to study the impact of radiation treatment after surgery in patient with locally advanced thyroid cancer.

Conditions: Thyroid Cancer Stage IV; Radiation Toxicity

Summary: this trial deals with cancers of the thyroid gland which are advanced at the local site of thyroid. these cancers are treated with surgery and complete removal of the thyroid gland. but due to advanced nature, there is risk of re-occurrence. radiotherapy can be used to prevent this re-occurrence. this study attempt to see the effect of radiotherapy in preventing re-occurrence and its side effects in advanced thyroid cancer.

surgery, when possible offers the best chance of cure for cancer of the thyroid gland. surgery for thyroid cancer involves removal of the thyroid gland along with removal of the lymph nodes which drain the gland. after surgery most patients will receive radio-iodine treatment to diagnose and treat any spread of the cancer in the body. most thyroid cancers will have good outcomes with the above mentioned treatment. however, in advanced thyroid cancer there is a higher chance of recurrence even with surgery and radio iodine. surgery for recurrence of these cancers is very morbid this may entail surgeries which may also involve removing portions of the voice box and food pipe. you may therefore develop and discomfort or inability to eat or speak. radiation therapy can be given to the neck along with radio-iodine therapy to decrease these re occurrences of the cancer. a number of studies have shown a benefit with the use of radiation therapy in advanced cases of thyroid cancer. however, the side effects of radiation, if any, have not been well documented. this study is being done to assess the impact of radiation on the outcome of cancer and the exact side effects of radiation therapy. if the side effects are not too many, then radiation therapy can be used to decrease the chances of recurrence in the neck after thyroid. in this study, patients undergoing total thyroidectomy for thyroid cancer will be assessed for high risk features on the histopathology report and the intra operative findings. those with advanced thyroid cancer as per the eligibility criteria will be counselled and consented for the study. those patients willing to participate in the study will be randomised to either receive only surgery and radio-iodine or surgery, radio-iodine and external beam radiation.

Eligibility criteria:
inclusion criteria: a) all patients of differentiated thyroid cancer (papillary/follicular/poorly differentiated/) who have undergone total/completion thyroidectomy at our institute and having at least two of the following features (listed below) intra-operatively and/or on histopathology 1. gross extrathyroidal spread into soft tissues of the neck, trachea, esophagus, recurrent laryngeal nerve (constituting stage t4a) 2. r1/ shave resections (minimal residual disease) 3. r2 resections (gross residual disease) 4. multiple lymph nodes positive(\>2) with perinodal extension at level vi b) normal baseline haematological and biochemical parameters. exclusion criteria: 1. anaplastic or medullary thyroid cancer 2. previous history of radiation 3. pregnancy 4. \< 18 years patient unwilling to participate in the study.

Keywords: locally advanced thyroid cancers, imrt, toxicity