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Impact of the 2009 AJCC staging guidelines for melanoma on the number of mitotic figures reported by dermatopathologists at one institution
Author(s) -
Larson Allison R.,
Rothschild Brian,
Walls Andrew C.,
Granter Scott R.,
Qureshi Abrar A.,
Murphy George F.,
Laga Alvaro C.
Publication year - 2015
Publication title -
journal of cutaneous pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.597
H-Index - 75
eISSN - 1600-0560
pISSN - 0303-6987
DOI - 10.1111/cup.12517
Subject(s) - medicine , breslow thickness , melanoma , mitotic index , retrospective cohort study , significant difference , mitosis , pathology , cancer , biology , sentinel lymph node , cancer research , breast cancer , microbiology and biotechnology
Background In 2009 the revised seventh staging system for melanoma recommended the use of mitotic count to separate stage T1a from T1b. However, careful scrutiny of cases may lead to an inadvertent selection effect, with consequent increased reporting of mitotic counts. Methods We investigated whether there is a significant increase in mitotic counts reported since 2009 for melanomas with a Breslow thickness of 1.0 mm or less. We conducted a retrospective, case‐controlled study examining invasive melanoma cases at a large academic center. Mitotic counts were compared between pathology reports before 2009 (n = 61) and after 2009 (n = 125), with a subset of slides re‐examined in a blinded fashion. Results Before the 2009 staging guidelines, 51% of cases had one or more mitosis reported compared to 38% after 2009 (p = 0.113). Blinded re‐counting did not yield a significant difference when compared with the original pathology reports in either group. Conclusions There was not a significant difference in the number of mitoses reported after the implementation of the new guidelines.