**3. Discussion**

The stories and issues presented in this paper are emblematic of the flaws in the screening policies in Canada. The 46-year-old diagnosed in Story 1 with de novo stage IV breast cancer who was denied a mammogram in her 40s due to the specific screening practices within her province was dismissed on multiple occasions by her family doctor and was not informed of her breast density. Women in their 40s are not acceptable losses, particularly considering that 17% of breast cancer cases occur in this age group [67]. Many of these women have young children, are caring for aging parents, and are contributing to the economy.

Dense Breasts Canada has successfully advocated for patient notification of breast density, and ten jurisdictions (Table 4) have made changes to their practice over the past six years, but, as the stories demonstrate, more must be done to ensure access to the early detection of breast cancer for all women in Canada. We are asking for support from the medical community in advocating for: (a) updated guidelines for breast cancer screening; (b) sharing current evidence with all healthcare providers; and (c) tracking the incidence of metastatic breast cancer.

Updated policies in Canada based on scientific evidence of reduced mortality and morbidity would include: self-referral for annual mammograms across jurisdictions starting at the age of 40; directly informing all women having a screening mammogram of their breast density and the associated risks of dense breasts; and offering annual supplemental ultrasound screening (in addition to mammograms) to all women with dense breasts (Category C and D), regardless of family history. Additionally, high-risk women should be identified and offered supplemental MRI where available.

Furthermore, although this study focuses on Canada, we recommend that internationally updated guidelines be based on the latest scientific evidence. The documentation suggests that breast screening policies in other countries have been influenced by the outcomes of the CNBSS, which is cited in screening guidelines and recommendations for the US [10], UK [68], Europe [69,70], and Australia [71]. The CNBSS study has been discredited [12] and should be retracted from the medical literature. Oncologists and other breast cancer specialists globally can advocate for updated screening guidelines.

We recognise that advocacy will not change outdated screening guidelines and practices overnight. To reduce the incidence of stage IV breast cancer, medical professionals, advocates, and patients need to be presented with the benefits and limitations of screening based on current evidence. This specifically includes: directly addressing gaps in education relating to breast density; the benefits of screening at the age of 40 and breast cancer in younger women; and an increased awareness of eligibility of women for screening. Advocacy is the responsibility of all stakeholders in the breast cancer community. Contradictions in the guidelines compared with the latest evidence can be presented at local, national, and international conferences of medical practitioners; specifically, nurses and family practitioners. Information can be included in the content for continuing medical education sessions. Importantly, whilst women are referred to oncologists at the stage of breast cancer

identification and treatment, conversations with patients are essential to highlight the latest evidence of screening.

Finally, we need to track the incidence of stage IV breast cancer across the jurisdictions in Canada to actively support the development of policies and practices that target a reduction in the incidence of late detection. This has recently been implemented in the province of Quebec where the incidence of stage IV breast cancer is being tracked to support research into screening, diagnosis, manifestation, and treatment [72].

Our article includes six stories from women with stage III and de novo stage IV breast cancers to demonstrate the significant impacts of misguided policies as well as misinformation among the medical community and patients. These stories were chosen as they exhibit the impacts of late diagnosis, but there are also many positive stories of screening and early detection.

**Story 7.** *A 41-year-old woman living in Prince Edward Island self-refers for a mammogram, which leads to the detection of stage I Invasive Ductal Carcinoma. It is confirmed by the general practitioner and surgeon that the tumour could not have been identified by a physical examination. She has surgery to remove the tumour and sample the lymph nodes, 21 rounds of radiation, and hormone therapy scheduled for the next 5–10 years. She knows that access to self-referral for screening from the age of 40 in her province allowed her breast cancer to be found early.*

**Story 8.** *A 40-year-old woman from British Columbia is encouraged by her family doctor to have a screening mammogram to obtain a "baseline" and understanding of her breast density. Her breasts are identified as dense, and an abnormality is detected. She has a diagnostic mammogram, ultrasound, and then biopsy and is diagnosed with stage I breast cancer 17 days after her initial screening mammogram. She has a lumpectomy, completes 20 rounds of radiation, and receives hormone therapy, which is scheduled for the following 5 years. She is grateful to have been able to self-refer for screening at the age of 40, and that her proactive family doctor recommended her to go.*
