The Results of Low-Dose Total Skin Electron Beam Radiation Therapy (TSEB) in Patients With Mycosis Fungoides From the UK Cutaneous Lymphoma Group

Bone marrow suppression as a complication of total skin helical tomotherapy in the treatment of mycosis fungoides

Background

Total skin electron beam therapy (TSEBT) is an effective treatment in mycosis fungoides. Total skin helical tomotherapy (TSHT) may be an alternative to TSEBT and may offer several dosimetric and treatment advantages. There are currently very few published treatment results using TSHT in place of TSEBT for treatment of mycosis fungoides.

Case presentation

Two patients with mycosis fungoides were treated at our institution using TSHT. The first patient was a 69-year-old Caucasian female with stage IVA2 (T2 N3 M0 B2) disease who was treated to a dose of 12 Gy in 8 fractions, with a bone marrow mean dose of 1.66 Gy and V10 = 0.41%. Two weeks after ending treatment the patient developed myelosuppression including grade 4 thrombocytopenia and required blood and platelet transfusions. The second patient was a 29-year-old Caucasian female with stage I (T2 N0 M0 B0) disease. This patient previously had been treated for mycosis fungoides using helical tomotherapy (HT) at a dose of 20 Gy to a localized region and experienced mild thrombocytopenia at that time. The patient then underwent retreatment 17 months later with TSHT to a dose of 12 Gy in 6 fractions with a mean bone marrow dose of 2.3 Gy and V10 = 4.28%. This patient once again experienced myelosuppression that included grade 4 thrombocytopenia. She also required blood and platelet transfusions.

Conclusions

Both patients treated with TSHT experienced severe bone marrow suppression including grade 4 thrombocytopenia. This was more severe than expected considering the relatively low overall prescription dose and despite a planning constraint placed on the bone marrow of a mean dose of < 2 Gy. These outcomes suggest that patients treated using TSHT should be closely monitored for myelosuppression and caution used even when treating to a dose of 12 Gy.

Low-dose total skin electron beam therapy for cutaneous lymphoma : Minimal risk of acute toxicities

BACKGROUND

Low-dose total skin electron beam therapy (TSEBT) is attracting increased interest for the effective palliative treatment of primary cutaneous T‑cell lymphoma (pCTCL). In this study, we compared toxicity profiles following various radiation doses.

PATIENTS AND METHODS

We reviewed the records of 60 patients who underwent TSEBT for pCTCL between 2000 and 2016 at the University Hospital of Munster. The treatment characteristics of the radiotherapy (RT) regimens and adverse events (AEs) were then analyzed and compared.

RESULTS

In total, 67 courses of TSEBT were administered to 60 patients. Of these patients, 34 (51%) received a standard dose with a median surface dose of 30 Gy and 33 patients (49%) received a low dose with the median surface dose of 12 Gy (7 salvage low-dose TSEBT courses were administered to 5 patients). After a median follow-up of 15 months, the overall AE rate was 100%, including 38 patients (57%) with grade 2 and 7 (10%) with grade 3 AEs. Patients treated with low-dose TSEBT had significantly fewer grade 2 AEs than those with conventional dose regimens (33 vs. 79%, P < 0.001). A lower grade 3 AE rate was also observed in patients who had received the low-dose regimen compared to those with the conventional dose regimens (6 vs. 15%, P = 0.78). Multiple/salvage low-dose TSEBT courses were not associated with an increased risk of acute AEs.

CONCLUSION

Low-dose TSEBT regimens are associated with significantly fewer grade 2 acute toxicities compared with conventional doses of TSEBT. Repeated/Salvage low-dose TSEBT, however, appears to be tolerable and can even be applied safely in patients with cutaneous relapses.