What is the role of radiotherapy in the management of cutaneous T cell lymphoma?

From the Guidelines

Radiotherapy is a crucial treatment modality in the management of cutaneous T cell lymphoma (CTCL), particularly for localized disease or as palliative treatment for advanced cases. The role of radiotherapy in CTCL is supported by recent guidelines, which recommend its use in early-stage disease, particularly for patients with unilesional mycosis fungoides (MF) and pagetoid reticulosis 1. For early-stage CTCL (stages IA-IIA), localized radiation therapy using 20-36 Gy delivered over 8-10 fractions can achieve complete response rates of 90-100% with excellent local control.

Key Considerations for Radiotherapy in CTCL

• Total skin electron beam therapy (TSEBT) is effective for more extensive skin involvement, typically delivered at doses of 30-36 Gy over 8-10 weeks, though lower doses of 10-12 Gy may be used to reduce toxicity while maintaining efficacy 1.
• Palliative focal radiation with 2-8 Gy can provide symptom relief for troublesome lesions in advanced disease.
• Radiotherapy works by directly damaging the DNA of malignant T cells, inducing apoptosis.
• Side effects include skin erythema, desquamation, and temporary alopecia, with long-term risks of skin atrophy and secondary malignancies.
• Radiotherapy is often combined with other treatments like topical corticosteroids, retinoids, or systemic therapies depending on disease stage and patient characteristics.

Disease Stage and Treatment Approach

• For patients with only patches and/or plaques covering <10% (stage IA) or ≥10% of the skin surface (stage IB), skin-directed therapies, including topical steroids, psoralens + ultraviolet A (PUVA), narrow-band ultraviolet B (UVB), and topical cytostatic agents, are recommended 1.
• In patients developing one or few infiltrated plaques or tumours (stage IIB), additional local radiotherapy may suffice.
• For patients with more extensive infiltrated plaques and tumours or patients refractory to skin-directed therapies, a combination of PUVA and interferon alpha or PUVA and retinoids, a combination of interferon alpha and retinoids, or total skin electron beam irradiation can be considered 1.

Recent Guidelines and Recommendations

• The European Society for Medical Oncology (ESMO) clinical practice guidelines for diagnosis, treatment, and follow-up of primary cutaneous lymphomas recommend radiotherapy as a valuable treatment option for CTCL 1.
• The guidelines emphasize the importance of careful radiation field planning and dose considerations to maximize therapeutic benefit while minimizing toxicity.

From the Research

Role of Radiotherapy in Cutaneous T Cell Lymphoma

• Radiotherapy is an effective treatment for cutaneous T-cell lymphoma (CTCL), with lymphocytes being extremely sensitive to radiation 2.
• It has several important roles in the management of mycosis fungoides, including potentially curative treatment for unilesional disease and effective palliation of symptomatic disease for more advanced cutaneous disease 2.
• Skin-directed radiation therapy can be used to treat mild to refractory CTCL, with a high response rate and complete response rate after treatment 3.
• Radiation therapy is particularly advantageous because it can effectively penetrate and treat thicker plaques and tumors compared to other skin-directed therapies 2.

Efficacy and Toxicities of Skin-Directed Radiotherapy

• Skin-directed radiotherapy has been shown to be effective for local control and well-tolerated with less toxicity in CTCL patients 4.
• The complete response rates are high across different groups of patients, including those with early-stage and advanced-stage disease 4.
• Acute toxicities are mainly grade 1 or 2, with no grade 3 or higher events reported 4.
• Low-dose radiotherapy (<30 Gy) has been advocated for due to similar response rates and less toxicity compared to higher doses (≥30 Gy) 5.

Trends in Radiation Doses and Patterns of Care

• Despite the effectiveness of low-dose radiotherapy, a minority of patients receive it, and high-volume facilities are more likely to use low-dose radiotherapy 5.
• The annual percentage of patients receiving low-dose radiotherapy has increased over time, but most patients with CTCL still receive doses that may be higher than needed to palliate their disease effectively 5.
• Systemic therapy often becomes necessary as the disease progresses, and various treatment options are available, including monoclonal antibodies, retinoids, interferons, and HDAC inhibitors 6.