- Email: [email protected]
Seasonal variations in the diagnosis of cutaneous melanoma
REPORTS
Seasonal variations in the diagnosis of cutaneous melanoma Monika-Hildegard Schmid-Wendtner, MD, Jens Baumert, MSc, Gerd Plewig, MD, and Matthias Volkenandt, MD Munich, Germany Seasonal patterns in diagnosis were examined in 7836 patients with cutaneous melanoma (clinical stage I and II) documented at the Department of Dermatology and Allergology at Ludwig-Maximilian-University in Munich, Germany, between 1977 and 2000. Of these patients, 2362 were first given a diagnosis in the summer months (June-August) and 1757 were first given a diagnosis in the winter months (DecemberFebruary). A summer-to-winter ratio was determined for sex, age, anatomic tumor site, histopathologic subtype, and tumor thickness. The summer-to-winter ratio was 1.34 (95% confidence interval: 1.27-1.43) for all patients, with a ratio of 1.22 (95% confidence interval: 1.12-1.33) for men and 1.47 (95% confidence interval: 1.35-1.60) for women. The frequency of diagnosis of cutaneous melanoma was seasonal for all age classes, for all anatomic tumor sites, for all histopathologic subtypes except acrolentiginous melanomas, and for melanomas with a tumor thickness ⬍3.0 mm. Comparing supgroups of the above-mentioned clinical and histopathologic parameters, significant differences could be observed for sex and anatomic tumor site. On the basis of this data, possible explanations for the diagnostic summer peak may be a greater awareness as a result of clothing habits in summertime or because of incurred sunburns in patients with skin type I and II, and the influence of public-health campaigns usually performed at the beginning of summer. (J Am Acad Dermatol 2004;50:679-82.)
F
or cutaneous melanoma, an increase in the frequency of diagnosis during the summer months has been reported by several groups.1-6 A direct influence of the increased UV radiation on melanoma development in summer was discussed as a possible reason for this diagnostic peak in summertime,1,2,4 as was a change in clothing habits during the summer months,5,6 resulting in an increased melanoma detection rate. However, there are few studies reporting on different seasonal peaks for subgroups of patients with melanoma. Polednak1 reported a diagnostic summer peak only for stage-I melanomas in women whereas men with stage-II and stage-III melanomas of the From the Department of Dermatology and Allergology, LudwigMaximilian-University. Supported by the Bayerisches Staatsministerium fu¨r Landesentwicklung und Umweltfragen, which is a government institution. Conflicts of interest: None identified. Accepted for publication September 13, 2003. Reprint requests: Monika-Hildegard Schmid-Wendtner, MD, Department of Dermatology and Allergology, LudwigMaximilian-University, Frauenlobstrasse 9-11, D-80337 Munich, Germany. E-mail: [email protected]. 0190-9622/$30.00 © 2004 by the American Academy of Dermatology, Inc. doi:10.1016/j.jaad.2003.09.021
upper extremity showed a significant diagnostic peak in spring (March-April). Scotto and Nam7 found no evidence of seasonal variation in the incidence of melanoma of the head, face, and neck in either sex in their collective; but did find a summer peak for melanomas located on the upper and lower limbs of women. Swerdlow8 reported a diagnostic peak in October for the subgroup of men with melanomas of the face. The aim of this study was to analyze the seasonality of diagnosis for 7836 patients with cutaneous melanoma (clinical stage I and II) treated at the Department of Dermatology and Allergology at Ludwig-Maximilian-University in Munich, Germany, taking into account patient age, anatomic tumor site, histopathologic melanoma subtype, and tumor thickness.
METHODS Retrospective analysis of the data collected between 1977 and 2000 revealed a diagnosis of cutaneous melanoma in 2362 patients during the summer months (June-August) and in 1757 patients during the winter months (December-February). In addition to the increase in melanoma diagnoses during the summer months, there was a diagnostic decrease during winter with lowest frequencies in December (Fig 1). A summer-to-winter ratio was 679
680 Schmid-Wendtner et al
Fig 1. Monthly distribution of frequency of diagnosis of cutaneous melanoma (clinical stage I and II) for 7836 patients between 1977 and 2000.
defined as the number of diagnoses in summer months divided by the number of diagnoses in winter months. The 95% confidence intervals (CI) were calculated by Poisson regression.9
RESULTS The summer-to-winter ratio was 1.34 (95% CI: 1.27-1.43) for all patients, with a ratio of 1.22 (95% CI: 1.12-1.33) for men and 1.47 (95% CI: 1.35-1.60) for women. In addition to significant variations according to sex, summer-to-winter ratios of melanoma diagnosis varied significantly according to the site of the primary melanoma, the histopathologic subtype, and the tumor thickness. Highest summer-to-winter ratios were found for women; primary melanomas located at the feet, the legs without foot involvement, and the arms; and for unclassified, superficial spreading, and lentigo maligna melanomas. According to tumor thickness groups, the highest summer-to-winter ratio was found for tumors ⬎0.75 and ⬍1.5 mm followed by tumors ⱕ0.75 mm. If one looks to all thin cutaneous melanomas, the frequency of diagnoses appears to be 72.6% for summer lesions being less than 1.5 mm and 69.8% for winter lesions being less than 1.5 mm, resulting in a summer-to-winter ratio of 1.41 (95% CI: 1.30-1.53). This difference was found to be significant (P ⬍ .0001). Only for patients with a tumor thickness ⬎ 3.0 mm and those with acrolentiginous melanomas was there no seasonal variation in diagnosis (Table I). A prospective subgroup analysis was performed using a collective of 233 patients with melanoma who were given a diagnosis at our department between January 1999 and January 2001. This group of patients was initially investigated to improve knowledge about factors associated with detection of cutaneous melanoma and reasons for delay in diagno-
J AM ACAD DERMATOL MAY 2004
sis.10 Because there was no significant difference between the subgroup of 233 patients and the entire group of 1127 patients with melanoma who were given a diagnosis in 1999 and 2000 (P ⫽ .1098), this subgroup may be representative for this period of time. Varying parameters prospectively documented in the former study were tested for their influence on seasonal patterns in diagnosis. Only the skin type was found to have a significant influence on the seasonal diagnosis of melanomas, comparing skin types I/II and III/IV, with a more pronounced summer peak for skin types I/II (P ⫽ .0029). There was no significant difference concerning the seasonal diagnosis between patients who detected their lesions themselves and those with melanomas primarily given a diagnosis by their physicians (P ⫽ .7892).
DISCUSSION The frequency of diagnosis of cutaneous melanoma in our investigation is seasonal for women and men, for all major anatomic tumor sites, and for all histologic subtypes except the acrolentiginous subtype. As in former investigations,4,5 the anatomic site of melanoma was the factor with the greatest difference between summer and winter, especially for melanomas located on the legs and arms (Table I). In accordance with Blum et al,5 this phenomenon was most pronounced for thin tumors with a tumor thickness between 0.75 and 1.5 mm (Table I). The reasons for this seasonality of melanoma diagnosis have been controversial in the past, focusing mostly on the following explanations: several groups supported the role of UV radiation, which may have a short-term proliferative effect leading to the development of cutaneous melanomas diagnosed during summertime.1,4 Our data do not support this explanation because in Germany, the main period of sun exposure is between July and August, and the peak of melanoma diagnosis was in June. However, a long-term effect of UV radiation can not be excluded completely. This was discussed by other groups as a late-stage promoter effect of UV radiation leading to the development of melanomas after periodic sun exposure.2,3,11 In our investigation, this theory might be reflected in a more pronounced diagnostic summer peak for invasive melanomas (often growing over years) than for melanomas in situ (Table I). A further possible explanation for the diagnostic peak in summer is the higher detection rate of cutaneous melanoma because of clothing habits.5 Koh et al12 postulated that women are more likely than men to discover their own lesions, which may in part explain the more elevated summer-to-winter ratio for diagnosis of melanomas located on the arms and legs because this is when women tend to
Schmid-Wendtner et al 681
J AM ACAD DERMATOL VOLUME 50, NUMBER 5
Table I. Seasonality of cutaneous melanoma: a comparison of the number of diagnoses in winter, spring, summer, and fall along with summer-to-winter ratios with 95% confidence intervals Season Winter
All patients Sex M F Age class ⬍50 y 50-69 y ⱖ70 y Tumor site Head/neck Trunk Arms Legs without feet Feet Tumor type Mis SSM NM ALM LM UCM Tumor thickness (mm) ⱕ0.75 ⬎0.75-⬍1.5 ⱖ1.5-⬍3.0 ⱕ3.0
Spring
Summer
Fall
n
%
n
%
n
%
n
%
Summer-to-winter ratio (95% CI)
1757
22.4
1956
25.0
2362
30.1
1761
22.5
1.34 (1.26-1.43)†
882 875
23.7 21.2
905 1051
24.3 25.5
1077 1285
29.0 31.2
853 908
22.9 22.0
1.22 (1.12-1.33)† 1.47 (1.35-1.60)†
719 765 273
22.6 22.8 21.0
787 838 331
24.7 25.0 25.5
984 992 386
30.9 29.6 29.7
691 760 310
21.7 22.7 23.8
1.37 (1.24-1.51)† 1.30 (1.18-1.42)† 1.41 (1.21-1.65)†
272 770 240 411 64
22.9 24.0 21.1 21.2 18.2
296 758 304 502 96
24.9 23.6 26.7 25.8 27.3
340 934 348 638 102
28.6 29.1 30.6 32.9 29.0
281 753 246 391 90
23.6 23.4 21.6 20.1 25.6
1.25 (1.07-1.47)† 1.21 (1.11-1.33)† 1.45 (1.23-1.71)† 1.55 (1.37-1.76)† 1.59 (1.17-2.18)†
123 880 445 47 99 163
22.1 22.3 23.1 24.5 21.6 21.4
146 961 505 51 112 181
26.3 24.4 26.2 26.6 24.4 23.8
159 1187 586 46 133 251
28.6 30.1 30.4 24.0 29.0 33.0
128 911 394 48 115 165
23.0 23.1 20.4 25.0 25.1 21.7
1.29 (1.02-1.64)* 1.35 (1.24-1.47)† 1.32 (1.16-1.49)† 0.98 (0.65-1.47) 1.34 (1.04-1.74)* 1.54 (1.26-1.88)†
655 358 276 163
22.3 21.6 23.8 22.5
709 422 296 198
24.1 25.5 25.6 27.3
904 524 343 196
30.8 31.6 29.6 27.1
669 352 243 167
22.8 21.3 21.0 23.1
1.38 (1.25-1.53)† 1.46 (1.28-1.67)† 1.24 (1.06-1.46)† 1.20 (0.98-1.48)
ALM, Acrolentiginous melanoma; CI, confidence interval; F, female; LM, lentigo melanoma; M, male; Mis, melanoma in situ; NM, nodular melanoma; SSM, superficial spreading melanoma; UCM, unclassified melanoma. *P ⬍ .05. † P ⬍ .01.
wear lighter clothing. In our investigation, higher summer-to-winter ratios for melanomas located on the arms, legs, and feet versus the head and neck region supports this theory. Moreover, the diagnostic peak in June may be explained by people being more attentive to changes in pigmented lesions and seeking medical advice just before summer holidays. Another explanation may include the possibility that patients with skin types I and II, incurring sunburns at the beginning of the summer, may be more consciously and proactively looking at their skin thereafter. In addition, public-health campaigns are usually performed at the beginning of summer.13 Analysis of variations in the summer-to-winter ratio in this study according to different years revealed the highest summer-to-winter ratio in 1989 with 2.43 (95% CI: 1.92-3.08) after the first general publiceducation program in Germany (Breitbart EW, Roser M. Fru¨ herkennung und Pra¨ vention des malignen Melanoms der Haut. Hausa¨ rzteblatt).
It should be also taken into account that the total number of excised melanocytic lesions during a certain period of time may have an influence on the diagnostic frequency of cutaneous melanoma. Therefore, the decrease of melanoma diagnoses in December might be a recognition artefact as a result of Christmas holidays, which may, at least in part, explain the following diagnostic increase in January. In conclusion, our results indicate an excess of cutaneous melanomas diagnosed during the summer months. A greater awareness as a result of clothing habits in summertime or because of incurred sunburns in patients with skin types I and II, and the influence of public-health campaigns usually performed at the beginning of summer, might be more relevant explanations than a short-term UV radiation effect. However, there is obvious need for future prospective studies of seasonality in occurrence of cutaneous melanoma, addressing questions such as what the recent history is concerning sun-
682 Schmid-Wendtner et al
burns or who first detects a melanoma (patients or their physicians). The second point did not prove to have a significant influence in our small subgroup analysis, but prospective studies including larger patient collectives might help to further elucidate the influence of the factor. Especially if future studies showed that patients detect lesions of concern rather than physicians (during a skin check), the above given possible explanation for the diagnostic peak in early summer would be supported. Moreover, associated factors like skin type, which was found to be of significance in our subgroup analysis, should be at the center of further prospective evaluations. In addition, a more detailed analysis of subgroups, for example of older patients who usually tend to have more covered skin sites, may help to better understand diagnostic summer peaks and may be of special value for the design of melanoma prevention programs in the future. REFERENCES 1. Polednak AP. Seasonal patterns in the diagnosis of malignant melanoma of skin and eye in upstate New York. Cancer 1984;54: 2587-94. 2. Akslen LA, Hartveit F. Cutaneous melanoma–season and invasion? Acta Derm Venereol 1988;68:390-4. 3. Schwartz SM, Armstrong BK, Weiss NS. Seasonal variation in the
J AM ACAD DERMATOL MAY 2004
4.
5.
6.
7. 8.
9. 10.
11.
12. 13.
incidence of cutaneous melanoma: an analysis by body site and histologic type. Am J Epidemiol 1987;126:104-11. Braun MM, Tucker MA, Devesa SS. Seasonal variation in frequency of diagnosis of cutaneous malignant melanoma. Melanoma Res 1994;4:235-41. Blum A, Ellwanger U, Garbe C. Seasonal patterns in the diagnosis of cutaneous malignant melanoma: analysis of the data of the German central malignant melanoma registry. Br J Dermatol 1997;136:968-81. Tronnier M, Mu¨ller C. Relationship between season and diagnoses of melanocytic tumours. Acta Derm Venereol 2001;81:112-5. Scotto J, Nam JN. Skin melanoma and seasonal patterns. Am J Epidemiol 1980;111:309-14. Swerdlow AJ. Seasonality of presentation of cutaneous melanoma, squamous cell cancer and basal cell cancer in the Oxford region. Br J Cancer 1985;52:893-900. McCullagh P, Nelder JA. Generalized linear models. 2nd ed. Cambridge: University Press; 1989. p. 193-244. Schmid-Wendtner MH, Baumert J, Stange J, Volkenandt M. Delay in the diagnosis of cutaneous melanoma: an analysis of 233 patients. Melanoma Res 2002;12:1-6. Holman CDJ, Armstrong BK, Heenan PJ. A theory of the etiology and pathogenesis of human cutaneous malignant melanoma. J Natl Cancer Inst 1983;71:651-6. Koh HK, Miller DR, Geller AC, Clapp RW, Mercer MB, Lew RA. Who discovers melanoma? J Am Acad Dermatol 1992;26:914-9. Theobald T, Marks R, Hill D, Dorevitch A. “Goodbye sunshine”: effects of a television program about melanoma on beliefs, behavior, and melanoma thickness. J Am Acad Dermatol 1991;25: 717-23.
Seasonal variations in the diagnosis of cutaneous melanoma Monika-Hildegard Schmid-Wendtner, MD, Jens Baumert, MSc, Gerd Plewig, MD, and Matthias Volkenandt, MD Munich, Germany Seasonal patterns in diagnosis were examined in 7836 patients with cutaneous melanoma (clinical stage I and II) documented at the Department of Dermatology and Allergology at Ludwig-Maximilian-University in Munich, Germany, between 1977 and 2000. Of these patients, 2362 were first given a diagnosis in the summer months (June-August) and 1757 were first given a diagnosis in the winter months (DecemberFebruary). A summer-to-winter ratio was determined for sex, age, anatomic tumor site, histopathologic subtype, and tumor thickness. The summer-to-winter ratio was 1.34 (95% confidence interval: 1.27-1.43) for all patients, with a ratio of 1.22 (95% confidence interval: 1.12-1.33) for men and 1.47 (95% confidence interval: 1.35-1.60) for women. The frequency of diagnosis of cutaneous melanoma was seasonal for all age classes, for all anatomic tumor sites, for all histopathologic subtypes except acrolentiginous melanomas, and for melanomas with a tumor thickness ⬍3.0 mm. Comparing supgroups of the above-mentioned clinical and histopathologic parameters, significant differences could be observed for sex and anatomic tumor site. On the basis of this data, possible explanations for the diagnostic summer peak may be a greater awareness as a result of clothing habits in summertime or because of incurred sunburns in patients with skin type I and II, and the influence of public-health campaigns usually performed at the beginning of summer. (J Am Acad Dermatol 2004;50:679-82.)
F
or cutaneous melanoma, an increase in the frequency of diagnosis during the summer months has been reported by several groups.1-6 A direct influence of the increased UV radiation on melanoma development in summer was discussed as a possible reason for this diagnostic peak in summertime,1,2,4 as was a change in clothing habits during the summer months,5,6 resulting in an increased melanoma detection rate. However, there are few studies reporting on different seasonal peaks for subgroups of patients with melanoma. Polednak1 reported a diagnostic summer peak only for stage-I melanomas in women whereas men with stage-II and stage-III melanomas of the From the Department of Dermatology and Allergology, LudwigMaximilian-University. Supported by the Bayerisches Staatsministerium fu¨r Landesentwicklung und Umweltfragen, which is a government institution. Conflicts of interest: None identified. Accepted for publication September 13, 2003. Reprint requests: Monika-Hildegard Schmid-Wendtner, MD, Department of Dermatology and Allergology, LudwigMaximilian-University, Frauenlobstrasse 9-11, D-80337 Munich, Germany. E-mail: [email protected]. 0190-9622/$30.00 © 2004 by the American Academy of Dermatology, Inc. doi:10.1016/j.jaad.2003.09.021
upper extremity showed a significant diagnostic peak in spring (March-April). Scotto and Nam7 found no evidence of seasonal variation in the incidence of melanoma of the head, face, and neck in either sex in their collective; but did find a summer peak for melanomas located on the upper and lower limbs of women. Swerdlow8 reported a diagnostic peak in October for the subgroup of men with melanomas of the face. The aim of this study was to analyze the seasonality of diagnosis for 7836 patients with cutaneous melanoma (clinical stage I and II) treated at the Department of Dermatology and Allergology at Ludwig-Maximilian-University in Munich, Germany, taking into account patient age, anatomic tumor site, histopathologic melanoma subtype, and tumor thickness.
METHODS Retrospective analysis of the data collected between 1977 and 2000 revealed a diagnosis of cutaneous melanoma in 2362 patients during the summer months (June-August) and in 1757 patients during the winter months (December-February). In addition to the increase in melanoma diagnoses during the summer months, there was a diagnostic decrease during winter with lowest frequencies in December (Fig 1). A summer-to-winter ratio was 679
680 Schmid-Wendtner et al
Fig 1. Monthly distribution of frequency of diagnosis of cutaneous melanoma (clinical stage I and II) for 7836 patients between 1977 and 2000.
defined as the number of diagnoses in summer months divided by the number of diagnoses in winter months. The 95% confidence intervals (CI) were calculated by Poisson regression.9
RESULTS The summer-to-winter ratio was 1.34 (95% CI: 1.27-1.43) for all patients, with a ratio of 1.22 (95% CI: 1.12-1.33) for men and 1.47 (95% CI: 1.35-1.60) for women. In addition to significant variations according to sex, summer-to-winter ratios of melanoma diagnosis varied significantly according to the site of the primary melanoma, the histopathologic subtype, and the tumor thickness. Highest summer-to-winter ratios were found for women; primary melanomas located at the feet, the legs without foot involvement, and the arms; and for unclassified, superficial spreading, and lentigo maligna melanomas. According to tumor thickness groups, the highest summer-to-winter ratio was found for tumors ⬎0.75 and ⬍1.5 mm followed by tumors ⱕ0.75 mm. If one looks to all thin cutaneous melanomas, the frequency of diagnoses appears to be 72.6% for summer lesions being less than 1.5 mm and 69.8% for winter lesions being less than 1.5 mm, resulting in a summer-to-winter ratio of 1.41 (95% CI: 1.30-1.53). This difference was found to be significant (P ⬍ .0001). Only for patients with a tumor thickness ⬎ 3.0 mm and those with acrolentiginous melanomas was there no seasonal variation in diagnosis (Table I). A prospective subgroup analysis was performed using a collective of 233 patients with melanoma who were given a diagnosis at our department between January 1999 and January 2001. This group of patients was initially investigated to improve knowledge about factors associated with detection of cutaneous melanoma and reasons for delay in diagno-
J AM ACAD DERMATOL MAY 2004
sis.10 Because there was no significant difference between the subgroup of 233 patients and the entire group of 1127 patients with melanoma who were given a diagnosis in 1999 and 2000 (P ⫽ .1098), this subgroup may be representative for this period of time. Varying parameters prospectively documented in the former study were tested for their influence on seasonal patterns in diagnosis. Only the skin type was found to have a significant influence on the seasonal diagnosis of melanomas, comparing skin types I/II and III/IV, with a more pronounced summer peak for skin types I/II (P ⫽ .0029). There was no significant difference concerning the seasonal diagnosis between patients who detected their lesions themselves and those with melanomas primarily given a diagnosis by their physicians (P ⫽ .7892).
DISCUSSION The frequency of diagnosis of cutaneous melanoma in our investigation is seasonal for women and men, for all major anatomic tumor sites, and for all histologic subtypes except the acrolentiginous subtype. As in former investigations,4,5 the anatomic site of melanoma was the factor with the greatest difference between summer and winter, especially for melanomas located on the legs and arms (Table I). In accordance with Blum et al,5 this phenomenon was most pronounced for thin tumors with a tumor thickness between 0.75 and 1.5 mm (Table I). The reasons for this seasonality of melanoma diagnosis have been controversial in the past, focusing mostly on the following explanations: several groups supported the role of UV radiation, which may have a short-term proliferative effect leading to the development of cutaneous melanomas diagnosed during summertime.1,4 Our data do not support this explanation because in Germany, the main period of sun exposure is between July and August, and the peak of melanoma diagnosis was in June. However, a long-term effect of UV radiation can not be excluded completely. This was discussed by other groups as a late-stage promoter effect of UV radiation leading to the development of melanomas after periodic sun exposure.2,3,11 In our investigation, this theory might be reflected in a more pronounced diagnostic summer peak for invasive melanomas (often growing over years) than for melanomas in situ (Table I). A further possible explanation for the diagnostic peak in summer is the higher detection rate of cutaneous melanoma because of clothing habits.5 Koh et al12 postulated that women are more likely than men to discover their own lesions, which may in part explain the more elevated summer-to-winter ratio for diagnosis of melanomas located on the arms and legs because this is when women tend to
Schmid-Wendtner et al 681
J AM ACAD DERMATOL VOLUME 50, NUMBER 5
Table I. Seasonality of cutaneous melanoma: a comparison of the number of diagnoses in winter, spring, summer, and fall along with summer-to-winter ratios with 95% confidence intervals Season Winter
All patients Sex M F Age class ⬍50 y 50-69 y ⱖ70 y Tumor site Head/neck Trunk Arms Legs without feet Feet Tumor type Mis SSM NM ALM LM UCM Tumor thickness (mm) ⱕ0.75 ⬎0.75-⬍1.5 ⱖ1.5-⬍3.0 ⱕ3.0
Spring
Summer
Fall
n
%
n
%
n
%
n
%
Summer-to-winter ratio (95% CI)
1757
22.4
1956
25.0
2362
30.1
1761
22.5
1.34 (1.26-1.43)†
882 875
23.7 21.2
905 1051
24.3 25.5
1077 1285
29.0 31.2
853 908
22.9 22.0
1.22 (1.12-1.33)† 1.47 (1.35-1.60)†
719 765 273
22.6 22.8 21.0
787 838 331
24.7 25.0 25.5
984 992 386
30.9 29.6 29.7
691 760 310
21.7 22.7 23.8
1.37 (1.24-1.51)† 1.30 (1.18-1.42)† 1.41 (1.21-1.65)†
272 770 240 411 64
22.9 24.0 21.1 21.2 18.2
296 758 304 502 96
24.9 23.6 26.7 25.8 27.3
340 934 348 638 102
28.6 29.1 30.6 32.9 29.0
281 753 246 391 90
23.6 23.4 21.6 20.1 25.6
1.25 (1.07-1.47)† 1.21 (1.11-1.33)† 1.45 (1.23-1.71)† 1.55 (1.37-1.76)† 1.59 (1.17-2.18)†
123 880 445 47 99 163
22.1 22.3 23.1 24.5 21.6 21.4
146 961 505 51 112 181
26.3 24.4 26.2 26.6 24.4 23.8
159 1187 586 46 133 251
28.6 30.1 30.4 24.0 29.0 33.0
128 911 394 48 115 165
23.0 23.1 20.4 25.0 25.1 21.7
1.29 (1.02-1.64)* 1.35 (1.24-1.47)† 1.32 (1.16-1.49)† 0.98 (0.65-1.47) 1.34 (1.04-1.74)* 1.54 (1.26-1.88)†
655 358 276 163
22.3 21.6 23.8 22.5
709 422 296 198
24.1 25.5 25.6 27.3
904 524 343 196
30.8 31.6 29.6 27.1
669 352 243 167
22.8 21.3 21.0 23.1
1.38 (1.25-1.53)† 1.46 (1.28-1.67)† 1.24 (1.06-1.46)† 1.20 (0.98-1.48)
ALM, Acrolentiginous melanoma; CI, confidence interval; F, female; LM, lentigo melanoma; M, male; Mis, melanoma in situ; NM, nodular melanoma; SSM, superficial spreading melanoma; UCM, unclassified melanoma. *P ⬍ .05. † P ⬍ .01.
wear lighter clothing. In our investigation, higher summer-to-winter ratios for melanomas located on the arms, legs, and feet versus the head and neck region supports this theory. Moreover, the diagnostic peak in June may be explained by people being more attentive to changes in pigmented lesions and seeking medical advice just before summer holidays. Another explanation may include the possibility that patients with skin types I and II, incurring sunburns at the beginning of the summer, may be more consciously and proactively looking at their skin thereafter. In addition, public-health campaigns are usually performed at the beginning of summer.13 Analysis of variations in the summer-to-winter ratio in this study according to different years revealed the highest summer-to-winter ratio in 1989 with 2.43 (95% CI: 1.92-3.08) after the first general publiceducation program in Germany (Breitbart EW, Roser M. Fru¨ herkennung und Pra¨ vention des malignen Melanoms der Haut. Hausa¨ rzteblatt).
It should be also taken into account that the total number of excised melanocytic lesions during a certain period of time may have an influence on the diagnostic frequency of cutaneous melanoma. Therefore, the decrease of melanoma diagnoses in December might be a recognition artefact as a result of Christmas holidays, which may, at least in part, explain the following diagnostic increase in January. In conclusion, our results indicate an excess of cutaneous melanomas diagnosed during the summer months. A greater awareness as a result of clothing habits in summertime or because of incurred sunburns in patients with skin types I and II, and the influence of public-health campaigns usually performed at the beginning of summer, might be more relevant explanations than a short-term UV radiation effect. However, there is obvious need for future prospective studies of seasonality in occurrence of cutaneous melanoma, addressing questions such as what the recent history is concerning sun-
682 Schmid-Wendtner et al
burns or who first detects a melanoma (patients or their physicians). The second point did not prove to have a significant influence in our small subgroup analysis, but prospective studies including larger patient collectives might help to further elucidate the influence of the factor. Especially if future studies showed that patients detect lesions of concern rather than physicians (during a skin check), the above given possible explanation for the diagnostic peak in early summer would be supported. Moreover, associated factors like skin type, which was found to be of significance in our subgroup analysis, should be at the center of further prospective evaluations. In addition, a more detailed analysis of subgroups, for example of older patients who usually tend to have more covered skin sites, may help to better understand diagnostic summer peaks and may be of special value for the design of melanoma prevention programs in the future. REFERENCES 1. Polednak AP. Seasonal patterns in the diagnosis of malignant melanoma of skin and eye in upstate New York. Cancer 1984;54: 2587-94. 2. Akslen LA, Hartveit F. Cutaneous melanoma–season and invasion? Acta Derm Venereol 1988;68:390-4. 3. Schwartz SM, Armstrong BK, Weiss NS. Seasonal variation in the
J AM ACAD DERMATOL MAY 2004
4.
5.
6.
7. 8.
9. 10.
11.
12. 13.
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