RA, Lupus, Systemic Sclerosis Linked to Higher Squamous Cell Carcinoma Risk

A retrospective analysis of the National Inpatient Sample (NIS) found that adults with rheumatoid arthritis, systemic lupus erythematosus, and systemic sclerosis carried higher odds of cutaneous squamous cell carcinoma than matched counterparts without autoimmune disease — while showing no corresponding elevation in melanoma or basal cell carcinoma risk. Drs. Sami Rabah and Xiangyi Kang of Lincoln Medical Center, New York, presented the findings at the American College of Rheumatology (ACR) Convergence 2026 in Orlando, FL.

The study population was concrete: hospitalized patients aged 18 and older, drawn from NIS records covering admissions between 2016 and 2019. The design is retrospective, so the investigators worked from billing-coded inpatient data rather than prospective follow-up — a caveat worth holding in mind, but one that doesn't blunt the practical signal for dermatology clinics.

The pattern splits cleanly by tumor type. Three autoimmune diseases — rheumatoid arthritis, SLE, and systemic sclerosis — tracked with increased odds of cutaneous squamous cell carcinoma, the second most common skin cancer and the one dermatologists already watch most closely in immunosuppressed patients. Basal cell carcinoma did not show the same association in these cohorts. Neither did melanoma.

Then there's the outlier. Patients with dermatomyositis had significantly increased odds of melanoma in this dataset, yet their odds of both cutaneous squamous cell carcinoma and basal cell carcinoma did not reach statistical significance. That's an inversion of the pattern seen in the other three conditions, and it echoes a known clinical instinct: dermatomyositis has long carried a malignancy-workup association in internal medicine. Here the signal lands on melanoma specifically.

Did the numbers survive adjustment?

Yes. The associations held after the researchers adjusted for confounders including:

• Age and sex
• Race
• Smoking status
• History of immunosuppression
• Organ transplantation
• HIV infection
• Presence of the specific autoimmune diseases under study

That adjustment set matters. Immunosuppression and transplant history are the classic drivers of squamous cell carcinoma risk, and the fact that the autoimmune associations persisted after controlling for them suggests the inflammatory diseases themselves — or their treatment trajectories — carry independent weight.

What does this change for dermatologists?

For a specialty that already fields referrals on rheumatology patients on methotrexate, biologics, and JAK inhibitors, the study sharpens the case for structured surveillance rather than ad hoc checks. The investigators put it plainly: "These results highlight the need for regular dermatologic screenings for individuals with autoimmune diseases," Drs. Rabah and Kang conclude.

In practice, that argues for total-body skin exams at defined intervals for RA, lupus, and systemic sclerosis patients — with squamous cell carcinoma as the index lesion to watch — and a lower threshold for melanoma surveillance in dermatomyositis, where the melanoma signal was the strongest finding. The tumor-type split also helps triage education: counseling these patients on actinic keratosis awareness and photoprotection has a clearer evidence hook than generic "skin cancer" warnings.

The retrospective, inpatient-based design means the work raises hypotheses as much as it settles them. Whether the elevated squamous cell carcinoma odds reflect disease-related immune dysregulation, cumulative immunosuppressive therapy, or surveillance bias — autoimmune patients simply see doctors more often — will need prospective cohorts to untangle. Still, with data spanning 2016–2019 national admissions and adjustments covering the major known confounders, the screening recommendation is one dermatology can act on now.