Skin biopsy rates and incidence of melanoma: population based ecological studyBMJ 2005; 331 doi: https://doi.org/10.1136/bmj.38516.649537.E0 (Published 01 September 2005) Cite this as: BMJ 2005;331:481
- H Gilbert Welch, professor of medicine ()1,
- Steven Woloshin, associate professor of medicine1,
- Lisa M Schwartz, associate professor of medicine1
- 1 VA Outcomes Group, Department of Veterans Affairs Medical Center, White River Junction, VT 05009, USA
- Correspondence to: H Gilbert Welch, Center for the Evaluative Clinical Sciences, Dartmouth Medical School, Hanover, NH 03755-1404, USA
- Accepted 7 June 2005
Objectives To describe changes in skin biopsy rates and to determine their relation with changes in the incidence of melanoma.
Design Population based ecological study.
Setting Nine geographical areas of the United States.
Participants Participants of the Surveillance Epidemiology and End Results (SEER) programme aged 65 and older.
Main outcome measures For the period 1986 to 2001, annual skin biopsy rates for each surveillance area from Medicare claims and incidence rates for melanoma for the same population.
Results Between 1986 and 2001 the average biopsy rate across the nine participating areas increased 2.5-fold among people aged 65 and older (2847 to 7222 per 100 000 population). Over the same period the average incidence of melanoma increased 2.4-fold (45 to 108 per 100 000 population). Assuming that the occurrence of true disease was constant, the extra number of melanoma cases that were diagnosed after carrying out 1000 additional biopsies was 12.6 (95% confidence interval 11.2 to 14.0). After controlling for a potential increase in the true occurrence of disease, 1000 additional biopsies were still associated with 6.9 (3.1 to 10.8) extra melanoma cases diagnosed. Stage specific analyses suggested that 1000 biopsies were associated with 4.4 (2.1 to 6.8) extra cases of in situ melanoma diagnosed and 2.3 (0.0 to 4.6) extra cases of local melanoma, but not with the incidence of advanced melanoma. Mortality from melanoma changed little during the period.
Conclusion The incidence of melanoma is associated with biopsy rates. That the extra cases diagnosed were confined to early stage cancer while mortality remained stable suggests overdiagnosis—the increased incidence being largely the result of increased diagnostic scrutiny and not an increase in the incidence of disease.
Detailed model outputs are on bmj.com
We thank Elliott Fisher for his guidance and help in obtaining claim data from Medicare, Weiping Zhou for analysing the claims, and Jennifer A Snide for analysing the surveillance data.
Contributors HGW analysed the data and wrote the first draft. SW and LMS participated in the design of the analyses and made important contributions to the presentation of the work. HGW is the guarantor. The views expressed do not necessarily represent those of the Department of Veterans Affairs or the United States government.
Funding This study was supported in part by a research enhancement award from the Department of Veterans Affairs (03-098) and with a grant from the National Institute of Aging (PO1 AG19783-01). LMS is supported by Veterans Affairs career development awards in health services research and development. LMS and SW are supported by the generalist physician faculty scholars programme of the Robert Wood Johnson Foundation.
Competing interests None declared.
Ethical approval Dartmouth institutional review board.
- Accepted 7 June 2005