Most people diagnosed with cancer have the same visceral reaction: “Get this tumour out of me – and do it fast.”
But a provocative new study suggests that prompt treatment may not be required for many cases of thyroid cancer. In fact, there seems to be very little difference in the survival odds of patients who get immediate therapy compared to those who wait a year or more to begin treatment.
“I now feel much safer telling patients … it’s okay to monitor the cancer to see if it falls into the category that needs treatment or not,” said the lead researcher, Louise Davies at the Veterans Affairs Medical Center in White River Junction, Vermont.
In recent years, Dr. Davies noted, there has been a sharp rise in the number of people diagnosed with thyroid cancer partly because of new technologies. MRIs, CT scans, ultrasounds and fine-needle aspiration biopsies can now pinpoint suspicious lumps than once evaded detection.
“These really sensitive tests may be picking up cancers that aren’t actually important. You might not need treatment – ever,” said Dr. Davies.
To assess the risks of taking a wait-and-see approach to treatment, the research team scanned patient registries of U.S. National Cancer Institute for examples of papillary thyroid cancer – the most common form of thyroid tumours – diagnosed between 1973 and 2005.
In total, they identified 35,663 cases, which included 440 people who did not undergo immediate therapy.
Among patients who were treated right away, 161 (or fewer than 0.5 per cent) died of thyroid cancer over an average of 7.6 years of follow up. Among those who weren’t treated or had their therapy delayed, there were six thyroid cancer deaths (roughly 1.4 per cent) over an average of six years.
Based on these figures, the researchers estimated that the 20-year survival rate was 97 per for those in the delayed treatment group and 99 per cent for those in the prompt treatment group, according to the findings published in the journal Archives of Otolaryngology – Head &Neck Surgery. So, overall, the death rates are very similar.
Many doctors also recommend a watchful-waiting approach for some cases of prostate cancer. But, as a general rule, thyroid tumours tend to be far less aggressive than prostate cancers.
Dr. Davies said thyroid cancers are seldom fatal. “The very rare deadly types – anaplastic and medullary – make up 2 per cent of all thyroid cancers.”
She believes immediate treatment is required in only certain circumstances, such as when patients are experiencing symptoms. A tumour in the thyroid – a butterfly-shaped gland in the neck – can affect speech, breathing and swallowing. Others in need of prompt care include patients under 20 and over 70 because they tend to get more assertive forms of the disease. People with a family history of thyroid cancer and those who have previously undergone head and neck radiation therapy are also considered to be at an elevated risk of death if diagnosed with thyroid cancer.
Still, the idea of delaying cancer treatment for most thyroid cancers is going to make many people uneasy – including some doctors. In an commentary accompanying the study, Erich Sturgis and Steven Sherman of M.D. Anderson Cancer Center in Houston caution against delay. They argue that prompt treatment is usually preferable because it’s impossible to accurately predict who among those with postponed treatment will die from the disease.
But Dr. Davies believes doctors must be up front with patients about the pros and cons of treatment. After all, undergoing cancer therapy isn’t a pleasant walk in the park. And patients who have the gland surgically removed must take a thyroid hormone pill for the rest of their lives, she said.Report Typo/Error
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