Marcia Davis

Anatomic Site, Sun Exposure, and Risk of Cutaneous Melanoma

PURPOSE Sunlight is the principal environmental risk factor for cutaneous melanoma. A current hypothesis postulates that the role of sunlight in causing melanoma differs according to anatomic site. We tested this hypothesis in a population-based case-case comparative study of melanoma patients. METHODS Patients were sampled from the Queensland cancer registry in three groups: superficial spreading or nodular melanomas of the trunk (n = 154), of the head and neck (HN; n = 76), and lentigo maligna (LM) and lentigo maligna melanoma (LMM; for both LM and LMM, n = 76). Data were collected on school-age sun exposure and occupational and recreational sun exposure in adulthood. Odds ratios (OR) and 95% CIs were calculated using polytomous logistic regression. RESULTS HN melanoma patients were substantially more likely than trunk patients to have higher levels of sun exposure in adulthood (OR, 2.43; 95% CI, 0.98 to 5.99) and specifically, higher levels of occupational exposure (OR, 3.25; 95% CI, 1.32 to 8.00), but lower levels of recreational sun exposure (OR, 0.50; 95% CI, 0.21 to 1.19). LM and LMM patients reported higher occupational exposure and lower recreational sun exposure than trunk melanoma patients, although this was not significant. We found no significant differences between the groups for school-age sun exposures. CONCLUSION Melanomas developing at different body sites are associated with distinct patterns of sun exposure. Melanomas of the head and neck are associated with chronic patterns of sun exposure whereas trunk melanomas are associated with intermittent patterns of sun exposure, supporting the hypothesis that melanomas may arise through divergent causal pathways.

Prevalence and Risk Factors for Oral HPV Infection in Young Australians

The prevalence of human papillomavirus (HPV)–associated head and neck cancers is increasing, but the prevalence of oral HPV infection in the wider community remains unknown. We sought to determine the prevalence of, and identify risk factors for, oral HPV infection in a sample of young, healthy Australians. For this study, we recruited 307 Australian university students (18–35 years). Participants reported anonymously about basic characteristics, sexual behaviour, and alcohol, tobacco and illicit drugs use. We collected oral rinse samples from all participants for HPV testing and typing. Seven of 307 (2.3%) students tested positive for oral HPV infection (3 HPV-18, one each of HPV-16, -67, -69, -90), and six of them were males (p = 0.008). Compared to HPV negative students, those with oral HPV infection were more likely to have received oral sex from more partners in their lifetime (p = 0.0004) and in the last year (p = 0.008). We found no statistically significant associations with alcohol consumption, smoking or numbers of partners for passionate kissing or sexual intercourse. In conclusion, oral HPV infection was associated with male gender and receiving oral sex in our sample of young Australians.

Site-Specific Determinants of Cutaneous Melanoma: A Case–Case Comparison of Patients with Tumors Arising on the Head or Trunk

Background: Cutaneous melanomas have been hypothesized to arise through different pathways according to phenotype, body site, and sun exposure. To further test this hypothesis, we explored associations between phenotype and melanoma at different sites using a case–case comparative approach. Methods: Melanoma patients (n = 762) aged 18 to 79 years and diagnosed from 2007 to 2010 were ascertained from pathology laboratories in Brisbane, Australia. Patients reported phenotypic information and a dermatologist counted melanocytic nevi and solar keratoses. We compared data for patients with trunk melanoma (n = 541, the reference group), head/neck melanoma (n = 122), or lentigo maligna melanoma (LMM) of the head/neck (n = 69). ORs and 95% confidence intervals were calculated using classical or polytomous logistic regression models. Results: Compared with trunk melanoma patients, those with head/neck melanoma were significantly less likely to have high nevus counts (≥135: OR = 0.27; Ptrend = 0.0004). Associations between category of nevus count and LMM head/neck were weaker and significantly different (≥135: OR = 1.09; Ptrend = 0.69; Phomogeneity = 0.02). Patients with head/neck melanoma were more likely than those with truncal melanoma to have high solar keratosis counts (≥7: OR = 1.78, Ptrend = 0.04). Again, associations with LMM head/neck were weaker, albeit not significantly different (≥7: OR = 1.61; Ptrend = 0.42; Phomogeneity = 0.86). Conclusion: Trunk melanomas are more strongly associated with nevus counts than head/neck melanomas, but are less strongly associated with number of solar keratoses, a marker of chronic sun exposure. Impact: These findings underscore the notion that melanomas on the trunk typically arise through a causal pathway associated with nevus propensity, whereas melanomas on the head/neck arise through a pathway associated with cumulative sun exposure. Cancer Epidemiol Biomarkers Prev; 22(12); 2222–31. ©2013 AACR.

Solar elastosis and cutaneous melanoma: A site-specific analysis

Cutaneous melanomas are postulated to arise through at least two causal pathways, namely the “chronic sun exposure” and “nevus” pathways. While chronic sun exposure probably causes many head/neck melanomas, its role at other sites is unclear. In a population‐based, case‐case comparison study conducted in Brisbane, Australia, we determined the prevalence and epidemiologic correlates of chronic solar damage in skin adjacent to invasive, incident melanomas on the trunk (n = 418) or head/neck (n = 92) among patients aged 18–79 in 2007–2010. Participants self‐reported information about environmental and phenotypic factors, and a dermatologist counted nevi and actinic keratoses. Dermatopathologists assessed solar elastosis adjacent to each melanoma using a four‐point scale (nil, mild, moderate, marked), and noted the presence or absence of adjacent neval remnants. We measured associations between various factors and solar elastosis using polytomous logistic regression. Marked or moderate solar elastosis was observed in 10% and 27%, respectively, of trunk melanomas, and 60% and 17%, respectively, of head/neck melanomas. At both sites, marked elastosis was positively associated with age (ptrend < 0.0001) and inversely associated with neval remnants (ptrend < 0.001). For trunk melanomas, marked elastosis was associated with highest quartiles of total sun exposure [odds‐ratio (OR) = 5.47, 95% confidence interval (CI) = 1.08–27.60] and facial freckling (OR = 2.98, 95% CI = 1.17–7.56), and inversely associated with deeply tanning skin (OR = 0.29, 95% CI = 0.08–1.11) and high nevus counts (OR = 0.08, 95% CI = 0.01–0.66). Mostly similar associations were observed with moderate solar elastosis. About one in three trunk melanomas in Queensland have evidence of moderate‐to‐marked sun damage, and they differ in risk associations from those without.

Sun Protection Behavior in Organ Transplant Recipients in Queensland, Australia.

Background: Organ transplant recipients (OTRs) have a high risk of skin cancer, and excessive sun exposure is a major contributing factor. Objective: To document the prevalence of sun protection and associated factors in OTRs in Queensland, Australia. Methods: Cross-sectional study of the frequency of wearing hats, long sleeves and using sunscreens among OTRs and factors associated with regular use. Adjusted prevalence ratios (PRs) and 95% confidence intervals (CIs) were estimated using Poisson regression models. Results: Among 446 OTRs, 66, 49 and 39% wore a hat, sunscreen and long sleeves, respectively, mostly when outdoors. 52% regularly practiced multiple sun protection measures while 19% did not. Sunburn-prone skin (PR = 1.43, 95% CI = 1.06-1.93) and frequent whole-body skin examinations (PR = 1.48, 95% CI = 1.19-1.84) were independently associated with regular use of multiple sun protection measures. Conclusion: Findings are consistent with sun-conscious OTRs also having more regular skin screening and that having frequent skin examinations promotes sun-protective habits.