Cancer and hypertension induced by anticancer drugs: The need for increased awareness, improved detection and proactive management

Cancer can be a devastating disease and new anticancer drug therapies in combination with radiotherapy and surgery have markedly improve survival in these patients. Nonetheless, it is increasingly recognised how some cancer drug therapies have associated toxicities on the cardiovascular system, resulting in incident cardiovascular conditions or exacerbating underlying cardiac conditions1. Indeed, cardio-oncology has dramatically grown as a subspecialty, providing specialist care input for these patients.

Cardiovascular toxicities associated with anticancer drugs can include cardiac arrhythmias, such as atrial fibrillation, but one of the more common side effects of some anticancer drugs is hypertension which may be undetected². Of course, patients with cancer may also have underlying hypertension given how common this cardiovascular risk factor is present. Anticancer drugs such as tyrosine kinase inhibitors and proteosome inhibitors are commonly associated with hypertension, as is antiandrogen hormone therapy for prostate cancer². In addition, many patients with cancer require ancillary drug therapies, including corticosteroids and nonsteroidal anti-inflammatory drugs, which worsen hypertension.

The recent American Heart Association (AHA) Scientific Statement on Cancer Therapy-Related Hypertension is therefore a timely document which will be welcomed by the medical community³. The scientific statement provides a background of the epidemiology and clinical studies relating to hypertension associated with anticancer drugs and delves into molecular and pathophysiological mechanisms that may contribute to increases in blood pressure. Given that many patients in active cancer are excluded from large prospective randomised trials of hypertension, the document also provides a pathway for the diagnosis, management and follow up of cancer therapy induced hypertension.

Whilst the approach in the American Heart Association (AHA) Scientific Statement is aligned with hypertension guidelines, this largely extrapolates evidence from clinical trials in non-cancer patients.

It is also possible that cancer therapy induced hypertension could be associated with other ancillary cardiovascular complications such as atrial fibrillation and heart failure. Hence, it is important that these that physicians looking after such cancer patients be aware of these potential complications given that this may well contribute to an increase in cardiovascular events amongst cancer survivors.

What are the take home messages? The assessment of patients with cancer prior to being started on specific anticancer drugs should include a comprehensive cardiovascular risk assessment and proactive management of associated comorbidities¹. Since cardiovascular risk is not static, but dynamic, it is important to continue re-assessments of the patient during the cancer therapy delivery.

Management of hypertension requires not just antihypertensive drug therapies but also attention to lifestyle changes and addressing predisposing factors leading to hypertension, such as sleep apnea. Cardiovascular risk is also mitigated by attention to lifestyle factors such as physical activity, smoking and alcohol consumption, which need to be addressed as part of the holistic approach to managing such patients. Should further complications occur, such as atrial fibrillation then these patients would require management accordingly, with oral anticoagulation, rate or rhythm control, and attention to comorbidities^{4, 5}.

Clearly, there is an opportunity for a multidisciplinary approach to proactive management of such patients with cancer, which will require a team approach that should include oncologists, cardiovascular physicians (including hypertension specialists), primary care, pharmacists, and patient and their carers or relatives.

In summary, the AHA statement provides a useful approach to patients with cancer who develop hypertension or those with underlying prevalent hypertension whose blood pressure is further exacerbated by initiation of anticancer drugs. Increased awareness, detection and proactive management of the condition, and any associated hypertension-related complications would improve care of such patients.