Treatment features of systemic chemotherapy in young adults with unresectable advanced or recurrent gastric cancer

Purpose: Gastric cancer in young adults (GCYA) is known to have distinct clinicopathological features, including a female predominance and diffuse-type histology. Previous reports have focused on patients who had undergone gastrectomy with curative intent. Information concerning the treatment of unresectable advanced-or recurrent-stage GCYA is lacking. Therefore, we aimed to investigate whether the distinct clinicopathological features of GCYA affect the outcome of systemic chemotherapy. Patients and methods: We conducted a retrospective cohort study at a single institution in Japan. GCYA was classified as a disease in individuals who were <40 years of age at diagnosis. Initial systemic chemotherapy regimens for GCYA were investigated with a focus on patients who received S-1 plus cisplatin (SP) as a representative standard regimen. The efficacy, safety, and feasibility of systemic chemotherapy were evaluated. Results: Eighty-nine (7.5%) of 1,184 consecutive patients who received systemic chemotherapy at our institute between December 2005 and June 2016 were enrolled. As reported previously, the female sex (57.3%) and diffuse-type histology (91.0%) were the dominant features of GCYA. Thirty-two patients (36.0%) received SP as first-line treatment. The median overall survival and progression-free survival times were 13.2 (95.0% CI: 9.5-18.7) and 5.6 (95.0% CI: 4.7-7.9) months, respectively. The median number of treatment cycles, relative dose intensity, and cumulative dose of cisplatin were 4.5 (range: 1-10), 92.0% (IQR: 83.5-98.3), and 286.5 mg/m2 (IQR: 172.5-367.5), respectively. The most common adverse event of Grade 3 or higher was neutropenia (n=5 patients; 15.6%). No patient had febrile neutropenia. Non-hematological adverse events of Grade 3 or higher were only observed in 2 (6.3%) of 32 patients. Conclusion: Standard chemotherapy used for general-aged GC patients has similar efficacy, reduced toxicity, and higher intensity in GCYA patients.