Most patients with dermatofibrosarcoma protuberans respond to imatinib


By Anne Harding

NEW YORK (Reuters Health) - About 60% of patients with locally advanced or metastatic dermatofibrosarcoma protuberans (DFSP) will respond to imatinib treatment, according to a new review.

While the response rate was the same with 400-mg and 800-mg doses, adverse events were less frequent with the lower dose, Dr. Cristian Navarrete-Dechent of Memorial Sloan Kettering Cancer Center in New York City and colleagues found.

"We know efficacy, we know the adverse effects profile, we know the starting dose, so we are moving forward," the researcher told Reuters Health by phone.

DFSP is rarely lethal, but it can destroy local tissue and recurs frequently, Navarrete-Dechent and his colleagues note in JAMA Dermatology, online January 2. Surgical resection with negative margins is the "gold standard" of treatment, they add, but is not always possible due to the extension or size of a tumor, concerns about cosmetic and/or functional impairment, or medical comorbidities.

In 2002, researchers reported the case of a patient with metastatic DFSP who was able to undergo surgery after one month of imatinib treatment. The U.S. Food and Drug Administration approved imatinib for DFSP in 2006, and guidelines now recommend it for unresectable DFSP.

Nevertheless, "limited and variable data exists regarding the response rate, ideal starting dose, and treatment schema of imatinib for the treatment of DFSP," the authors state.

To investigate, they reviewed nine studies of imatinib for DFSP, including 152 patients in total.

Eight patients, or 5.2%, showed a complete response to imatinib, while 84 (55.2%) had a partial response. Disease remained stable in 27.6%, and progressed in 9.2%.

Responses to the 400-mg and 800-mg doses were similar.

Adverse events occurred in 78 of 106 cases (73.5%), and were severe in 20 (15.1%). Half of the severe adverse events required patients to stop taking imatinib.

Patients who receive imatinib before surgery may continue to take the medication for up to a year afterwards, Dr. Navarrete-Dechent said, but the optimal treatment duration is still not known.

He underscored the importance of multidisciplinary treatment for DFSP patients. "Everyone should be involved in the care of these patients," he said. "Any of these patients will be a complicated case and will need discussion."


JAMA Dermatol 2019.

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