Cutaneous T-cell lymphoma

The prognosis of CTCL is closely related to the stage at diagnosis. Survival of patients with stage IA disease (patches and/or plaques only, <10% body surface area involved) is excellent, with 5-year survival rates of 96% to 100%. The natural course of the disease is gradual extension of skin patches and plaques over many years. Although treatment may induce remission, patients are expected to relapse after a variable interval, and are unlikely to be cured.

Progression of disease

The most important prognostic indicator is the stage of disease at diagnosis, with TNM stage 1 or 2 having better survival than stage 3 or 4. Stage progression with development of ulcerated tumours and peripheral blood, lymph node, and bone marrow involvement all indicate a worsening prognosis.​[32]National Comprehensive Cancer Network. NCCN clinical practice guidelines in oncology: primary cutaneous lymphoma [internet publication]. https://www.nccn.org/guidelines/category_1

Transformation of disease

Up to 50% of patients with CTCL may show transformation from low-grade to high-grade lymphoma during the course of the disease, and after a variable period of time. This is characterised by the occurrence of large tumours that frequently ulcerate. Skin biopsy usually shows dense, deep, cohesive infiltrates of large pleomorphic cells. Transformation carries an unfavourable prognosis.[32]National Comprehensive Cancer Network. NCCN clinical practice guidelines in oncology: primary cutaneous lymphoma [internet publication]. https://www.nccn.org/guidelines/category_1 ​