Baroness Delyth Morgan, chief executive of Breast Cancer Now, said: "It's fantastic news this landmark study could enable thousands more breast cancer patients over 50 to be safely spared gruelling chemotherapy". Others want chemo for even the smallest chance of benefit.
"We have been waiting for these results for years", said Allison Kurian, an oncologist at Stanford University who wasn't involved in the trial. Most women in this situation don't need treatment beyond surgery and hormone therapy, he said.
"These data confirm that using a 21-gene expression test to assess the risk of cancer recurrence can spare women unnecessary treatment if the test indicates that chemotherapy is not likely to provide benefit", lead author Dr. Joseph A. Sparano, associate director for clinical research at the Albert Einstein Cancer Center, said in a statement.
Following 10,273 women who had the most common type of breast cancer, researchers examined outcomes for the 69 per cent of patients who scored between 11 - 25 on the test.
Breast cancer is the leading cause of cancer death in women worldwide, causing some 1.7 million new cases annually and over half a million deaths.
Patients with a recurrence score of up to ten out of 100 have previously been shown not to benefit from chemotherapy and need only hormone treatment. Now they can have confidence in those decisions, experts said.
The cancer in question is driven by hormones, has not spread to the lymph nodes and doesn't contain a protein called HER2.
These were divided into groups that will receive chemotherapy followed by hormonal therapy or hormonal therapy alone.
Breast cancer is the most common cancer among women in India.
Sunday's results came from a federally sponsored trial called TailorX, which was created to help doctors more precisely tailor treatments for early-stage breast cancer.
Dr. Steven Shak, chief scientific officer at Genomic Health, said about four in 10 women in the United States with early stage breast cancers are not tested for recurrence risk.
A 21-gene test called Oncotype Dx that has been around for years has helped guide some decisions. Those who score low on the test - from zero to 10 - are already told to skip chemotherapy after their tumors are removed and they receive hormone therapy.
To find the answer, researchers randomly assigned more than 6,700 women with intermediate scores - 11 to 25 - to two groups. Chemotherapy could still be on the table for people who fall outside of this group.
Women aged 50 or younger were the notable exception.
Laccetti's cancer has not returned.
These gene tests are only applicable to patients with early-stage invasive breast cancer, Loyola's Albain says. Because of that, many women with early-stage cancer used to be urged to get chemotherapy in hopes of preventing any spread.
Other less common but more serious side effects of chemotherapy include bone loss and osteoporosis, heart and vision problems.
Oncotype DX first hit the market in 2004.
Yet the move away from chemotherapy has been hotly debated, with some doctors warning that chemo can save lives and that a "de-escalation" of treatment could be risky.
Commenting on the results, Professor Bryan Hennessy, Clinical Lead, Cancer Trials Ireland, said this could be critical for how breast cancer patients are treated. He expects treatment guidelines to quickly change based on the study, which was conducted by a research group named ECOG-ACRIN.
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The company now provides tests to more than 900,000 patients in more than 90 countries, Shak said. "I'm a firm believer in medical research".
"One of the challenges that we've had in breast cancer is we thought once size fit all, and everyone was getting too much treatment", Olopade said. The drug was approved in 2014 for melanoma and in 2015 for lung cancer.
Harold Burstein, a breast cancer specialist at Dana-Farber Cancer Institute, said that in some ways the debate over de-escalation misses a larger issue. However, there was a range between favourable and unfavourable where it was not clear whether we should give chemotherapy.
China condemns USA comment on disputed Island
Additional officials from the Departments of Commerce, Treasury, Energy, Agriculture and the U.S. The Philippines has already sought accommodation with China, rather than contest its claims.
Petrol, diesel prices cut by 9 paise each
The new price for subsidised cylinder in Delhi is Rs. 493.55, while that of non-subsidised cylinder is Rs. 698.50. In the 16 consecutive increases since May 14, petrol price was hiked by Rs 3.8 per litre and diesel by Rs 3.38.