The SWOG S1512 Phase 2 trial studied giving pembrolizumab (Keytruda) before surgery to patients with resectable desmoplastic melanoma, a rare type of skin cancer usually found on sun-exposed areas.
After just three doses of pembrolizumab, 71% of patients had no cancer left in their surgical tissue samples. At three years, 74% of patients had no cancer return, and 87% were still alive. The benefit was seen in all patient groups, regardless of age, sex, or whether the cancer was newly diagnosed or had come back locally.
In the study, 28 patients (median age 75) received 200 mg of pembrolizumab every three weeks for three cycles before surgery. The treatment was generally well tolerated. Most side effects were mild, such as fatigue and rash. Only 7% had more serious side effects (such as colitis or mucositis), and no one had to delay or cancel surgery because of treatment problems or cancer progression.
Desmoplastic melanoma is usually treated with extensive surgery and radiation, which can be especially difficult for older patients. This study suggests that giving drug treatment first is a safe and effective approach. The high response rate may also reduce the need for more aggressive surgery and radiation, potentially improving quality of life.