Title: Bidirectional Association Between Parkinson's Disease and Skin Cancer: A Systematic Review and Meta-Analysis
Authors: Jamir Pitton Rissardo, Ana Leticia Fornari Caprara, and Ian M. Walker
Conference: 2026 MDS-PAS, Houston, TX
Objective
To quantify the bidirectional association between Parkinson’s disease (PD) and skin cancers, including melanoma and non-melanoma skin cancer (NMSC), and to explore subgroup differences.
Background
Observational studies suggest a link between PD and melanoma, but the magnitude, directionality, and influence of subgroups remain unclear.
Design/Methods
We systematically reviewed PubMed-indexed observational studies reporting melanoma or NMSC occurrence in PD patients or vice versa. Pooled effect sizes were calculated using fixed- and random-effects models, and heterogeneity was assessed with τ² and I². Most included studies were case-control designs, and results are summarized as risk ratios (RR).
Results
Thirty-one studies were included. For melanoma preceding PD, the random-effect estimate was 1.34 (95% CI, 1.02–1.78). For PD preceding melanoma, the random-effect estimate was 1.45 (0.98–2.13). For NMSC preceding PD, the estimate was 0.9 (0.71–1.14). When analyzed by cancer type, melanoma overall (22 studies) showed a random-effects estimate of 1.48 (1.15–1.91). NMSC overall (10 studies) showed a fixed-effect estimate of 1.15 (0.73–1.81). Gender-specific estimates from single studies were as follows: melanoma in males 2.75 (0.25–30.10), melanoma in females 0.69 (0.06–7.52), NMSC in males 0.93 (0.59–1.46), and NMSC in females 1.18 (0.56–2.47).
Conclusions
PD and melanoma demonstrate a consistent bidirectional association with low heterogeneity. Evidence for NMSC and gender-specific effects is limited and inconclusive.
Citation
Rissardo JP, Caprara ALF, Walker I. Bidirectional Association Between Parkinson's Disease and Skin Cancer: A Systematic Review and Meta-Analysis. Mov Disord Clin Pract 2026;13(S1):S68. doi: 10.1002/mdc3.7047.
Figure 1. Scatterplot of standardized treatment effects against inverse standard error, with regression line illustrating the relationship between study precision and effect magnitude.
Figure 2. L’Abbé plot showing experimental versus control event rates with study‑size weighting and fitted treatment‑effect trend lines
Figure 3. Contour‑enhanced funnel plot illustrating study effect sizes, confidence regions, and fixed‑ and random‑effects model estimates.