Inter-observer agreement between dermatologists and oncologists in assessing dermatological toxicities in patients with metastatic colorectal cancer treated by cetuximab-based chemotherapies: A pilot comparative study

The aim of this study was to measure the inter-observer agreement between two teams of three dermatologists and oncologists in labelling and grading the cetuximab-induced dermatological toxicities from 98 photographs performed in a cohort of 15 patients with metastatic colorectal cancer receiving cetuximab-based chemotherapy. Kappa coefficient (κ) assessed inter-observer grading agreement. Both teams defined by the same terms eight of the 13 (62%) toxic effects reported together. Discrepancies concerned the labelling of rash desquamation, hand–foot syndrome and xerosis and the grading (different and often going in the opposite direction) of various toxicities such as paronychia, xerosis, desquamation and hand–foot syndrome (κ value less than 0.40). Acneiform eruption was recognised by both teams, but the grading allocated by oncologists was lower. Our results suggested the need for a real consensus between oncologists and dermatologists for labelling and grading these dermatological toxicities. Better training of oncologists by using a dermatological atlas would improve inter-observer agreement.