Older women with early breast cancer may not need radiation: McMaster study

Older women with early-stage breast cancer may not have to undergo radiation therapy after surgery, a new study by McMaster University revealed.

The study tracked 501 women with early breast cancer who had undergone surgery between 2013 and 2017.

Women were given hormone-blocking pills post surgery, but did not undergo radiotherapy.

Five years later, only 2.3 per cent of women experienced a recurrence of breast cancer - well below the five per cent projection McMaster researchers had set.

The study found that women 55 and over with early-stage breast cancer can be treated with just surgery and endocrine therapy.

Dr. Timothy Whelan, a Canada Research Chair in breast cancer research and a professor at McMaster University, said cancer relapse after surgery has steadily decreased" over the last two decades as science progressed.

So far, radiation therapy has been the most effective way to prevent cancer relapse in the breast.

But Whelan said it's an inconvenient" and expensive therapy that requires between three and five weeks of daily treatment, and is associated with various side effects like skin irritation, fatigue, breast pain and breast distortion.

On rare occasions, radiation therapy can cause life-threatening complications like cardiac disease and second cancers, Whelan said.

At least 27,400 women in Canada were diagnosed with breast cancer in 2020, with 83 per cent of those aged over 50. A majority of breast cancer cases (82 per cent) are identified when they're in stage one or two.

Whelan said the number of women with breast cancer is much higher" across North America, and between 30,000 to 40,000 women could be eligible for this approach."

The Canada-wide study was carried out in 26 centres including Vancouver, Hamilton, and Toronto. Women with a cancerous tumour that was less than two centimetres, who had already undergone lumpectomy, were treated with endocrine therapy - including regularly measuring estrogen and progesterone receptors, and other hormone controlling medication, Whelan said.

If radiotherapy is omitted, it will also bring down the costs of the treatment, besides the physical discomfort and pain of radiation.

Whelan noted radiation therapy can amount to $5,000, alongside other expensive molecular testing on cancers that help determine the need for chemotherapy.

That said, Whelan noted endocrine therapy may also have side effects for some patients, including exacerbated menopausal symptoms" or arthritis, but generally, they're well-tolerated."

McMaster researchers are now looking into the treatment efficacy without radiotherapy in postsurgery patients with breast cancer for 10 years.

Ritika Dubey is a reporter at The Spectator. rdubey@thespec.com