold M, Zolfaghari E, Jubran R, Kim JW. Long-term outcomes of Group

D retinoblastoma eyes during the intravitreal melphalan era. Pediatr Blood Cancer. 2017;64(12).

15. Francis JH, Brodie SE, Marr B, Zabor EC, Mondesire-Crump I, Abramson DH. Efficacy and

Toxicity of Intravitreous Chemotherapy for Retinoblastoma: Four-Year Experience. Ophthalmology.

2017;124(4):488-95.

16. Mallipatna AC, Dimaras H, Chan HS, Heon E, Gallie BL. Periocular topotecan for intraocular

retinoblastoma. Arch Ophthalmol. 2011;129(6):738-45.

17. Zhao J, Li Q, Wu S, Jin L, Ma X, Jin M, et al. Pars Plana Vitrectomy and Endoresection of

Refractory Intraocular Retinoblastoma. Ophthalmology. 2018;125(2):320-2.

18. Sastre X, Chantada GL, Doz F, Wilson MW, de Davila MT, Rodriguez-Galindo C, et al.

Proceedings of the consensus meetings from the International Retinoblastoma Staging Working Group on

the pathology guidelines for the examination of enucleated eyes and evaluation of prognostic risk factors

in retinoblastoma. Archives of pathology & laboratory medicine. 2009;133(8):1199-202.

19. Racher H, Soliman S, Argiropoulos B, Chan HS, Gallie BL, Perrier R, et al. Molecular analysis

distinguishes metastatic disease from second cancers in patients with retinoblastoma. Cancer Genet.

2016;209(7-8):359-63.

20. Shields CL, Mashayekhi A, Au AK, Czyz C, Leahey A, Meadows AT, et al. The International

Classification of Retinoblastoma predicts chemoreduction success. Ophthalmology. 2006;113(12):2276-

80.

21. Finger PT, Harbour JW, Murphree AL, Karcioglu ZA, Seregard S, Albert D, et al.

Retinoblastoma. In: Edge SB, Byrd DR, Carducci MA, Compton CC, editors. AJCC Cancer Staging

Manual. 7th ed. New York, NY: Springer; 2010. p. 561-8.

22. Khelfaoui F, Validire P, Auperin A, Quintana E, Michon J, Pacquement H, et al. Histopathologic

risk factors in retinoblastoma: a retrospective study of 172 patients treated in a single institution. Cancer.

1996;77(6):1206-13.

23. Shields CL, Shields JA, Baez KA, Cater J, De Potter PV. Choroidal invasion of retinoblastoma:

metastatic potential and clinical risk factors [see comments]. British Journal of Ophthalmology.

1993;77(9):544-8.

24. Shields CL, Shields JA, Baez K, Cater JR, De-Potter P. Optic nerve invasion of retinoblastoma.

Metastatic potential and clinical risk factors. Cancer. 1994;73(3):692-8.

25. Wilson MW, Qaddoumi I, Billups C, Haik BG, Rodriguez-Galindo C. A clinicopathological

correlation of 67 eyes primarily enucleated for advanced intraocular retinoblastoma. The British journal

of ophthalmology. 2011;95(4):553-8.

26. Yousef YA, Al-Hussaini M, Mehyar M, Sultan I, Jaradat I, AlRawashdeh K, et al. Predictive

Value of Tnm Classification, International Classification, and Reese-Ellsworth Staging of Retinoblastoma

for the Likelihood of High-Risk Pathologic Features. Retina. 2015.

27. Kaliki S, Shields CL, Rojanaporn D, Al-Dahmash S, McLaughlin JP, Shields JA, et al. High-risk

retinoblastoma based on international classification of retinoblastoma: analysis of 519 enucleated eyes.

Ophthalmology. 2013;120(5):997-1003.

28. Mallipatna AC, Sutherland JE, Gallie BL, Chan H, Heon E. Management and outcome of

unilateral retinoblastoma. J AAPOS. 2009;13(6):546-50.

29. Kaliki S, Srinivasan V, Gupta A, Mishra DK, Naik MN. Clinical Features Predictive of High-

Risk Retinoblastoma in 403 Asian Indian Patients: A Case-Control Study. Ophthalmology. 2015.

30. Fabian ID, Stacey AW, Chowdhury T, Duncan C, Karaa EK, Scheimberg I, et al. High-Risk

Histopathology Features in Primary and Secondary Enucleated International Intraocular Retinoblastoma

Classification Group D Eyes. Ophthalmology. 2017;124(6):851-8.

31. Berry JL, Kogachi K, Aziz HA, McGovern K, Zolfaghari E, Murphree AL, et al. Risk of

metastasis and orbital recurrence in advanced retinoblastoma eyes treated with systemic chemoreduction

versus primary enucleation. Pediatr Blood Cancer. 2017;64(4).

32. Honavar SG, Singh AD, Shields CL, Meadows AT, Demirci H, Cater J, et al. Postenucleation

adjuvant therapy in high-risk retinoblastoma. Arch Ophthalmol. 2002;120(7):923-31.

33. Kaliki S, Shields CL, Shah SU, Eagle RC, Jr., Shields JA, Leahey A. Postenucleation adjuvant

chemotherapy with vincristine, etoposide, and carboplatin for the treatment of high-risk retinoblastoma.

Arch Ophthalmol. 2011;129(11):1422-7.

34. Kim JW. Retinoblastoma: evidence for postenucleation adjuvant chemotherapy. Int Ophthalmol

Clin. 2015;55(1):77-96.

35. Chantada GL, Dunkel IJ, de Davila MT, Abramson DH. Retinoblastoma patients with high risk

ocular pathological features: who needs adjuvant therapy? Br J Ophthalmol. 2004;88(8):1069-73.

36. Bosaleh A, Sampor C, Solernou V, Fandino A, Dominguez J, de Davila MT, et al. Outcome of

children with retinoblastoma and isolated choroidal invasion. Arch Ophthalmol. 2012;130(6):724-9.

37. Fabian ID, Stacey AW, Johnson KC, Chowdhury T, Duncan C, Reddy MA, et al. Primary

enucleation for group D retinoblastoma in the era of systemic and targeted chemotherapy: the price of

retaining an eye. Br J Ophthalmol. 2017.

38. Zhao J, Dimaras H, Massey C, Xu X, Huang D, Li B, et al. Pre-enucleation chemotherapy for

eyes severely affected by retinoblastoma masks risk of tumor extension and increases death from

metastasis. Journal of clinical oncology : official journal of the American Society of Clinical Oncology.

2011;29(7):845-51.

39. Shome D, Honavar SG, Raizada K, Raizada D. Implant and prosthesis movement after

enucleation: a randomized controlled trial. Ophthalmology. 2010;117(8):1638-44.

40. Kashyap S, Meel R, Pushker N, Sen S, Bakhshi S, Sreenivas V, et al. Clinical predictors of high

risk histopathology in retinoblastoma. Pediatr Blood Cancer. 2012;58(3):356-61.

41. Chantada GL, Gonzalez A, Fandino A, de Davila MT, Demirdjian G, Scopinaro M, et al. Some

clinical findings at presentation can predict high-risk pathology features in unilateral retinoblastoma. J

Pediatr Hematol Oncol. 2009;31(5):325-9.

42. Chawla B, Sharma S, Sen S, Azad R, Bajaj MS, Kashyap S, et al. Correlation between clinical

features, magnetic resonance imaging, and histopathologic findings in retinoblastoma: a prospective

study. Ophthalmology. 2012;119(4):850-6.

43. Berry JL, Zolfaghari E, Chen A, Murphree AL, Jubran R, Kim JW. Optic Nerve Obscuration in

Retinoblastoma: A Risk Factor for Optic Nerve Invasion? Ocul Oncol Pathol. 2017;3(4):283-91.

Tables

Table 1. American Joint Committee on Cancer pathological staging manual 8th Edition.

pT Category pT CriteriapTX Unknown evidence of intraocular tumorpT0 No evidence of intraocular tumorpT1 Intraocular tumor(s) without any local invasion, focal choroidal invasion, or pre- or

intralaminar involvement of the optic nerve headpT2 Intraocular tumor(s) with local invasion pT2a Concomitant focal choroidal invasion and pre- or intralaminar involvement of the

optic nerve head pT2b Tumor invasion of stroma of iris and/or trabecular meshwork and/or Schlemm's

canalpT3 Intraocular tumor(s) with significant local invasion pT3a Massive choroidal invasion (>3 mm in largest diameter, or multiple foci of focal

choroidal involvement totaling >3 mm, or any full-thickness choroidal involvement) pT3b Retrolaminar invasion of the optic nerve head, not involving the transected end of

the optic nerve pT3c Any partial-thickness involvement of the sclera within the inner two thirds pT3d Full-thickness invasion into the outer third of the sclera and/or invasion into or

around emissary channelspT4 Evidence of extraocular tumor: tumor at the transected end of the optic nerve, tumor

in the meningeal spaces around the optic nerve, full-thickness invasion of the sclera with invasion of the episclera, adjacent adipose tissue, extraocular muscle, bone, conjunctiva, or eyelids.

Table 2. Demographic Characteristics of studied patients/eyes

Mean ± SD Median Range

Age of Diagnosis (Month) 21 ± 12 23 2 – 48

Time from Diagnosis to Enucleation (Days) 4 ± 3 4 0 – 14

Time from Staging EUA to Enucleation (Days) 0.2 ± 1.1 0 0 – 7

No. %

Stage at Diagnosis

(IIRC/TNMH)

D/cT2a 2 5

D/cT2b 36 95

Table 3. Clinical findings of studied eyes

Table 4. Histopathologic feature the studied eyes

No. %

Low Risk Histopathologic

Features

Sub-RPE Tumor

Deposits

No 32 84

Yes 6 16

Focal Choroidal Invasion

No 30 79

Yes 8 21

Pre- or intralaminar Optic Nerve

Invasion

No 11 29

Yes 27 71

Anterior Chamber Invasion

No 37 97

Yes 1 3

High Risk Histopathologic

Features

Massive choroidal Invasion

No 34 89

Yes 4 11

No. %

EUA Findings

Macula involvement

No 7 18

Yes 31 82

Optic Nerve obscured

No 11 29

Yes 27 71

Retinal Detachment

No 10 26

Yes 28 74

Retrolaminar Optic Nerve

Invasion

No 37 97

Yes 1 3

Scleral Invasion

No 37 97

Yes 1 3

Tumor at Transected end

No 38 100

Yes 0 0

High Risk EyeNo 34 90

Yes 4 10

Table 5. Association between clinical finding of macular involvement and histopathologic risk of enucleated eye

Pathologic RiskTotal

Low High

EUA Finding of Macular

Involvement

No 7 (100%) 0 (0%) 7

Yes 27 (87%) 4 (13%) 31

Total 34 4 38

Table 6. Association between clinical finding of optic nerve obscurity and histopathologic risk of enucleated eye

Pathologic RiskTotal

Low High

EUA Finding of Optic Nerve

Obscurity

No 10 (91%) 1 0 (9%) 1110

Yes 24 (89%) 3 4 (11%) 2728

Total 34 4 38

Table 7. Association between clinical finding of significant exudative retinal detachment and histopathologic risk of enucleated eye

Pathologic RiskTotal

Low High

EUA Finding of Retinal

Detachment

No 10 (100%) 0 (0%) 10

Yes 24 (86%) 4 (14%) 28

Total 34 4 38

Table 8. Association between clinical findings and histopathologic features of enucleated eyes.

Histopathology Features P-value

Clinical Findings

EUA Finding of Macular

Involvement

Sub-RPE Deposits 0.569Focal Choroidal Invasion 1.000

Pre- or intralaminar optic nerve invasion 1.000Anterior Chamber Invasion 1.000Massive choroidal invasion 0.557

Retrolaminar Optic Nerve Invasion 1.000Scleral Invasion 1.000

EUA Finding of Optic Nerve

Obscurity

Sub-RPE Deposits 0.650Focal Choroidal Invasion 1.000

Pre- or intralaminar optic nerve invasion 0.125Anterior Chamber Invasion 1.000Massive choroidal invasion 1.000

Retrolaminar Optic Nerve Invasion 1.000Scleral Invasion 1.000

EUA Finding of Retinal

Detachment

Sub-RPE Deposits 0.168Focal Choroidal Invasion 0.385

Pre- or intralaminar optic nerve invasion 0.094Anterior Chamber Invasion 1.000Massive choroidal invasion 0.287

Retrolaminar Optic Nerve Invasion 1.000Scleral Invasion 1.000