Outcomes and Risk Factors in Patients with Multiple Primary Melanomas

Incidence and Factors Associated With Second Primary Invasive Melanoma in Norway

Importance

Patients diagnosed with a primary melanoma are at high risk of subsequent melanomas. Understanding the risk of second primary invasive melanoma and associated factors is crucial to optimize patient follow-up.

Objective

To assess the incidence rate of second primary invasive melanoma and time between the first and second primary invasive melanoma in the Norwegian population.

Design, Setting, and Participants

This population-based cohort study included data from deidentified records of all invasive melanomas diagnosed in Norway in 2008 to 2020, obtained from the Cancer Registry of Norway. Data were from adults aged 18 years or older diagnosed with a first primary melanoma. Data analysis was performed from March to August 2023.

Main Outcomes and Measures

The main outcome was the incidence rate of second primary invasive melanoma at least 30 days after the first. Accelerated failure time models were fitted to examine potential associations with patient and tumor characteristics. Median time between first and second primary melanomas and 95% CIs were calculated. The likelihood of, and median interval for, second primary melanomas on the same or different site as the first primary were calculated.

Results

A total of 19 196 individuals aged 18 years or older were diagnosed with a first primary melanoma. The mean (SD) age at diagnosis of the first primary melanoma was 62 (16) years (range, 18-104 years), and 9763 (51%) were female. The incidence rate in the year following diagnosis was 16.8 (95% CI, 14.9-18.7) per 1000 person-years, which decreased to 7.3 (95% CI, 6.0-8.6) during the second year and stabilized thereafter. Median time between first and second primaries decreased with advancing age and was 37 months (95% CI, 8-49) in patients younger than 40 years, 18 (95% CI, 13-24) in patients aged 50 to 59 years, and 11 (95% CI, 7-18) in patients aged 80 years or older. The second primary was on the same site as their first primary for 47% (359 patients), and on a different site for 53% (407 patients). The median interval until second melanoma on the same site as the initial melanoma was 12 (95% CI, 7-19) months in men and 22 (95% CI, 11-35) months in women.

Conclusions and Relevance

Older age and male sex were associated with an increased risk, suggesting that increased surveillance intensity may be considered for men, especially those older than 50 years, for at least 3 years after their initial diagnosis, regardless of the characteristics of their first invasive melanoma.

Risk factors for subsequent primary melanoma in patients with previous melanoma: a systematic review and meta-analysis

BACKGROUND

Compared with the general population, people with a previous melanoma are at increased risk of developing another primary melanoma. Understanding the risk factors associated with multiple primary melanomas can inform patient education and tailored surveillance.

OBJECTIVES

To examine the risk factors for subsequent primary melanoma in people with a previous melanoma, by conducting a systematic review and meta-analysis of the available data.

METHODS

A systematic literature search was conducted in CINAHL, Cochrane Central Register of Controlled Trials (CENTRAL), Embase and MEDLINE. Studies that reported a risk estimate or raw frequencies and conducted between 1982 and August 2022 were included. Adjusted risk estimates were prioritized over univariable risk estimates. PRISMA reporting guidelines were followed. Random effects meta-analysis was conducted to derive pooled estimates. Quality assessment was conducted by two researchers using the Newcastle-Ottawa scale. GRADE was used to rate the certainty and quality of the evidence.

RESULTS

Data from 27 studies involving 413 181 participants were pooled and analysed. Risk factors assessed included age and sex, environmental, lifestyle, phenotypic, genetic and histopathological factors, and there was wide variation in how they were categorized and analysed. Independent risk factors identified from pooled analyses included male sex [hazard ratio (HR) 1.46, 95% confidence interval (CI) 1.40-1.53], increasing age per 10 years (HR 1.19, 95% CI 1.14-1.24), light skin colour (HR 1.44, 95% CI 1.23-1.70), family history [odds ratio (OR) 1.79, 95% CI 1.25-2.56], CDKN2A mutation (OR 5.29, 95% CI 2.70-10.37), a high or moderate naevus count [OR 2.63 (95% CI 1.61-4.30) and OR 1.64 (95% CI 1.07-2.51), respectively], one or more atypical naevi (OR 3.01, 95% CI 1.52-5.97), first lesions occurring on the head or neck, lentigo maligna subtype (HR 1.16, 95% CI 1.15-1.17), other subtype (HR 1.14, 95% CI 1.03-1.27) and inadequate sun protection (HR 1.85, 95% CI 0.98-3.50). Based on the GRADE criteria, there was high to very low confidence in the pooled effect estimates.

CONCLUSIONS

This meta-analysis identified several consistent, independent risk factors for the development of subsequent primary melanoma. These findings will help stratify the risk of subsequent melanoma, tailor skin-check schedules and inform patient education.

Gastric and colonic metastases of malignant melanoma diagnosed during endoscopic evaluation of symptomatic anemia presenting as angina: a case report

A 72-year-old man visited cardiology for exertional chest pain, lightheadedness, and fatigue. Six years prior, he was surgically treated for cutaneous malignant melanoma of the lower back. After a negative cardiac work-up, primary care diagnosed severe iron deficiency anemia. Emergent upper and lower gastrointestinal (GI) endoscopy revealed simultaneous melanoma metastases to the stomach and colon with discrete macroscopic features. Metastatic disease, including brain, lung, and bone, was discovered on imaging. Treatment included immunotherapy with nivolumab and stereotactic radiosurgery of the brain metastases, and our patient has remained in continued remission even after 2 years. Melanoma with GI tract (GIT) metastasis has a poor prognosis and rarely presents symptomatically or with synchronous gastric and colonic lesions. This case illustrates the importance of early primary care involvement to expedite work-up for multifocal GI metastases in patients with a remote melanoma history presenting with symptoms related to iron deficiency anemia (IDA).

Potential risk factors, clinicopathological features and determinants of survival for multiple primary melanoma patients compared to single primary melanoma: a large single-center Italian study

Melanoma patients have a high risk of developing subsequent primary melanomas, a condition known as multiple primary melanoma (MPM). We aimed to compare risk factors of patients with MPM and single primary melanoma (SPM). Primary MPM and SPM consecutively treated at the National Cancer Institute in Milan, Italy, from 1978 to 2021 were retrospectively investigated. Demographic and clinicopathological characteristics were analyzed. Multivariate hazard ratios and mortality were estimated using Cox proportional hazards regression models. Overall, 9122 patients with SPM and 944 with MPM were included. A total of 1437 and 85 deaths occurred in SPM and MPM group, respectively. Of these, 1315 (14.4%) within SPM patients and 60 (6.4%) in MPM group were melanoma-specific deaths (MSDs). Males had a higher risk for MPM (hazard ratio = 1.29), while age was not associated with MPM (hazard ratio = 0.98). The risk of MPM decreased by about 50% for Breslow thickness >1 mm, and by about 45 and 75% in presence of mitoses and ulceration, respectively. The multivariate hazard ratio of death for MPM compared to SPM patients was 0.85 (95% confidence interval, CI: 0.67-1.06), while considering MSD the corresponding hazard ratio was 0.93 (95% CI: 0.71-1.22). Melanoma patients should receive regular follow-up with complete skin examination to detect early subsequent primary melanoma. Patients with more advanced primary have decreased risk of MPM, while males have higher risk. Our study reported no significant difference in mortality between SPM and MPM, but the issue is still open for discussion and further studies.

A practical nomogram and risk stratification system predicting the cancer-specific survival for patients aged >50 with advanced melanoma

Objective

To investigate risk factors for advanced melanoma over 50 years of age and to develop and validate a new line chart and classification system.

Methods

The SEER database was screened for patients diagnosed with advanced melanoma from 2010 to 2019 and Cox regression analysis was applied to select variables affecting patient prognosis. The area under curve (AUC), relative operating characteristic curve (ROC), Consistency index (C-index), decision curve analysis (DCA), and survival calibration curves were used to verify the accuracy and utility of the model and to compare it with traditional AJCC tumor staging. The Kaplan-Meier curve was applied to compare the risk stratification between the model and traditional AJCC tumor staging.

Results

A total of 5166 patients were included in the study. Surgery, age, gender, tumor thickness, ulceration, the number of primary melanomas, M stage and N stage were the independent prognostic factors of CSS in patients with advanced melanoma (P<0.05). The predictive nomogram model was constructed and validated. The C-index values obtained from the training and validation cohorts were 0.732 (95%CI: 0.717-0.742) and 0.741 (95%CI: 0.732-0.751). Based on the observation and analysis results of the ROC curve, survival calibration curve, NRI, and IDI, the constructed prognosis model can accurately predict the prognosis of advanced melanoma and performs well in internal verification. The DCA curve verifies the practicability of the model. Compared with the traditional AJCC staging, the risk stratification in the model has a better identification ability for patients in different risk groups.

Conclusion

The nomogram of advanced melanoma and the new classification system were successfully established and verified, which can provide a practical tool for individualized clinical management of patients.

Risk of Mortality After a Diagnosis of Melanoma In Situ

Importance

The incidence of melanoma in situ (MIS) is increasing more rapidly than any invasive or in situ cancer in the US. Although more than half of melanomas diagnosed are MIS, information about long-term prognosis following a diagnosis of MIS remains unknown.

Objective

To evaluate mortality and factors associated with mortality after a diagnosis of MIS.

Design, Setting, and Participants

This population-based cohort study of adults with a diagnosis of first primary MIS from 2000 to 2018 included data from the US Surveillance, Epidemiology, and End Results Program, which were analyzed from July to September 2022.

Main Outcomes and Measures

Mortality after a diagnosis of MIS was evaluated using 15-year melanoma-specific survival, 15-year relative survival (ie, compared with similar individuals without MIS), and standardized mortality ratios (SMRs). Cox regression was used to estimate hazard ratios (HRs) for death by demographic and clinical characteristics.

Results

Among 137 872 patients with a first-and-only MIS, the mean (SD) age at diagnosis was 61.9 (16.5) years (64 027 women [46.4%]; 239 [0.2%] American Indian or Alaska Native, 606 [0.4%] Asian, 344 [0.2%] Black, 3348 [2.4%] Hispanic, and 133 335 [96.7%] White individuals). Mean (range) follow-up was 6.6 (0-18.9) years. The 15-year melanoma-specific survival was 98.4% (95% CI, 98.3%-98.5%), whereas the 15-year relative survival was 112.4% (95% CI, 112.0%-112.8%). The melanoma-specific SMR was 1.89 (95% CI, 1.77-2.02); however, the all-cause SMR was 0.68 (95% CI, 0.67-0.7). Risk of melanoma-specific mortality was higher for older patients (7.4% for those 80 years or older vs 1.4% for those aged 60-69 years; adjusted HR, 8.2; 95% CI, 6.7-10.0) and patients with acral lentiginous histology results (3.3% for acral lentiginous vs 0.9% for superficial spreading; HR, 5.3; 95% CI, 2.3-12.3). Of patients with primary MIS, 6751 (4.3%) experienced a second primary invasive melanoma and 11 628 (7.4%) experienced a second primary MIS. Compared with patients without a subsequent melanoma, the risk of melanoma-specific mortality was increased for those with a second primary invasive melanoma (adjusted HR, 4.1; 95% CI, 3.6-4.6) and was decreased for those with a second primary MIS (adjusted HR, 0.7; 95% CI, 0.6-0.9).

Conclusions and relevance

The results of this cohort study suggest that patients with a diagnosis of MIS have an increased but low risk of melanoma-specific mortality and live longer than people in the general population, suggesting that there is significant detection of low-risk disease among health-seeking individuals. Factors associated with death following MIS include older age (≥80 years) and subsequent primary invasive melanoma.

Association of multiple primary melanomas with malignancy risk: A population-based analysis of entries from the Surveillance, Epidemiology, and End Results program database during 1973-2014

BACKGROUND

Genetic and environmental risk factors have been associated with the development of multiple primary melanomas (MPMs). We hypothesized that individuals with MPMs might have an increased incidence of internal malignancies.

OBJECTIVE

To identify the risk for subsequent malignancies in MPM patients.

METHODS

Multiple primary standardized incidence ratios were analyzed for individuals with ≥1, ≥2 and ≥3 primary melanomas (PMs) recorded in the Surveillance, Epidemiology, and End Results database during 1973-2014.

RESULTS

We identified 223,799 individuals with ≥1 PM, 19,709 with ≥2 PMs, and 3,995 with ≥3 PMs. Risks of subsequent internal malignancy increased with number of PMs, with observed:expected ratios of 0.99, 1.14, and 1.23 (P < .05) for patients with ≥1 PM, ≥2 PMs, and ≥3 PMs, respectively. Internal malignancy was higher in younger MPM patients and those with superficial spreading melanoma. The most common malignancies among MPM patients included breast, prostate, thyroid, soft tissue, brain, kidney, non-Hodgkin lymphoma, and chronic lymphocytic leukemia. Risk for subsequent cutaneous melanoma increased with observed:expected ratios of 8.09, 22.52, 41.03 (P < .05) for patients with ≥1 PM, ≥2 PMs, and ≥3 PMs, respectively.

LIMITATIONS

Surveillance, Epidemiology, and End Results records limited information about pigmentation phenotypes, histology, and treatments.

CONCLUSION

Patients with MPMs have an increased risk for subsequent internal and cutaneous malignancies and might benefit from tight adherence to age-specific cancer screening.

Synchronous gastric cancer complicated with chronic myeloid leukemia (multiple primary cancers): A case report

BACKGROUND

With the advancement of medical technology and improvement in living standards, the incidence of multiple primary cancers has gradually increased. In particular, tumors of the digestive system account for a large proportion of multiple primary cancers. The diagnosis and treatment of chronic myeloid leukemia, particularly with synchronous gastric cancer, at the first consultation is relatively rare.

CASE SUMMARY

Herein, we present the case of a middle-aged man who was referred to the Department of Hematology owing to an elevated white blood cell count. After the examination, he was diagnosed with chronic myeloid leukemia and was administered imatinib. Three months after the initial diagnosis, he visited our hospital again for abdominal pain, and further examination revealed gastric malignancy. After discussion with a multidisciplinary team, S-1 (Tegafur, Gimeracil, and Oteracil Potassium Capsules) combined with oxaliplatin—SOX regimen—was initiated. Later, the patient’s condition rapidly progressed. He developed colonic obstruction and underwent an ostomy; however, he died less than 6 months after the initial diagnosis.

CONCLUSION

Multiple primary cancers are influenced by environmental and genetic factors; a standardized multidisciplinary discussion plays a key role in treatment.

Comparison of phenotypic features in patients with single vs multiple primary cutaneous melanomas: a prospective single-center study

BACKGROUND

There is sparse data regarding total body nevus count (TBNC), nevus count in specific locations, phenotypic factors, anthropometric indices, sunburn, and the relation to multiple primary cutaneous melanomas (MPCM) development. We aim to compare these variables in a cohort of patients diagnosed with single primary melanoma (SPM) and MPCM with histologic diagnoses of melanoma in situ, superficial spreading, and nodular melanoma in our clinic.

METHODS

Prospective observational studies for the evaluation of nevus counts in biopsy-proven melanoma patients from 2017 to 2020 at Ankara University were conducted. Age, gender, family history of melanoma, increased sun exposure, nonmelanoma skin cancers (NMSC), height, sunburn history, TBNC, and nevi count in specific anatomical locations were evaluated by multivariate logistic regression analysis.

RESULTS

A total number of 156 patients consisting of 22 MPCM and 134 SPM were included. Mean TBNC for SPM vs MPCM patients were 96.87 (SD ± 124.71) vs 247.00 (SD ± 261.58), respectively (P < 0.0001). TBNC was correlated to the left arm, trunk, lower extremity, and head and neck nevus counts but not with the right arm nevus count. Multiple regression analysis showed that having more than 10 nevi on the head and neck area is associated with MPCM (OR, 3.882 [95% CI, 1.084-13.899]). TBNC and nevus count in specific locations were found to be significantly higher in MPCM.

CONCLUSION

The risk of MPCM was associated with having ≥10 nevi on the head and neck.

Synchronous and metachronous malignant melanomas arising in a human immunodeficiency virus-positive patient after the commencement of highly active antiretroviral therapy treatment: a case report

BACKGROUND

We present an unusual case of a patient who developed four melanomas within a few months of diagnosis with human immunodeficiency virus and commencement of highly active antiretroviral therapy therapy. The patient had no previous history of melanoma, and previous skin checks were normal.

CASE PRESENTATION

A 50-year-old Caucasian male drainlayer with Fitzpatrick type 2 skin presented for a routine skin examination. He had been diagnosed with human immunodeficiency virus 4 months earlier and commenced on highly active antiretroviral therapy therapy. He was found to have three melanomas (melanoma in situ stage) on excision biopsies, and when he presented for wider excisions of these sites a few weeks later, another new melanoma in situ was found. He had no other medical history of note, and no symptoms to report. He is being followed up 3-monthly.

CONCLUSIONS

This case of a human immunodeficiency virus-positive person presenting with four cutaneous melanomas-occurring in both synchronous and metachronous fashion within a 4-month period-is being presented both for its uniqueness and also to highlight the increased need for close skin surveillance in human immunodeficiency virus-positive patients.

A Novel Nomogram and Risk Classification System Predicting the Cancer-Specific Mortality of Patients with Initially Diagnosed Metastatic Cutaneous Melanoma

BACKGROUND

Cutaneous melanoma and distant organ metastasis has varying outcomes. Considering all prognostic indicators in a prediction model might assist in selecting cases who could benefit from a personalized therapy strategy.

OBJECTIVE

This study aimed to develop and validate a prognostic model for patients with metastatic melanoma.

METHODS

A total of 1535 cases diagnosed with metastatic cutaneous melanoma (stage IV) were identified from the Surveillance, Epidemiology, and End Results database. Patients were randomly divided into the training (n = 1023) and validation (n = 512) cohorts. A prognostic nomogram was established based predominantly on results from the competing-risk regression model for predicting cancer-specific death (CSD). The area under the time-dependent receiver operating characteristic curve (AUC), calibration curves, and decision curve analyses (DCAs) were used to evaluate the nomogram.

RESULTS

No significant differences were observed in the clinical characteristics between the training and validation cohorts. In the training cohort, patient-, tumor-, and treatment-related predictors of CSD for metastatic melanoma included age, sex, race, marital status, insurance, American Joint Committee on Cancer T and N stage, number of metastatic organs, surgical treatment, and chemotherapy. All these factors were used for nomogram construction. The time-dependent AUC values of the training and validation cohorts suggested a favorable performance and discrimination of the nomogram. The 6-, 12-, and 18-month AUC values were 0.706, 0.700, and 0.706 in the training cohort, and 0.702, 0.670, and 0.656 in the validation cohort, respectively. The calibration curves for the probability of death at 6, 12, and 18 months showed acceptable agreement between the values predicted by the nomogram and the observed outcomes in both cohorts. DCA curves showed good positive net benefits in the prognostic model among most of the threshold probabilities at different time points (death at 6, 12, and 18 months). Based on the total nomogram scores of each case, all patients were divided into the low-risk (n = 511), intermediate-risk (n = 512), and high-risk (n = 512) groups, and the risk classification could identify cases with a high risk of death in both cohorts.

CONCLUSIONS

A predictive nomogram and a corresponding risk classification system for CSD in patients with metastatic melanoma were developed in this study, which may assist in patient counseling and in guiding clinical decision making for cases with metastatic melanoma.

A risk prediction model for the development of subsequent primary melanoma in a population-based cohort

BACKGROUND

Guidelines for follow-up of patients with melanoma are based on limited evidence.

OBJECTIVES

To guide skin surveillance, we developed a risk prediction model for subsequent primary melanomas, using demographic, phenotypical, histopathological, sun exposure and genomic risk factors.

METHODS

Using Cox regression frailty models, we analysed data for 2613 primary melanomas from 1266 patients recruited to the population-based Genes, Environment and Melanoma study in New South Wales, Australia, with a median of 14 years' follow-up via the cancer registry. Discrimination and calibration were assessed.

RESULTS

The median time to diagnosis of a subsequent primary melanoma decreased with each new primary melanoma. The final model included 12 risk factors. Harrell's C-statistic was 0·73 [95% confidence interval (CI) 0·68-0·77], 0·65 (95% CI 0·62-0·68) and 0·65 (95% CI 0·61-0·69) for predicting second, third and fourth primary melanomas, respectively. The risk of a subsequent primary melanoma was 4·75 times higher (95% CI 3·87-5·82) for the highest vs. the lowest quintile of the risk score. The mean absolute risk of a subsequent primary melanoma within 5 years was 8·0 ± SD 4.1% after the first primary melanoma, and 46·8 ± 15·0% after the second, but varied substantially by risk score.

CONCLUSIONS

The risk of developing a subsequent primary melanoma varies considerably between individuals and is particularly high for those with two or more primary melanomas. The risk prediction model and its associated nomograms enable estimation of the absolute risk of subsequent primary melanoma, on the basis of on an individual's risk factors, and can be used to tailor surveillance intensity, communicate risk and provide patient education. What's already known about this topic? Current guidelines for the frequency and length of follow-up to detect new primary melanomas in patients with one or more previous primary melanomas are based on limited evidence. People with one or more primary melanomas have, on average, a higher risk of developing another primary invasive melanoma, compared with the general population, but an accurate way of estimating individual risk is needed. What does this study add? We provide a comprehensive risk prediction model for subsequent primary melanomas, using data from 1266 participants with melanoma (2613 primary melanomas), over a median 14 years' follow-up. The model includes 12 risk factors comprising demographic, phenotypical, histopathological and genomic factors, and sun exposure. It enables estimation of the absolute risk of subsequent primary melanomas, and can be used to tailor surveillance intensity, communicate individual risk and provide patient education.

High-Throughput Sequencing Identifies 3 Novel Susceptibility Genes for Hereditary Melanoma

Cutaneous melanoma is one of the most aggressive human cancers due to its high invasiveness. Germline mutations in high-risk melanoma susceptibility genes have been associated with development hereditary melanoma; however, most genetic culprits remain elusive. To unravel novel susceptibility genes for hereditary melanoma, we performed whole exome sequencing (WES) on eight patients with multiple primary melanomas, high number of nevi, and negative for high and intermediate-risk germline mutations. Thirteen new potentially pathogenic variants were identified after bioinformatics analysis and validation. CDH23, ARHGEF40, and BRD9 were identified as the most promising susceptibility genes in hereditary melanoma. In silico analysis of CDH23 and ARHGEF40 variants provided clues for altered protein structure and function associated with the identified mutations. Then, we also evaluated the clinical value of CDH23, ARHGEF40, and BRD9 expression in sporadic melanoma by using the TCGA dataset (n = 461). No differences were observed in BRD9 expression between melanoma and normal skin samples, nor with melanoma stage, whereas ARHGEF40 was found overexpressed, and CDH23 was downregulated and its loss was associated with worse survival. Altogether, these results reveal three novel genes with clinical relevance in hereditary and sporadic melanoma.

The interplay of sun damage and genetic risk in Australian multiple and single primary melanoma cases and controls

BACKGROUND

Skin phenotype, host genotype and ultraviolet (UV) damage play a role in the development of melanoma.

OBJECTIVES

To ascertain whether the level of UV damage at the site of melanomas was associated with genetic polymorphisms.

METHODS

Deep phenotyping was performed on 1244 individuals; 281 with multiple primary melanomas (MPMs), 304 with single primary melanoma (SPM) and 659 convenience controls. Genotype data was generated using the Illumina CoreExome microarray platform, assaying over 500 000 single-nucleotide polymorphisms. A subset of variants were combined to assess a polygenic risk score (PRS) for melanoma.

RESULTS

Most MPM cases were diagnosed in patients aged > 40 years, in sites with visible chronic UV damage. Women and those diagnosed at age ≤ 40 years were less likely to have perilesional UV damage. Patients with MPM had higher frequencies of MITF E318K, MC1R R-alleles and the ASIP risk haplotype. Individuals who had melanoma in a visibly UV-damaged site were more likely to carry MC1R rs75570604 [odds ratio (OR) 2·5], 9q31.2 rs10816595 (OR 1·4) and MTAP rs869329 (OR 1·4). These same alleles were more common in patients with MPM who were diagnosed at age ≤ 40 years. The mean PRS was significantly higher in MPM than in SPM and controls. Naevus count was comparable in early-onset MPM cases and those diagnosed at age > 40 years.

CONCLUSIONS

Our cohort demonstrated higher frequencies of previously reported alleles associated with melanoma. MPM melanomas more commonly occur in UV-damaged areas, and these individuals are more likely to carry MC1R red hair colour alleles. Awareness of the interplay of genetic vulnerability with UV damage can stratify risk and guide recommendations for melanoma screening. What's already known about this topic? Skin phenotype, host genotype and ultraviolet (UV) damage all play a role in melanoma development. One of the main risk factors is a personal history of melanoma; second and subsequent primary melanomas account for over 20% of all melanomas registered in Queensland. Multiple loci are associated with melanoma risk, including many low-penetrance loci, which may have a cumulatively significant risk. Population-wide screening programmes for melanoma are not yet economically viable. What does this study add? Patients diagnosed with melanoma at age ≤ 40 years were more likely than older patients to have melanomas in non-UV-damaged sites. Patients with multiple melanomas had higher frequencies of MITF E318K, MC1R R-alleles, and the ASIP extended risk haplotype than patients with single melanoma. CDKN2A, MC1R and MTAP variants were more frequent in patients who developed melanomas at a younger age, but also in those whose melanomas were all on visibly UV-damaged sites. What is the translational message? Incorporating these genetic findings into the known risk factors of skin phenotype and visible UV damage may allow for a more customized and economically feasible approach to early detection of melanoma, particularly in younger patients. Plain language summary available online.