RADIATION THERAPY ONCOLOGY GROUP 98-11

RADIATION THERAPY ONCOLOGY GROUP. RTOG 98-11

A PHASE III RANDOMIZED STUDY OF 5-FLUOROURACIL, MITOMYCIN-C, AND RADIOTHERAPY VERSUS 5-FLUOROURACIL, CISPLATIN AND RADIOTHERAPY IN CARCINOMA OF THE ANAL CANAL
* Chemotherapy (Note: In Arm 1, both courses of chemotherapy will be administered during radiotherapy. In Arm 2, patients will receive two courses of induction chemotherapy in addition to 2 courses during radiotherapy).

5-FU + Mitomycin-C: Mitomycin-C 10 mg/m2 i.v. bolus on days 1 and 29 (not to exceed 20 mg per course) 5-FU 1000 mg/m2 /day by continuous infusion on days 1-4 and 29-32

5-FU + Cisplatin: Cisplatin 75 mg/m2 i.v. over 60 min. on days 1 and 29, and also repeated on days 57 and 85 (days 57 and 85 should correspond to days 1 and 29 of radiotherapy). 5-FU 1000 mg/m2/day by continuous infusion on days 1-4 and 29-32, and also repeated on days 57-60 and 85-88 (days 57 and 85 should correspond to days 1 and 29 of radiotherapy)
* External Beam Irradiation (EBRT): (Note: treatment break of < 10 days will be optional for severe local skin reactions)

Note: Large pelvic field (to 30.6 Gy) and reduced field #1 (to 45 Gy) will be used in all patients; reduced field #2 is to be used for all patients with T3, T4, or N+ lesions and for those patients with T2 lesions that have residual disease after 45 Gy.

(1) Initial Field: 30.6 Gy in 17 Fx (1.8 Gy/fx) to large pelvic field with superior border at L5-S1.

(2) Field reduction #1: Reduce superior border to inferior level of SI joints

(a) Deliver 14.4 Gy in 8 Fx (1.8 Gy/fx) for a total of 45 Gy
(b) For N0 patients, reduce off inguinal nodes after 36 Gy

(3) Reduction #2 (for all T3, T4, or N+ lesions and T2 lesions with residual cancer after 45 Gy)
Deliver 10-14 Gy (2 Gy/fx) to gross primary or nodal disease plus a 2.0 to 2.5 cm margin for a total dose of 55-59 Gy within boost field #2.

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Figures 1 & 2: Examples of acceptable AP/PA fields for N0 or N+ patients. The pelvis, anus, perineum and inguinal lymph nodes will be treated with either AP-PA fields or a 4-field (Figures 3 & 4) technique to include lateral inguinal nodes within AP/lateral fields but not PA field. Patient lies supine with a full bladder. Superior border reduced at 30.6 Gy level to level SI joint.

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Figures 3 & 4: When a 4-field technique is used, shaped lateral fields are required and may vary according to individual anatomy. Inguinal nodes must not be undertreated and may require electron boost to required dose level. Lymphangiogram or CT to define volume with 1.5 cm margin beyond nodal volume.

Note: Boost treatment (59.4 Gy arms) is not demonstrated but will require a target volume to include the tumor plus a 2-2.5 cm margin individualized to the patient. Nodal disease (45-59.4 Gy arms) will also require a boost target volume to include nodal metastases plus a 2-2.5 cm margin.