Splenomegaly and Its Associations with Genetic Polymorphisms and Treatment Outcome in Colorectal Cancer Patients Treated with Adjuvant FOLFOX

PURPOSE Splenomegaly is a clinical surrogate of oxaliplatin-induced sinusoidal obstruction syndrome (SOS). We investigated development of splenomegaly and its association with treatment outcome and genetic polymorphisms following adjuvant 5-fluorouracil, leucovorin, and oxaliplatin (FOLFOX) in colorectal cancer (CRC) patients. MATERIALS AND METHODS Splenomegaly was determined by spleen volumetry using computed tomography images obtained before initiation of chemotherapy and after completion of adjuvant FOLFOX in CRC patients. Ten genetic polymorphisms in 4 SOS-related genes (VEGFA, MMP9, NOS3, and GSTP1) were analyzed using DNA from peripheral blood mononuclear cells. RESULTS Of 124 patients included, increase in spleen size was observed in 109 (87.9%). Median change was 31% (range, -42% to 168%). Patients with splenomegaly had more severe thrombocytopenia compared to patients without splenomegaly during the chemotherapy period (p < 0.0001). The cumulative dose of oxaliplatin and the lowest platelet count during the chemotherapy period were clinical factors associated with splenomegaly. However, no significant associations were found between genetic polymorphisms and development of splenomegaly. Disease-free survival was similar regardless of the development of splenomegaly. CONCLUSION Splenomegaly was frequently observed in patients receiving adjuvant FOLFOX and resulted in more severe thrombocytopenia but did not influence treatment outcome. Examined genetic polymorphisms did not predict development of splenomegaly.