Ultra-low dose EBRT feasible in primary cutaneous B-cell lymphoma

Patients with primary cutaneous B-cell lymphoma (PCBCL) treated with ultra-low dose external beam radiation therapy (EBRT) to 4 Gy total dose in two fractions experience durable local control without skin toxicity, reports a study.

At 4 months, all lesions showed a response to EBRT, which appeared as flattening with changes in pigmentation. At the last follow-up (20, 16.5, and 4 months, respectively), all lesions had flattened and showed no evidence of local recurrence and skin toxicity.

“These results are encouraging for both the success of treatment and the potential to use similarly low doses for retreatment should patients exhibit local recurrence,” the investigators said.

In this study, two male patients with four biopsy-confirmed PCBCL lesions (one anterior thigh and three chest) received treatment with 2 Gy x 2 fraction EBRT using electrons through a clinical setup. A clamshell was used to treat the anterior thigh lesion to protect the scrotum from scatter dose.

Treatment was done using 9 MeV electrons to the 85-percent isodone line using no bolus, with follow-up every 4 months and potential retreatment and possible retreatment for patients who showed no response at 8 to 9 months.

“PCBCL is a relatively rare disease, associated with 5-year overall survival of nearly 95 percent when treated with EBRT alone,” the investigators said. “However, standard EBRT doses yield acute skin toxicity in more than 70 percent of patients and grade 3 to 4 acute skin toxicity in nearly 10 percent of patients.”