For patients with both cancer and autoimmune skin diseases, a surprising pattern emerged from one of the largest nationwide studies to date: they tend to live longer.
Patients with autoimmune skin diseases had better survival outcomes following cancer treatment compared with those without such conditions, according to a large-scale nationwide cohort study conducted in Taiwan.
The findings, based on 197,895 cancer patients receiving antineoplastic therapies, highlighted lower rates of both all-cause and cancer-specific mortality among patients with preexisting autoimmune skin diseases (ASDs).
The researchers analyzed data from Taiwan’s National Health Insurance and Cancer Registry databases, focusing on patients who received chemotherapy, targeted therapy, or immunotherapy between January 1, 2019, and June 30, 2021. Of the 197,895 adult patients included, 26,008 had at least one diagnosis of an autoimmune skin disease prior to treatment, such as alopecia areata, psoriasis, vitiligo, cutaneous lupus erythematosus, and Sjögren syndrome.
Researchers found that the incidence of all-cause mortality was 23.10 per 100 person-years in the ASD group compared to 25.99 in the non-ASD group. After applying inverse probability of treatment weighting to account for confounding variables, the hazard ratio for all-cause mortality in patients with ASDs was 0.94 (95% CI, 0.92-0.96). Cancer-specific mortality showed a similar trend, with an incidence rate of 21.23 per 100 person-years in the ASD group versus 24.19 in the non-ASD group. The adjusted subdistribution hazard ratio was 0.94 (95% CI, 0.92-0.96).
Survival benefits were most evident among patients with alopecia areata and Sjögren syndrome. Patients with alopecia areata had an adjusted hazard ratio of 0.83 (95% CI, 0.77-0.90) for all-cause mortality and 0.84 (95% CI, 0.77-0.91) for cancer-specific mortality. Patients with Sjögren syndrome also showed reduced risks for both outcomes.
These associations remained consistent after propensity score matching and in various subgroup analyses stratified by cancer stage, treatment type, and cancer site. For example, the survival advantage associated with ASDs was observed across stage 1 (HR, 0.89; 95% CI, 0.83-0.96) and stage 3 cancers (HR, 0.94; 95% CI, 0.89-0.99), and among those treated with chemotherapy (HR, 0.94; 95% CI, 0.92-0.97) or protein kinase inhibitors (HR, 0.90; 95% CI, 0.86-0.94).
“Our findings provide novel population-based evidence of the potential role of ASDs in more favorable cancer prognosis,” wrote the researchers, led by Li-Ting Kao, PhD, from the School of Pharmacy, National Defense Medical Center, Taipei, Taiwan. “Notably, specific ASD types, such as alopecia areata and Sjögren syndrome, consistently exhibited significant associations with improved survival.”
Researchers conducted multiple sensitivity analyses, including restricting analyses to patients with three or more ASD diagnoses and those diagnosed by dermatologists. Results remained robust. A negative control outcome using burn injury showed no association with ASD, reducing concern over residual confounding.
The researchers noted that while ASDs and cancer are both linked to immune system dysfunction, they appear to diverge in immune activity. ASDs are marked by hyperactive immune responses, whereas cancer often involves immune evasion. The findings suggest that immune mechanisms underlying ASDs may influence cancer outcomes.
Future studies are warranted to better understand how these immunologic factors might be leveraged to improve cancer management and patient care.
Full disclosures can be found in the published study.
Source: JAMA Dermatology
