KEY POINTS
- The retrospective cohort included 55 patients with T1 anal squamous cell carcinoma treated with curative-intent RT between 1990 and 2022. Median age was 67 years, and 42 patients were node-negative while 13 had nodal involvement.
- All patients received external-beam RT with a median prescribed tumor dose of 58 Gy; 45% received concurrent chemotherapy and 35% received a brachytherapy boost. Treatment evolved substantially over three decades from 2D/3D RT toward IMRT/VMAT, smaller volumes and shorter courses.
- Long-term outcomes were favorable: estimated 5-year overall survival was 84.7%, disease-free survival 80.1%, and colostomy-free survival 85.3%. Importantly, no patient required a treatment-related colostomy.
- Only three local or locoregional recurrences occurred over follow-up. All three were managed with local excision, and none required abdominoperineal resection; no inguinal nodal or distant relapse was observed.
- No recurrence occurred among the 19 patients who received a brachytherapy boost, but this highly selected subgroup showed no statistically significant OS or DFS advantage, and treatment selection was nonrandomized.
- Concurrent chemotherapy was associated with numerically higher 5-year outcomes—OS 100% versus 77.3% and DFS 93.3% versus 73.7%—but neither difference reached statistical significance and treatment was strongly confounded by era and technique.
- Acute grade ≥3 toxicity occurred in 5% and late grade ≥3 toxicity in 11%. All severe late events occurred after historical 2D/3D treatment, but simultaneous changes in dose, fields, chemotherapy and supportive care prevent attributing the improvement specifically to IMRT/VMAT.
CLINICAL TAKEAWAY
Definitive RT-based treatment produced excellent long-term disease control and organ preservation in this uncommon T1 anal cancer cohort, with no treatment-related colostomies. The study provides a useful historical benchmark, but it cannot determine whether chemotherapy, brachytherapy, smaller modern volumes or any specific contemporary strategy can safely be omitted or preferred.