Local radiation for cutaneous T-cell lymphoma other than mycosis fungoides and Sézary syndrome
Primary cutaneous lymphoma is the second most common type of extranodal lymphoma. The clinical behavior of this lymphoma differs from that of other extranodal lymphomas and thus requires a particular pretreatment evaluation and treatment strategy. Cutaneous T-cell lymphoma (CTCL) accounts for 80% of primary cutaneous lymphoma cases and includes several confirmed disease entities as well as provisional entities. Local radiation for CTCLs is applicable for both curative and palliative intents and is based on the involved-site radiotherapy (ISRT) concept. Primary cutaneous CD30-positive lymphoproliferative disorders include primary cutaneous anaplastic large-cell lymphoma (C-ALCL), lymphomatoid papulosis (LyP), and borderline lesions, all of which exhibit indolent behavior. One half of all LyP cases show spontaneous regression and do not require active treatment. Solitary or localized C-ALCL cases are treated with surgical excision or local radiation of 24−36 Gy. The most common relapse site after local treatment is other skin areas; however, skin relapse is not associated with worsened prognosis. Subcutaneous panniculitis-like T-cell lymphoma (SPTL) without hemophagocytic syndrome exhibits indolent behavior, and localized lesions can be successfully treated with local radiation of 40 Gy or more. Extranodal NK/T-cell lymphoma, nasal type has an aggressive clinical behavior even with intensive chemotherapy and a dose of 50 Gy or higher might be required for good tumor control. Palliative local radiation of 8 Gy in one or two fractions is effective in treating refractory or relapsed CTCLs. ISRT with curative intent should encompass the original suspicious lesions plus a 2−3 cm margin, while ISRT with palliative intent should encompass visible lesions plus a 1−2 cm margin. Appropriate electron beam energy and bolus thickness should be selected according to the skin surface dose and thickness of the patch and plaque lesions. All CTCL cases should be reviewed by a multidisciplinary team to ensure an appropriate treatment strategy.