Volume 90 � Number 1S � Supplement 2014 Oral Scientific Sessions S33

were treated with infusional 5-FU (1000 mg/m2/day for 4 days) and MMC

(10 mg/m2) during wks 1 and 5 (5-FU group) and 27 pts were treated with

cape (825 mg/m2 BID) M-F throughout RT and MMC (10 mg/m2) during

wks 1 and 5 (Cape group). Data regarding pt, tumor and treatment char-

acteristics and acute heme toxicity according to CTCAE v4.0 based on

weekly CBC performed during CRTwere recorded. The incidence of Grade

3/4 heme toxicity and the duration of treatment were compared between the

two groups.

Results: The median age at diagnosis was 59 yrs and 64 (72%) were

women. Patient characteristics were similar between the two groups. All

pts were treated with IMRT delivered in a median of 28 fractions and with

a median dose of 56 Gy (range, 49-56 Gy) for both groups. Twenty pts

(31%) in the 5-FU group developed Grade 3/4 neutropenia while only

one pt (4%) had Grade 3/4 neutropenia in the cape group (p Z 0.002).

Grade 3/4 thrombocytopenia and anemia occurred in 8 pts (13%) and 2 pts

(3%), respectively, in the 5-FU group and none of the pts in the cape group.

Treatment breaks were necessary for 26 pts (42%) treated with 5-FU and 5

pts (19%) treated with cape (p Z 0.03). The most common reasons for

delaying treatment in the 5-FU group were Grade 3/4 neutropenia or

mucositis, while in the cape group, they were diarrhea (n Z 2),

rectovaginal fistula (n Z 1), neutropenia (n Z 1), and Hurricane Sandy

(n Z 1). Median treatment duration was 40 days in the 5-FU group and 37

days in the cape group (p Z 0.002).

Conclusions: An adequately powered non-inferiority comparison of cape

vs 5-FU is not numerically feasible in ASCC. Our data suggest that cape is

associated with decreased Grade 3/4 heme toxicity when compared to

standard 5-FU for pts undergoing definitive CRT for ASCC. The reduction

in treatment breaks due to heme toxicity may be expected to yield

improved outcomes. Moreover, since cape with MMC appears to be better

tolerated, this regimen may serve as a backbone for further studies eval-

uating novel agents with CRT for ASCC.

Author Disclosure: K.A. Goodman: None. D. Rothenstein: None. C.

Lajhem: None. A. Wu: None. A. Cercek: None. L.B. Saltz: None.

63Lower Pelvis Bone Marrow Dose Constraints to Reduce HematologicToxicity in the Treatment of Anal CancerA.Y. Lee,1 J.G. Bazan,2 C.A. Pelizzari,1 D.T. Chang,3 and S.L. Liauw1;1University of Chicago, Chicago, IL, 2The Ohio State University,

Columbus, OH, 3Stanford University, Stanford, CA

Purpose/Objective(s): Hematologic toxicity can be a serious and limiting

event in the treatment of squamous cell carcinoma of the anus (SCCA)

with concurrent chemotherapy and radiation therapy (RT). Some groups

have proposed that radiation dose to the pelvic bone marrow correlates

with hematologic toxicity. We attempted to define marrow dose constraints

to limit severe neutropenia and leukopenia in a multi-institutional series.

Materials/Methods: Fifty-six patients with stage I-III SCCA were treated

at 2 academic centers with concurrent 5-FU and mitomycin C (days 1, 28)

and RT. Median age was 59 years, and median body mass index (BMI) was

24.9 kg/m2. Median RT dose was 54 Gy to the primary tumor, 45 Gy to the

true pelvis, and 40 Gy to the whole pelvis. 49 patients were treated with

intensity-modulated radiation therapy, and 7 patients were treated with 3D

planning. The pelvic bone marrow was retrospectively contoured accord-

ing to standardized guidelines and subdivided into the low pelvis, ilium,

and lumbosacral spine. The V5, V10, V15, V20, V30, and V40 Gy were

collected for each structure and the total marrow. Dose-volume statistics

were analyzed with respect to acute grade 3 toxicity within 6 weeks of

completion of treatment by univariate (UVA) and multivariable (MVA)

analysis.

Results: Acute grade 3 neutropenia and leukopenia were seen in 30% and

34% of patients, respectively. On UVA, RT dose to the primary or whole

pelviswas not associatedwith grade 3 hematologic toxicity. BMI< 25 kg/m2

was associated with grade 3 neutropenia (p < 0.01), female gender was

associated with grade 3 leukopenia (p Z 0.03), and mean dose to the total

marrowwas associatedwith severe leukopenia (p< 0.01) and neutropenia (p

Z 0.07). Exploration of various marrow parameters revealed that toxicity

appeared to be driven by dose to the low pelvis more so than the ilium or

lumbosacral spine. Patients who met a duad of V20 Gy� 90% and V40 Gy

� 25% (nZ 15) to the low pelvis had lower rates of grade 3 leukopenia (13%

vs. 41%, pZ 0.04) and neutropenia (0%vs. 40%, p< 0.01). The relationship

with grade3 leukopeniawas larger for patientswith aBMI<25kg/m2 (0%vs

55%, p < 0.01), compared to those with a BMI � 25 kg/m2 (25% vs 26%,

p Z 0.94). The relationship with grade 3 neutropenia was also larger for

patients with a BMI < 25 kg/m2 (0% vs 62%, p < 0.01), compared to those

with a BMI � 25 kg/m2 (0% vs 16%, p Z 0.16). On MVA, the V20/40 Gy

duad to the low pelvis (p < 0.01) and BMI (p < 0.01) were associated with

grade 3 neutropenia, while female gender (p Z 0.43) was not. All these

parameters showed trends towards association with grade 3 leukopenia,

including V20/40 Gy to the low pelvis (p Z 0.11), BMI (p Z 0.054), and

female gender (pZ 0.054).

Conclusions: Acute grade 3 neutropenia and leukopenia may be limited by

constraining the low pelvis bone marrow to V40 Gy � 25% and a V20 Gy

� 90%. This guideline may be particularly important for patients with a

BMI < 25 kg/m2.

Author Disclosure: A.Y. Lee: None. J.G. Bazan: None. C.A. Pelizzari:

None. D.T. Chang: G. Consultant; Nanobiotix. M. Stock; ViewRay. S.L.

Liauw: None.

64Disparities in the Treatment and Outcome of Anal Cancer in Publicand Private Hospital PatientsD.S. Bitterman,1 D. Grew,2 C.G. Leichman,2 L. Leichman,2 and K.L. Du2;1New York University School of Medicine, New York City, NY, 2NYU

Clinical Cancer Center, New York City, NY

Purpose/Objective(s): Socioeconomic status (SES) is associated with the

incidence of HPV associated cancers, and is an important determinant of

cancer-related outcomes. However, few studies have specifically addressed

the importance of SES in determining anal cancer treatment outcomes. We

asked whether referral from a public hospital system (PHS) or a private,

not-for-profit hospital (NPH), a surrogate for SES, was a predictor of anal

cancer outcomes when the treating physicians are the same.

Materials/Methods: We retrospectively reviewed 110 consecutive sub-

jects, 31 from PHS and 79 from NPH, who underwent definitive chemo-

radiation for anal cancer between 2004 and 2013 at a single radiation

facility, serving patients from both a PHS and NPH. Main outcome mea-

sures were achievement of clinical complete response (cCR), disease free

survival rate (DFS), and overall survival (OS). Student’s t-test was used to

compare means, chi-square test to compare frequency, and multivariate

logistic regression to assess the predictive strength of referral hospital on

outcomes.

Results: There was no difference in gender (p Z 0.07), age at diagnosis

(p Z 0.13), tumor histology (p Z 0.64), and time from biopsy to start

radiotherapy (RT) (pZ 0.21) between the two groups. The median follow-

up time was 10.3 months (range, 0-94 months), with no difference between

the groups. PHS subjects presented at higher T stage (p < 0.05), but there

was no difference in stage group. Significantly more PHS subjects were

HIV+ (53% vs 30%, p < 0.05, chi-square test). 65% of patients were

treated with intensity modulated RT (IMRT), with no difference in the

rates of IMRT between PHS and NPH (51.6% vs 62%, p Z 0.32). Referral

from PHS was a predictor of cCR when gender, age at diagnosis, and stage

were controlled for (OR Z 0.124, 95% CI Z 0.03-0.62, p < 0.05), but not

DFS or OS. When outcome was stratified by HIV status, there was a

difference in cCR and DFS only among HIV+ subjects (46% vs 93%,

p < 0.05 and 39% vs 88%, p < 0.05, respectively). PHS and NPH subjects

experienced the same rates of RTOG classified toxicities, including diar-

rhea (p Z 0.13), fatigue (p Z 0.50), and dermatitis (p Z 0.10). PHS

subjects were more likely to have > 10 days of RT interruption (45% vs

22%, p < 0.05). Stratifying by RT break length revealed lower cCR and

DFS in PHS compared to NPH only when RT duration exceeded expected

length by � 10 days (64% vs 91%, p < 0.05 and 82% vs 54%,

respectively).