Hypertension and cancer: 9 things to know about high blood pressure

Hypertension is the scientific term for high blood pressure — that is, when the force exerted on the walls of the blood vessels is consistently too high. Hypertension is one of the most common chronic health conditions affecting adults. It’s even more common than diabetes or high cholesterol. Almost half of all American adults have it.

But can having high blood pressure affect your cancer treatment? Is there any connection between hypertension and cancer? And, is there anything you can do to prevent it? Read on for answers to these and six other questions.

What constitutes a ‘normal’ blood pressure?

Normal blood pressure is below 120/80 mmHg. It is measured in millimeters of mercury (mmHg) and recorded as two numbers, separated by a line. 

• Systolic pressure is the top (or first) number. It represents the pressure exerted when the heart beats.
• Diastolic pressure is the bottom (or second) number. It represents the pressure exerted when the heart is resting, between beats.

 Generally speaking, high blood pressure occurs in two stages: 

• Stage I: systolic between 130 and 139 or diastolic between 80 and 89 mmHg 
• Stage II: systolic of 140 mmHg or higher; diastolic of 90 mmHg or higher 

How would I know if I have high blood pressure?

Hypertension is often called “the silent killer” because it typically has no symptoms, yet it causes significant damage to the body over time. So, the easiest way to find out is by checking your blood pressure several times a week.

To get the most accurate readings, measure your blood pressure while seated, after a few minutes of rest. Your feet should also be flat on the floor and not crossed at the ankles. Your other arm should be held at the level of your heart or resting on your lap.

Who is most likely to develop hypertension?

Hypertension can occur at any age, but your risk increases significantly as you get older. Aging causes the blood vessels to become stiffer, which contributes to rising blood pressure. 

Men tend to develop hypertension earlier than women, though after menopause, women’s risk catches up. Hypertension is also being diagnosed increasingly in younger people due to sedentary lifestyles, diet, and excess body weight. 

When should hypertension be treated?  

If your blood pressure readings are elevated on multiple occasions, talk to a doctor. Your doctor will assess your individual situation, including age, medical conditions like diabetes or kidney disease, risk factors like smoking, and any family history of heart disease. 

Treatment for stage I hypertension typically starts with lifestyle modifications such as weight loss, exercise and a low-sodium diet. Medication may be recommended if you have other risk factors, or if your blood pressure does not respond adequately within 3-6 months.

For stage II hypertension, treatment usually involves both lifestyle changes and medication. 

Why is it important to control hypertension?

If left untreated, hypertension can damage the body in several significant ways. 

Heart

Hypertrophy, or a thickening of the left ventricle, can be seen on an echocardiogram. It is a sign of longstanding high blood pressure. It happens because your heart must work harder to push blood through the circulatory system. 

Blood vessels

Over time, high blood pressure can literally wear your blood vessels out, causing them to leak fluid into surrounding tissues. It can also cause arteries to stiffen and thicken, making them more brittle. 

Kidneys

When subjected to chronic high blood pressure, the kidneys may start allowing albumin to leak into the urine. Albumin is a circulating protein that helps keep water in the bloodstream and out of surrounding tissues. 

Eyes

Retinopathy occurs when the tiny blood vessels in the back of the eye are damaged by high blood pressure, resulting in blurred vision or even vision loss. Hypertension may also cause bleeding in the eyes, known as subconjunctival hemorrhage. 

Brain

Hypertension can reduce blood flow, which may affect brain function, contributing to cognitive decline or dementia. 

The good news is that controlling your blood pressure significantly reduces all of these risks. 

How does having hypertension affect cancer treatment? 

Several therapies are known to cause or worsen hypertension. So, high blood pressure can significantly impact your cancer treatment. 

Targeted therapies

Many new cancer drugs, particularly those targeting blood vessel formation (antiangiogenic agents) like bevacizumab; as well as tyrosine kinase inhibitors (TKIs) like sunitinib, sorafenib and pazopanib; commonly cause hypertension because they interfere with vascular endothelial growth factor inhibitors (VEGF), which help regulate blood pressure. 

Immunotherapy

Some immune checkpoint inhibitors and other immunotherapy drugs can affect blood pressure. 

Chemotherapy

Certain classic chemotherapy agents, including cisplatin, can elevate blood pressure. Hormone therapies can, too. 

Corticosteroids

Prednisone, hydrocortisone, and dexamethasone are steroids commonly used to manage side effects that can raise blood pressure and cause fluid retention.

The risks of heart failure, heart attack, irregular heartbeat, and kidney damage are significantly higher if someone has hypertension and they’re receiving cancer treatments that could potentially damage the heart. So, hypertension can limit the use of certain therapies.

If you have high blood pressure, your doctors may need to change the dose of your blood pressure medications or swap them out for other drugs.

Does cancer itself ever cause high blood pressure? 

Yes. Adrenal tumors, neuroendocrine tumors and renal cell carcinoma are just three of the cancer types that can cause high blood pressure as a symptom. But there are likely others.

Is there any known link between high blood pressure and cancer?

Studies have shown a very weak association between hypertension and the risk of developing certain cancers. But the link between high blood pressure and breast cancer, colorectal cancer, endometrial cancer and renal cell carcinoma is not yet fully understood.  

Is there any way to prevent hypertension?

Cancer and hypertension share many risk factors, such as smoking, obesity, inactivity and diabetes. So, the same strategies that reduce your risk of one will also reduce your risk of the other. The best ways to prevent hypertension are: don’t use tobacco products, maintain a healthy body weight, and exercise regularly.

Gloria Iliescu, M.D., is an internist in UT MD Anderson’s Suspicion of Cancer Clinic with a special interest in the management of comorbidities in cancer patients.  

Request an appointment at UT MD Anderson online or call 1-877-632-6789.