Patients with treated solid tumors are at an increased risk for malignancy compared with the general population. When treating psoriasis in patients with a history of treated solid tumors, clinicians may be concerned about the immunosuppressive nature of psoriasis therapies and the possibility of promoting cancer recurrence or progression.

Psoriasis is an immune disease. To effectively treat it, we need to suppress immune function. Because one of the things that keeps people from developing cancer is a well-functioning immune system, we do not want to suppress the immune system in someone who has a higher risk of malignancy. And, of course, patients who have had a malignancy in the past have a higher risk of developing it again.

That said, some of the pathways that we are now using to treat psoriasis are very specific to the disease itself. To the best of our current knowledge, the IL-17 and IL-23 pathways do not seem to be related to the body’s ability to fight cancer. However, evidence-based data on the association between systemic treatments for psoriasis and cancer recurrence are somewhat limited because there are so few patients with plaque psoriasis and a history of malignancy.

We have data from the Psoriasis Longitudinal Assessment and Registry, a safety database that has been used to evaluate the rates of malignancy in patients with psoriasis who are taking ustekinumab and other biologic therapies. The registry reported no statistically significant increased risk of malignancy with ustekinumab. However, it did find that patients treated long-term (≥12 months) with a TNF-a inhibitor may have a higher risk of developing malignancy. Additionally, there are some real-world data on patients with psoriasis and a history of treated solid tumors. Researchers from Mount Sinai published a case series of 30 patients treated with an IL-23 inhibitor, approximately one-third of whom had a history of malignancy. The authors did not identify an increased risk of malignancy. Other studies have also suggested a favorable safety profile for biologics in patients with psoriasis in terms of the risk of developing malignancy.

Patient preference also plays a role. I remember a recent patient with an active malignancy whose psoriasis was so severe and whose quality of life was so poor that the potential benefit of psoriasis treatment to improve their symptoms outweighed the possible risk. In a patient like this, we may want to consider starting with something like phototherapy or oral retinoid therapy, and then progress to an IL-23 or IL-17 inhibitor if needed.

Of course, we always want to involve the oncologist in treatment decisions for patients with a history of malignancy. In my experience, most oncologists are aligned with the use of biologics in this population, and they may recommend that we treat these patients as though they never had cancer.

Overall, the agents in our treatment armamentarium have become safer and more effective because of their targeting of the specific pathways related to the pathogenesis of psoriasis. These treatments allow us to treat people who have serious comorbidities, such as a history of cancer, with greater confidence.