ASO Author Reflections: Opportunity to Improve Outcomes in Patients with Gastric Cancer.

Gastric cancer peritoneal metastasis is associated with extremely poor survival.1 Unfortunately, radiographically occult peritoneal metastasis is present in 30-40% of newly diagnosed gastric cancer cases.2–4 Therefore, staging laparoscopy (SL) with peritoneal cytology is considered a critical component of the staging workup and the National Comprehensive Cancer Network strongly recommends SL with cytology for adequate staging of gastric cancer.5
Regrettably, we found that the compliance with SL prior to neoadjuvant systemic therapy (NST) in patients that were referred/treated at our tertiary academic institutions was only 30%.6 The poor compliance with SL is even more worrisome as the incidence of peritoneal metastasis in patients who underwent SL was as high as 38%. Not surprisingly, in the patients in whom SL was omitted prior to NST, the median time to recurrence after gastrectomy was 11 months and the most common site of recurrence was the peritoneum. These results raise serious concerns about the management approach of patients with newly diagnosed gastric cancer particularly in the context of increasing incidence of gastric cancer in the United States. Surveillance, epidemiology and end results (SEER) data show that since 2019 the annual percentage incidence of new gastric cancer cases has been increasing by 3.6% in both sexes combined, and by 6.2% in females alone. Even more alarming is that the highest percentage change in increasing incidence (4.3%) is seen in people < 50 years of age.7 These trends are worrisome and further amplify the issue about inadequate staging and treatment in the youngest group of patients in whom there is a tremendous impact with missed opportunity for meaningful extension of life.
While the reasons for poor compliance with SL are difficult to determine, it is likely multifactorial and possibly influenced by institutional and provider practice preferences, insurance barriers, access issues, and the sense of urgency to start systemic therapy. Nevertheless, the importance of identification of metastatic disease and formulating a treatment plan that is stage appropriate cannot be overemphasized. In the past decade, treatment of gastric cancer, particularly metastatic gastric cancer has evolved with the addition of immune checkpoint inhibitors and targeted therapies, and these combinatorial approaches are associated with improved overall survival.8,9 Furthermore, the utilization of regional therapies in combination with systemic therapy through clinical trials are also options for these patients. For example, in the United States, EA2234 STOPGAP II (NCT 07001748) is a randomized controlled clinical trial evaluating the role of intraperitoneal paclitaxel combined with systemic therapy in patients with synchronous gastric cancer peritoneal metastasis (CYT+ or peritoneal carcinomatosis).10 Hence, regardless of the reasons behind the poor compliance, under staging patients would deprive them from receiving the appropriate first line systemic therapy or be considered for clinical trials.
Significant efforts are urgently needed to improve compliance with SL with cytology. These efforts should include education through community outreach, improving multidisciplinary care with the involvement of surgeons at the onset of cancer care, and eliminating barriers to care. An additional strategy is to develop an artificial intelligence (AI) deep learning (DL) model based on staging computed tomography scans and clinical risk factors to diagnose peritoneal disease. Such a model can be applied at the time of diagnosis or even after the initiation of NST to obtain an objective risk assessment regarding the of presence of peritoneal metastasis even when a SL with cytology was not performed at the time of diagnosis. Our team has developed an AI/DL model for peritoneal metastasis which is currently being validated in a large international cohort of patients with a plan for clinical translation in the near future.
Although there is significant work ahead of us to improve the outcomes of patients with gastric cancer peritoneal metastasis, the first step is to become aware of the current state of poor compliance with SL with cytology and failure to detect peritoneal metastasis. Undoubtedly, with the advances in management of patients with metastatic gastric cancer, increasing compliance with SL will lead to better management and improved patient outcomes.