FGD-PET/CT three months after (chemo)radiotherapy for head and neck squamous cell carcinoma spares considerable number of patients from a salvage neck dissection

Radiother Oncol. 2024 Sep:198:110407. doi: 10.1016/j.radonc.2024.110407. Epub 2024 Jun 26.

Abstract

Purpose: In the last decades FDG-PET/CT is increasingly used in combination with the standard diagnostic modalities (MRI + US-FNA) to identify residual neck disease (RND) after (chemo)radiotherapy for head-and-neck squamous cell carcinoma (HNSCC). The purpose of the current study is to identify the impact of increasing use of FDG-PET/CT on the accuracy of patient selection for salvage neck dissection (SND).

Materials and methods: Between 2008 and 2022, 908 consecutive patients with node-positive HNSCC were treated with (chemo)radiotherapy in our institution.

Primary endpoint: positive predictive value (PPV) of FDG-PET/CT for pathologic-confirmed RND (pRND) after SND, compared to the standard of care; MRI + US-FNA. Secondary endpoints: oncologic outcomes.

Results: Of the entire group, 130 patients (14 %) received SND. Of them only 53 patients (41 %) had pRND at the SND-specimens. The PPV of FDG-PET/CT for the detection of pRND was considerably better, compared to MRI + US-FNA; 89 % and 65 %, respectively. If FDG-PET/CT showed metabolic CR, these patients did not undergo SND. The NPV was 97.5 %, as only 2.5 % of these patients developed delayed regional failure. FDG-PET/CT considerably improved the accuracy of patient selection for SND, as significantly more patients treated in the second period, compared to first period of the study (n = 454 each) still had vital tumor at SND-specimen (53 % and 31 %, p = 0.008). Regional recurrence free-survival, DFS, OS and HNSCC-death were significantly worse in patients with pRND (p < 0.05) CONCLUSIONS: Incorporating FDG-PET/CT into the diagnostic pathway for the response evaluation after (chemo)radiotherapy significantly improved the accuracy of patient selection for SND and spared considerable number of patients (>20 %) from unnecessary SND. For patients with metabolic CR, SND can safely be omitted while for patients with no metabolic CR, SND is strongly advocated.

Keywords: Chemotherapy; FDG-PET/CT; HNSCC; Radiotherapy; Residual neck disease; Response evaluation; Salvage neck dissection.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Chemoradiotherapy*
  • Female
  • Fluorodeoxyglucose F18*
  • Head and Neck Neoplasms* / diagnostic imaging
  • Head and Neck Neoplasms* / pathology
  • Head and Neck Neoplasms* / therapy
  • Humans
  • Male
  • Middle Aged
  • Neck Dissection*
  • Neoplasm, Residual
  • Patient Selection
  • Positron Emission Tomography Computed Tomography* / methods
  • Radiopharmaceuticals
  • Salvage Therapy* / methods
  • Squamous Cell Carcinoma of Head and Neck* / diagnostic imaging
  • Squamous Cell Carcinoma of Head and Neck* / pathology
  • Squamous Cell Carcinoma of Head and Neck* / therapy

Substances

  • Fluorodeoxyglucose F18
  • Radiopharmaceuticals