586P - Does the Compliance to Adjuvant Chemotherapy Depend on Neoadjuvant Radiation Therapy Modality?

Abstract

ABSTRACT One of the standard approach for the locally advanced rectal cancer patients is neoadjuvant chemoradiation therapy (CRT), followed by total mesorectal excision (TME) and adjuvant chemotherapy (ACT). ACT compliance has been a major concern for these patients. In this study we assessed the possible impact of neoadjuvant radiation therapy (RT) modality on ACT compliance. Methods We, retrospectively, analyzed the data of 114 locally advanced rectal cancer patients, after neoadjuvant RT and referred for consideration of ACT, at McGill University hospitals. ACT compliance was defined as pts who received at least 6 cycles of ACT and optimal dose compliance (ODC) was defined as pts who received at least 85% of the recommended chemotherapy dose. Neoadjuvant RT modalities included high dose rate endorectal brachytherapy (HDREBT) alone with no chemotherapy; conformal external beam RT (3D-CRT) with chemotherapy and intensity-modulated RT (IMRT) with chemotherapy. We applied a chi-square test for 2-way categorical associations and multivariable logistic regression with compliance as the outcome. Results The data of 114 consecutive locally advanced rectal cancer patients, mean age 64y (range:32-85), were analyzed. 41 patients (36%) were treated with neoadjuvant HDREBT alone, 33 (29%) with 3D-CRT and chemotherapy, and 40 (35%) with IMRT and chemotherapy. The HDREBT dose was 26 Gy in 4 consecutive fractions alone and that of 3D-CRT and IMRT was 50 Gy in 25 fractions, Monday to Friday with concurrent 5-FU. 41 pts (36%) received FOLFOX, 13 (11%) XELOX, 11 (10%) 5-FU, 7 (6%) Xeloda and 9 (8%) received other chemotherapy, while 33 pts refused the ACT. ACT compliance after HDREBT, 3D-CRT and IMRT were respectively: 70.7%, 45.5%, 37.5% (p = 0.008). Age was a negative factor (p Conclusion Our data suggests that neoadjuvant HDREBT yields significantly higher rates of ACT compliance and ODC compared to 3D-CRT with chemotherapy and IMRT with chemotherapy. Disclosure All authors have declared no conflicts of interest.