A population-based study on treatment and outcomes in patients with gastric adenocarcinoma diagnosed with distant interval metastases

The clinical implications of staging laparoscopy in the diagnostic workup of gastric cancer patients: A population based study

BACKGROUND

Since 2016, staging laparoscopy has been implemented in the diagnostic workup of patients with gastric cancer. Staging laparoscopy aims to detect incurable disease (peritoneal metastases and irresectable tumors) and to prevent futile laparotomies.

METHODS

In this population-based nationwide study, we sought patient- and tumor characteristics associated with undergoing a staging laparoscopy. Additionally, we analyzed the prevalence of synchronous peritoneal metastases, the outcome of the staging laparoscopy and its clinical impact on treatment decisions. All patients diagnosed with non-cardia gastric cancer from the Netherlands Cancer Registry between 2016 and 2021 were included.

RESULTS

Alongside tumor characteristics, patient characteristics such as younger age, absence of comorbidities and lower WHO performance status were associated with performing a staging laparoscopy. In the study period, an increase in the proportion of patients who underwent a staging laparoscopy was observed, from 19.6% in 2016 to 32.3% in 2021 (p-value<0.001). In the same period, the prevalence of synchronous peritoneal metastases increased from 25% to 31%. In 37.6% of the patients who had the outcome of their staging laparoscopy reported, had incurable disease diagnosed during staging laparoscopy. Significantly less of these patients were treated with triplet regimens as compared to patients with a negative staging laparoscopy (18.5 vs. 76.3%; p-value<0.001).

CONCLUSION

The implementation of staging laparoscopy in gastric cancer patients paralleled the increase in diagnosis of incurable disease and a decrease in the application of triplet systemic therapies in these patients.

Peritoneal metastases from gastric cancer in a nationwide cohort: Incidence, treatment and survival

The aims of this study were to investigate incidence, risk factors and treatment of synchronous or metachronous peritoneal metastases (PM) from gastric cancer and to estimate survival of these patients using population-based data. Patients diagnosed with gastric cancer in 2015 to 2016 were selected from the Netherlands Cancer Registry. The incidence of synchronous and metachronous PM were calculated. Multivariable regression analyses were performed to identify factors associated with the occurrence of PM. Treatment and survival were compared between patients with synchronous and metachronous PM. Of 2206 patients with gastric cancer, 741 (34%) were diagnosed with PM. Of these, 498 (23%) had synchronous PM. The cumulative incidence of metachronous PM in patients who underwent potentially curative treatment (n = 675) was 22.8% at 3 years. A factor associated with synchronous and metachronous PM was diffuse type histology. Patients diagnosed with synchronous PM more often received systemic treatment than patients with metachronous PM (35% vs 18%, respectively, P < .001). Median overall survival was comparable between synchronous and metachronous PM (3.2 vs 2.3 months, respectively, P = .731). Approximately one third of all patients with gastric cancer are diagnosed with PM, either at primary diagnosis or during 3-year follow-up after potentially curative treatment. Patients with metachronous PM less often received systemic treatment than those with synchronous PM but survival was comparable between both groups. Future trials are warranted to detect gastric cancer at an earlier stage and to examine strategies that lower the risk of peritoneal dissemination. Also, specific treatment options for patients with gastric PM should be further investigated.

Neoadjuvant chemotherapy in older patients with gastric cancer undergoing surgery: a population-based cohort study

BACKGROUND

In trials evaluating perioperative chemotherapy for gastric cancer, which serve as the basis for treatment guidelines, patients are selected. The generalizability of these trial findings to older patients is uncertain.

METHODS

This population-based retrospective cohort study compared the survival outcomes of patients ≥ 75 years with gastric adenocarcinoma treated with or without neoadjuvant chemotherapy between 2015 and 2019. Additionally, the percentage of patients < 75 years and ≥ 75 years who did not proceeded to surgery after receiving neoadjuvant chemotherapy were examined.

RESULTS

A total of 1995 patients, of whom 1249 aged < 75 years and 746 aged ≥ 75 years, were included. In the group of patients ≥ 75 years, 275 patients received neoadjuvant chemotherapy and 471 patients were directly scheduled for gastrectomy. Patients ≥ 75 years treated with or without neoadjuvant chemotherapy differed significantly from one and another in characteristics. Overall survival of patients ≥ 75 years treated with or without neoadjuvant chemotherapy was not significantly different (median 34.9 vs. 32.3 months; P = 0.506), also after adjusting for potential confounders (HR 0.87; P = 0.263). Of patients ≥ 75 years who received neoadjuvant chemotherapy, 43 (15.6%) did not proceed to surgery compared to 111 (8.9%) patients < 75 years (P < 0.001).

CONCLUSION

Patients ≥ 75 years treated with or without chemotherapy were highly selected, and overall survival was not significantly different between both groups. Nonetheless, the proportion of patients who did not proceed to surgery following neoadjuvant chemotherapy was higher in patients ≥ 75 years compared to patients < 75 years. Therefore, neoadjuvant chemotherapy should be considered with more caution in patients ≥ 75 years, while identifying those who may benefit.

Soluble factors in malignant ascites promote the metastatic adhesion of gastric adenocarcinoma cells

BACKGROUND

Adenocarcinoma of the proximal stomach is the fastest rising malignancy in North America. It is commonly associated with peritoneal accumulation of malignant ascites (MA), a fluid containing cancer and inflammatory cells and soluble proteins. Peritoneal metastasis (PM) is the most common site of gastric cancer (GC) progression after curative-intent surgery and is the leading cause of death among GC patients.

METHODS/RESULTS

Using a panel of gastric adenocarcinoma cell lines (human: MKN 45, SNU-5; murine: NCC-S1M), we demonstrate that prior incubation of GC cells with MA results in a significant (> 1.7-fold) increase in the number of cells capable of adhering to human peritoneal mesothelial cells (HPMC) (p < 0.05). We then corroborate these findings using an ex vivo PM model and show that MA also significantly enhances the ability of GC cells to adhere to strips of human peritoneum (p < 0.05). Using a multiplex ELISA, we identify MIF and VEGF as consistently elevated across MA samples from GC patients (p < 0.05). We demonstrate that agents that block the effects of MIF or VEGF abrogate the ability of MA to stimulate the adhesion of GC cells to adhere to human peritoneum and promote both ex vivo and in vivo metastases.

CONCLUSION

Agents targeting MIF or VEGF may be relevant to the treatment or prevention of PM in GC patients.