Chemoradiotherapy Is Inferior to Chemotherapy Alone in Adjuvant Setting for Signet Ring Cell Containing Gastric Cancer

Yue-Ting Zhu; Xin-Zu Chen; Ye Chen; Yu-Wen Zhou; Lian-Sha Tang; De-Yun Luo; Qiu Li; Meng Qiu; Xin Wang; Dan Cao; Yu Yang; Ya-Li Shen; Zhi-Ping Li; Feng Bi; Ji-Yan Liu; Hong-Feng Gou

doi:10.3389/fonc.2020.570268

Chemoradiotherapy Is Inferior to Chemotherapy Alone in Adjuvant Setting for Signet Ring Cell Containing Gastric Cancer

Front Oncol. 2020 Nov 26:10:570268. doi: 10.3389/fonc.2020.570268. eCollection 2020.

Authors

Yue-Ting Zhu¹, Xin-Zu Chen², Ye Chen³, Yu-Wen Zhou¹, Lian-Sha Tang¹, De-Yun Luo³, Qiu Li³, Meng Qiu³, Xin Wang³, Dan Cao³, Yu Yang³, Ya-Li Shen³, Zhi-Ping Li³, Feng Bi³, Ji-Yan Liu¹, Hong-Feng Gou³

Affiliations

¹ Department of Biotherapy, Cancer Center, West China Hospital, Sichuan University, Chengdu, China.
² Department of Gastrointestinal Surgery and Laboratory of Gastric Cancer, State Key Laboratory of Biotherapy, West China Hospital, Collaborative Innovation Center for Biotherapy, Sichuan University, Chengdu, China.
³ Department of Abdominal Cancer, Cancer Center, West China Hospital, Sichuan University, Chengdu, China.

Abstract

Background: Signet ring cell containing gastric cancer (SRCGC) is a rare subtype of gastric cancer, and its adjuvant therapy is based on general gastric cancer. However, the effectiveness of radiotherapy for those SRCGC patients remains unknown.

Purpose: The purpose of the study was to analyze whether the addition of radiotherapy to adjuvant chemotherapy (CT) can benefit survival in resected SRCGC patients.

Methods: Patients with SRCGC, who underwent D2 gastrectomy followed by adjuvant chemotherapy or chemoradiotherapy (CRT), were retrospectively collected. According to the proportion of signet ring cells, patients were histologically classified as pure SRCGC (pSRCGC) containing 100% of signet ring cells, mixed SRCGC (mSRCGC) containing >50% of signet ring cells, and contaminated SRCGC (cSRCGC) containing <50% of signet ring cells. Among the 272 patients, 156 were treated by CT alone and 116 by CRT. The primary endpoint was 3-year overall survival rate (3-year OS rate).

Results: With a median follow-up of 80.5 months, the 3-year OS rate was significantly higher in the CT group (70.5% vs. 58.6%, HR = 0.633, P = 0.017) compared with CRT group. Three independent characteristics were predictive of a poor overall survival: CRT treatment (P = 0.019), tumor size ≥5 cm (P < 0.001), and the presence of vessel invasion (P = 0.009). Subgroup analyses showed CRT significantly impaired prognosis in SRCGC patients in the cSRCGC subset, as well as lesions located in lower-middle sites, subtotal gastrectomy, male, <60 year, and no vessel invasion. Peritoneal was the most common recurrence site in SRCGC patients. The adverse events leukopenia and neutropenia were more common in the CRT group (P = 0.007).

Conclusions: Adjuvant chemoradiotherapy was associated with poor survival compared with adjuvant chemotherapy in SRCGC patients with D2 gastrectomy.

Keywords: adjuvant therapy; chemoradiotherapy; chemotherapy; gastric cancer; signet ring cell carcinoma.