10/24/2017 16:56 EDT | Updated 10/24/2017 17:00 EDT

HER2+ Breast Cancer Is Aggressive And Scary, But There's Good News Too

The cancer, which can affect women of any age, is responding successfully to targeted therapies.

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October is Breast Cancer Awareness month (BCAM), and while plenty of campaigns are raising money and awareness, the number of Canadians diagnosed with this illness keeps increasing. The Canadian Cancer Society estimates that more than 25,000 men and women were diagnosed with breast cancer in 2016, and nearly 5,000 died as a result.

One less known variation of this disease is HER2+, a particularly fast-growing type of cancer that disproportionately affects younger women — some even in their 20s and 30s. HER2+ diagnoses account for around 500 cases each year, and before recent developments in targeted cancer treatment, carried a high mortality rate.

Earlier on HuffPost:

Overexpression of the HER2 growth factor receptor is what drives the extreme growth of breast cancer cells in HER2+ patients, and also makes it resistant to chemotherapy and endocrine treatments, explains Dr. Philippe Bedard, medical oncologist in the breast cancer program at Princess Margaret Cancer Centre, University Health Network.

"These are typically fast-growing cancers that often present in between screening mammograms," he says. Younger women especially are sometimes diagnosed with breast cysts rather than cancer. While some rare genetic conditions predispose a HER2+ mutation, it's otherwise random in who it affects.

With no family history of breast cancer and no symptoms, the diagnosis came as a shock.

Bedard says those with metastatic HER2+ breast cancer have a median survival rate of about five years, but if diagnosis and targeted treatment happen early, those rates can be greater than 90 per cent after three years.

"Advent of HER2-targeted therapy has completely changed the outcome of this disease," he says.

He says that recognition of the HER2+ subtype and the development of targeted therapies for HER2+ breast cancer was one of the first successful examples of modern targeted therapy and precision medicine for solid tumours, representing the culmination of several decades of research.

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Debbie Mills, of Vancouver, received her HER2+ cancer diagnosis in January 2017 at the age of 52. With no family history of breast cancer and no symptoms, the diagnosis came as a shock following a routine screening mammogram.

"My heart sunk. I was shocked and of course, scared," she says. It took several rounds of testing before doctors confirmed she had invasive ductal carcinoma. Further testing confirmed the HER2+ variation. A PET scan showed the cancer may have spread to her lymph nodes, but not elsewhere.

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Top view of a female breast with a tumour.

"Not the best news but not the worst news either," she says. "Getting the PET scan results was a big relief — I realized that I still didn't know what would happen in the future, but at least I wasn't going to die right away."

She describes those first few weeks following her diagnosis as a whirlwind.

I never realized just how many different factors and nuances there are to a diagnosis and a treatment plan.

"Waiting for results is really hard, especially when they have to go back and retest. You get your hopes up, but in the darkest moments you imagine the worst, and then the truth is somewhere in between. You want to be doing something because you have visions of the cancer multiplying and spreading in your body while you wait. It's a real roller coaster.

"And it was really confusing and overwhelming, because the doctor would explain to me that if this test showed this, we would do that and if not, we would do something else. I never realized just how many different factors and nuances there are to a diagnosis and a treatment plan."

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Cancer treatment chemotherapy room

When HER2 cancer is diagnosed will determine treatment options, notes the Canadian Cancer Society. For early stage disease, Bedard says chemotherapy, HER2-targeted treatment (with the drug trastuzumab), and possibly endocrine therapy are used.

Those with advanced disease will often undergo chemotherapy and dual HER2-targeted treatment initially. If that treatment is unsuccessful, the drug Kadcyla (TDM1) is the next stage treatment.

I'm just really f---ing tired of having cancer.

For Mills, whose treatment plan will take 14 months in total, it's been a rigorous schedule of chemotherapy and radiation, targeted drug treatments, and most recently, a single mastectomy. She will also take the drug Letrozole for the next five years, in order to block estrogen production to lower her risk of recurrence.

"Going through treatment takes up a lot of your mindspace until it's easy to feel like you don't have a life outside of cancer," she says. "Right now I'm finding going to radiation to be especially emotionally wearing. Probably because I've already gone through so many months of treatment and still have many more to go. I'm just really f---ing tired of having cancer."

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One thing that has given her hope is the Canadian Cancer Society's online support group Cancer Connection. (The organization also offers a telephone-based service to allow people with cancer to speak with former patients.) Mills says that hearing from other women about what they have gone through has been inspiring and helpful.

"[It] makes the whole experience less scary."

Mills and her oncologist are both optimistic about her prognosis, given that her disease was caught in the early stages, and she has been responding well to treatments.

I'm just not sure how to get women like me, who think that it won't happen to them, to listen.

"I've never really lost hope," says Mills. "There were a few times at the very beginning when I didn't know if it had spread that I would start to think 'what if' but I tried not to dwell on that too much. That doesn't mean I never have down days.

"I wish I had learned more about risk factors and prevention and I think there is opportunity for BCAM to contribute there. I'm just not sure how to get women like me, who think that it won't happen to them, to listen."

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