A fecal occult blood test followed by a colonoscopy is a useful approach for detecting hemorrhagic colitis in patients with chronic myeloid leukemia (CML) treated with dasatinib, according to a study published in the journal Blood.1
Some patients with CML treated with a tyrosine kinase inhibitor (TKI) test positive upon a fecal occult blood test, and hemorrhagic colitis has been reported in patients treated with dasatinib. Therefore, researchers sought to examine the frequency of TKI-induced hemorrhagic colitis and evaluate the efficacy of screening with a fecal occult blood test followed by colonoscopy.
For the prospective study, investigators enrolled 30 patients with CML treated with a TKI. All patients underwent a fecal occult blood test, and researchers performed a colonoscopy in patients with a positive fecal occult blood test. When investigators pathologically identified TKI-induced hemorrhagic colitis, the TKI was interrupted and the fecal occult blood test was reassessed.
Results showed that the first fecal occult blood test was positive in one-third of patients. All patients with positive tests were treated with dasatinib and developed no symptoms of colitis.
Researchers confirmed dasatinib-induced hemorrhagic colitis in 33% of 18 patients treated with dasatinib. Endoscopy demonstrated that dasatinib-induced hemorrhagic colitis was characterized by a red flare and/or erosion and immunohistological analyses showed CD3+, CD8+, CD56+, and Granzyme B+ cytotoxic T lymphocyte infiltration.
Following discontinuation of dasatinib, all but 1 patient had a negative second fecal occult blood test. The patient with a positive test had concurrent colorectal polyps.
The findings ultimately suggest that dasatinib-induced hemorrhagic colitis may be asymptomatic and effectively detected with a fecal occult blood test followed by a colonoscopy.
1. Nishiwaki S, Maeda M, Yamada M, et al. Clinical efficacy of fecal occult blood test and colonoscopy for dasatinib-induced hemorrhagic colitis in CML patients. Blood. 2016 Nov 18. doi: 10.1182/blood-2016-08-734947. [Epub ahead of print]