ASTRO Issues Clinical Guideline for Use of Radiation Therapy in Anal Cancer

WEDNESDAY, March 12, 2025 (HealthDay News) — In a clinical practice guideline issued by the American Society for Radiation Oncology and published online Feb. 27 in Practical Radiation Oncology, evidence-based recommendations are presented to address indications for definitive treatment of primary squamous cell carcinoma of the anal canal and anal margin.

Mary Feng, M.D., from the University of California in San Francisco, and colleagues recommend multidisciplinary evaluation and decision-making for all patients. For most patients, definitive treatment with combined modality therapy is recommended using concurrent 5-fluorouracil or capecitabine plus mitomycin, with cisplatin as a conditional alternative to mitomycin with radiation therapy (RT). Local excision alone may be considered for select patients with early-stage disease. The primary tumor/anal canal and rectum and mesorectal, presacral, internal and external iliac, obturator, and inguinal lymph nodes should be included in RT target volumes.

The authors also present a recommendation for intensity-modulated RT-based treatment approaches. Depending on disease stage and RT approach and adapted for risk, the primary tumor should receive doses of 4,500 to 5,940 cGy in 25 to 33 fractions, and clinically involved lymph nodes should receive 5,040 to 5,400 cGy in 28 to 30 fractions. To minimize acute and chronic treatment-related toxicity, dose guidance for normal tissues and measures are provided by the guideline. Treatment breaks should be kept to a minimum.

“Radiation therapy plays a central role in managing anal cancer, offering patients an effective, organ-preserving definitive treatment,” Feng said in a statement.

Several authors disclosed ties to the biopharmaceutical industry.

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