Radiotherapy alone or combined with surgery for adenoid cystic carcinoma of the head and neck
BACKGROUND: The purpose of this study was to analyze the results of radiotherapy (RT) alone or combined with surgery for adenoid cystic carcinoma. METHODS: Between September 1966 and November 2001, 101 previously untreated patients were treated with curative intent with RT alone or combined with surgery. Follow-up ranged from 0.4 to 30.6 years (median, 6.6 years). All living patients had follow-up for at least 1 year. RESULTS: The 5- and 10-year rates of local control were as follows: RT alone, 56% and 43%; surgery and RT, 94% and 91%; and overall, 77% and 69%. Multivariate analysis of local control revealed that T stage (p=.0101) and treatment group (p=.0008) significantly influenced this endpoint. The 5- and 10-year rates of distant metastases-free survival were 80% and 73%. The 5- and 10-year absolute survival rates were as follows: RT alone, 57% and 42%; surgery and RT, 77% and 55%; and overall, 68% and 49%. Multivariate analysis of absolute survival revealed that T stage (p=.0043) and clinical nerve invasion (p=.0011) significantly influenced this endpoint. The 5- and 10-year cause-specific survival rates were as follows: RT alone, 65% and 48%; surgery and RT, 81% and 71%; and overall, 74% and 61%. Multivariate analysis revealed that T stage (p=.0008) and clinical nerve invasion (p=.0005) significantly influenced cause-specific survival. CONCLUSIONS: The optimal treatment for patients with adenoid cystic carcinoma is surgery and adjuvant RT. A significant proportion of patients with incompletely resectable disease are cured after RT alone. Improvements in locoregional control are offset, in part, by the relatively high incidence of distant metastases.