Comparison of 11 staging classifications in carcinoma of the external auditory canal.

BACKGROUND AND PURPOSE

To compare overall survival (OS) differences across 11 different staging classifications.

MATERIALS AND METHODS

Patient data were retrospectively collected. OS curves were estimated by Kaplan-Meier method. Hazard ratios (HR) were calculated by Cox regression. Concordance between HR of each system was evaluated by C-index. Absolute net reclassification improvement (NRI) was performed.

RESULTS

Thirty-five patients fitted study criteria with median follow-up of 27.3 months. 80% were diagnosed with squamous cell carcinoma. 14.3% had ECOG > 1. Eighteen patients underwent surgery, while 31 patients received radiotherapy. For AJCC 8th edition cutaneous carcinoma of the head and neck, 3-year OS of stage 1-3 and 4 was 26.7% (median OS of 0.8 years) and 64.1% (median OS of 4.3 years) (HR 0.33; 95%CI 0.09-1.2). 3-year OS of T1-3 and T4 in modified Pittsburgh classification were 65% and 55.4% with median OS of not reached and 3.1 years (HR 1.86; 95%CI 0.66-5.23). Regarding Kinney system, patients with stage 1-2 and 3 had 3-year OS of 67.1% and 45.5%, while median OS was 4.7 years and 1 year (HR 1.94; 95%CI 0.75-4.97). C-indices were 0.577, 0.523 and 0.569. NRI comparing Kinney with modified Pittsburgh classifications was 2.86%.

CONCLUSION

Kinney's may offer improved prognostic accuracy compared to other classifications.