The body has different estrogens: E1 (pro-inflammatory) and E2 (protective). Current breast cancer therapies are blunt instruments, blocking both types. This indiscriminate blocking contributes to negative side effects like cardiometabolic dysfunction, highlighting a need for more targeted future treatments.
Chemotherapy is known to worsen metabolic parameters, but this should be viewed as an opportunity, not just a side effect. By actively correcting this metabolic dysfunction with adjunctive therapies, clinicians may be able to enhance the overall life-saving benefit of the chemotherapy itself.
Patients often worry that anti-estrogen therapies directly cause weight gain. However, the mechanism is more nuanced: the drugs induce a postmenopausal state characterized by inflammation and metabolic dysfunction, which, combined with natural aging, makes weight gain more likely and weight loss more difficult.
Body Mass Index (BMI) is an imperfect tool for risk assessment. A patient can have a normal BMI but a high percentage of body fat—a condition called "normal weight obesity." This is a significant, yet often overlooked, risk factor for both breast cancer development and recurrence.
Generic advice like "diet and exercise" is ineffective for cancer patients. Clinicians should adopt a pharmaceutical model, prescribing specific types and "doses" of diet and exercise based on a patient's unique metabolic profile, treatment, and clinical goals, rather than handing out a generic brochure.
The clinical goal for prescribing exercise dictates the regimen. A prescription for managing treatment-related fatigue will differ significantly from one intended as a direct anti-cancer therapy or for preventing long-term cardiometabolic disease. The type, dose, and intensity must match the specific indication.