Splenomegaly during oxaliplatin-based chemotherapy in colon cancer.

88 Background: Splenic enlargement has been reported in patients treated with oxaliplatin. However, the characteristics of oxaliplatin-induced splenomegaly were not well studied. Here we evaluated the change of splenic volume and its clinical significance in patients treated by oxaliplatin-based regimen. Methods: Patients with stage II-IV primary colon cancer treated with oxaliplatin and capecitabine in China National Cancer Center from January 2016 to December 2017 were screened for this retrospective study. Those with complete laboratory tests and computed tomographic data before, during and up to 1.5 years after the chemotherapy were selected. The splenic size was measured by AWVolumeshare5. Splenomegaly was defined as an over 30% increase of splenic size from baseline. Recovery of splenomegaly was defined as the splenic size fell back to a 0.9 to1.1-fold range of baseline. Results: Out of a total of 144 patients, 102 (70.8%) had over 30% increase, 72 (50.0%) had over 50% increase, and 22 (15.3%) had over 100% increase in splenic size after oxaliplatin-based regimen. Among the 102 splenomegaly patients, 5 (4.9%) develop splenomegaly within 3 chemotherapy cycles, 53 (53.0%) within 6 cycles, 73 (71.6%) within 9 cycles, and 102 (100.0%) within 3 months after the last administration of oxaliplatin. Compared to the group without splenomegaly, patients with splenomegaly received more cycles of oxaliplatin administrations (median 8 vs 6, p < 0.001) and greater dose intensity (total dose per square meter) (median 822.8mg/m2 vs 629.3mg/m2, p < 0.001). Patients with splenomegaly had higher incidence of thrombocytopenia (61.7% vs 38.1%, p = 0.009) and are more likely to undergo oxaliplatin dose reduction due to thrombocytopenia (21.6% vs 7.1%, p = 0.038). The recovery rates of splenic size within 0.5, 1 and 1.5 years after the end of oxaliplatin treatment were 23.2%, 50.6% and 74.3%, respectively. Conclusions: Splenomegaly are common in patients treated with oxaliplatin-based chemotherapy, and most would recover in 1.5 years after completion of therapy. Patients with splenomegaly are prone to experience thrombocytopenia and oxaliplatin dose reduction. Further studies are needed to reveal the mechanism how oxaliplatin induce splenomegaly.