Standard Methodology Needed to Evaluate Pruritus in Cutaneous T Cell Lymphoma
Though the majority of patients with cutaneous T cell lymphomas experience pruritus, the pathophysiology of the symptom is relatively unclear.
Cutaneous T cell lymphoma (CTCL) is a group of lymphoproliferative disorders characterized by the localization of neoplastic T lymphocytes to the skin and is the most common type of cutaneous lymphoma. It is relatively rare and comprises less than 4% of non-Hodgkin lymphoma cases diagnosed in the United States, with mycosis fungoides (MF) and its leukemic variant Sézary syndrome being the most common forms of the disease.
CTCL generally presents with red, scaly patches or plaques on the skin that mimic any number of benign conditions including eczema, psoriasis, fungal infections, or other chronic dermatitises, which can lead to a delay in diagnosis. While treatable, CTCL remains incurable with currently available therapeutics, and therapy relies on achieving and maintaining remission, controlling symptoms, limiting toxicities, and maintaining or improving quality of life.
Pruritus (severe itching) is experienced by the majority of CTCL patients and can be distressing and debilitating. It is frequently the ﬁrst symptom that manifests and can negatively affect quality of life (QOL), as pruritus often interferes with sleeping patterns and daily activities. Patients who experience prolonged symptoms may eventually require treatment for depression and insomnia.
Pruritus is experienced at all stages of CTCL, although disease progression is usually associated with an increase in both incidence and severity of symptoms. However, studies evaluating the pathophysiology of pruritus are limited and, because of this, treatment has primarily relied on therapies that target and treat the lymphoma. In addition, because the pathophysiology remains unclear, a standardized approach or a stepwise treatment algorithm has not been developed for treating pruritus in patients with CTCL.
“There are no guidelines available for treating pruritus,” commented Brian Poligone, MD, PhD, director of the Rochester Skin Lymphoma Medical Group, PLLC, in New York. “There is a more standardized approach that typically uses a treatment ladder, and this uses common therapies first and then less common therapies if patients [do not respond to] the more common ones.”
A review article published in Dermatologic Therapy provided an overview of both approved and investigational systemic CTCL treatments that have reported activity against pruritus. The authors, led by Henry K Wong, MD, of the University of Arkansas in Little Rock, noted that guidelines from the National Comprehensive Cancer Network (NCCN) recommend several different types of topical and systemic antipruritic treatments, but because the pruritus is caused by the underlying lymphoma, controlling the disease itself may be an effective way to manage the symptoms.
By way of topical treatments, phototherapies (psoralen and ultraviolet A [PUVA] and ultraviolet B [UVB]) have induced remissions in patients with early-stage disease, but limited data are available about their ability to reduce pruritus. In some case studies, PUVA did appear to improve pruritus in patients with Sézary syndrome. Narrowband UVB has also been used to treat pruritus, but data are scant in the setting of CTCL-related itching. Other topical treatments with antilymphoma activity, including carmustine, retinoids, and mechlorethamine, have induced objective responses in early stage MF, but associated skin-related adverse events can exacerbate pruritus rather than mitigate it. However, the authors pointed to a case series of 11 patients with CTCL whose pruritus was completely resolved after being treated with topical mechlorethamine.
Systemic treatments have also demonstrated antipruritic effects, but methods of assessing pruritus and reporting the data vary across studies. The lack of standardized methodology had previously made comparing systemic therapies difficult. In this paper, the authors reviewed both the design of and the methods used by several studies to measure and report pruritus to allow for better evaluation of treatments.