# Real-World Treatment Patterns and Outcomes Amongst Patients with Resectable Gastric and Gastroesophageal Junction Cancer in the United States

## TL;DR

This study examined real-world treatment patterns and outcomes for patients in the US with resectable gastric and gastroesophageal junction cancer, finding that treatment use was lower than expected and survival rates were poor.

## Contribution

The study provides real-world data on treatment patterns and outcomes for resectable GC/GEJC in the US, highlighting the gap between guidelines and clinical practice.

## Key findings

- Perioperative treatment use for resectable GC/GEJC was lower than expected in real-world settings.
- Median event-free and overall survival rates were poor, indicating a need for improved treatment options.
- FLOT and chemoradiotherapy were the most common treatments for GC and GEJC, respectively.

## Abstract

This study looked at treatments given before and after surgery and outcomes for patients in the US with resectable gastric or gastroesophageal cancer (GC/GEJC) in routine clinical practice (real-world) rather than a clinical trial. Data from electronic health records were studied for adult patients diagnosed with resectable GC/GEJC between 1 January 2016 and 1 January 2023. This real-world study found the most common treatments used were those recommended in clinical guidelines at the time of the study. However, the use of treatments before and after surgery for patients with resectable GC/GEJC was lower than expected. The length of time before an event where the patient’s disease worsens significantly or the patient dies, and the length of time patients were alive after treatment, were both poor, underscoring the need for new treatment options to improve outcomes.

Background: Resectable gastric and gastroesophageal junction cancer (GC/GEJC) treatment patterns in the real-world are poorly described. This study described real-world perioperative treatment and outcomes for patients in the US with resectable GC/GEJC. Methods: Data from the Flatiron Health Enhanced Datamart were analyzed for adult patients diagnosed with resectable GC/GEJC between 1 January 2016 and 1 January 2023. The primary objective was to describe perioperative treatments (neoadjuvant only, adjuvant only, both). Secondary objectives included real-world event-free survival (rwEFS) and real-world overall survival (rwOS). Results: Data from 1717 patients (901/816 with GC/GEJC) were included. Median age of patients with GC/GEJC was 68.0/69.0 years, 62.4%/83.3% were male, and 97.3%/96.7% had adenocarcinoma, respectively. For GC/GEJC, 71.1%/47.9% underwent surgery, of which 15.6%/70.1% received neoadjuvant treatment only, 26.4%/5.6% received adjuvant treatment only, 25.0%/17.4% received both, and 33.1%/6.9% received no perioperative treatment, respectively. For GC, the most frequent neoadjuvant treatment was FLOT (43.0% neoadjuvant only; 53.8% both) and the most frequent adjuvant treatments were chemoradiotherapy (39.6% adjuvant only) and FLOT (43.1% both). For GEJC, chemoradiotherapy was the most frequent neoadjuvant (66.4% neoadjuvant only; 67.6% both) and adjuvant only (54.5%) treatment. When patients received both, the most frequent adjuvant treatment was nivolumab (45.6%). For GC/GEJC, median rwEFS (95% CI) was 29.1 (24.7–38.7)/20.8 (17.4–23.7) months for patients who had planned or cancelled surgery and 11.3 (9.6–13.5)/12.7 (11.6–15.4) months for patients without planned surgery. Median rwOS (95% CI) was 50.9 (43.7–62.4)/38.6 (31.4–47.2) months for patients who had planned or cancelled surgery and 15.4 (13.1–18.6)/21.0 (17.6–22.6) months for patients without planned surgery. Conclusions: Real-world data showed lower use of perioperative treatments for resectable GC/GEJC than expected. rwEFS and rwOS remain poor. Optimization of perioperative treatments is needed to improve long-term outcomes.