Oxaliplatin‐induced increase in splenic volume; irreversible change after adjuvant FOLFOX

Background and Objectives Oxaliplatin can cause hepatic sinusoidal obstruction syndrome (SOS). SOS can cause chemotherapy‐related adverse effects or morbidity after liver resection. Conventionally, SOS is diagnosed using liver biopsy. Recently, it was reported that increased splenic volume (SV) can be used to detect SOS. In this study, we evaluated the changes in SV during adjuvant chemotherapy. Methods We enrolled 103 consecutive patients with stage III and high‐risk stage II colorectal cancer treated with mFOLFOX6 ( n = 37) or oral fluorouracil and leucovorin ( n = 66) after curative surgery. SV was measured three times; pre‐operatively, after chemotherapy, and 1 year after chemotherapy. Results SV was higher after mFOLFOX6 (median 135.89 mL) than pre‐operatively (105.75 mL) ( P < 0.001); SV at 1‐year after finishing mFOLFOX6 (114.16 mL) returned to the same level as before surgery ( P = 0.0015). SV increased in 28 patients (75.7%) treated with mFOLFOX6 (95%CI, 61.8‐89.5), but had not recovered in 12 of these cases (42.9%) 1 year after finishing treatment (95%CI, 17.3‐47.5). In contrast, oral fluorouracil and leucovorin did not change SV. Conclusions SV increased after adjuvant mFOLFOX6, and had not recovered in almost half of cases 1‐year after finishing chemotherapy. This increase may indicate continuous SOS, which can adversely affect treatment after recurrence.