Primary cutaneous T-cell lymphomas (CTCL) are a subgroup of blood cancers called non-Hodgkin lymphomas. CTCL manifests primarily in the skin. It is characterised by an uncontrolled proliferation of T-lymphocytes, a special kind of white blood cells. Most people are older than 60 years of age. Compared to other malignant T-lymphocyte diseases they show a better prognosis with usually slow progression, but to date are still incurable. The most common subtype of CTCL is Mycosis fungoides (MF) which typically runs an indolent course in early stages. However, approximately 20% of people in early-stage of the disease will develop worsening of the disease and progression into tumour stage or the leukaemic variant which is called Sézary syndrome. Most of these people are then subjected to cytotoxic chemotherapies with one or more agents (mono- or polychemotherapies). Although initial response rates are high, remissions are often short lived and the prolongation of life time is questionable. Furthermore, there is considerable toxicity associated with this treatment in many cases. In the last few years, several publications reported durable responses following allogeneic stem cell transplantation (alloSCT), which is in contrast to autologous transplantation using stem cells not from the patient himself but from stem cell donors. Prior to transplantation, full-intensity or reduced-intensity conditioning (RIC) needs to be performed to induce reduction of tumour. RIC allows the avoidance of conventional regimes of high-dose therapy and appears to be equally effective but with significantly less toxicity. The use of reduced intensity conditioning offers the possibility to treat older individuals, which are the majority of patients.
Researchers in the Cochrane Collaboration conducted a review of the effect of allogeneic stem cell transplantation versus conventional therapy in patients with cutaneous T-cell lymphomas. After searching for all relevant studies, no studies could be identified.
From the published experience we can therefore only summarize case series and clinical evaluations, precluding the possibility of clearly assessing the possibilities and limitations of this treatment. Nevertheless, alloSCT was shown to induce durable successes with acceptable side effects. Therefore, allogeneic stem cell transplantation should be considered as a promising treatment option for patients with advanced CTCL.
Prospective genetically randomised controlled trials are needed to be initiated to evaluate the precise role of alloSCT in advanced cutaneous T-cell lymphomas.