On average, women with breast cancer in 1976 had only a 45% to 50% chance of survival over the next 5 years. Now, individual patients have an impressive 80% to 85% chance of an actual cure, according to Dr. Mark Clemens, a medical oncologist at Princess Margaret Hospital in Toronto.
Three decades ago, only two forms of breast cancer were recognized: hormone positive and hormone negative. Treatment was limited to two main choices – removal of the ovaries in hormone-positive cancer and chemotherapy for hormonenegative cancer. Chemotherapy was limited to tamoxifen or aminogluthamide and was given by a one-shot-fits-all approach, said Dr. Clemens. Both drugs had a variety of uncomfortable side effects. Surgically, women were likely to undergo a complete breast removal (mastectomy), even if their tumours were small. Back then, “patients presented with more advanced disease. There wasn’t much awareness about the disease, people didn’t really talk about their breasts back then, and screening was almost unheard of,” Dr. Clemens said.
At the turn of the millennium, almost everything about breast cancer changed. Researchers discovered that several different types of breast cancer exist, each with a different level of risk. New medications are available to fight the disease, including drugs that target specific types of breast cancer. There are hormone-blocking therapies, new types of chemotherapy, and more biological agents that affect tumour growth.
Screening programs are now commonplace in Canada, and awareness of breast cancer is higher. This means that women seek help much earlier. Surgical approaches have changed, too. Only cancerous tissue is removed from the breast (lumpectomy) in women with non-aggressive cancers. There is a greater understanding of other aspects of the disease, such as the involvement of specific lymph nodes.
“Surgery and radiation treatments are much more targeted and refined than they once were. They can get rid of diseased tissue but save tissue that is healthy,” Dr. Clemens said.
Researchers are working to refine drug treatment of breast cancer even further. As more is understood about different types of tumours and what makes them work, drugs can be designed to target specific parts of specific tumours. Importantly, researchers are determining which drugs will work for specific patients – and which ones won’t. “Knowing that a drug won’t work on an individual patient is important, because then you can avoid exposing that patient to toxic effects,” he said.
While improvements in breast cancer survival are attributed to better screening, greater awareness, and a mix of scientific advances, the driving force behind that – women themselves – needs to be recognized, said Dr. Clemens. In many ways, research in breast cancer has moved ahead more quickly than in other areas of cancer, because active advocacy groups and grassroots organizations push for better treatments and cures. Their energy promises to encourage more progress in future.