Published: Thu, November 09, 2017
Medicine | By Brett Sutton

Dormant breast cancer 'can resurface 15 years later'

Dormant breast cancer 'can resurface 15 years later'

Some experts believe the treatment should be extended to 10 years.

Researchers analyzed data from 88 clinical trials involving almost 63,000 women with estrogen-receptor (ER) positive breast cancer, one of the most common types.

Every patient received treatments such as tamoxifen or aromatase inhibitors which block the effects of oestrogen or shut off the hormone's supply.

Even once the cancer has gone, these drugs are taken daily for 5 years.

Over recent years, research has found that extending the length of time that these medications are taken could reduce risks further still.

But these drugs are not without disadvantages.

Side effects can include hot flashes, vaginal dryness, osteoporosis and joint pain.

Response: The research was funded by Cancer Research UK and was made possible by a collaboration between clinical trial researchers worldwide, called the Early Breast Cancer Trialists' Collaborative Group. Pathologist Dr Done is affiliated with The Campbell Family Institute for Breast Cancer Research at the University Health Network, and an associate professor at the University of Toronto, Canada.


The figures, published in the New England Journal of Medicine, show that out of the women included in the study, 11,000 had their cancer come back in another part of the body such as the bone, liver and lung in the 15 years after stopping treatment.

Despite the cancer disappearing after five years of treatment, over the next 15 years a number found that cancer spread throughout their bodies. The authors of the article explored both the benefits and the risks of screening mammography for women ages 75 years and older.

Those who had small, low-grade tumours that had not spread had a 10% risk.

Even if the patients were recurrence-free when they stopped the endocrine therapy, they had a 40 percent risk of cancer recurrence within 15 years.

Dr Hongchao Pan, from Oxford University, said: "It is remarkable that breast cancer can remain dormant for so long and then spread many years later, with this risk remaining the same year after year".

Research suggests ten years of hormone therapy may be more effective at preventing recurrence and death.

Professor Richard Gray, one of the lead authors from the University of Oxford, said that treatment has improved since numerous women were diagnosed so recurrence rates would be somewhat lower for today's patients. Dr. Hayes told MNT that "it appears that prognosis is better for patients diagnosed over the last 10-15 years".

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