Claus Garbe1, Thomas K Eigentler2, Jürgen Bauer2, Norbert Blödorn-Schlicht3, Lorenzo Cerroni4, Falko Fend5, Markus Hantschke6, Peter Kurschat7, Heinz Kutzner6, Dieter Metze8, Volker Mielke9, Harald Preßler5, Michael Reusch9, Ursula Reusch9, Rudolf Stadler10, Michael Tronnier11, Amir Yazdi2, Gisela Metzler2. 1. Department of Dermatology, University Hospital, Tübingen, Germany. claus.garbe@med.uni-tuebingen.de. 2. Department of Dermatology, University Hospital, Tübingen, Germany. 3. Dermatologicum Hamburg, Germany. 4. Department of Dermatology and Venereology, University Hospital, Graz, Austria. 5. Institute for Pathology, General Pathology, and Anatomic Pathology, Tübingen, Germany. 6. Dermatopathology Practice Friedrichshafen/Lake Constance, Friedrichshafen, Germany. 7. Department of Dermatology and Venereology, University Hospital, since 2014 HKS - Hautärzte Köln Süd, Dermatology Practice. Cologne, Cologne, Germany. 8. Department of Dermatology, University Hospital, Münster, Germany. 9. Dermatological Practice am Tibarg, Hamburg, Germany. 10. Department of Dermatology, Venereology, Allergology, and Phlebology, Johannes Wesling Hospital, Minden, Germany. 11. Department of Dermatology, Venereology, and Allergolgy, HELIOS Hospital, Hildesheim, Germany.
Abstract
BACKGROUND: In 2009, the AJCC issued a revised melanoma staging system. In addition to tumor thickness and ulceration, the mitotic rate was introduced as the third major prognostic parameter for the classification of primary cutaneous melanoma. Given that, according to the 2009 AJCC classification, the detection of one or more dermal tumor mitoses leads to an upstaging - from stage Ia to Ib - of melanomas with a tumor thickness of ≤ 1.0 mm, we set out to investigate the reproducibility of this new parameter. METHODS: In order to assess interobserver reliability, 17 dermatopathologists und pathologists - all well versed in the diagnosis of cutaneous melanoma - analyzed the mitotic rate in 15 thin primary cutaneous melanomas (mean tumor thickness 0.91 mm) using identical slides. Mitotic rates were determined on H&E and phosphohistone H3 (Ser10)-stained samples. Without knowledge of their previous assessment, five of the aforementioned examiners reevaluated the samples after more than one year in order to ascertain intraobserver reliability. RESULTS: Interobserver reliability of the mitotic rate in thin primary melanomas is disappointing and independent of whether H&E or immunohistochemically stained samples are used (kappa value: 0.088 [H&E], 0.154 [IH], respectively). Kappa values improved to 0.345 (H&E) and 0.403 (IH) when using a cutoff of 0/1 vs. 2+ mitoses. Similarly unsatisfactory, kappa values for intraobserver reliability ranged from 0.18 and 0.348, depending on the individual examiner. DISCUSSION: Given the unsatisfactory reproducibility and large variations in assessing the mitotic rate, it remains a matter of debate whether this diagnostic parameter should play a role in therapeutic decisions.
BACKGROUND: In 2009, the AJCC issued a revised melanoma staging system. In addition to tumor thickness and ulceration, the mitotic rate was introduced as the third major prognostic parameter for the classification of primary cutaneous melanoma. Given that, according to the 2009 AJCC classification, the detection of one or more dermal tumor mitoses leads to an upstaging - from stage Ia to Ib - of melanomas with a tumor thickness of ≤ 1.0 mm, we set out to investigate the reproducibility of this new parameter. METHODS: In order to assess interobserver reliability, 17 dermatopathologists und pathologists - all well versed in the diagnosis of cutaneous melanoma - analyzed the mitotic rate in 15 thin primary cutaneous melanomas (mean tumor thickness 0.91 mm) using identical slides. Mitotic rates were determined on H&E and phosphohistone H3 (Ser10)-stained samples. Without knowledge of their previous assessment, five of the aforementioned examiners reevaluated the samples after more than one year in order to ascertain intraobserver reliability. RESULTS: Interobserver reliability of the mitotic rate in thin primary melanomas is disappointing and independent of whether H&E or immunohistochemically stained samples are used (kappa value: 0.088 [H&E], 0.154 [IH], respectively). Kappa values improved to 0.345 (H&E) and 0.403 (IH) when using a cutoff of 0/1 vs. 2+ mitoses. Similarly unsatisfactory, kappa values for intraobserver reliability ranged from 0.18 and 0.348, depending on the individual examiner. DISCUSSION: Given the unsatisfactory reproducibility and large variations in assessing the mitotic rate, it remains a matter of debate whether this diagnostic parameter should play a role in therapeutic decisions.
Authors: Shirin Bajaj; Douglas Donnelly; Melissa Call; Paul Johannet; Una Moran; David Polsky; Richard Shapiro; Russell Berman; Anna Pavlick; Jeffrey Weber; Judy Zhong; Iman Osman Journal: J Natl Cancer Inst Date: 2020-09-01 Impact factor: 13.506
Authors: Joann G Elmore; David E Elder; Raymond L Barnhill; Stevan R Knezevich; Gary M Longton; Linda J Titus; Martin A Weinstock; Margaret S Pepe; Heidi D Nelson; Lisa M Reisch; Andrea C Radick; Michael W Piepkorn Journal: JAMA Netw Open Date: 2018-05