The significance of mucin pools following neoadjuvant chemoradiotherapy for locally advanced rectal cancer. Ian S. Reynolds Deborah A. McNamara Elaine W. Kay Brian O'Neill Joseph Deasy John P. Burke 10779/rcsi.10790375.v1 https://repository.rcsi.com/articles/journal_contribution/The_significance_of_mucin_pools_following_neoadjuvant_chemoradiotherapy_for_locally_advanced_rectal_cancer_/10790375 <p><strong>BACKGROUND:</strong> Neoadjuvant chemo-radiotherapy is utilized for locally advanced rectal cancer to optimize local control. A subset of patients form mucin pools following radiotherapy but the association between mucin pools and pathological and oncological outcomes following curative proctectomy for rectal cancer remains unknown.</p> <p><strong>OBJECTIVE:</strong> The aim of this study was to determine the significance of mucin pool formation after neoadjuvant chemoradiotherapy for rectal cancer.</p> <p><strong>METHODS:</strong> This is a retrospective analysis of a prospectively maintained rectal cancer database. Patients who underwent curative proctectomy for rectal cancer following long course chemoradiotherapy between January 2007 and December 2016 were eligible for inclusion.</p> <p><strong>RESULTS:</strong> A total of 297 patients were eligible for inclusion; of these 36 (12.1%) had mucin pools on final histopathology. Tumors with mucin pools were less likely to be ypT3/T4 (25.0 vs 51.0%, P = 0.003), were more likely to have a good response (83.3 vs 53.6%, P < 0.001) and more likely to have a pathologic complete response (41.7 vs 19.2%, P = 0.006) to radiotherapy. The presence of mucin pools was associated with less distant recurrence ( P < 0.05) and improved overall survival ( P = 0.02).</p> <p><strong>CONCLUSIONS:</strong> The presence of mucin pools following neoadjuvant chemoradiotherapy for rectal cancer represents a surrogate marker of response to treatment and downstaging and is associated with improved survival.</p> 2019-11-22 16:55:10 Mucin pools neoadjuvant treatment radiotherapy rectal cancer response. Physiology Medical Physics