Thank you.

Honourable members, thank you for your invitation to testify today on breast cancer screening.

As a medical oncologist as well as a 41-year-old woman, concerned for both the well-being of my patients and the health of my generation, I was deeply disappointed with the draft report from the Canadian Task Force for Preventive Health Care last month.

The report significantly overstates the harms of screening while ignoring the benefits of early detection. What has been missing from the ongoing public discourse are the benefits of early detection of breast cancer from a treatment perspective. We hear frequently about the harms of screening, but there's been little discussion about the differences in treating a cancer that is clinically evident versus screen detected.

Treatment of breast cancer is complicated, and it is expensive. Beyond surgery and radiation, I offer patients medical treatments to reduce their risk of recurrence or dying of cancer. While the task force mentioned chemotherapy and no chemotherapy, our treatments today go far beyond that, including things like immunotherapy, targeted therapies, antibody-drug conjugates, cell cycle blockers and up to 10 years of hormone-blocking therapy for patients with stage 3 hormone-sensitive breast cancer.

Catching a breast cancer at an early age when it becomes clinically detectable reduces the need for extensive medical treatment and lowers the risk for distant recurrence and death. A larger tumour with lymph node involvement, which has become clinically evident to a patient, means higher risk disease and, therefore, more treatments to achieve similar outcomes, leading to higher costs for both individuals and our society.

Individual costs include time out of work, hair loss, cognitive dysfunction, chronic fatigue, sexual dysfunction, infertility, premature menopause, nerve damage, cardiac complications and mental health issues, not to mention the constant fear of recurrence.

The financial toxicity of breast cancer treatment is real and is carried by all of us in our publicly funded health care system. As was just mentioned, we know that the costs significantly increase by stage, with screen-detected stage 0 cancer costing only about $14,000, whereas stage 3 cancer management in Ontario today, based on the treatments we use and publicly funded, costs nearly $400,000.

This year we took those numbers and put them into cost-effective analysis using the same OncoSim modelling that CPAC has endorsed. We found that not only is this cost-effective; it's cost saving because the treatment of breast cancer at stage 4 is so very expensive.

Screening typically diagnoses breast cancers at an early stage. Only 35.7% of women age 40 to 49 in Ontario are diagnosed with stage 1 disease in the absence of an organized screening program, whereas, for those who participate in the Ontario breast screening program between ages 50 and 74, nearly 87% will be diagnosed with stage 1 or stage 0 cancer.

The communication tool provided by the task force meant to inform discussions between patients and their primary care providers about the risks and benefits of screening at an earlier age makes no mention of the downstaging that's achieved by early detection with a screening program.

The updated guidelines raise many questions. There are major discrepancies between the Canadian and U.S. task forces in terms of the benefits estimated for population-based screening. The U.S. task force predicts more deaths averted and lives saved than the Canadian task force by reducing the age of screening to 40, but even with the conservative Canadian estimate, lowering the age of screening to 40 from 50 would prevent an additional 2,600 deaths over the 10 years of screening in the demographic of women aged 40 to 49.

The task force has opined that this benefit does not justify the harms of additional testing and a few overdiagnosed cases. On this point, I disagree as does the literature, from which we know that women will accept up to six overdiagnosed cases to save one life.

The task force has also ignored the long-term benefits of early detection by focusing only on a 10-year time frame in terms of both the report and the discussion tools to evaluate the benefits of screening. The reality is that, for the most common type of breast cancer, which is hormone sensitive, even if you have a stage 2 or stage 3 breast cancer that may come back some way, probably, even if it does recur within that 10-year time frame, in 10 years you're still going to be alive. You'll just have stage 4 disease and be living through chronic treatments.

As my patients will tell you, living with cancer is not the same thing as surviving it, but the tools being provided to our family physicians make no differentiation of the two points.

Until we figure out a way to prevent breast cancers from developing, the only way to reduce morbidity and mortality as well as the cost to our health care system is with early detection. The task force has significantly minimized the benefits of early detection and has not provided transparent modelling data about the downstaging that can be achieved with an organized screening program. Without this crucial part of the conversation, we are only informing women about half of the story.

I hope my testimony today will start a broader conversation about the harms of breast cancer treatment and the risks of delayed diagnosis.

Thank you.