Survival when treating adenoid cystic carcinoma of the external auditory canal: quantitative assessment of case reports.
BACKGROUND
Adenoid cystic carcinoma (ACC) of the external auditory canal is a rare neoplastic condition. The purpose of this study was to conduct a quantitative review of case reports to assess the efficacy of treatment options and assess prognostic factors.


METHODS
Cases were identified using PubMed. Kaplan-Meier curves were used to plot overall and disease-free survival. The log-rank test was used to compare survival curves in the univariate analysis for perineural invasion, margin status, and specific treatment modalities. A Cox proportional hazard model was used for multivariate analysis.


RESULTS
Sixty-six cases were identified. The univariate analysis suggests an increased overall (p = .03) and disease-free (p = .03) survival for those treated with parotidectomies, whereas temporal bone resection decreased survival (p = .07). There was no overall or disease-free survival advantage using radiation (p = .8). Positive margins decreased both overall (p = .05) and disease-free survival (p = .02). Perineural invasion was not significant. The multivariate analysis confirmed the findings for parotidectomies (p = .02) and temporal bone resections (p = .01).


CONCLUSIONS
Although the short-term survival for ACC is high, the risk of metastasis and poor long-term survival is high. In addition to local excision with negative margins, the surgeon should perform a parotidectomy.
Bonaparte
James P
JP
Department of Otolaryngology, University of Ottawa, Ottawa, Ontario.
Trites
Jonathan
J
Hart
Rob
R
Taylor
S Mark
SM
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003528:Carcinoma, Adenoid Cystic / Q000401:mortality* / Q000628:therapy; D004424:Ear Canal; D004428:Ear Neoplasms / Q000401:mortality* / Q000628:therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D016019:Survival Analysis; D016896:Treatment Outcome; D055815:Young Adult