Low-dose total skin electron beam therapy yields favorable outcomes in mycosis fungoides

Nearly 90% of a small cohort of individuals with mycosis fungoides responded to intervention with a condensed, low dose of total skin electron beam therapy, according to a study.

“Low-dose total skin electron beam therapy (TSEBT) for mycosis fungoides is popular because of reduced toxicity with effective palliation,” Andrew Song, MD, of the department of radiation oncology at Thomas Jefferson University, and colleagues wrote.

Clinicians condensed the TSEBT treatment regimen by cutting visits in half and reducing overall treatment length by one-third. They aimed to assess the efficacy of this approach in a cohort of 25 patients.

The cohort study ran from 2014 to 2018 and had a median follow-up duration of 22.8 months. Patients underwent 12 Gy per six fractions using the modified Stanford technique. Protocols called for three fractions per week, “with boosts to shadowed sites at risk between treatments, completing in 2 weeks,” according to the findings.

Response as defined by the modified Skin Weighted Assessment Tool (mSWAT) served as the primary outcome measure. A complete response was defined as mSWAT of 0, while near complete response was defined as greater than 90% but less than 100% response from baseline, and partial response was defined as mSWAT reduction between 50% and 90%. Progression of disease and stable disease also were included in the primary outcome analysis, along with duration of response, time to response and toxicity.

Patient-reported quality of life (QOL) parameters such as pain, pruritis and Dermatology Life Quality Index served as secondary endpoints. In addition, the researchers assessed for physician-scored disease burden as defined by body surface area involvement and mSWAT.

The researchers reported that 36% of patients were stage IB at the time of TSEBT.

Results showed an overall response rate of 88%. The most commonly observed outcome was near complete response, which occurred in 36% of the cohort, while 24% experienced a complete response, 28% experienced a partial response and 12% reported stable disease.

Patients experienced a median duration of response of 17.5 months (range, 3.5 to 44.2 months). A median of 2 months (range, 0.9 to 4.1 months) was required before response was observed.

Safety data showed no adverse events of grade 3 or higher.

Turning to QOL parameters, pruritis (P < .001), pain (P < .001), body surface area (P < .001) and DLQI (P < .001) all significantly improved from baseline after intervention with TSEBT.

While the researchers acknowledged that the cohort study had a small sample size, they suggested that condensed, low-dose TSEBT may be an attractive intervention option for this patient population based on these results.

“This schedule has great potential for improving patient satisfaction due to increased logistical convenience with comparable clinical results,” they wrote.