Chemoradiotherapy for squamous cell anal carcinoma: a review of prognostic factors

Previous literature has sought prognostic factors for the survival of anal cancer patients. The present study aimed to determine prognostic factors for local disease recurrence, distant metastasis and survival for patients treated with radical chemoradiotherapy (CRT) at the Rosemere Cancer Centre, Preston, UK.

Patients treated with CRT for nonmetastatic squamous cell anal cancer between September 2000 and January 2013 were studied. Kaplan-Meier and Cox regression analysis assessed the prognostic value of age, sex, tumour size, the proportion of the anal canal circumference involved (ACCI), nodal disease, tumour location and pretreatment haemoglobin.

One hundred and 48 patients with a mean age of 63 years were studied, of whom 15% suffered local disease recurrence and 10% developed distant metastasis. The 5-year overall and cancer-specific survival rates were 84% and 86%, respectively. Predictors of local recurrence were tumour size >5 cm and over two-thirds ACCI (P < 0.01). Predictors of distant metastasis and poor survival were tumour size >5 cm (P < 0.01), node positive disease on imaging (P < 0.05), over two-thirds ACCI (P < 0.01) and a pretreatment haemoglobin level below 130 g/l (P < 0.05). Multivariate analysis found large tumour size to be the most significant factor for local recurrence (P = 0.002) and survival (P = 0.02) whilst over two-thirds ACCI was most predictive of distant metastasis (P < 0.001). Age, gender, palpable lymph nodes and tumour location were not of prognostic value for local disease recurrence, distant metastasis or survival.

Tumour size, nodal disease, over two-thirds ACCI and low pretreatment haemoglobin confer poorer prognostic and survival outcomes. Use of intensity-modulated radiation therapy may allow greater radiation doses to be given for locally advanced tumours, thus improving local control and survival and reducing morbidity.