Radiotherapy for epidermoid carcinoma of the anus: thirty years' experience

Abstract

Purpose: To evaluate the factors associated with disease control and morbidity after radiotherapy for anal carcinoma.

Methods and materials: Between 1975 and 2005, 194 patients with localized epidermoid anal carcinoma underwent radiotherapy. Treatment evolved from radiotherapy with or without surgery, to preoperative chemoradiotherapy, to definitive chemoradiotherapy (CRT). The radiotherapy techniques also evolved.

Results: With a median follow-up of 61 months, 57 patients had persistence or recurrence, 9 of whom were successfully salvaged, resulting in 146 (75%) ultimately free of disease (UNED). Univariate analysis for UNED survival showed a strong association with the T and N stage (5-year UNED rate, 88.5% +/- 3.4% for those with Stage T1-T2N0; 70.1% +/- 4.2% for Stage T3N0; and 52.7% +/- 6.6% for Stage III; p > .001) and mobility on palpation (5-year UNED rate, 89.2% +/- 4.6% for those with mobile tumors vs. 59.3% +/- 6.1% for those with tethered/fixed tumor; p > .001). No association was found with gender, age, preoperative vs. definitive CRT, or human immunodeficiency virus status. The 20 human immunodeficiency virus+ patients all received CRT. The radiotherapy factors associated with Grade 3 or greater late morbidity included anorectal morbidity with tumor dose (29% with a dose > or =55 Gy vs. 9% otherwise), small bowel injury with technique (9% with anteroposterior-posteroanterior supine vs. 0.7% with multiple fields prone), and bone injury with femoral head dose (9% with a dose of > or =44 Gy vs. 0.7% otherwise). Of the 194 patients, 56 had 68 additional malignancies, mainly either antedating the anal cancer or outside the radiation fields.

Conclusion: Our results have confirmed that CRT is an effective approach. Patients with human immunodeficiency virus can be treated with CRT. Tumor mobility significantly predicts the outcome; the implications for management are discussed. We also discuss the treatment planning implications of the late morbidity findings. The substantial incidence of additional malignancies underscores the importance of full oncologic screening during follow-up.