Stage Shifting by Modifying the Determinants of Breast Cancer Stage at Diagnosis: A Simulation Study

Gyanendra Pokharel; Qinggang Wang; Momtafin Khan; Paula J Robson; Lorraine Shack; Karen A Kopciuk

doi:10.3390/cancers16061201

Stage Shifting by Modifying the Determinants of Breast Cancer Stage at Diagnosis: A Simulation Study

Cancers (Basel). 2024 Mar 19;16(6):1201. doi: 10.3390/cancers16061201.

Authors

Gyanendra Pokharel¹, Qinggang Wang², Momtafin Khan², Paula J Robson^{3

4}, Lorraine Shack⁵, Karen A Kopciuk^{2

6

7}

Affiliations

¹ Department of Mathematics and Statistics, University of Winnipeg, 515 Portage Avenue, Winnipeg, MB R3B 2E9, Canada.
² Cancer Epidemiology and Prevention Research, Cancer Care Alberta, Alberta Health Services, 2210 2nd Street SW, Calgary, AB T2S 3C3, Canada.
³ Department of Agricultural, Food and Nutritional Science and School of Public Health, University of Alberta, 116 Street & 85 Avenue, Edmonton, AB T6G 2P5, Canada.
⁴ Cancer Care Alberta and Cancer Strategic Clinical Network, Alberta Health Services, 10030-107 Street NW, Edmonton, AB T5J 3H1, Canada.
⁵ Cancer Surveillance and Reporting, Cancer Care Alberta, Alberta Health Services, 2210 2nd Street SW, Calgary, AB T2S 3C3, Canada.
⁶ Department of Oncology, University of Calgary, 1331 29 Street NW, Calgary, AB T2N 4N2, Canada.
⁷ Departments of Community Health Sciences and Mathematics and Statistics, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada.

Abstract

Background: Breast cancer is the most common cancer in Canadian women; nearly 25% of women diagnosed with cancer have breast cancer. The early detection of breast cancer is a major challenge because tumours often grow without causing symptom. The diagnosis of breast cancer at an early stage (stages I and II) improves survival outcomes because treatments are more effective and better tolerated. To better inform the prevention of and screening for breast cancer, simulations using modifiable rather than non-modifiable risk factors may be helpful in shifting the stage at diagnosis downward.

Methods: Breast cancer stages were simulated using the data distributions from Alberta's Tomorrow Project participants who developed breast cancer. Using multivariable partial proportional odds regression models, modifiable lifestyle factors associated with the stage of cancer at diagnosis were evaluated. The proportions or mean levels of these lifestyle factors in the simulated population were systematically changed, then multiplied by their corresponding estimated odds ratios from the real data example. The effects of these changes were evaluated singly as well as cumulatively.

Results: Increasing total dietary protein (g/day) intake was the single most important lifestyle factor in shifting the breast cancer stage downwards followed by decreasing total dietary energy intake (kcal/day). Increasing the proportion of women who spend time in the sun between 11 am and 4 pm in the summer months, who have had a mammogram, who have been pregnant or reducing the proportion who are in stressful situations had much smaller effects. The percentage of Stage I diagnoses could be increased by approximately 12% with small modifications of these lifestyle factors.

Conclusion: Shifting the breast cancer stage at diagnosis of a population may be achieved through changes to lifestyle factors. This proof of principle study that evaluated multiple factors associated with the stage at diagnosis in a population can be expanded to other cancers as well, providing opportunities for cancer prevention programs to target specific factors and identify populations at higher risk.

Keywords: Alberta’s Tomorrow Project; breast cancer stage; breast neoplasms; early detection of cancer; lifestyle; neoplasm staging; simulation study; stage shift.

Grants and funding

This work was supported by an operating grant received from the Canadian Institutes for Health Research (Primary Investigators Kopciuk, Robson, and Shack), grant number PJT-148774.