Radiation therapy for early-stage carcinoma of the oropharynx

To evaluate the outcomes of radiation therapy treatment of patients with Stage I and II squamous cell carcinoma (SCC) of the oropharynx and discover adverse prognostic factors that may help select a subgroup of patients for a different management approach.

A search of the database maintained by the Department of Radiation Oncology of The University of Texas M. D. Anderson Cancer Center for patients with Stage I or II SCC of the oropharynx was performed. This search identified 175 patients treated between 1970 and 1998 who met the inclusion criteria for this retrospective study. Distribution of primary sites was: tonsillar fossa/pillar, 60 patients; soft palate, 55 patients; base of tongue, 40 patients; and pharyngeal wall, 20 patients. Twenty-five patients were stage T1, 124 were T2, and 26 were Tx. All patients were treated with fractionated radiation to a median dose of 66 Gy. Eighty-five patients were treated with conventionally fractionated radiation, 73 were treated with the concomitant boost fractionation schedule, and the remaining 17 were treated with other altered fractionation schedules or with intraoral or interstitial boosts.

The median follow-up for all patients was 76 months (range, 2-302 months). The actuarial 5-year local control (LC), regional control, locoregional control (LRC), and disease-free survival (DFS) rates were 85%, 93%, 81%, and 77%, respectively. Only 7 patients (5%) with LC developed nodal metastases, and 10 patients (7%) with LRC developed distant metastases. Eleven patients (32%) with locoregional recurrence were rendered without evidence of disease after a surgical salvage procedure, resulting in a 5- year ultimate LRC rate of 87%. T-stage classification was statistically significant (p = 0.03) in univariate analysis for actuarial 5-year LRC, 88% for Stage I vs. 72% for Stage II. The 5- and 10-year disease-specific survival rates were 85% and 79%, respectively, while the actuarial 5- and 10-year overall survival rates were 70% and 43%, respectively. Fifty-one patients (29%) developed second primary tumors, 86% of which were cancers of the upper aerodigestive tract (UADT). Heavy alcohol consumption was associated with both an increased risk of disease recurrence and development of a second cancer of the UADT.

Patients with early-stage oropharynx cancer have high rates of disease control when treated with radiation. Lymphatic and hematogenous metastases are uncommon. Surgical salvage of disease recurrence is successful in approximately one-third of patients. As the majority of recurrences occur within the first 2 years from treatment, close observation during this time period is important. The development of second primary tumors of the UADT adversely impacts survival in these patients to as great a degree as the index cancer.