A New MRI-Defined Biomarker for Rectal Mucinous Adenocarcinoma: Mucin Pool Patterns in Determining the Efficacy of Neoadjuvant Therapy

Wuteng Cao; Lei Wu; Yandong Zhao; Jie Zhou; Wenli Li; Xinhua Wang; Jianbo Xu; Zhiyang Zhou; Changhong Liang

doi:10.3389/fonc.2020.01425

A New MRI-Defined Biomarker for Rectal Mucinous Adenocarcinoma: Mucin Pool Patterns in Determining the Efficacy of Neoadjuvant Therapy

Front Oncol. 2020 Aug 20:10:1425. doi: 10.3389/fonc.2020.01425. eCollection 2020.

Authors

Wuteng Cao^{1

2}, Lei Wu^{1

3}, Yandong Zhao⁴, Jie Zhou², Wenli Li², Xinhua Wang², Jianbo Xu², Zhiyang Zhou^{2

5}, Changhong Liang^{1

3}

Affiliations

¹ School of Medicine, South China University of Technology, Guangzhou, China.
² Department of Radiology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Disease, Guangzhou, China.
³ Department of Radiology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.
⁴ Department of Pathology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Disease, Guangzhou, China.
⁵ Guangzhou Universal Medical Imaging Diagnostic Center, Guangzhou, China.

Abstract

Background and Aim: This work aims to study the relationship between MRI-defined mucin pool (MP) patterns prior to treatment and the efficacy of neoadjuvant therapy (NAT) in locally advanced rectal mucinous adenocarcinoma (RMAC). Methods: This retrospective study included 278 RMAC patients evaluated between January 2012 and January 2019. After having been trained by using 118 cases with postoperative pathological images, radiologists distinguished MRI-defined MP status as mixed type (MTMP) and separate type (STMP) in a NAT cohort (160 patients) in addition to tumor characteristics, invasion of mesorectal facia, and nodal status. Reader reproducibility was determined using the κ coefficient. The main outcome was the accuracy of MP dichotomy in predicting whether patients had tumor responsiveness or not. Results: Among 278 cases, MTMP and STMP accounted for 49.6 and 50.4% of MPs, respectively. A total of 72 patients received neoadjuvant chemoradiotherapy and 88 received chemotherapy. The tumor responsiveness rate in the chemoradiotherapy group was higher than that in the chemotherapy group (58.3 vs. 21.6%, P < 0.001). In the chemotherapy group, the tumor responsiveness rate in patients with MTMPs was lower than that in patients with STMPs (4.9 vs. 25.5%, P = 0.002). The baseline MRI-defined MTMP was associated with lower responsiveness rates after NAT in the chemotherapy group (odds ratio, 11.050, with 95% CI, 2.368-51.571, P = 0.002). Conclusions: MP dichotomy can be reliably evaluated by using MRI. In the chemotherapy group, MTMP may be a dependent predictor to indicate a lower likelihood of tumor responsiveness after NAT.

Keywords: magnetic resonance imaging; mucins; neoadjuvant therapy; rectal neoplasms; treatment outcome.