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Seasonal variation in diagnosis of invasive cutaneous melanoma
Cancer Epidemiology 40 (2016) 196–197
Contents lists available at ScienceDirect
Cancer Epidemiology The International Journal of Cancer Epidemiology, Detection, and Prevention journal homepage: www.cancerepidemiology.net
Letter to the Editor Seasonal variation in diagnosis of invasive cutaneous melanoma Keywords: Skin cancer Melanoma Seasonal variation Ultraviolet radiation
Walter et al. reported results of a large registry-based study addressing seasonal variation in diagnosis of invasive cutaneous melanoma based on 11,611 cases notified to cancer registries from Eastern England and Scotland between 2006 and 2010 [1]. We read with great interest their thorough description of the study which confirmed the seasonal pattern of monthly frequencies of melanoma diagnoses. Such a pattern has already been observed in numerous studies after the initial report about this phenomenon had been published more than three decades ago [2]. In one of the subsections of their Discussion, when comparing their results with other studies, the authors refer also to our investigation [3] and state, “A more recent study by Keller and colleagues, set in Bavaria in Germany and analysing 11,901 malignant melanomas registered from 2003 to 2008 again shows contrasting results: in this population seasonal variation was most evident in thicker (>2 mm) melanomas on the limbs” (p. 557, right column). While the facts about the study concerning region, time frame and sample size are correct, the main findings are misrepresented in this statement. In our study we followed exactly the methodological approach of an earlier study by Chaillol et al. [4] based on the Northern Ireland Cancer Registry (NICR) data to be able to compare our findings directly to the NICR results. Thus, we analysed the monthly frequencies of melanoma diagnoses in a series of negative binomial regression models (including appropriate offset terms for the corresponding Bavarian population size) for melanoma cases stratified first by sex, age group (<50, 50 years of age) and Breslow thickness (2 mm, >2 mm) followed then by a stratification for sex, Breslow thickness (2 mm, >2 mm) as well as anatomical site of the lesions (head and neck, trunk, upper limbs, lower limbs). Due to this stratified approach results from 24 models describing presence and magnitude of a seasonal effect in the corresponding subgroup were presented (Tables 4 and 5 in [3]). Walter et al. [1] focus in their summary of our findings on those with thicker (>2 mm) melanomas on the limbs which comprise actually four subgroups in our analysis as we considered upper and lower limbs separately in both sexes. In three of these four subgroups, namely for thicker melanomas on upper and lower limbs in women and only for thicker melanomas on upper limbs in men, we found indeed a significant seasonal pattern. The magnitude of this effect in thicker melanomas was, however, very similar to that in thinner (2 mm) melanomas on the limbs, where even all four subgroups—including men with thinner melanomas on the lower limbs – showed a significant http://dx.doi.org/10.1016/j.canep.2015.10.028 1877-7821/ ã 2015 Elsevier Ltd. All rights reserved.
seasonal pattern. The Bavarian results do not suggest (and have not been interpreted that way by us) that seasonal variation in melanoma diagnoses plays a more prominent role in thicker melanomas (on the limbs or on other anatomical sites) than in thinner melanomas. In the meantime, after having published the results referenced by [1], we have confirmed this finding in an additional analysis by replacing calendar time indicators of seasonality by regionally aggregated quantifications of exposure to ultraviolet radiation (UVR). Again, for thicker and thinner melanomas at the same anatomical site we found a similar pattern of association with respect to an increasing frequency of melanoma diagnoses for higher levels of UVR exposure [5]. In addition, Walter et al. [1] also referred to our work at another place in the discussion when stating, “While initiation of a melanoma seems unlikely to occur within a short interval following exposure, there is increasing evidence that short sun exposures can also promote rapid pathological changes in existing lesions which may result in visible changes, thereby contributing to seasonal variations in help-seeking and subsequent detection.” (p. 558, right column) as support for this claim. Although we share this notion, we would like to point out that our data can only be indirectly used to provide evidence for it. The short-term promotional effect of UVR exposure has been investigated in other studies [6–8]. These more experimental studies identified short-term UVR-induced changes in size and structure of pigmented lesions supporting the statement above. Conflict of interest None declared. Acknowledgements We thank Andrea K. Keller, first author of the manuscript prompting this letter, for her dedicated work on the topic of seasonality of melanoma diagnoses. She left the academic world after finishing her Ph.D. which is the reason why she does not share responsibility for this letter. References [1] F.M. Walter, G.A. Abel, G. Lyratzopoulos, J. Melia, D. Greenberg, D.H. Brewster, et al., Seasonal variation in diagnosis of invasive cutaneous melanoma in Eastern England and Scotland, Cancer Epidemiol. 39 (2015) 554–561. [2] J. Scotto, J.M. Nam, Skin melanoma and seasonal patterns, Am. J. Epidemiol. 111 (1980) 309–314. [3] A.K. Keller, W. Uter, A.B. Pfahlberg, M. Radespiel-Troger, O. Gefeller, Seasonality of cutaneous melanoma diagnoses: a comprehensive comparison of results in Bavaria and Northern Ireland, Melanoma Res. 23 (2013) 321–330. [4] I. Chaillol, M. Boniol, R. Middleton, J.F. Dore, P. Autier, A. Gavin, Seasonality of cutaneous melanoma diagnosis in Northern Ireland with a review, Melanoma Res. 21 (2011) 144–151. [5] A.K. Keller, W.J. Uter, A.B. Pfahlberg, M. Radespiel-Troger, I. Mayer, O. Gefeller, Replacing surrogate measures by direct quantifications of ultraviolet radiation
Letter to the Editor / Cancer Epidemiology 40 (2016) 196–197 exposure in registry-based analyses of seasonality of melanoma diagnoses, Melanoma Res. 25 (2015) 543–549. [6] R. Hofmann-Wellenhof, P. Wolf, J. Smolle, A. Reimann-Weber, H.P. Soyer, H. Kerl, Influence of UVB therapy on dermoscopic features of acquired melanocytic nevi, J. Am. Acad. Dermatol. 37 (1997) 559–563. [7] I. Stanganelli, P. Bauer, L. Bucchi, M. Serafini, P. Cristofolini, S. Rafanelli, et al., Critical effects of intense sun exposure on the expression of epiluminescence microscopy features of acquired melanocytic nevi, Arch. Dermatol. 133 (1997) 979–982. [8] M. Tronnier, J. Smolle, H.H. Wolff, Ultraviolet irradiation induces acute changes in melanocytic nevi, J. Invest. Dermatol. 104 (1995) 475–478.
Olaf Gefeller* Annette Pfahlberg Wolfgang Uter Department of Medical Informatics, Biometry and Epidemiology, Friedrich Alexander University of Erlangen-Nuremberg, Germany
197
Martin Radespiel-Tröger Bavarian Health and Food Safety Authority, Centre of Early Cancer Detection and Cancer Registration, Schweinauer Hauptstr. 80, 90441 Nürnberg, Germany * Corresponding author at: Department of Medical Informatics, Biometry and Epidemiology Waldstr. 6, 91054 Erlangen, Germany. Fax: +49 9131 85 22721. E-mail address: [email protected] (O. Gefeller). Received 17 September 2015 Accepted 26 October 2015 Available online 26 November 2015
Contents lists available at ScienceDirect
Cancer Epidemiology The International Journal of Cancer Epidemiology, Detection, and Prevention journal homepage: www.cancerepidemiology.net
Letter to the Editor Seasonal variation in diagnosis of invasive cutaneous melanoma Keywords: Skin cancer Melanoma Seasonal variation Ultraviolet radiation
Walter et al. reported results of a large registry-based study addressing seasonal variation in diagnosis of invasive cutaneous melanoma based on 11,611 cases notified to cancer registries from Eastern England and Scotland between 2006 and 2010 [1]. We read with great interest their thorough description of the study which confirmed the seasonal pattern of monthly frequencies of melanoma diagnoses. Such a pattern has already been observed in numerous studies after the initial report about this phenomenon had been published more than three decades ago [2]. In one of the subsections of their Discussion, when comparing their results with other studies, the authors refer also to our investigation [3] and state, “A more recent study by Keller and colleagues, set in Bavaria in Germany and analysing 11,901 malignant melanomas registered from 2003 to 2008 again shows contrasting results: in this population seasonal variation was most evident in thicker (>2 mm) melanomas on the limbs” (p. 557, right column). While the facts about the study concerning region, time frame and sample size are correct, the main findings are misrepresented in this statement. In our study we followed exactly the methodological approach of an earlier study by Chaillol et al. [4] based on the Northern Ireland Cancer Registry (NICR) data to be able to compare our findings directly to the NICR results. Thus, we analysed the monthly frequencies of melanoma diagnoses in a series of negative binomial regression models (including appropriate offset terms for the corresponding Bavarian population size) for melanoma cases stratified first by sex, age group (<50, 50 years of age) and Breslow thickness (2 mm, >2 mm) followed then by a stratification for sex, Breslow thickness (2 mm, >2 mm) as well as anatomical site of the lesions (head and neck, trunk, upper limbs, lower limbs). Due to this stratified approach results from 24 models describing presence and magnitude of a seasonal effect in the corresponding subgroup were presented (Tables 4 and 5 in [3]). Walter et al. [1] focus in their summary of our findings on those with thicker (>2 mm) melanomas on the limbs which comprise actually four subgroups in our analysis as we considered upper and lower limbs separately in both sexes. In three of these four subgroups, namely for thicker melanomas on upper and lower limbs in women and only for thicker melanomas on upper limbs in men, we found indeed a significant seasonal pattern. The magnitude of this effect in thicker melanomas was, however, very similar to that in thinner (2 mm) melanomas on the limbs, where even all four subgroups—including men with thinner melanomas on the lower limbs – showed a significant http://dx.doi.org/10.1016/j.canep.2015.10.028 1877-7821/ ã 2015 Elsevier Ltd. All rights reserved.
seasonal pattern. The Bavarian results do not suggest (and have not been interpreted that way by us) that seasonal variation in melanoma diagnoses plays a more prominent role in thicker melanomas (on the limbs or on other anatomical sites) than in thinner melanomas. In the meantime, after having published the results referenced by [1], we have confirmed this finding in an additional analysis by replacing calendar time indicators of seasonality by regionally aggregated quantifications of exposure to ultraviolet radiation (UVR). Again, for thicker and thinner melanomas at the same anatomical site we found a similar pattern of association with respect to an increasing frequency of melanoma diagnoses for higher levels of UVR exposure [5]. In addition, Walter et al. [1] also referred to our work at another place in the discussion when stating, “While initiation of a melanoma seems unlikely to occur within a short interval following exposure, there is increasing evidence that short sun exposures can also promote rapid pathological changes in existing lesions which may result in visible changes, thereby contributing to seasonal variations in help-seeking and subsequent detection.” (p. 558, right column) as support for this claim. Although we share this notion, we would like to point out that our data can only be indirectly used to provide evidence for it. The short-term promotional effect of UVR exposure has been investigated in other studies [6–8]. These more experimental studies identified short-term UVR-induced changes in size and structure of pigmented lesions supporting the statement above. Conflict of interest None declared. Acknowledgements We thank Andrea K. Keller, first author of the manuscript prompting this letter, for her dedicated work on the topic of seasonality of melanoma diagnoses. She left the academic world after finishing her Ph.D. which is the reason why she does not share responsibility for this letter. References [1] F.M. Walter, G.A. Abel, G. Lyratzopoulos, J. Melia, D. Greenberg, D.H. Brewster, et al., Seasonal variation in diagnosis of invasive cutaneous melanoma in Eastern England and Scotland, Cancer Epidemiol. 39 (2015) 554–561. [2] J. Scotto, J.M. Nam, Skin melanoma and seasonal patterns, Am. J. Epidemiol. 111 (1980) 309–314. [3] A.K. Keller, W. Uter, A.B. Pfahlberg, M. Radespiel-Troger, O. Gefeller, Seasonality of cutaneous melanoma diagnoses: a comprehensive comparison of results in Bavaria and Northern Ireland, Melanoma Res. 23 (2013) 321–330. [4] I. Chaillol, M. Boniol, R. Middleton, J.F. Dore, P. Autier, A. Gavin, Seasonality of cutaneous melanoma diagnosis in Northern Ireland with a review, Melanoma Res. 21 (2011) 144–151. [5] A.K. Keller, W.J. Uter, A.B. Pfahlberg, M. Radespiel-Troger, I. Mayer, O. Gefeller, Replacing surrogate measures by direct quantifications of ultraviolet radiation
Letter to the Editor / Cancer Epidemiology 40 (2016) 196–197 exposure in registry-based analyses of seasonality of melanoma diagnoses, Melanoma Res. 25 (2015) 543–549. [6] R. Hofmann-Wellenhof, P. Wolf, J. Smolle, A. Reimann-Weber, H.P. Soyer, H. Kerl, Influence of UVB therapy on dermoscopic features of acquired melanocytic nevi, J. Am. Acad. Dermatol. 37 (1997) 559–563. [7] I. Stanganelli, P. Bauer, L. Bucchi, M. Serafini, P. Cristofolini, S. Rafanelli, et al., Critical effects of intense sun exposure on the expression of epiluminescence microscopy features of acquired melanocytic nevi, Arch. Dermatol. 133 (1997) 979–982. [8] M. Tronnier, J. Smolle, H.H. Wolff, Ultraviolet irradiation induces acute changes in melanocytic nevi, J. Invest. Dermatol. 104 (1995) 475–478.
Olaf Gefeller* Annette Pfahlberg Wolfgang Uter Department of Medical Informatics, Biometry and Epidemiology, Friedrich Alexander University of Erlangen-Nuremberg, Germany
197
Martin Radespiel-Tröger Bavarian Health and Food Safety Authority, Centre of Early Cancer Detection and Cancer Registration, Schweinauer Hauptstr. 80, 90441 Nürnberg, Germany * Corresponding author at: Department of Medical Informatics, Biometry and Epidemiology Waldstr. 6, 91054 Erlangen, Germany. Fax: +49 9131 85 22721. E-mail address: [email protected] (O. Gefeller). Received 17 September 2015 Accepted 26 October 2015 Available online 26 November 2015