Lessons from a standardized program using PET-CT to avoid neck dissection after primary radiotherapy for N2 squamous cell carcinoma of the oropharynx

Abstract

Objectives: To report the results of a standardized program using positron emission tomography (PET)-computed tomography (CT) approximately 12 weeks after primary radiotherapy to determine the need for a planned neck dissection in patients with radiographic N2 squamous cell carcinoma (SCC) of the oropharynx.

Methods: Fifty consecutive patients with T1-4 and hemineck radiographic stage N2A-B SCC of the oropharynx for whom the only indication for planned neck dissection was a positive PET-CT performed ∼12 weeks after completing primary treatment with radiotherapy.

Results: Results of PET-CT to identify residual neck disease were as follows: sensitivity and positive predictive value, 0%; specificity, 89%; negative predictive value, 91%; potential neck recurrence from using this 12-week PET-CT program, 2%. The time between negative PET-CT and detection of neck recurrence was 0.5, 0.6, 1.2, and 2.0 years. The rate of successful (>1 year) salvage of neck recurrence was 25% (1/4).

Conclusions: PET-CT approximately 12 weeks after radiotherapy for oropharyngeal cancer is an excellent way to identify patients who do not need neck dissection. Approximately half of neck recurrences present over 1 year after negative PET-CT and the chance of successful salvage is low.

Keywords: Neck dissection; Oropharynx; PET; Radiation therapy; Radiochemotherapy.