Management of adenoid cystic carcinoma of the head and neck: a single-institute study with over 25-year follow-up

Abstract

Background: Adenoid cystic carcinoma is a rare malignant tumor arising from exocrine glands such as the major and minor salivary glands of the paranasal sinuses or the external auditory canal. Although multiple retrospective clinical studies of ACC have been reported to date, clinical questions, such as 1) long-term prognosis beyond 20 years, 2) usefulness and suitability for treatment of therapeutic interventions, 3) therapeutic goal to aim for, and 4) prognosis by recurrence sites, are still unclear.

Methods: To improve understanding and management of adenoid cystic carcinoma of the head and neck (ACC), a retrospective study with 58 new ACC cases between 1991 and 2016 was performed. The median observation period was 66.8 months (range 3-316 months). The overall clinical stages were as follows: I, 6.9%; II, 25.9%; III, 19.0%; and IV, 48.2%. Histology was cribriform/tubular type (C-T type) in 62.0% and solid type in 27.5%. The main treatment strategy was definitive surgery, which was performed in 75.2% of cases.

Results: Overall 10-year, 20-year, and 25-year survivals were 63.7, 27.3, and 20.0%, respectively. Similarly, disease-specific survival (DSSs) was 65.7, 51.2, and 38.4%, respectively, and disease-free survival was 25.2, 9.4, and 9.4%, respectively. Conducting surgery (HR: 0.19, 95% CI: 0.06-0.61, p = 0.005) and C-T type (HR: 0.32, 95% CI: 0.11-0.93, p = 0.036) were independent prognostic predictors of DSS. DSS was significantly prolonged after salvage surgery for both locoregional recurrence (p = 0.004) and lung metastatic recurrence (p = 0.012, vs best supportive care).

Conclusions: In ACC cases, both initial surgical treatment and repetitive surgical resection of resectable recurrent lesions, including both locoregional and lung metastases, resulted in longer survival. The major goal of treatment for ACC may be long-term survival including cancer-bearing survival, resulting in either natural death or intercurrent-disease death, since judging cure of ACC is almost impossible.

Trial registration: Retrospectively registered.

Keywords: Adenoid cystic carcinoma; Head and neck; Histology; Lung metastasectomy; Management; Prognostic predictors; Salvage treatment; Solid type; Surgery; Treatment.

Fig. 1

Overall survival (OS), disease-specific survival (DSS), locoregional recurrence-free survival (LRFS), distant metastasis-free survival (DMFS), and disease-free survival (DFS) of all ACC cases. Kaplan-Meier method was adopted for creating each survival curve

Fig. 2

Survival curves of disease-specific survival (DSS) and disease-free survival (DFS). Kaplan-Meier method for creating each survival curve and Log-rank test for significance test between groups were adopted, respectively

Fig. 3

Correlations between solid type of histology and clinical stage. Solid type was observed in only advanced staged cases. The more clinical stage advanced, the higher percentage of solid type became

Fig. 4

Disease-specific survival (DSS) after salvage treatment for locoregional recurrence were shown in (a), and for lung metastatic recurrence were shown in (b). Kaplan-Meier method for creating each survival curve and Log-rank test for significance test between groups were adopted, respectively. Significance level of 0.05 was used for comparison of all groups, and the Bonferroni correction was adopted to determine the proper significance levels in multiple pairwise comparisons. * represents significant p value. Abbreviations: DSS; disease-specific survival, Tx; therapy, BSC; best supportive care