PET/CT had high negative predictive value for disease response at primary SCCHN

The combination of PET and CT imaging tests conducted six to eight weeks after the completion of chemoradiotherapy in patients with squamous cell carcinoma of the head and neck reliably predicted if there was disease response or if surgical follow-up was necessary, according to the results of a retrospective analysis.

“Our data support the recent paradigm shift toward observation of patients with negative PET/CT findings after the completion of chemoradiotherapy for advanced disease,” the researchers wrote. “Consequently, the morbidity and cost associated with biopsy of the primary tumor site and/or planned neck dissection are avoided in a significant number of patients.”

In this analysis, 31 patients were treated with concomitant intra-arterial chemoradiotherapy and subsequently underwent PET/CT six to eight weeks after treatment completion. Researchers sought to assess the presence or absence of residual disease during the median 24-month follow-up period.

Assessing the response of the tumor to treatment with PET/CT had a sensitivity of 83%, a specificity of 54%, positive predictive value of 31% and negative predictive value of 92%.

In the 78% of patients with node-positive disease before treatment, sensitivity was 75%, specificity was greater than 94%, positive predictive value was greater than 75%, and negative predictive value was 94%. In the 32% of patients whose cancer was located in the neck only, specificity was 92% and negative predictive value was greater than 92%.

Malone JP. Arch Otolaryngol Head Neck Surg. 2009;135:1119-1125.