Diagnostic error, uncertainty, and overdiagnosis in melanoma

Abstract

Diagnostic error can be defined as deviation from a gold standard diagnosis, typically defined in terms of expert opinion, although sometimes in terms of unexpected events that might occur in follow-up (such as progression and death from disease). Although diagnostic error does exist for melanoma, deviations from gold standard diagnosis, certainly among appropriately trained and experienced practitioners, are likely to be the result of uncertainty and lack of specific criteria, and differences of opinion, rather than lack of diagnostic skills. In this review, the concept of diagnostic error will be considered in relation to diagnostic uncertainty, and the concept of overdiagnosis in melanoma will be presented and discussed.

Keywords: Melanoma; dermatopathology; diagnostic uncertainty; overdiagnosis; standardised classification tool; surgical pathology.

Fig. 1

SEER age-adjusted incidence and mortality rates for melanoma of the skin, 1975–2019. Rates are per 100,000 and age-adjusted to the 2000 US Standard Population (19 age groups) (M. Eguchi). Source for incidence rate: Surveillance, Epidemiology, and End Results (SEER) Program (www.seer.cancer.gov) SEER*Stat Database: Incidence -; SEER Research Data, 8 Registries, Nov 2021 Sub (1975–2019) - Linked To County Attributes - Time Dependent (1990–2019) Income/Rurality, 1969–2020 Counties, National Cancer Institute, DCCPS, Surveillance Research Program, released April 2022, based on the November 2021 submission. Source for mortality rate: Surveillance, Epidemiology, and End Results (SEER) Program (www.seer.cancer.gov) SEER*Stat Database: Mortality - All COD, Aggregated Total US (1969–2020) <Katrina/Rita Population Adjustment>, National Cancer Institute, DCCPS, Surveillance Research Program, released June 2022. Underlying mortality data provided by NCHS (www.cdc.gov/nchs).

Fig. 2

Prognostic model for Stage 1 melanoma. The importance of Clark level II. The diagram displays the number of patients in each node and the proportion of patients in the node who died. Blue leaves indicate subsets of patients classified as at low risk of death and orange leaves indicate subset of patients classified as relatively higher risk of death. These models were constructed in the training dataset weighting patients who died within 7 years 160:1 compared to patients that survived. Data from Eguchi et al.

Fig. 3

A thin melanoma with an early Clark level II vertical growth phase papule. Despite a Breslow thickness of considerably less than 1 mm, this T1a Clark level II melanoma has a cluster of cells in the dermis that is larger than the clusters of cells in the epidermis, consistent with its having capacity for growth as a mass lesion in the dermis, and increased potential for metastasis, illustrating that while most Clark level II melanomas will lack VGP, there are a few where the tumour cells do not fill and expand the papillary dermis and thus do not qualify as level III.