Concordance of the WHO, RTOG, and CTCAE v4.0 grading scales for the evaluation of oral mucositis associated with chemoradiation therapy for the treatment of oral and oropharyngeal cancers

Abstract

Background: The ability to consistently and accurately assess oral mucositis (OM) is critical to descriptions of its incidence and severity and in evaluating the effectiveness of potential interventions. The lack of a single grading scale compounds outcome interpretation. Consequently, we assessed the concordance of three of the most commonly used OM grading criteria (World Health Organization (WHO), Radiation Therapy Oncology Group (RTOG), and the common terminology criteria for adverse events (CTCAE).

Methods: Data was evaluated from two hundred patients with oropharyngeal or oral cavity cancers who underwent chemoradiation therapy and were enrolled in a double-blind, randomized, placebo-controlled trial in which trained assessors evaluated patients twice weekly. WHO, RTOG, and CTCAE scores were assigned centrally by independent evaluators blinded to the study group. Concordance among the three scales for all OM scores and severe OM scores (score ≥ 3) was defined as the percentage agreement and measured using Cohen's weighted Kappa.

Results: Of 3,578 OM assessments, 57% had identical scores for all three scales. When any score was considered, the concordance between WHO and RTOG scales was 71% (kappa 0.58; 95%CI: 0.56-0.60), 62% for the WHO and CTCAE scales (kappa 0.46; 95%CI: 0.44-0.48) and 78% for the CTCAE and RTOG scales (kappa 0.69; 95%CI: 0.68-0.71). When patients had severe OM (WHO score ≥ 3), 99.6% (521/523) of the CTCAE OM assessments had scores of 3 or 4 (kappa 0.98; 95%CI: 0.98-0.999) and 97.7% of the RTOG ones (511/523) had scores of 3 or 4 (kappa 0.69; 95%CI: 0.62-0.75). Among patients who had a WHO score of 4, 31.7% (63/199) and 96.0% (196/199) of patients had RTOG or CTCAE scores of 2 or 3, respectively.

Conclusions: Discordance was seen with patients who exhibited mild to moderate OM or most severe OM (grade 4) as described by WHO criteria. Whereas scale selection seems less critical in studies in which general "severe mucositis" is the primary outcome, it is particularly important in accurately describing OM's clinical trajectory and the frequency and impact in its most severe forms.

Keywords: Grading scales; Oral mucositis; Radiation therapy.