IMRT Reduces Acute Toxicity in Patients Treated With Preoperative Chemoradiation for Gastric Cancer

Phase 1 Trial of Total Neoadjuvant Therapy With Short-Course Chemoradiotherapy Followed by Chemotherapy for Patients With Potentially Resectable Gastric Cancer

PURPOSE

The purpose of this phase 1 trial was to evaluate the safety and toxicity of preoperative short-course chemoradiotherapy (CRT) as part of total neoadjuvant therapy (TNT) for patients with potentially resectable gastric or gastroesophageal adenocarcinoma.

METHODS AND MATERIALS

Patients were enrolled between March 2021 and December 2022 and received CRT (30 Gy radiation in 10 fractions with concurrent capecitabine or 5-fluorouracil), then received systemic therapy for 2 months, and then underwent surgery. The primary endpoint was CRT safety; secondary endpoints were pathologic complete response, perioperative complications, and overall survival (OS).

RESULTS

Of the 24 patients enrolled in the trial, 10 (42%) had bleeding, 3 (13%) had gastric outlet obstruction, and 2 (8%) had cirrhosis. Twelve patients (50%) had clinical nodal involvement. Twenty patients (83%) had poorly differentiated tumors, and 13 (54%) had signet ring cell histology. All patients completed CRT. CRT treatment-related toxic effects included grade 3 lymphopenia in 7 patients (29%), grade 4 lymphopenia in 1 (4%), and grade 3 anemia in 1 (4%). After CRT, 22 patients (92%) received chemotherapy, 1 patient (4%) with a microsatellite instability-high tumor received immunotherapy, and 1 patient (4%) underwent resection without systemic therapy. All patients underwent attempted resection, and gastrectomy was performed in 20 (83%). The R0 resection rate was 95%. Two patients had pathologic complete response, and an additional 5 had ≤1% viable tumor. Three patients had surgical complications [grade 1 in 1 patient (4%), grade 3b in 1 (4%), and grade 4a in 1 (4%)]; no patients died within 90 days. The median follow-up time was 28 months, and median OS was not reached. The 1- and 3-year OS rates were 96% and 85%, respectively.

CONCLUSION

Short-course CRT may be safely used as part of planned TNT for patients with potentially resectable gastric or gastroesophageal adenocarcinoma. The promising rates of treatment completion, pathologic response, and OS support further research of TNT for gastric cancer.

Role of Preoperative Radiation Therapy for Resectable Gastric Cancer

PURPOSE

While surgery is the primary curative treatment for resectable gastric and gastroesophageal junction (GEJ) cancer, rates of locoregional and distant recurrence remain high with surgery alone, especially in more advanced disease. Multimodal approaches with perioperative therapy including chemotherapy and/or radiation therapy (RT) have thus evolved as ways to reduce the rates of disease recurrence and improve survival outcomes. This review article provides a comprehensive literature review on the role of preoperative RT for resectable gastric and GEJ cancer.

METHODS

A literature review on the role of preoperative RT for resectable gastric and GEJ cancer was conducted.

RESULTS

Preoperative RT has the potential to facilitate tumor downstaging and improved R0 resection, allowing for better locoregional control and thereby survival. For resectable locally advanced GEJ cancer, preoperative chemoradiotherapy (CRT) is currently a standard of care option along with perioperative chemotherapy, based on evidence from randomized trials. In resectable gastric cancer, however, the role of preoperative CRT is less defined with no randomized data to date, although phase II single-arm studies have shown promising results. Current standard of care for gastric cancer remains perioperative chemotherapy, with consideration for preoperative CRT in select cases.

CONCLUSION

Results from ongoing and future randomized controlled trials are expected to help define the role of preoperative CRT compared to perioperative chemotherapy alone as well as postoperative CRT for gastric and GEJ cancer.

Neoadjuvant Chemoradiotherapy for Locally Advanced Gastric Cancer: Where Are We at?

Simple Summary

More than 50% of gastric cancer are at least locally advanced at presentation. For such patients, a multimodal approach rather than mere surgical resection leads to better long-term prognosis. Neoadjuvant chemoradiotherapy is one of the common treatment strategies for local advanced gastric cancer. Based on the experience and evidence from esophago-gastric cancers, the incorporation of systemic and locoregional therapy has shown superior disease control and reduced local recurrence. However, the optimal chemotherapy regimen, patient selection, technical consideration and potential biomarkers are still under investigation. Furthermore, the comparison of neoadjuvant chemoradiotherapy with neoadjuvant/perioperative chemotherapy is also an important issue to be answered. In the review article, we addressed the current available evidence to provide a comprehensive understanding and the use of neoadjuvant chemoradiotherapy for locally advanced gastric cancer. Future studies and ongoing trials will be necessary to determine the best candidate and the role of newer systemic and radiation therapies in such patients. NCRT is a feasible treatment option for LAGC, with the ability to achieve favorable disease control and enable higher radical resection rates over those afforded by perioperative chemotherapy or surgery alone. Large clinical trials examining the comparative efficacy of NCRT and NCT are underway. The discrepancy between the satisfactory pCR rates associated with NCRT and the nonsignificant association between NCRT and survival warrants further exploration. Furthermore, newer therapies such as immunotherapy and adaptive radiotherapy may be implemented in con-junction with NCRT, and the development of useful biomarkers may ultimately lead to the de-velopment of personalized treatments for LAGC. These research directions may lead to the dis-covery of the optimal approach to administering NCRT to patients with LAGC. They may also aid in the determination of the optimal candidates for undergoing NCRT.

Abstract

Locally advanced gastric cancer (LAGC) has a poor prognosis with surgical resection alone, and neoadjuvant treatment has been recommended to improve surgical and oncological outcomes. Although neoadjuvant chemotherapy has been established to be effective for LAGC, the role of neoadjuvant chemoradiotherapy (NCRT) remains under investigation. Clinical experience and research evidence on esophagogastric junction adenocarcinoma (e.g., cardia gastric cancers) indicate that the likelihood of achieving sustainable local control is higher through NCRT than through resection alone. Furthermore, NCRT also has an acceptable treatment-related toxicity and adverse event profile. In particular, it increases the likelihood of achieving an R0 resection and a pathological complete response (pCR). Moreover, NCRT results in higher overall and recurrence-free survival rates than surgery alone; however, evidence on the survival benefits of NCRT versus neoadjuvant chemotherapy (NCT) remains conflicting. For noncardia gastric cancer, the efficacy of NCRT has mostly been reported in retrospective studies, and several large clinical trials are ongoing. Consequently, NCRT might play a more essential role in unresectable LAGC, for which NCT alone may not be adequate to attain disease control. The continual improvements in systemic treatments, radiotherapy techniques, and emerging biomarkers can also lead to improved personalized therapy for NCRT. To elucidate the contributions of NCRT to gastric cancer treatment in the future, the efficacy, potential toxicity, predictive biomarkers, and clinical considerations for implementing NCRT in different types of LAGC were reviewed.

Shifting sands: the role of radiotherapy for patients with gastric and gastroesophageal adenocarcinoma

Gastric adenocarcinoma, a leading cause of cancer-related mortality worldwide, is treated primarily with surgical resection in the non-metastatic setting. However, the optimal role and sequencing of adjunctive therapies, including radiotherapy (RT) as well as systemic therapy, remains unclear. A complex milieu of trials spanning several decades has evaluated different treatment strategies for gastric cancer, including the role of RT. In this review, we summarize the trial-level evidence for the diverse gastric cancer treatment paradigms. Despite initial success, postoperative RT has not shown a clear benefit in modern prospective studies in the setting of more aggressive surgical nodal dissection. On the other hand, the role of preoperative RT in optimizing oncologic outcomes for gastric cancer patients remains relatively under-explored; ongoing trials assessing preoperative RT aim to illuminate the optimal treatment strategy for non-metastatic gastric cancer patients.

Oncologic Benefit of Adjuvant Chemoradiation after D2 Gastrectomy: A Stepwise Hierarchical Pooled Analysis and Systematic Review

Our study aimed to evaluate the benefits of chemoradiotherapy (CRT) after D2 gastrectomy, as compared to adjuvant chemotherapy, alone. PubMed, MEDLINE, Embase, and the Cochrane Library were systematically searched. We applied stepwise analyses that enabled the evaluation of data from randomized controlled trials (RCTs), balanced studies, and all studies separately and in a hierarchical manner. Thirteen controlled studies, including six RCTs involving 2603 patients, were included. Overall pooled analysis revealed a disease-free survival benefit of CRT (odds ratio (OR): 1.264, p = 0.053), which was more evident in the subgroup analysis of RCTs (OR: 1.440, p = 0.006) and balanced studies (OR: 1.417, p < 0.001). Overall survival was insignificantly different in the overall pooled analysis (OR: 1.124, p = 0.347). However, the difference was marginally significant in the subgroup analysis of balanced studies (OR: 1.279, p = 0.055) and significant in the subgroup analysis of studies involving stage ≥III patients only (OR: 1.663, p = 0.005). Locoregional recurrence (LRR) reduction was noted in the overall pooled analysis (OR: 0.559, p = 0.012; pooled rate: 11.3% vs. 18.1%) and was more robust in the subgroup analyses. Grade ≥3 leukopenia was higher in the CRT arm (OR: 1.387, p = 0.004; pooled rate: 26.4% vs. 15.7%). CRT after D2 gastrectomy should be applied for patients with high risk of LRR (e.g., stage ≥ III), along with efforts to reduce leukopenia.