No difference in PET-CT surveillance versus planned neck dissection in advanced head and neck cancer

1. The overall survival rate for advanced head and neck (H&N) cancer patients undergoing PET-CT guided surveillance was similar to planned neck dissection in both HPV-positive and HPV-negative patient populations.

2. Surveillance resulted in fewer operations performed and was more cost-effective, with similar global quality-of-life scores compared to planned neck dissection.

Evidence Rating Level: 1 (Excellent)

Study Rundown: Chemoradiotherapy is considered among first-line treatments for squamous cell carcinomas of the H&N.  However, in patients with advanced nodal disease (N2 or N3), variations in management exist. Prior studies, involving small numbers, non-randomization and single centers, have PET-CT surveillance post-chemoradiotherapy showing high negative predictive values. As such, planned neck dissection may not be necessary, with PET-CT surveillance presenting an option for better patient stratification post-chemoradiation. This study was the first to examine PET-CT surveillance versus planned neck dissection in advanced H&N cancer patients (N2/N3, M0) in a prospective, randomized, multicenter trial.

This study indicated that overall survival rates were similar between the two groups, with PET-CT surveillance portending to fewer operations and in turn, increased cost-effectiveness.  The major clinical implication from these findings is the viable option for advanced H&N cancer patients to be surveilled with serial PET-CT imaging post-chemoradiotherapy, with surgery offered as clinically indicated rather than definitively planned. Further, this allows for better patient stratification and, from a systems perspective, can aid in cost-saving measures. Significant strengths of this study allowing for valid conclusions to be made include the manner in which the study was conducted (randomized, prospective, multicenter), large patient numbers, and overall homogeneity of patient population characteristics between study arms. In contrast, limitations of this study include small overall numbers of N3 disease patients, making PET-CT surveillance extrapolation to such individuals less certain. Furthermore, there were different uptake values of the PET imaging systems across different centres involved in the trial, resulting in limited ability to assess patient response to therapy. However, such calibration became available post trial completion, enabling retrospective completion by study authors.

Click to read the study in NEJM

Relevant Reading: Necessity of adjuvant neck dissection in setting of concurrent chemoradiation for advanced head and neck cancer

In-Depth [randomized controlled trial]: This was a prospective, randomized controlled, multicentre trial. The primary endpoint was overall survival. A total of 562 patients involved in the trial, recruited from across 37 centres in the United Kingdom. While 17% of patients had N2a nodal disease, 61% had N2b disease. The majority of patients (81%) had oropharyngeal cancer, and 75% of patients where tissue samples were obtained (335/446) had p16 positivity (indicating HPV was causative for cancer). The median follow-up was 36 months, with 520 patients (92%) followed for at least 2 years.  The 2-year overall survival rate was 84.9% (95% [CI], 80.7-89.1) in the surveillance group versus 81.5% (95% [CI], 76.9-86.3) in the planned surgery group. The HR for death was 0.92 (95% [CI], 0.65-1.32) for surveillance versus surgery, indicating non-inferiority of the former compared to the latter (<1.5; p=0.004). There was no significant difference in overall survival with p16 positive tumours between surveillance and planned surgery (HR=0.74; 95% [CI], 0.4-1.37), and those with p16 negative tumours (HR=0.98; 95% [CI], 0.58 – 1.66). The quality of life scores were no different at 2 years (mean change, – 0.81, p=0.85).  After 2 years of follow-up, PET-CT surveillance was found to be more cost effective with a savings of approximately $2190 (USD), and addition of 0.08 QALYs per person.

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