GRELL – SYRACUSE – MAY 2013
SEASONAL VARIATION OF CUTANEOUS MALIGNANT MELANOMA INCIDENCE AND SURVIVAL: ANALYSES FROM THE BELGIAN CANCER REGISTRY (2004-2009) Isabelle Savoye ; David Jegou ; Marina Kvaskoff ; 1 2 Yves Coppieters ; Julie Francart 1,2
2
3,4
1 École de Santé Publique (ESP) de l’Université libre de Bruxelles (ULB), Belgique 2 Fondation Registre du Cancer (Belgian Cancer Registry), Bruxelles, Belgique 3 Inserm U1018, Centre de recherche en Épidémiologie et Santé des Populations (CESP), Équipe 9 : “Nutrition, Hormones et Santé de la Femme”, Institut Gustave Roussy, F-94805, Villejuif, France 4 Université Paris Sud 11, UMRS 1018, F-94807, Villejuif, France
INTRODUCTION
RESULTS
Over the past decades, the incidence of cutaneous malignant melanoma has risen more than that of any other cancer in whiteskinned populations. The seasonal variation in melanoma incidence, with a peak in summer, is an important and well documented phenomenon, albeit still poorly understood.
Over the period 2004-2009, a total of 9782 cases were available for study. Among these cases most were female (61%), the lesion occurred on the lower limbs (29%) and trunk (27%), and were of the superficial spreading melanoma (SSM) type (45%). The Breslow thickness was mainly lower than 1 mm (43%). A peak of number of melanoma cases was observed in June (RJune/January=1.64 ; 95% CI=1.54-1.73) (Fig. 1).
OBJECTIVES
STUDY POPULATION AND METHODS All cases of cutaneous malignant melanoma over 15 years of age registered by the Belgian Cancer Registry between 2004 and 2009. Monthly variations were estimated using the ratio (R) of the number of cases diagnosed each month to that diagnosed in January (Nam’s method). The characteristics of cases diagnosed during the peak were compared to those diagnosed during the other months of the year using the Pearson’s chi-squared test. Overall and relative 5-year survival rates were estimated using Cox proportional hazards regression models, and generalized linear models with a Poisson error structure, respectively, adjusted for patient and tumour characteristics (age, sex, number of primary cancers, histological type, anatomical site, Breslow thickness, ulceration, presence of nodes and metastases). To take into account missing values in statistical models, an extra-category was added for categorical data. Sensitivity analyses were performed using multiple imputation techniques.
CONTACT AUTHOR David Jegou
[email protected]
Figure 2. Adjusted Hazard ratios (95% CI) for patient and tumour characteristics of melanoma by month of diagnosis in Belgium (2004-2009). January is the reference category (the dashed line).
RMonth/January (95% CI) 1.00
1.05
1.10
1.17
1.38
1.64
1.21
1.25
1.27
1.26
1.08
1.02
(ref)
(0.99-1.11)
(1.04-1.16)
(1.11-1.24)
(1.30-1.45)
(1.54-1.73)
(1.24-1.39)
(1.18-1.32)
(1.20-1.34)
(1.20-1.34)
(1.02-1.14)
(0.97-1.08)
Figure 1. Monthly number of melanoma cases in Belgium (20042009) and monthly variation ratios (RMonth/January(95% CI))
SSMs were more likely to be diagnosed in June as compared to the other months (51% vs 44% ; p
