Efficacy and safety of FDG-PET for determining target volume during intensity-modulated radiotherapy for head and neck cancer involving the oral level

Yasuo Kosugi; Keisuke Sasai; Naoya Murakami; Tatsuki Karino; Yoichi Muramoto; Terufumi Kawamoto; Masaki Oshima; Noriyuki Okonogi; Jun Takatsu; Kotaro Iijima; Shuhei Karube; Akira Isobe; Naoya Hara; Mitsuhisa Fujimaki; Shinichi Ohba; Fumihiko Matsumoto; Koji Murakami; Naoto Shikama

doi:10.1186/s41824-024-00197-6

Efficacy and safety of FDG-PET for determining target volume during intensity-modulated radiotherapy for head and neck cancer involving the oral level

EJNMMI Rep. 2024 Mar 15;8(1):6. doi: 10.1186/s41824-024-00197-6.

Authors

Yasuo Kosugi¹, Keisuke Sasai^{1

2}, Naoya Murakami³, Tatsuki Karino¹, Yoichi Muramoto¹, Terufumi Kawamoto¹, Masaki Oshima¹, Noriyuki Okonogi¹, Jun Takatsu¹, Kotaro Iijima¹, Shuhei Karube⁴, Akira Isobe⁴, Naoya Hara⁴, Mitsuhisa Fujimaki⁵, Shinichi Ohba⁵, Fumihiko Matsumoto⁵, Koji Murakami⁶, Naoto Shikama¹

Affiliations

¹ Department of Radiation Oncology, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
² Department of Radiation Oncology, Kansai Electric Power Hospital, Osaka, Japan.
³ Department of Radiation Oncology, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan. n.murakami.zi@juntendo.ac.jp.
⁴ Department of Radiology, Juntendo University Hospital, Tokyo, Japan.
⁵ Department of Otorhinolaryngology, Faculty of Medicine, Juntendo University, Tokyo, Japan.
⁶ Department of Radiology, Juntendo University, Tokyo, Japan.

Abstract

Purpose: To determine the efficacy and safety of target volume determination by ¹⁸F-fluorodeoxyglucose positron emission tomography-computed tomography (PET-CT) for intensity-modulated radiation therapy (IMRT) for locally advanced head and neck squamous cell carcinoma (HNSCC) extending into the oral cavity or oropharynx.

Methods: We prospectively treated 10 consecutive consenting patients with HNSCC using IMRT, with target volumes determined by PET-CT. Gross tumor volume (GTV) and clinical target volume (CTV) at the oral level were determined by two radiation oncologists for CT, magnetic resonance imaging (MRI), and PET-CT. Differences in target volume (GTV_PET, GTV_CT, GTV_MRI, CTV_PET, CTV_CT, and CTV_MRI) for each modality and the interobserver variability of the target volume were evaluated using the Dice similarity coefficient and Hausdorff distance. Clinical outcomes, including acute adverse events (AEs) and local control were evaluated.

Results: The mean GTV was smallest for GTV_PET, followed by GTV_CT and GTV_MRI. There was a significant difference between GTV_PET and GTV_MRI, but not between the other two groups. The interobserver variability of target volume with PET-CT was significantly less than that with CT or MRI for GTV and tended to be less for CTV, but there was no significant difference in CTV between the modalities. Grade ≤ 3 acute dermatitis, mucositis, and dysphagia occurred in 55%, 88%, and 22% of patients, respectively, but no grade 4 AEs were observed. There was no local recurrence at the oral level after a median follow-up period of 37 months (range, 15-55 months).

Conclusions: The results suggest that the target volume determined by PET-CT could safely reduce GTV size and interobserver variability in patients with locally advanced HNSCC extending into the oral cavity or oropharynx undergoing IMRT. Trial registration UMIN, UMIN000033007. Registered 16 jun 2018, https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000037631.

Keywords: 18F-FDG; Dental artifacts; Head and neck cancer; Intensity-modulated radiation therapy; Interobserver variability; Oral cavity; Oropharynx; PET-CT; Target delineation.

Grants and funding

22K07779/Grant-in-Aid for Scientific Research