Maintenance Therapy for Cutaneous T-cell Lymphoma After Total Skin Electron Irradiation: Evidence for Improved Overall Survival With Ultraviolet Therapy

BACKGROUND

Treatment of cutaneous T-cell lymphoma (CTCL) with total skin electron beam (TSEB) therapy has been associated with deep responses but short progression-free intervals. Maintenance therapy might prolong the response duration; however, limited data assessing the outcomes with maintenance therapy after TSEB are available. We evaluated the effect of maintenance therapy on the outcomes for patients with CTCL receiving TSEB therapy.

MATERIALS AND METHODS

We conducted a single-center retrospective analysis of 101 patients with CTCL who had received TSEB therapy from 1998 to 2018 at the Winship Cancer Institute of Emory University and compared the overall survival (OS) and progression-free survival (PFS) for patients had received maintenance therapy, including retinoids, interferon, ultraviolet therapy, nitrogen mustard, and extracorporeal photopheresis compared with those who had not.

RESULTS

We found that pooled maintenance therapies improved PFS (hazard ratio [HR], 0.60; P = .026) but not OS (median HR, 0.73; P = .264). The median PFS and OS was 7.2 months versus 9.6 months and 2.4 years versus 4.2 years for the no maintenance and maintenance groups, respectively. On exploratory analysis of the individual regimens, ultraviolet therapy was associated with improved OS (HR, 0.21; P = .034) and PFS (HR, 0.26; P = .002) compared with no maintenance.

CONCLUSION

Among the patients with CTCL who had received TSEB therapy, maintenance therapy improved PFS for all patients, and ultraviolet-based maintenance improved both PFS and OS in a subset of patients.

In-vivo dosimetric analysis in total skin electron beam therapy

Background and purpose

Thermoluminescent dosimetry (TLD) is an important element of total skin electron beam therapy (TSEBT). In this study, we compare radiation dose distributions to provide data for dose variation across anatomic sites.

Materials and methods

Retrospectively collected data on 85 patients with cutaneous lymphoma or leukemia underwent TSEBT were reviewed. Patients were irradiated on two linear accelerators, in one of two positions (standing, n = 77; reclined, n = 8) and 1830 in vivo TLD measurements were obtained for various locations on 76 patients.

Results

The TLD results showed that the two TSEBT techniques were dosimetrically heterogeneous. At several sites, the dose administered correlated with height, weight, and gender. After the first TLD measurement, fourteen patients (18%) required MU modification, with a mean 10% reduction (range, −25 to +35). Individual TLD results allowed us to customize the boost treatment for each patient. For patients who were evaluated in the standing position, the most common underdosed sites were the axilla, perineum/perianal folds, and soles (each receiving 69%, 20%, and 34% of the prescribed dose, respectively). For patients evaluated in a reclining position, surface dose distribution was more heterogeneous. The sites underdosed most commonly were the axilla and perineum/perianal folds (receiving less than one third of prescribed dose). Significant variables were detected with model building.

Conclusion

TLD measurements were integral to quality assurance for TSEBT. Dose distribution at several anatomical sites correlated significantly with gender, height, and weight of the treated individual and might be predicted.