[Cathya]

I think this could be what they're talking about.

Zuri Scrivens was 33 when she was diagnosed with breast cancer.

Now 35, she’s part of a study investigating the possible benefits of metformin, a drug normally used to treat diabetes. She is also on letrozole, a drug that is used for the treatment of estrogen-positive breast cancer.

“I feel as if my initial treatment in 2011 was not specific enough for me, because some cells stuck around,” Scrivens said. “Perhaps if I’d been able to be part of these studies earlier on, I might have been put on the appropriate chemotherapy, I might have gone on the letrozole earlier, and stopped any sort of spread.”

Specificity is a crucial element in the treatment of breast cancer. Dr. Stephen Chia believes that this is where we will see the most benefits when it comes to treating breast cancer in the coming years.

A medical oncologist and chair of the Provincial Breast Tumour Group, Chia has been with the BC Cancer Agency for 11 years. He says that the drugs that will likely prove to have the most effect on cancer treatment in the next year are T-DM1 and pertuzumab. Both are antibodies that target HER2-positive cancer, generally considered a more aggressive cancer than estrogen-positive cancer.

“Studies have shown giving both antibodies with chemo is better than giving either antibody alone with chemotherapy,” he said.

“It’s not just chemotherapy that is effective, it’s also blocking the pathway receptor. We don’t truly understand everything that happens when you give a patient the antibody in terms of how it works, but it works in a significant proportion of patients.”

T-DM1 combines an antibody called trastuzumab with a cancer-killing agent, DM1. Both trastuzumab and pertuzumab block the HER2 pathways by blocking the receptors on the cancer cells.

“We’re trying to become more sophisticated with biological agents that target the receptors, or pathways,” Chia said.

Targeting the receptor allows more selective delivery of chemotherapy to the cancer cells.

“When we give chemotherapy intravenously, it circulates through the body and gets taken up across cells, both normal and abnormal,” Chia said. “Typically, the cancer has more blood vessels and HER-2 receptors, so you would expect more drug distribution there. The antibody conjugate principle is that the antibody brings the drug specific to the cells, in this case the HER-2 cells. So you bring a lot more chemo drugs specifically to cancer cells.”

Another drug he believes will have an effect on cancer treatment is called everolimus.

In combination with a hormonal drug, everolimus doubles the benefit of the hormonal drug. “It blocks a specific pathway that is activated in probably half of estrogen-positive breast cancers,” he said. The pathway is called the PI3K-mTOR pathway.

Metformin, which Scrivens is being treated with, is also being investigated for its possible benefits in treating estrogen-positive breast cancer.

“There’s a lot of interest in the insulin pathway having effects on cancer cells,” said Chia. “If shown to be effective, it could be widely applicable and not expensive.”

Scrivens had numerous treatments following her 2011 diagnosis.

The Langley resident had a right-side mastectomy following three months of chemo and five weeks of radiation therapy.

She then went tamoxifen, a hormone drug for pre-menopausal women with estrogen-positive breast cancer. She also had her left breast removed “for easy of worry, to avoid anxiety,” she said.

Yet the cancer persisted. In December of last year she discovered a pea-sized lump below her clavicle. A biopsy revealed it to be cancerous.

Her doctor, oncologist Karen Gelmon, took her off the drugs she’d been on and put her on faslodex, which stops the ovaries from functioning. Scrivens was also put in a couple of studies, including a PET-CT study. The study applies an estrogen tracer in the body to find “hot areas” that respond to estrogen.

She was also put on a genetic sequencing study that compared her new and old tumours.

“I do feel that it has been able to give us a really good look at what kind of cancer I have,” she said. “There’s a huge variety of types. So to say that this or that drug or this or that treatment will work for all women or all people that get breast cancer is false. The more you can find out, the better. That’s why these tests are so great.”

Based on those findings, Scrivens was put on letrozole, a common treatment for estrogen-positive breast cancer, following chemotherapy, and metformin.

She believes these treatments have helped.

“I feel fantastic,” she said. “Though the tough thing about cancer sometimes is that you can feel quite well. But my side-effects have been kept to a minimum, and I’ve been doing a lot of additional therapies. I do acupuncture, meditation, yoga, I’ve changed my diet a bit. All the things you need to do to stay healthy.”

Besides drug treatments, advances in radiation therapy are also helping breast cancer patients, Dr. Chia said.

Called radio surgery, it’s used on women with an advanced stage of the disease, and usually targeted to a limited number of lesions.

“They’re considering giving fairly high-dose radiation to the area to obliterate those lesions much more so than ever before,” Chia said.

“The concept is the dose you’re giving is possibly going to kill off the cells. You’re not actually doing surgery but you’re giving higher-dose radiation.”

The BC Cancer Agency is also part of a trial which is investigating whether more chemotherapy delivered before surgery rather than after might be beneficial.

“I’d like to see a day where standard chemotherapy might be a thing of the past or minimally given,” Chia said. “I don’t think we’ll get away from hormonal therapy because, in the big picture, it’s not as toxic as other therapies, and has been clearly shown to have a lot of impact on these cancers.”

He notes that women with Stage 4, or advance breast cancer, are living longer now than they have in the past.

“We believe part of that is because of newer drugs,” he said.