Combination Radiotherapy and Radiopharmaceutical Therapy Treatment Planning for Thyroid Cancer
The goal of this study is to evaluate combined radioactive iodine (RAI, 131-I) and external beam radiotherapy (XRT) to optimize the radiation dose delivered to treat well differentiated thyroid cancers (DTC) with iodine-avid metastases. The investigators hypothesize that precise dosimetric planning will permit this combined RAI-XRT radiotherapeutic approach to be safe and permit higher tumor radiation doses than could otherwise be delivered. Patients with metastatic well-differentiated DTC) that is not completely resectable with macroscopic invasion of tumor into cervical soft tissues and/or non-resectable distant metastases, are the target study population. The primary objective is to evaluate safety as defined by the incidence of maximum grade 3 or greater NCI CTCAE toxicity observed during the treatment period and for the first 30 days following completion of radiotherapy. Secondary endpoints will evaluate efficacy at 6 months and feasibility of this combination to deliver a minimum cumulative dose of 80 Gy to the index tumors selected prior to treatment initiation. The investigators plan to enroll 48 subjects at an accrual rate of 1 subject per month over a study duration of 4 years.
• 18 and 85 years, inclusive.
• Histologically confirmed papillary or follicular thyroid carcinoma, collectively referred to as differentiated thyroid carcinoma (DTC), that is incompletely responsive to initial surgery +/- 131-Iodine as established by anatomic imaging (CT, MRI, and Ultrasound).
• DTC that is not completely resectable with macroscopic invasion of tumor into cervical soft tissues and/or non-resectable distant metastases.
• Iodine avid residual disease, but with a sub-therapeutic level of lesional radioiodine uptake demonstrated in either a pre-treatment diagnostic scan or a previous post-treatment radioiodine scan, making it unlikely that the patient would benefit from radioiodine therapy alone.
• Adequate organ function, including: a) adequate renal function, defined as a measured creatinine clearance \>70 ml/min/1.73 m2 or normal radioisotope glomerular filtration rate (GFR); and b) adequate hematologic function, defined as a platelet count \> 50,000 cells/mm3 and an absolute neutrophil count (ANC) \> 500 cells/mm3
• Life expectancy of at least 8 weeks.
• Karnofsky performance status (KPS) \> 50%
• Patients must have adequately recovered from the effects of any prior chemotherapy, as determined by the treating physician and study team, based in part on organ function defined above. Toxicities from previous therapies must have recovered to CTCAE v5.0 grade 2 or better.
• Patients with previously identified cardiac disease will be eligible, as Sodium Iodide I-131 (131I NaI) is not expected to cause cardiac dysfunction