The current treatment: The treatment of choice for thyroid cancer with metastatic neck nodes is surgery followed by treatment with Radioactive Iodine or Iodine-131 (RAI). RAI is a radioactive element that when ingested preferentially goes to the thyroid cancer cells. After being localized inside these cells they emit radiation to kill them. Studies have shown that treatment with RAI after surgery decreases the rate of cancer recurrence. This treatment is usually given in an oral formulation (either tablet or liquid) that patient has to swallow. The dose of RAI given varies quite a bit depending on institutions and local practice. Most prevalent practice in India is to give around 100-120 mCi. However, lots of studies have been published that suggest that a lower dose of RAI ( 30 mCi for example) amy be as beneficial as the more conventional higher dose.  

The clinical question:  Patients who receive high dose of RAI need to be admitted in an isolation ward, separate from everyone for few days till the radiation level in their body comes down to an acceptable level. This can be quite cumbersome for the patients. Also, establishing and operating these isolation wards are not easy and have significant operational hurdles. RAI is a generally well tolerated treatment, however it does have some toxicities which are dose dependent and are more common with higher doses.  In recent years lots of studies have been published that suggest that a lower dose of RAI ( 30 mCi for example) may be as beneficial as the more conventional higher dose. 30 mCi RAI give a much lower radiation burden to the patients and can be given on OPD basis. No isolation wards are necessary for this dose of RAI and patients can be discharged on the same day of treatment. Any form of toxicity is virtually non existent with 30 mCi of RAI. Even though studies support the role of 30 mCi RAI in these type of patients, no randomized clinical trials have been published so far. So, we want to conduct a phase 3 randomised trial where we can see if clinical effect of 30 mCi RAI in reducing future recurrence rates is comparable to that of 100-120 mCi RAI. 

Primary objective: 1) To see the rate of persistence of cancer or recurrent cancer at the end of 5 year follow up. Secondary objectives; 1) A host of secondary endpoints will be analysed, however most important are; the toxicity profiles of both doses of RAI and number of patients who needed retreatment. These rates will be estimated at the end of 5 year and 7 years.  Methodology: The study will take place in Tata Memorial hospital, Mumbai and in ACTREC, Navi Mumbai Patients: Patients with thyroid cancer with nodal metastasis who have undergone surgery will be included in this study. No patients aged <18 years, pregnant or nursing mothers will be included in the study.  Number of patients: We are expecting to recruit 580 patients

total Recruitment period: 6 years  

Rnadomisation: A computer program will randomly assign patients into two arms:  a) Arm A b) Arm B  

Follow up:  Arm B: 290 patients Patients in this arm will receive 30 mCi RAI Patients of both these arms will be followed up for total 7 years. During this time patients will be put on adequate thyroid hormone supplementation. During follow up routine investigations such as neck USG and some blood tests such as serum TSH, Thyroglobulin and Antithyroglobulin antibody will be done, every year. These tests will help us to detect recurrent cancer. All of these investigations are part of the established standard for thyroid cancer treatment.