Neoadjuvant versus Postoperative Chemoradiotherapy is Associated with Improved Survival for Patients with Resectable Gastric and Gastroesophageal Cancer

Current National Treatment Trends for Gastric Adenocarcinoma in the United States

PURPOSE

The treatment of gastric adenocarcinoma (GA) continues to evolve. While neoadjuvant chemotherapy (NAC) has demonstrated emerging benefit, the optimal treatment regimen, and sequence remain to be firmly established.

METHODS

Patients with nonmetastatic GA who underwent resection were identified within the 2020 National Cancer Database. Patients were compared between the mutually exclusive treatment groups of NAC, neoadjuvant chemoradiotherapy (NCRT), adjuvant chemotherapy, adjuvant chemoradiotherapy (CRT), and surgery only. The primary endpoint was receipt of NAC or NCRT. Patients were 1-to-1 propensity score matched for receiving any neoadjuvant therapy. Multivariable logistic regression was used to identify predictors of receipt of any neoadjuvant therapy and receipt of any adjuvant therapy.

RESULTS

Twenty-five thousand and seventy-three patients were included in the analysis. Patients were treated with NAC (25.0%), NCRT (31.4%), adjuvant chemotherapy (6.5%), adjuvant CRT (12.6%), and surgery only (24.5%). Compared to 2006-2011, patients diagnosed between 2012 and 2017 experienced the greatest increases in NAC (18.6% vs. 29.0%; p < 0.001) and NCRT (25.0% vs. 35.5%; p < 0.001). Median OS was 44.9 months. OS was longest for patients who received any neoadjuvant therapy compared to those receiving adjuvant or surgery only (51.0 vs. 42.4 vs. 38.0 months, respectively; p < 0.001). Patients who were Black, in the lowest income quartile or treated at lower volume facilities were less likely to receive NAT (all p < 0.001).

CONCLUSIONS

There has been significant acceleration in the use of neoadjuvant therapy for GA. Currently, NCRT followed by surgery are the most common treatment sequences in the United States. Additional trials are needed to further define the optimal treatment sequence.

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.

Stomach Motion and Deformation: Implications for Preoperative Gastric Cancer Radiation Therapy

PURPOSE

Selection and development of image guided strategies for preoperative gastric radiation therapy requires quantitative knowledge of the various sources of anatomic changes of the stomach. This study aims to investigate the magnitude of interfractional and intrafractional stomach motion and deformation using fiducial markers and 4-dimensional (4D) imaging.

METHODS AND MATERIALS

Fourteen patients who underwent preoperative gastric cancer radiation therapy received 2 to 6 fiducial markers distributed throughout the stomach (total of 54 markers) and additional imaging (ie, 1 planning 4D computed tomography [pCT], 20-25 pretreatment 4D cone beam [CB] CTs, 4-5 posttreatment 4D CBCTs). Marker coordinates on all end-exhale (EE) and end-inhale (EI) scans were obtained after a bony anatomy match. Interfractional marker displacements (ie, between EE pCT and all EE CBCTs) were evaluated for 5 anatomic regions (ie, cardia, small curvature, proximal and distal large curvature, and pylorus). Motion was defined as displacement of the center-of-mass of available markers (COMstomach), deformation as the average difference in marker-pair distances. Interfractional (ie, between EE pCT and all EE CBCTs), respiratory (between EE and EI pCT and CBCTs), and pre-post (pre- and posttreatment EE CBCTs) motion and deformation were quantified.

RESULTS

The interfractional marker displacement varied per anatomic region and direction, with systematic and random errors ranging from 1.6-8.8 mm and 2.2-8.2 mm, respectively. Respiratory motion varied per patient (median, 3-dimensional [3D] amplitude 5.2-20.0 mm) and day (interquartile range, 0.8-4.2 mm). Regarding COMstomach motion, respiratory motion was larger than interfractional motion (median, 10.9 vs 8.9 mm; P < .0001; Wilcoxon rank-sum), which was larger than pre-post motion (3.6 mm; P < .0001). Interfractional deformations (median, 5.8 mm) were significantly larger than pre-post deformations (2.6 mm; P < .0001), which were larger than respiratory deformation (1.8 mm; P < .0001).

CONCLUSIONS

The demonstrated sizable stomach motions and deformations during radiation therapy stress the need for generous nonuniform planning target volume margins for preoperative gastric cancer radiation therapy. These margins can be decreased by daily image guidance and adaptive radiation therapy.

Minimally invasive surgery for gastro-oesophageal junction adenocarcinoma: Current evidence and future perspectives

Minimally invasive surgery is increasingly indicated in the management of malignant disease. Although oesophagectomy is a difficult operation, with a long learning curve, there is actually a shift towards the laparoscopic/thoracoscopic/ robotic approach, due to the advantages of visualization, surgeon comfort (robotic surgery) and the possibility of the whole team to see the operation as well as and the operating surgeon. Although currently there are still many controversial topics, about the surgical treatment of patients with gastro-oesophageal junction (GOJ) adenocarcinoma, such as the type of open or minimally invasive surgical approach, the type of oesophago-gastric resection, the type of lymph node dissection and others, the minimally invasive approach has proven to be a way to reduce postoperative complications of resection, especially by decreasing pulmonary complications. The implementation of new technologies allowed the widening of the range of indications for this type of surgical approach. The short-term and long-term results, as well as the benefits for the patient - reduced surgical trauma, quick and easy recovery - offer this type of surgical treatment the premises for future development. This article reviews the updates and perspectives on the minimally invasive approach for GOJ adenocarcinoma.

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.