Seasonal variation in diagnosis of cutaneous invasive melanoma and cutaneous squamous cell carcinoma: A nationwide study in the Netherlands

BACKGROUND

Currently, there is no study that has reported on the seasonal trends of skin cancer in the Netherlands. This study aimed to investigate seasonal variation in diagnosis of cutaneous melanoma (CM) and cutaneous squamous cell carcinoma (cSCC) focusing on different subgroups.

METHODS

CM diagnosed from 2001 till 2019 and cSCCs from 2001 till 2015 were selected from the Netherlands Cancer Registry. The monthly distribution of CM and cSCC diagnoses were evaluated. Summer-to-winter ratios (SWRs) were calculated overall and stratified by patient and tumour characteristics.

RESULTS

Significant increases in melanoma incidence were noted over the summer months (SWR 1.39 (CI 1.37-1.40)). This increase was less apparent for cSCCs, as higher incidence rates were observed in the months September-November (SWR 1.13 (CI 1.12-1.14)). The seasonal variation of CM was greater in women and younger people, in superficial spreading melanoma and lentigo maligna melanoma, for the extremities, in thinner lesions, and for stage I at diagnosis. The seasonal variation of cSCC was similar for both sexes, most marked in patients 45-69 and ≥ 70, and for the extremities.

CONCLUSIONS

Our findings showed a pronounced seasonal variation in the diagnosis of CM with a peak in the summer months. For cSCC, no evident peak was observed, but an increase in diagnosis was noted in fall. Both CM and cSCC showed strong seasonal effects for the extremities.

Provoking factors, including chemicals, in Dutch patients with vitiligo

BACKGROUND

In vitiligo, many provoking factors have been described, but epidemiological data, especially on the role of contact with chemicals, are scarce.

OBJECTIVE

To obtain an insight into the patient-reported factors provoking vitiligo, including contact with chemicals.

METHODS

A retrospective cohort study was conducted on all 1264 patients with vitiligo who visited the Netherlands Institute for Pigment disorders from January 2003 to December 2007. Patients for whom an exogenous provoking factor was recorded were sent a questionnaire. Subsequently, patients who mentioned a chemical provoking factor were contacted to elucidate the alleged causal relationship between exposure to the chemical and the onset of vitiligo.

RESULTS

A total of 300 out of the 1264 patients indicated that provoking factors had played a role in their disease. Two hundred and forty-six patients were sent a questionnaire, which was returned by 177 (response rate of 72%). Emotional stress was indicated as a provoking factor in 98 patients (55.4%), 51 patients (28.8%) recorded sunburn, 34 patients (19.2%) recorded mechanical factors and 20 patients (11.3%) other factors. Of 29 patients (16.4%) who indicated a chemical factor, a presumed causal relationship could be corroborated in four. The chemicals involved were para-tertiary butylphenol (n = 2), captan (n = 1) and diphencyprone (n = 1).

CONCLUSION

The majority of the patients with vitiligo from this study did not mention provoking factors, but the ones who did point to emotional stress in more than half of the cases. Of the 29 patients who assigned chemical provoking factors, solvents were mainly indicated. However, a presumed relationship with the chemical could be corroborated in only four patients.

The prevalence of thyroid disease in patients with vitiligo: a systematic review

BACKGROUND

Thyroid disease has been suggested to be associated with vitiligo. However, the outcomes of prevalence studies on thyroid disease in vitiligo vary widely.

OBJECTIVES

To summarize and critically appraise current evidence of the prevalence of thyroid diseases in vitiligo.

METHODS

A systematic review was performed searching the electronic databases OVID MEDLINE, OVID EMBASE and PubMed. Guidelines for the critical appraisal of studies on prevalence of a health problem were adapted to evaluate the methodological quality of the included studies. Results were analysed in a meta-analysis with a risk ratio (RR).

RESULTS

Forty-eight studies published between 1968 and 2012 met the inclusion criteria. Most of the studies (50%) were of fair methodological quality, whereas 18 studies (38%) were of poor quality and six studies (12%) were of good quality. Thyroid disease, autoimmune thyroid disease and presence of thyroid-specific autoantibodies showed a mean prevalence of, respectively, 15·1%, 14·3% and 20·8% in patients with vitiligo and an RR of, respectively, 1·9, 2·5 and 5·2 (all statistically significant). This review shows an increased prevalence and an increased risk of (autoimmune) thyroid disease in patients with vitiligo compared with nonvitiligo. This risk seems to increase with age.

CONCLUSIONS

Clinicians should be aware of this increased risk in patients with vitiligo and should be attentive for symptoms of thyroid disease. To make recommendations on screening for thyroid disease in patients with vitiligo future research of good methodological quality, including differentiation of vitiligo types and the use of standardized outcome measures, is needed.