07 / COMPARISON OF OXALIPLATIN-RELATED SPLEEN ENLARGEMENT IN PATIENT WITH GASTRIC CANCER WHO RECEIVED S-1 VERSUS CAPECITABINE AS A COMBINATION PARTNER OF OXALIPLATIN

Background Oxaliplatin (OX)-based chemotherapy is known to cause hepatic sinusoidal injury, resulting portal hypertension with splenomegaly (SM). We compared this OX-induced hepatopathy, SM, and their clinical significance according to combined oral fluoropyrimidines, S-1 vs. capecitabine (X) in gastric cancer (GC). Methods We analyzed pts from two prospective trials for GC, adjuvant XELOX (X 1000 mg/m2 bid on D1-14 + OX 130 mg/m2 on D1 q3w, 8 cycles; n=52) and palliative SOX (S-1 40 mg/m2 bid on D1-14 + OX 130 mg/m2 on D1 q3w, continuous [SOX-c, n=52] vs. intermittent [SOX-i, discontinuing after 6th and restarting on progression, n=53]). Spleen volume (vol) was retrospectively measured by Rapidia software.Results Baseline sex, age, ECOG PS, BSA, spleen vol, levels of platelet (plt)/liver enzyme/bilirubin (bil) and OX cumulative dose during 8 cycles did not differ in XELOX and SOX-c. After 8 cycles, the SOX-c had more SM, hepatic enhancing heterogeneity, hyper-bil, and thrombocytopenia than the XELOX. The SOX-c was a risk factor for developing SM (adjusted odds ratio, 4.7; 95% CI, 2.0-10.8; p<.001) When tracking serial spleen vol and plt at baseline, 2nd, 4th and 6th cycles in SOX-c and SOX-i, spleen vol significantly increased over time (mean, 160, 182, 216, 247 cm3; p<.001), whereas plt were decreased (mean, 290, 168, 132, 116 x103/uL; p<.001). In SOX-i group, spleen vol decreased at 6th cycles, 6, 12, 18 and 24w after stopping SOX (mean, 194, 181, 167, 158, 150 cm3; p=.016). ConclusionsS-1 seems to enhance OX-induced hepatic sinusoidal injuries than capecitabine in pts with GC with clinical significance of higher incidences of splenomegaly, thrombocytopenia, and hyperbilirubinemia.