Preliminary clinical outcomes of accelerator-based BNCT for recurrent head and neck cancer
PO-1230
Abstract
Preliminary clinical outcomes of accelerator-based BNCT for recurrent head and neck cancer
Authors: Keiji Nihei1,2, Teruhito Aihara1,3, Satoshi Takeno1,4, Ryo Kakino1, Naonori Hu1,6, Masaaki Higashino3, Ryo Kawata3, Koji Ono5
1Osaka Medical and Pharmaceutical University, Kansai BNCT Medical Center, Takatsuki, Osaka, Japan; 2Osaka Medical and Pharmaceutical University, Radiation Oncology, Takatsuki, Osaka, Japan; 3Osaka Medical and Pharmaceutical University, Otorhinolaryngology - Head & Neck Surgery, Takatsuki, Osaka, Japan; 4Osaka Medical and Pharmaceutical University, Radiation Oncology, Takatsuki, Oaka, Japan; 5Osaka Medical and Pharmaceutical University, BNCT Joint Clinical Institute, Takatsuki, Osaka, Japan; 6Kyoto University, Institute for Integrated Radiation and Nuclear Science, Kumatori, Osaka, Japan
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Purpose or Objective
Boron neutron capture therapy (BNCT) is one of the cancer treatments using a nuclear reaction between a boron atom and a neutron. Since the alpha particle and Li (lithium) nucleus generated by the reaction of 10B(n, α) 7Li, have a short range (within a cell diameter), BNCT can selectively destroy tumor cells where such reaction occurs, without serious damage to the surrounding normal cells.
Early biological and clinical research of BNCT had been conducted by using a nuclear reactor, but to spread BNCT in clinical practice, accelerator-based BNCT system was newly developed. After good clinical outcome was revealed by some clinical trials using accelerator-based BNCT system, BNCT for unresectable locally advanced and/or recurrent head and neck cancers was approved by the Japanese government as a health insurance treatment in June 2020.
In the current study, the preliminary clinical outcomes of accelerator-based BNCT for recurrent head and neck cancers were retrospectively investigated.
Material and Methods
Successive patients who underwent accelerator-based BNCT after its approval as health insurance treatment for recurrent head and neck cancers were retrospectively analyzed. BNCT consisted of intravenous infusion of boronophenylalanine and neutron irradiation up to 60 minutes. The BNCT dose was calculated so that the minimum dose to the target lesions satisfied more than 20 Gy-Eq when the maximum dose to the mucosa was set as 12 Gy-Eq.
Results
From Jun 2020 to Jan 2022, 54 patients received BNCT in our institution. Patients’ characteristics were as follows: median age, 71 (range, 39-89); male/female, 33/21; squamous cell carcinoma (SCC)/non-SCC, 47/7; primary tumor/neck lesion/both, 34/18/2. Median follow-up period was 11.5 months (range, 2-27). One patient received the second BNCT for tumor regrowth.
The best response after BNCT of 55 treatments were as follows: complete response 25, partial response 19, stable disease 9, progress disease 2, and the overall response rate (ORR) was 80% with a 95% confidence interval (CI) of 67-88%. The 1-year progression-free survival (PFS) and local PFS were 56.1% (95% CI: 41.6-68.3) and 64.3% (49.4-75.9), respectively.
With regard to adverse events, hyperamylasemia, crystalluria, and renal failure were observed as acute toxicities in 44, 16, and 2 patients, respectively. Alopecia occurred in 17 patients, which was the most common subacute toxicity followed by intractable ulcer, tumor infection, and anorexia.
Conclusion
Accelerator-based BNCT can achieve 80% ORR for unresectable locally-advanced and recurrent head and neck cancers, which cannot be controlled sufficiently by any other modalities. To establish BNCT as a treatment option, the clinical data of both efficacy and safety with longer follow-up is needed.