Precision Medicine in Breast Cancer
Sara Hassan, MD
Arab Board of Medical Specializations Certificate in General Surgery
Associate Consultant of Oncoplastic Breast Surgery
Hamad Medical Corporation
Breast cancer is the most commonly diagnosed malignancy in females in Qatar (and worldwide), with a calculated percentage of 40% of all female cancers diagnosed between 2016-2018 in Qatar. It is also the second most common cause of cancer death in women.
Evidence is emerging on a daily basis to prove to us that breast cancer is a heterogenous group of diseases varying in presenting symptoms, clinical behavior, natural course of disease, prognosis, and response to treatment. Hence, the management of breast cancer is a multidisciplinary approach involving surgical oncology, radiation oncology and medical oncology. There is no “one size fits all” in the management of breast cancer; this necessitates the raising of awareness among the community and among healthcare workers in order to decrease the confusion between patients and families cause by contrasting and comparing their cases to other patients.
Immunohistochemistry has been used over decades to divide the types of breast cancer into ductal vs. lobular vs. rarer types, hormone receptor positive vs. negative, HER2 enriched vs. non-HER2 enriched tumors and so on, which gave general guidelines with regards to treatment approach. However, over the past 11 years or so this has been studied more extensively and looked into in detail to classify breast cancer into its currently widely accepted molecular subtypes: luminal A, luminal B, HER2 enriched, basal-like, and normal-like breast cancer. This classification proved more accurate in determining treatment response predictors and prognostic factors of breast cancer. Moreover, evidence is emerging that the same type of breast cancer may behave differently in patients of different age groups. One of these studies was performed at Hamad Medical Corporation (HMC), which reviewed breast cancer in the elderly and highlighted the differences in treatment response and management outcome.
A step further in the personalization of care was taken with modern technology kicking in and introducing gene expression profiling, which is “a genetic microarray analysis of genetic transcriptional variations between normal and malignant cells.” This helped us understand more fully the heterogeneity of the disease and shed more light on prognosis to guide treatment approach. The most commonly used such gene profile at HMC is the Oncotype Dx, which is a 21-gene recurrence score that helps to identify women with node-negative, hormone-receptor-positive breast cancer who would benefit from the addition of chemotherapy to the traditional hormonal therapy.
Surgical management has also progressed significantly from the Halsted radical mastectomy to breast conserving surgery to the current more complex oncoplastic surgical techniques of breast conservation and breast reconstruction - all depending on patient factors, tumor characteristics, breast size and shape, response to neoadjuvant treatment, and need for adjuvant radiotherapy. Radiotherapy in turn has progressed significantly with the help of modern technology and research with more personalized dose calculations and fractionation, and techniques of delivery of the radiotherapy to the breast/chest wall and the regional lymph node basin.
Hence, women must be advised to refrain from comparing themselves or their acquaintances to others. And healthcare professionals need to be able to explain to them and assure them that no “one size fits all” and that the treatment approach is multidisciplinary and personalized to each woman independently.
References:
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- Anand, A, et al. Clinical Presentation, prognostic factors, Management and Outcome of Breast Cancer in The Elderly: Does Age Matter? Presented in the Annual Breast Cancer Conference 2022- Qatar
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