Toxicity of Treatment for Anal Carcinoma: 2D versus 3D Planning

Anal cancer is a relatively uncommon disease, accounting for only 4% of cancers of the lower gastrointestinal tract.

To summarize a single-center experience in the treatment of anal carcinoma using various radiation techniques.

We conducted a retrospective chart review of consecutive patients who were treated for anal cancer between the years 2002 and 2011. The data extracted included demographics, type of radiation technique, treatment-associated acute toxicity, and patterns of failure and survival. For statistical analysis purposes, the patients were divided into two groups according to radiotherapy technique: 2D (group A) and 3D (group B).

A total of 42 patients--25 (59.5%) females and 17 males (40.5%)--underwent definitive chemo-radiation treatment (CRT) for anal cancer. Group A comprised 26 patients and group B 14 patients. Toxicity did not differ significantly between the groups; only in grade 1-2 skin toxicity which was more common in group B. There were significant differences in the unplanned interruptions in treatment, in both the number of patients who needed a treatment break and the number of days needed (more in group A). There were no differences in treatment response and patterns of failure between these two techniques, or in overall survival between the two groups.

Our study results are consistent with reported large randomized trials, indicating that current treatments for anal carcinomas are associated with high grade acute toxicity that may result in significant treatment interruptions. The 2D technique was associated with significantly more treatment interruptions but did not differ from 3D with regard to treatment efficacy.