Psoriasis and cancer. An Australian/New Zealand narrative

Abstract

Patients with psoriasis have an increased risk of cancer, which may be due to impaired immune surveillance, immune modulatory treatments, chronic inflammation and/or co-risk factors such as obesity. The increase in treatment-independent solid cancers, including urinary/bladder cancers, oropharynx/larynx, liver/gallbladder and colon/rectal cancers, seem to be linked to alcohol and smoking. Lung cancer and nonmelanoma skin cancer are also increased in patients with psoriasis. The risk of nonmelanoma skin cancer increases with age and severity of psoriasis. It is also higher in men, particularly for squamous cell carcinoma, which may reflect previous exposure to PUVA and/or ciclosporin. The risk of cutaneous T-cell lymphoma is substantially higher in patients with moderate-to-severe psoriasis. Biologic therapies are independently associated with a slight increase risk of cancer, but this is less than ciclosporin, with the risk confounded by disease severity and other co-risk factors. The risk of cancer from low-dose methotrexate is likely minimal. In contrast, acitretin is likely protective against a variety of solid and haematological malignancies. The data on small molecule therapies such as apremilast are too immature for comment, although no signal has yet been identified. The decision whether to stop psoriasis immune modulatory treatments following a diagnosis of cancer, and when to resume, needs to be considered in the context of the patients' specific cancer. However, there is no absolute need to stop any treatment other than possibly ciclosporin, unless there is a concern over an increased risk of serious infection or drug-drug interaction with cancer-directed therapies, including radiotherapy.

Beyond skin deep: addressing comorbidities in psoriasis

“…Based on the high level of evidence to date from the dermatology and rheumatology literature, there is little evidence of an association between non‐cutaneous malignancies and systemic immunomodulators for psoriasis . Optimisation of comorbid, well established risk factors, including obesity, smoking and alcohol use, is more impactful on cancer risk reduction than cessation or avoidance of immunosuppressive therapy for psoriasis …”

“… Primary care providers should be cognisant that psoriasis is associated with an increased relative risk of certain cancers. Clinical features suggestive of occult malignancy should be investigated and, if appropriate, referred for further management. People with psoriasis should be ensured to be up‐to‐date with age‐appropriate cancer screening. Patients who have received more than 100 treatments of PUVA, especially if given in combination with cyclosporine, are recommended to have regular skin cancer surveillance Atypical skin lesions that are not responding to psoriatic treatment should be biopsied or referred for consideration of non‐melanoma skin cancer and cutaneous T‐cell lymphoma. …”

Practical recommendations for systemic treatment in psoriasis in case of coexisting inflammatory, neurologic, infectious or malignant disorders (BETA‐PSO: Belgian Evidence‐based Treatment Advice in Psoriasis; part 2)

“…Solid cancer Patients with psoriasis have a slight increase in the relative risk of developing solid organ malignancies, which increases with the severity of psoriasis. 66 Therefore, careful consideration must be given to the systemic treatment of psoriasis patients with a history of a solid cancer.…”

“…remains very low. 66 Therefore, from a safety perspective we recommend that the following conventional systemic drugs, methotrexate, fumarates and acitretin, are used as first-line treatment of psoriasis patients with a history of haematological malignancies. We also advise that apremilast is often a good treatment option for these patients, based on our Green: will be efficacious and cause no specific harm in this patient group; Light green: will likely be efficacious and likely cause no specific harm in this patient group; Orange: might/may be less efficacious or might/may cause harm in this patient group; Red: likely to cause harm in this patient group; Grey: insufficient evidence to make a recommendation.…”

“…77 However, we wish to emphasize that reduction in common risk factors such as sun exposure or phototherapy (in particular PUVA) has a much greater effect on reducing cancer burden in patients with psoriasis than stopping or avoiding systemic immune modulatory agents. 66…”