The results  of a large Cancer Research UK trial have set a new gold standard for treating thyroid cancer, reducing radiation doses to just one third of the current level, according to research in The new England Journal of Medicine.

The HiLo trial of 438 patients at hospitals across the UK, led by researchers at UCL (University College London), showed that giving selected patients a much lower dose of radioactive iodine taken in a single oral capsule, has similar treatment success to the current higher dose – destroying all thyroid gland cells remaining after surgery, with fewer side effects.

Currently patients have surgery to remove the entire thyroid gland and a few weeks later they take a capsule containing radioactive iodine. The iodine destroys any remaining healthy thyroid gland tissue and any potential cancer cells.  but improvements in surgery mean more of the thyroid gland is removed initially leaving fewer remaining cells to be ‘mopped up’ – so lower radiation doses are adequate and equally effective.  

Previously the higher doses of radioactive iodine meant that patients stayed in a hospital isolation unit for at least two days while the radiation left their bodies, without physical contact from family and friends. The high doses can have several side effects – the more serious occur later in life, such as a permanent dry mouth, and a small chance that a new cancer will develop.but patients taking the lower dose capsule can be treated more easily as an outpatient in hours and experience fewer side effects.

The thyroid gland makes and releases hormones and after removal patients require thyroid hormone tablets for the rest of their lives. Radioactive iodine works best when patients stop taking thyroid hormone tablets two to four weeks beforehand, but this leads to side effects such as lethargy, fatigue and weight gain, reducing patients’ quality of life and their ability to function at home and at work.

The HiLo study also showed that patients can avoid these symptoms if they continue with the thyroid tablets and are given an injection of Thyroid Stimulating Hormone (Thyrogen) just before they take the low dose radioactive iodine.Lead study author, Dr Ujjal Mallick, at the Freeman Hospital in Newcastle, said: “We’re delighted that this study of thyroid cancer will change international approaches to treat the disease more safely, by reducing the chance of another cancer developing later in life and other side effects.

“Patients will have a much better quality of life. They’ll be treated much more quickly, which will keep the disruption to their lives to a minimum, as well as saving the NHS money.”

Amy Horton, 24, from Scarborough took part in the HiLo trial after she was diagnosed with thyroid cancer in 2008.

Amy, who is currently studying medicine at Newcastle University, said: “It’s wonderful news that thyroid cancer patients can now be treated as outpatients. I was lucky to be on the trial and I received the lower dose of radio Iodine.

“Thankfully I didn’t experience too many side effects and was able to return to my studies almost straight away.“It was great not to have to stay at hospital or spend a long time feeling really unwell and I’m very pleased I could be part of research that means that future patients will now all have this quicker and safer treatment.”

Kate Law, director of clinical research at Cancer Research UK, said: “This pivotal study – which is the first for thyroid cancer in the UK – heralds a vastly improved treatment for the disease.

“Being treated as an outpatient means that patients should be able to be in their home surroundings on the same day as the treatment. The lower dose of radiation and thyrogen will help them carry on with their lives as usual at work or at home quicker without requiring several days to recover.

“More than 2,100 people are diagnosed with thyroid cancer in the UK every year – and it has the fastest rising incidence rate of the most common cancers in the UK. And we’re continuously striving to improve treatments and reduce side effects for this type of cancer.”

Note: The low dose was 1.1GBq compared with the previous higher dose of 3.7GBq. GBq is the symbol for the gigabecquerel unit of radioactivity. The patients were recruited between 2007 and 2010.

Reference: Low-dose radioiodine and thyrotropin alfa for thyroid cancer. The new England Journal of Medicine.

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Source: Cancer Research UK