Boron Neutron Capture Therapy (BNCT) for Locally Recurrent Head and Neck Cancer

Overview

This is a boron neutron capture (BNCT) therapy for patients with previously irradiated and locally recurrent head and neck cancer. The primary end points are treatment toxicities and response rate. The secondary endpoints are time to tumor progression, progression-free survival, overall survival and change quality of life. Head and neck carcinomas that recur locally after conventional irradiation pose a therapeutic challenge. Boron neutron capture therapy (BNCT) is based on the nuclear capture reaction that occurs when non-radioactive boron is irradiated with neutrons of thermal energy to yield high energy alpha particles and recoiling lithium nuclei. The effect of alpha and 7Li is primarily limited to boron- containing cells. Preferential uptake of boron into cancerous tissue is achieved using boron carriers such as a derivative of phenylalanine, boronophenylalanine (BPA). After administration of BPA by an intra-arterial or intravenous infusion, the tumor site is irradiated with neutrons, the source of which is currently a nuclear reactor. A few uncontrolled clinical trials have evaluated BNCT in the treatment of glioblastoma after brain surgery. In these studies, the median survival times have been 13-15 months after BNCT. However, efficacy and tolerability of BNCT in the treatment of limited number of head and neck cancer patients showed promising results. Though many basic researches about BNCT has been done using Tsing Hua Open-pool Reactor (THOR) at National Tsing Hua University, no clinical trial utilizing BNCT is performed in our country. This study will be the first BNCT trial to treat head and neck cancer in Taiwan.

This is a prospective, single arm, open label phase I/II trial with boron neutron capture (BNCT) therapy for patients with previously irradiated and locally recurrent head and neck cancer. The eligibility criteria are patients with locoregionally recurrent head and neck cancer; good performance status; inoperable, clinical measurable tumor size; good organ function and good compliance. No systemic treatment is in use. Once entering this study, patients will receive angiographies to evaluate bloody supply of the tumor and PET scan with 18F-fluoro-L-BPA as the tracer. Tumor-to- normal tissue ratios were evaluated from static emission scans. Boron concentration of normal tissues is derived from measurement of BPA concentration in the blood. Treatment planning with THORplan will be done after Computerized Tomography (CT) simulation. After treatment plan approved and on the day of treatment, intravenous or intra-arterial L-BPA- Fructose complex 500 mg/kg was administered at a constant rate over about 3 hours before and during neutron irradiation. Neutron beam irradiations were given at the THOR with prescription dose of 20 to 25 Gy (Eq) for the tumor in one fraction on day 1 and repeated on day 30. Patients will be regularly followed up at OPD for toxicities (NCI Common Terminology Criteria) and response evaluation (RECIST criteria)by MRI and PET, time to progression measurement, survival status and change of quality of life. Maximally 27 patients will be enrolled. After first 10 patients, the preliminary results will be reviewed before further patients' enrollment.