Presenting the HiLo trial results at the 2018 NCRI Cancer Conference (4–6 November 2018, Glasgow, Scotland) Jonathan Wadsley (Weston Park Hospital, Sheffield, UK) reported no significant difference in the recurrence rate between thyroid cancer patients given a low radiation dose compared to the standard higher dose.
The investigation included 434 patients with low risk thyroid cancer in the HiLo trail with a median follow-up time of 6.5 years. The patients were randomized and received either low administered radioactive iodine activity or standard high radioactive iodine activity.
In addition patients either received a genetically-engineered thyroid stimulating hormone to stimulate the absorption of radioactive iodine by thyroid cancer cells, or were asked to stop taking their thyroid hormone tablets achieving the same effect as it allows their natural thyroid stimulating hormone levels to rise.
The 7 year follow-up saw 21 recurrences of cancer, with similar recurrence rates between the two doses, and also between patients using Thyrogen or thyroid hormone withdrawal. Wadsley commented: “The study showed that patients receiving a lower activity experienced fewer side effects, in particular less risk of feeling sick or suffering damage to the salivary glands, which can potentially lead to a permanently dry mouth.”
He continued: “The use of a lower activity also raises the possibility of giving the treatment in one day rather than having to admit patients to be nursed in isolation for 2–3 nights. Therefore, not only is lower activity preferable for patients, it can also result in cost savings to the health service.”
“Now that we have confirmation that there is no difference in recurrence rates over a longer follow-up period, these recommendations can be strengthened and clinicians and patients can be confident that use of the lower activity is acceptable and in fact preferable,” Wadsley concluded.