Dis Colon Rectum. 2021 Jun 1. doi: 10.1097/DCR.0000000000001986. Online ahead of print.
ABSTRACT
BACKGROUND: Radiation dose schedules for neoadjuvant chemoradiation for rectal cancers differs, with the most common dose schedule using 5040 cGy in 28 fractions.
OBJECTIVES: The aim of this retrospective study was to assess the benefit of higher radiation doses beyond 5040cGy in the context of pathological response and follow up events.
SETTING: Database from a provincial tertiary cancer center in Canada.
PATIENTS: Five hundred eight consecutive rectal cancer patients with locally advanced disease (clinical T3/T4 or N1/N2) who received neoadjuvant chemoradiation followed by surgery were included in this study. Of the 508 patients, 281 received the standard radiation dose of 4500-5040 cGy and 227 received a dose >5040 cGy.
MAIN OUTCOME MEASURE: The postsurgical pathology, late toxicities and follow-up outcomes were analyzed. The outcomes were evaluated in relation to the dose of radiation received.
RESULTS: Data regarding the clinical outcomes were comparable between the 4500-5040 cGy and >5040 cGy radiation groups with pathological complete response rates of 20.9% and 15.4% respectively (p=0.104); distant recurrence rates of 17.4% and 19.4%, respectively (p=0.36); local recurrence rates of 3.2% and 3.5%, respectively (p=0.36); and the median overall survival rates of 61 and 60.5 months respectively (p=0.8). No statistically significant correlation of improvement in outcomes was noted with radiation doses beyond 5040 cGy.
LIMITATIONS: This is a retrospective study.
CONCLUSION: Our study showed that dose escalation beyond the standard dose of 4500-5040cGy failed to achieve meaningful clinical outcomes. See Video Abstract at http://links.lww.com/DCR/B633.
PMID:34082437 | DOI:10.1097/DCR.0000000000001986
