Primary bilateral uveal melanoma: a population-based study and systematic review.

IMPORTANCE: Primary bilateral uveal melanoma (UM) is a rare and incompletely described entity. It is not known how these patients compare to those with unilateral UM. BACKGROUND: We sought to comprehensively characterize and compare patients with primary bilateral and unilateral UM. DESIGN: Retrospective, population-based and systematic review. PARTICIPANTS: Patients with bilateral (n = 52) and unilateral UM (n = 8915). METHODS: We analysed cases of primary bilateral UM from three data sources: (i) the University Hospitals Cleveland Medical Center pathology database from 1996 to 2016 (n = 1); (ii) the Surveillance, Epidemiology and End-Results (SEER)-18 database from 1973 to 2013 (n = 5) and (iii) a systematic review of the English language literature (n = 46). Cases of unilateral UM were obtained from the SEER-18 database from 1973 to 2013 for comparison (n = 8915). MAIN OUTCOME MEASURES: Demographics, clinicopathological characteristics, treatments and survival. RESULTS: There were no differences in sex, race, mean age at diagnosis, site of uveal involvement, metastases at diagnosis, or treatment among patients with bilateral as compared to unilateral UM. Additionally, there were no clinicopathological differences between the two UMs in each patient with bilateral disease. Overall survival did not differ between unilateral and bilateral UM patients, or between bilateral UM patients who presented with, or subsequently developed, bilateral disease. CONCLUSIONS AND RELEVANCE: Bilateral and unilateral UM patients share similar demographics, clinicopathological characteristics, treatments and prognoses. Moreover, the development of bilateral disease does not portend a poorer prognosis and patients should be treated similarly to those with unilateral disease.

Genetic vs Environmental Factors That Correlate With Rosacea: A Cohort-Based Survey of Twins.

IMPORTANCE: To our knowledge, this is the first study on rosacea to formally define genetic and environmental contributions. OBJECTIVES: To study a cohort of identical and fraternal twins to determine whether genetic factors contribute to rosacea development and, if genetic factors are present, quantitatively estimate the genetic contribution, as well as to identify environmental factors that correlate with rosacea by controlling for genetic susceptibility. DESIGN, SETTING, AND PARTICIPANTS: Identical and fraternal twins were surveyed regarding risk factors implicated in rosacea. Faculty dermatologists determined a rosacea score for each twin participant according to the National Rosacea Society (NRS) grading system. Data were collected at the annual Twins Days Festival in Twinsburg, Ohio, on August 4-5, 2012, and August 2-3, 2013. Analysis was conducted for several months after each meeting. A cohort of 550 twin individuals, with most from Ohio, Pennsylvania, and the northeastern United States, participated. MAIN OUTCOMES AND MEASURES: The NRS score and rosacea subtype were assessed using the NRS grading system and physical examination by board-certified dermatologists. RESULTS: Among the 275 twin pairs (550 individuals), there were 233 identical twin pairs with a mean rosacea score of 2.46 and 42 fraternal twin pairs with a mean rosacea score of 0.75. We observed a higher association of NRS scores between identical vs fraternal twins (r = 0.69 vs r = 0.46; P = .04), demonstrating a genetic contribution. Using the ACE model (proportion of variance in a trait heritable secondary to additive genetics [A] vs the proportions due to a common environment [C] and unique environment [E]), we calculated this genetic contribution to be 46%. A higher NRS score was also significantly associated with the following factors: age (r = 0.38; P < .001) and lifetime UV radiation exposure (r = 0.26; P < .001). These associations remained after use of propensity score matching to adjust for multicollinearity. Other correlated variables included body mass index (r = 0.21; P < .001), smoking (r = 0.10; P < .02), alcohol consumption (r = 0.11; P = .01), cardiovascular comorbidity (r = 0.17; P < .001), and skin cancer comorbidity (r = 0.19; P < .001). CONCLUSIONS AND RELEVANCE: The study of twins allows us to separate genetic susceptibility and the influence of environmental factors affecting rosacea. We found that approximately half of the contribution to the NRS score could be accounted for by genetics and the other half by environment. We identified correlations between rosacea and UV radiation exposure, alcohol, smoking, skin cancer history, cardiac comorbidity, and age. These findings may help improve current management and expectations of individuals affected by rosacea.