Mucinous degeneration on MRI after neoadjuvant therapy in patients with rectal adenocarcinoma: Frequency and association with clinical outcomes Journal Article


Authors: Miranda, J.; Pinto, P. V. A.; Kinochita, F.; Garcia, C. M.; El Homsi, M.; de Oliveira, C. V.; Pandini, R. V.; Nahas, C. S. R.; Nahas, S. C.; Gollub, M. J.; Horvat, N.
Article Title: Mucinous degeneration on MRI after neoadjuvant therapy in patients with rectal adenocarcinoma: Frequency and association with clinical outcomes
Abstract: BACKGROUND. Patients with nonmucinous rectal adenocarcinoma may develop mucinous changes after neoadjuvant chemoradiotherapy, which are described as mucinous degeneration. The finding's significance in earlier studies has varied. OBJECTIVE. The purpose of this study was to assess the frequency of mucinous degeneration on MRI after neoadjuvant therapy for rectal adenocarcinoma and to compare outcomes among patients with nonmucinous tumor, mucinous tumor, and mucinous degeneration on MRI. METHODS. This retrospective study included 201 patients (83 women, 118 men; mean age, 61.8 } 2.2 [SD] years) with rectal adenocarcinoma who underwent neoadjuvant chemoradiotherapy followed by total mesorectal excision from October 2011 to November 2015, underwent baseline and restaging rectal MRI examinations, and had at least 2 years of follow-up. Two radiologists independently evaluated MRI examinations for mucin content, which was defined as T2 hyperintensity in the tumor or tumor bed, and resolved differences by consensus. Patients were classified into three groups on the basis of mucin status: those with nonmucinous tumor (≤ 50% mucin content on baseline and restaging examinations), those with mucinous tumor (> 50% mucin content on baseline and restaging examinations), and those with mucinous degeneration (≤ 50% mucin content on baseline examination and > 50% content on restaging examination). The three groups were compared. RESULTS. Interreader agreement for mucin content, expressed as a kappa coefficient, was 0.893 on baseline MRI and 0.890 on restaging MRI. Of the 201 patients, 156 (77.6%) had nonmucinous tumor, 34 (16.9%) had mucinous tumor, and 11 (5.5%) had mucinous degeneration. Mucin status was not significantly associated with complete pathologic response (p = .41) or local or distant recurrence (both p > .05). The death rate during follow-up was not significantly different (p = .21) between patients with nonmucinous tumor (23.1%), those with mucinous tumor (29.4%), and those with mucinous degeneration (9.1%). In adjusted Cox regression analysis, with mucinous degeneration used as reference, the HR for the overall survival rate for the mucinous tumor group was 4.7 (95% CI, 0.6-38.3; p = .14), and that for the nonmucinous tumor group was 8.0 (95% CI, 0.9-59.9; p = .06). On histopathologic assessment, all 11 patients with mucinous degeneration showed acellular mucin, yet 10 of 11 patients showed viable tumor (i.e., in nonmucinous portions of the tumors). CONCLUSION. Mucinous degeneration on MRI is not significantly associated with pathologic complete response, recurrence, or survival. © 2023 American Roentgen Ray Society. All rights reserved.
Keywords: survival; adult; controlled study; middle aged; survival rate; major clinical study; overall survival; histopathology; cancer recurrence; cancer staging; nuclear magnetic resonance imaging; follow up; retrospective study; risk factor; colonoscopy; colloid carcinoma; mri; rectal cancer; digital rectal examination; rectal adenocarcinoma; clinical outcome; neoadjuvant chemoradiotherapy; rectoscopy; cancer prognosis; human; male; female; article
Journal Title: American Journal of Roentgenology
Volume: 221
Issue: 2
ISSN: 0361-803X
Publisher: American Roentgen Ray Society  
Date Published: 2023-08-01
Start Page: 206
End Page: 217
Language: English
DOI: 10.2214/ajr.23.29002
PUBMED: 36919880
PROVIDER: scopus
PMCID: PMC10777341
DOI/URL:
Notes: The MSK Cancer Center Support Grant (P30 CA008748) is acknowledged in the PDF -- Corresponding author is MSK author: Natally Horvat -- Source: Scopus
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MSK Authors
  1. Marc J Gollub
    208 Gollub
  2. Natally Horvat
    101 Horvat