Contextualizing the cardiovascular risk of breast cancer treatment
By Mia Wilkinson, MSc Candidate and TMED 801 Student
On January 12th the Departments of Medicine and Oncology had the pleasure of hearing from Dr. Husam Abdel-Qadir, MD, PhD during a joint Medical Grand Rounds. Dr. Abdel-Qadir introduced the field of cardio-oncology and spoke, more specifically, on cardiovascular disease (CVD) risk and outcomes in breast cancer survivors.
Cardio-oncology is an emerging field focused on reducing cardiovascular disease (CVD) risk in cancer patients and maximizing cancer treatment despite risks1. Dr. Abdel-Qadir highlighted the increasing focus on ensuring cancer patients are not receiving suboptimal cancer therapy due to fears of CVD risk. He explained that, due to the increasing aging population and medical advances, cancer survivorship is increasing2. Breast cancer is highly prevalent and has an optimistic prognosis, with a 5-year survival rate of 88%3. Due to the growing population of breast cancer survivors, Dr. Abdel-Qadir emphasized that it is no longer sufficient to 'cure' the cancer, the focus must shift to post-cancer care and the implications of surviving cancer treatment.
Dr. Abdel-Qadir then outlined the current knowledge on the cardiovascular implications of common breast cancer treatments such as chemotherapy, radiation, endocrine therapy, and trastuzumab4. While these treatments cause harm to the heart, Dr. Abdel-Qadir stressed that it is difficult to determine which patients will experience cardiotoxicity following therapy, making risk prediction complex. A trials investigating breast cancer treatment showed cardiac dysfunction in 27% of patients receiving concurrent treatment with anthracyclines and trastuzumab, a combination that is no longer prescribed5. This finding highlights the need for investigation into cancer treatment-related cardiovascular outcomes.
Dr. Abdel-Qadir then discussed how he became involved in this research. Through his work as a clinician, he noted practice variation in cancer treatment that was not guided by patient characteristics but attributed to differing perceived CVD risk. This led Dr. Abdel-Qadir to investigate CVD outcomes in breast cancer survivors. Defining risk as the likelihood of something happening or not, he explained how risk assessment can be difficult for patients to contextualize, while full understanding of the benefits and risks of treatment fosters patient autonomy. He then reviewed competing risk, or an event whose occurrence precludes occurrence of the primary event of interest. When considering time to clinically overt CVD, breast cancer is an important competing risk. He outlined the difficult process clinicians face when weighing competing risks, asking the question: which women are more likely to develop CVD and what is the impact of breast cancer treatment on these women?
Dr. Abdel-Qadir then described his research, starting with his investigations into cause of mortality following breast cancer survival. They showed that death is driven by breast cancer, except in women who had CVD prior to breast cancer onset, though, CVD risk is a more important concern in older women6. This data led Dr. Abdel-Qadir to the multi-hit hypothesis that cancer-related unhealthy lifestyle, less primary prevention of CVD, and cancer therapy all contribute to CVD risk. From these factors, Dr. Abdel-Qadir developed a risk model in which age and past medical history gives a score that correlates with CVD risk7. He also investigated the prognosis of heart failure (HF) related to breast cancer therapy or other causes; they found a poorer prognosis in non-cancer related HF patients8. He rationalised that this phenomenon likely occurs due to the acute nature of the cardiotoxic event cancer patients experience; typically, HF occurs due to persistent risk factors. Contextualizing this work, Dr. Abdel-Qadir explained a new framework in cardio-oncology, which consists of initial cardiac risk assessment, follow-up risk assessments, and advocates for long-term cardiac imaging following cancer survival.
He concluded with the concept of permissive cardiotoxicity as it applies to breast cancer treatment, where therapy is continued even though it is known to be harming the patient’s heart. He explained that HF with a poor prognosis typically emerges in women who had pre-existing CVD risk, and incident HF following breast cancer treatment may have a better prognosis. Overall, most women are better off receiving optimal cancer treatment and early detection of CVD and treatment geared to estimate risk may strike the best balance to optimize cancer and cardiovascular outcomes.
Following his lecture, Dr. Abdel-Qadir met with the TMED students to discuss the impact of his research on patients, EDII concerns, and representation in the lay press. We discussed the ethical concerns with risk assessments, specifically the barrier of wait-times for cardiac assessments, as prolonged cancer treatment delays would be unethical. We also spoke about the impact of sedentary lifestyle on CVD risk in these patients and issues with racial considerations in risk prediction. To conclude the discussion, Dr. Abdel-Qadir offered valuable insights into the pros and cons of MD/PhD programs and completing multiple degrees at one institution.
On behalf of the TMED 1st year class I would like to sincerely thank Dr. Abdel-Qadir for his stimulating lecture and invaluable advice.
- Kostakou, P.M., Kouris, N.T., Kostopoulos, V.S. et al. Cardio-oncology: a new and developing sector of research and therapy in the field of cardiology. Heart Fail Rev 2019;24:91–100. https://doi.org/10.1007/s10741-018-9731-y
- Miller, K.D., Nogueira, L., Devasia, T., Mariotto, A.B., Yabroff, K.R., Jemal, A., Kramer, J. and Siegel, R.L. Cancer treatment and survivorship statistics, 2022. CA A Cancer J Clin 2022;72:409-436. https://doi.org/10.3322/caac.21731
- Canadian Cancer Statistics Advisory Committee. Canadian Cancer Statistics 2019. Canadian Cancer Society(2019). Available at: cancer.ca/Canadian-Cancer-Statistics-2019-EN (accessed January 16, 2023).
- Mehta LS, Watson KE, Barac A, et al. Cardiovascular Disease and Breast Cancer: Where These Entities Intersect: A Scientific Statement From the American Heart Association. Circulation 2018;137(8):e30-e66. doi:10.1161/CIR.0000000000000556
- Seidman A, Hudis C, Pierri MK, et al. Cardiac dysfunction in the trastuzumab clinical trials experience. J Clin Oncol. 2002;20(5):1215-1221. doi:10.1200/JCO.2002.20.5.1215
- Abdel-Qadir H, Austin PC, Lee DS, et al. A Population-Based Study of Cardiovascular Mortality Following Early-Stage Breast Cancer. JAMA Cardiol. 2017;2(1):88-93. doi:10.1001/jamacardio.2016.3841
- Abdel-Qadir H, Thavendiranathan P, Austin PC, et al. Development and validation of a multivariable prediction model for major adverse cardiovascular events after early stage breast cancer: a population-based cohort study. Eur Heart J. 2019;40(48):3913-3920. doi:10.1093/eurheartj/ehz460
- Abdel-Qadir H, Tai F, Croxford R, et al. Characteristics and Outcomes of Women Developing Heart Failure After Early Stage Breast Cancer Chemotherapy: A Population-Based Matched Cohort Study. Circ Heart Fail. 2021;14(7):e008110. doi:10.1161/CIRCHEARTFAILURE.120.008110