Anal cancer outcomes in patients treated with intensity modulated versus 3-dimensional chemoradiotherapy.

662 Background: Combined chemoradiotherapy (CRT) has been successful in both tumor eradication and colostomy prevention in patients with squamous-cell carcinoma of the anal canal. Unfortunately, CRT can be toxic with high rates of acute gastrointestinal and skin toxicity. This can necessitate treatment interruptions, prolonging therapy, possibly leading to loss of local control. In RTOG 0529, intensity modulated radiation therapy (IMRT) decreased the rate of treatment interruption compared to historical controls. We aim to compare toxicity and outcomes in patients treated with CRT based on radiation technique. Methods: We retrospectively reviewed 107 consecutive patients, 39 HIV+, 68 HIV-, who underwent definitive CRT for anal cancer at a single institution between 2004 and 2013. Overall survival (OS), colostomy-free survival (CFS), local recurrence-free survival (LRFS) and distant metastasis-free survival (DMFS) were analyzed. Chi-square test was used to compare frequencies and t-test was used to compare...