Thyroid & Radioactive Isotope Therapy Unit

Location: Royal Marsden

Section: NHS Clinical Research Programme

Head of Unit: Dr C M Nutting MD MRCP FRCR

Head of Isotope Unit: Dr V J Lewington FRCP

The major advance in thyroid cancer treatment over the last decade has been the ability to calculate the absorbed radiation dose in recurrent or metastatic tumours that concentrate radioiodine. This has permitted construction of dose-response curves to determine the tumouricidal dose for differentiated thyroid carcinoma and so enable a more precise prescription of further I-131 therapy. For anaplastic cancer, both physical and biological optimisation of external beam radiotherapy are required to improve the poor control of locoregional disease: 3D conformal planning has been developed in association with accelerated fractionation. For medullary carcinoma improved chemotherapy is required; in patients with familial disease, location of the responsible gene on chromosome 10 has made genetic counselling feasible. For thyroid lymphoma, we are attempting to correlate MALT (mucosa associated lymphoid tissue) appearance with local control and survival, with the hope that the subgroup not requiring initial chemotherapy may be identified.

Relevance to the NHS Research and Development Programme

Differentiated cancer dosimetry is designed to optimise I-131 therapy. When successful, this will increase the effectiveness of these treatments whilst reducing both morbidity and cost. The thyroid cancer database now comprises more than 2,000 patients with up to 60 years follow-up and is unique in the UK. Analysis of prognostic factors and treatment outcomes will permit evidence-based decisions for future patient management and clinical governance. Establishment of the South West London Cancer Network permitted closer integration with St George's Hospital as well as with Epsom and St Helier NHS Trust.

Recent Highlights

Dose-response curves have been constructed to determine the tumouricidal dose for differentiated thryoid carcinoma metastases. This translational research will enable more precise activities of radioiodine to be prescribed in order to maximise tumour kill but minimise patient morbidity. To achieve this, both tumour and normal residual thyroid absorbed doses from radioiodine have been determined using a variety of imaging techniques. Three-dimensional dosimetry of successive I-131 treatments for thyroid cancer and neuroendocrine tumours has been related to clinical progress and maximum whole-body dose. A Senior Clinical Research Fellow has completed an MD thesis on thyroid cancer under the joint supervision of the departments of Radioisotope Physics and Nuclear Medicine Department, which will be submitted in 2006.

Future Aims

The cancer dosimetry results, which are unique in the UK, require confirmation by analysis of a larger number of patients and comparison of tumour volume as measured by positron emission tomography (PET) with alternative methods [such as ultrasound or computed tomography (CT)], in order to be used by centres where PET is not available. Recombinant human thyroid stimulating hormone (rh-TSH) is now licensed for use in the UK and is increasingly used to manage patients with differentiated thyroid cancer.

New isotope therapies include radioimmunotherapy for refractory non Hodgkin’s lymphoma and  radiolabelled peptides to treat neuroendocrine tumours.The department of isotope physics is developing quantitative imaging techniques in parallel with the clinical development programme to construct models for individual patient dosimetry using a range of therapeutic radionuclides. Further trials including targeted radioimmunotherapy for bone marrow conditioning are being considered

The Unit participated in a Phase II multicentre clinical study using radium compounds to treat hormone refractory prostate cancer and will be working jointly with the Academic Urology Unit to lead further trials using these agents in 2006/7.The Isotope Unit has been invited to contribute to the prestigious International Atomic Energy Authority clinical trial programme and to the European Neuroendocrine Tumour Network research project.