A Bounding Box-Based Radiomics Model for Detecting Occult Peritoneal Metastasis in Advanced Gastric Cancer: A Multicenter Study

Dan Liu,Lanqing Yang,Jiankun Hu,Pengxin Yu,Xin Fang,Xiao Zhang,Zixing Huang,Bin Song,Bing Wu,Fubi Hu,Weihan Zhang,Hongkun Yin

doi:10.3389/fonc.2021.777760

Abstract

PurposeTo develop a bounding box (BBOX)-based radiomics model for the preoperative diagnosis of occult peritoneal metastasis (OPM) in advanced gastric cancer (AGC) patients.Materials and Methods599 AGC patients from 3 centers were retrospectively enrolled and were divided into training, validation, and testing cohorts. The minimum circumscribed rectangle of the ROIs for the largest tumor area (R_BBOX), the nonoverlapping area between the tumor and R_BBOX (peritumoral area; PERI) and the smallest rectangle that could completely contain the tumor determined by a radiologist (M_BBOX) were used as inputs to extract radiomic features. Multivariate logistic regression was used to construct a radiomics model to estimate the preoperative probability of OPM in AGC patients.ResultsThe M_BBOX model was not significantly different from R_BBOX in the validation cohort [AUC: M_BBOX model 0.871 (95% CI, 0.814–0.940) vs. R_BBOX model 0.873 (95% CI, 0.820–0.940); p = 0.937]. M_BBOX was selected as the final radiomics model because of its extremely low annotation cost and superior OPM discrimination performance (sensitivity of 85.7% and specificity of 82.8%) over the clinical model, and this radiomics model showed comparable diagnostic efficacy in the testing cohort.ConclusionsThe BBOX-based radiomics could serve as a simpler reliable and powerful tool for the preoperative diagnosis of OPM in AGC patients. And M_BBOX-based radiomics is simpler and less time consuming.

Highlights

Gastric cancer (GC) is one of the most common and deadly carcinomas in the world [1]
There were no significant differences in age, sex, carcinoembryonic antigen (CEA), or carbohydrate antigen 19–9 (CA19–9) between occult peritoneal metastases (OPMs)-positive and OPM-negative patients in the entire cohort
Multivariate logistic regression analysis identified locationL/L+D [b = -0.791, OR = 0.453, P = 0.010] and Borrmann type [b = -1.132, OR = 3.103, P = 0.002] as independent predictors of OPM status

Summary

Introduction

Gastric cancer (GC) is one of the most common and deadly carcinomas in the world [1]. It was reported that the median survival time among PM patients is 3–6 months [5], and the treatment options are limited [6]. New treatment strategies such as intraperitoneal chemotherapy and extensive intraoperative peritoneal lavage are associated with an improved prognosis for those patients [7–9]. Noninvasive preoperative detection of PM of advanced gastric cancer (AGC) is crucial for avoiding unnecessary surgery and selecting optimal therapy in clinical practice. In 10 to 30% of patients with negative CT images, intraperitoneal metastases are found during either laparoscopy or surgical exploration [11, 12], called occult peritoneal metastases (OPMs)

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