Original article
A population-based registry study on relative survival from melanoma in Germany stratified by tumor thickness for each histologic subtype

https://doi.org/10.1016/j.jaad.2018.09.018Get rights and content

Background

Differences in relative survival (RS) of melanoma between histologic subtypes were discussed to be mainly caused by tumor thickness.

Objective

To investigate RS of melanoma, stratified by tumor thickness for each histologic subtype, and identify survival trends.

Methods

With use of cancer registry data on melanoma cases (International Classification of Diseases, 10th Revision, codes C43.0–C43.9) diagnosed in Germany in 1997–2013, 5- and 10-year age-standardized RS stratified by histologic subtype and stratified or standardized by T stage was estimated by standard and modeled period analyses. We restricted 10-year RS analyses to patients younger than 75 years.

Results

We analyzed 82,901 cases. Overall, the 5- and 10-year RS rates were 91.7% and 90.8%, respectively. Prognosis worsened with increasing T stage for all histologic subtypes, but T-stage distribution varied substantially. Survival differences by histologic subtype were strongly alleviated after adjustment for T stage but remained significant. Overall, 5-year RS increased significantly (by 3.8 percentage points) between the periods 2002–2005 and 2010–2013. This increase was no longer seen after adjustment for T stage.

Limitations

Exclusion of cases on account of missing information on T stages, changes in the definition of T stages, and lack of information on screening and treatment limit our analyses.

Conclusion

Differences in RS between histologic subtypes were strongly mediated by tumor thickness. Over time, RS of melanoma increased as a result of changes in T-stage distribution.

Section snippets

Database

This population-based study used routinely collected observational data from 12 cancer registries that were provided by the Cancer Survival Working Group of the Gesellschaft der epidemiologischen Krebsregister in Deutschland e.V. (Network of Epidemiologic Cancer Registries in Germany).14 Cancer registries were selected on the basis of the quality of their data regarding the proportion of death certificate–only (DCO) cases. Methods and quality requirements have been outlined in detail before.14

Results

In total, we included 82,901 melanoma cases with a balanced sex ratio (51.0% women) and a median patient age of 62 years at diagnosis (Table I). Median age at diagnosis ranged between 58 and 64 years in the different regions. The percentage of histologically confirmed cancer diagnosis was greater than 98.7% in all registries and was 99.6% overall. In 2002–2013, the percentage of excluded DCO cases was 2.2%. All together, 16,335 patients (19.7%) had melanoma of stage T0 or with an unknown or

Discussion

This population-based registry study focused on the mediating effect of T stage on differences in RS between the histologic subtypes of melanoma. For all histologic subtypes, we found that patients with thicker tumors had a lower RS. Survival differences by histologic subtype were mediated largely, but not completely, by the T-stage distribution. The remaining differences may have been due either to distinct disease processes25 or to residual confounding. Residual confounding could have

References (36)

  • Summary of Product Characteristics

    (2011)
  • European public assessment report (EPAR) Summary for the Public. Zelboraf vemurafenib. EMA/53181/2012 EMEA/H/C/002409. London, United Kingdom

    (2012)
  • N. Eisemann et al.

    Up-to-date results on survival of patients with melanoma in Germany

    Br J Dermatol

    (2012)
  • B. Barnes et al.

    Report on Cancer in Germany, 2016

    (2016)
  • P.E. LeBoit et al.

    World Health Organization Classification of Tumours. Pathology and Genetics of Skin Tumours

    (2006)
  • W. Liu et al.

    Rate of growth in melanomas: characteristics and associations of rapidly growing melanomas

    Arch Dermatol

    (2006)
  • H.K. Koh et al.

    Lentigo maligna melanoma has no better prognosis than other types of melanoma

    J Clin Oncol

    (1984)
  • N.H. Cox et al.

    Comparison between lentigo maligna melanoma and other histogenetic types of malignant melanoma of the head and neck. Scottish Melanoma Group

    Br J Cancer

    (1996)
  • Cited by (9)

    View all citing articles on Scopus

    Funding sources: Supported by German Cancer Aid (Deutsche Krebshilfe) (grants 10825 and 110446).

    Conflicts of interest: None disclosed.

    The study outline was presented in a poster presentation at the annual conference of the German Society for Epidemiology in Munich, Germany, on September 2, 2016. Recent trends in relative survival of melanoma in Germany stratified by age group, T stage, and histologic subtype were presented at the annual conference of the German Society for Epidemiology in Lübeck, Germany, on September 7, 2017, and at the annual conference of the International Association of Cancer Registries in Utrecht, The Netherlands, on October 17, 2017.

    View full text