medwireNews: Japanese researchers say that a fecal occult blood test could help screen for treatment-induced hemorrhagic colitis in chronic myeloid leukemia (CML) patients taking dasatinib.
They believe it could be “a useful, non-invasive screening test”, with the diagnosis confirmed by colonoscopy and pathologic analysis.
Among 30 CML patients who had received a tyrosine kinase inhibitor for at least 1 month – nilotinib in five patients, imatinib in seven, and dasatinib in 18 – 10 had a positive fecal occult blood test. All 10 patients had received dasatinib, and none exhibited clinically relevant symptoms.
Using colon fiberscopy, hemorrhagic colitis was confirmed in six of the 10 patients with a positive fecal occult blood test. Patients had received a median dasatinib dose of 70 mg, and there was no significant difference in the cumulative dose between patients who did and did not develop hemorrhagic colitis.
After confirmation of hemorrhagic colitis, dasatinib therapy was discontinued for a median of 14 days, following which all but one patient had a negative fecal occult blood test.
The patient with a positive test underwent colon fiberscopy again, the results of which indicated that the colitis had improved. Specifically, the patient had minimal red flare, and immunohistologic analysis of the biopsy samples demonstrated reduced infiltration of activated T lymphocytes, the researchers report in a letter published in Blood.
They note that no patient had CML progression as a result of interrupting dasatinib therapy.
Given that a third of dasatinib-treated patients developed hemorrhagic colitis, an “incidence [that] was higher than expected,” the team emphasizes the importance of understanding the clinical features of dasatinib-induced hemorrhagic colitis.
Satoshi Nishiwaki, from Nagoya University Hospital, and co-investigators stress the usefulness of a fecal occult blood test, as not all patients – especially if they are asymptomatic – are likely to agree to an invasive procedure like colon fiberscopy.
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