Indications for adjuvant radiation therapy with or without lymph nodes in salivary gland cancer

Claus Rödel

Department of Radiation Therapy

University of Frankfurt

Prognostic factors for locoregional control

• T stage (T1/2 better than T3/4)

• Resection margin status

• Tumor site (oral better than other sites)

• Bone invasion

• Perineural invasion

• Treatment modality (OP+RT better OP)

• Not the histologic type!?

Therhaard et al. Head Neck 2004

Postoperative RT recommended for:

• pT3/4 or pN+

• Close (≤5mm) or incomplete (<1mm) resection

• Bone invasion

• Perineural invasion

• Recurrent tumors

Risk of positive neck nodes

• Histologic type

• T stage (T1:15%,

T2:25%, T3/4:33%)

• Tumor location

Risk of positive neck nodes

High risk:• Squamous cell • Undifferentiated • Salivary duct Intermediate risk:• Mucoepidermoid Low risk:• Acinic cell • Adenoid cystic • Carcinoma ex pleomorphic adenoma

HISTOLOGY

Risk estimation for positive neck nodes

Total score

(T stage + histologic type

Parotid gland (%)

Submandib. gland (%)

Oral cavity (%)

2 4 0 4

3 12 33 13

4 25 57 19

5 33 60 -

6 38 50 -T1 = 1; T2 = 2; T3/4 = 3Acinic or adenoid cystic or carcinom ex pleomorhic adenoma = 1Mucoepidermoid = 2Squamous cell or undifferentiated = 3

Terhaard et al., IJROBP 2007

Elective treatment of neck nodes recommended for:

• Parotid tumors for a score ≥ 4: Level Ib -III

• Submandibular tumors: except for T1 acinic or adenoid cystic carcinoma: Level I-III

• Minor salivary gland tumors: tumors in the tongue, floor of the mouth, pharynx or larynx

• In case of pN+: homolateral level I-V

CRITICAL POINTS FOR RT:

• Clinical Target Definition• 3D-conformal, IMRT

• High-LET (neutron, ions)?

• Concurrent Chemotherapy or targeted therapy?