The Clinical Characteristics and Surgical Outcomes of Carcinoma of the External Auditory Canal: A Multicenter Study

Abstract

Objective: To analyze the clinical characteristics and evaluate the surgical outcomes of carcinoma of the external auditory canal (CEAC).

Materials and methods: Overall, 31 patients from four multicenter hospitals, who were diagnosed and surgically treated for CEAC in 2009-2014, were enrolled for this retrospective study. Medical records were reviewed to determine cancer stage according to the Pittsburgh classification. Clinical data of age, sex, site, initial symptoms, surgery extent, postoperative complications including recurrence, follow-up period, and current patient status were collected for analysis. Five-year cumulative survival rate was obtained using Kaplan-Meier method.

Results: At initial diagnosis, 22 patients were in the early stages (stage I: 15; stage II: 7) and 9 patients were in the advanced stages (stage III: 1; stage IV: 8). Lymph node metastasis was present in 5 patients and distant metastasis in 2. Of the 31 patients, 4 patients died (stage II: 1, stage IV: 3) during the follow-up period. Early-stage patients showed 100% 5-year estimated cumulative survival rate, whereas the advanced-stage patients showed 5-year estimated survival rate of 53.6% (p=.006). The overall survival rate of all enrolled patients was 90.3%. Although 5-year estimated disease-free survival rate of stage I was 100.0%, that for stage II was low at 30.0% because of considerable recurrences.

Conclusion: The results of this multicenter study suggest that more aggressive treatment modality, including adjuvant therapy, is necessary for patients with CEAC with Pittsburgh stage II or more.

Figure 1. a–d

Representative case of cancer of the external auditory canal. (a) Axial non-enhanced CT scan. Soft tissue obliterates in right external auditory canal. (b) Axial T1-weighted MRI image. The main tumor shows a heterogeneous intermediate signal intensity. (c) Specimen (size, 1.8×1.5 cm). (d) Histological section (H&E). Histological section of the specimen shows a well-differentiated squamous cell carcinoma characterized by hyperchromatic nuclei and keratin pearl formation.

Figure 2

The overall survival rate estimated with the Kaplan–Meier method. The 5-year survival rate of early stage was 100.0% and that for advanced stage was 53.6%. This difference between the two groups was statistically significant (p=.006).

Figure 3

The disease-free survival rate comparing each CEAC stage. The 5-year disease-free survival rate of each stage was as follows: stage I, 100.0%; stage II, 30.0%; stage III, 100.0%; and stage IV, 72.9%. There was no statistically significant difference between the stages (I vs. II, p=.098; I vs. IV, p=.084; II vs. III, p=.332; II vs. IV, p=.977; and III vs. IV, p=.589).