Hypertension (HTN) is prevalent in the general population, particularly in individuals over the age of 60 years. More than 50% of individuals aged 60 to 69 years and more than 75% of individuals age 70 or older are affected.
These populations also are more likely to have a diagnosis of cancer. Risk factors for HTN are well established and include modifiable risk factors (obesity, tobacco and alcohol(Drug information on alcohol) abuse, and physical inactivity), disease-related factors (diabetes mellitus, renal insufficiency or failure, thyroid or parathyroid disease, hyperlipidemia), increasing age, family history, and drug-induced or drug-related causes. Many of these same factors are associated with an increased risk of malignancy.
As the population ages, both HTN and cancer will become more common. Therefore, patients with cancer who have existing HTN and those who are at an increased risk because of age or other risk factors will be common in the oncology setting. There are numerous considerations in the patient with both cancer and HTN, either as a primary problem or secondary to other comorbid conditions such as diabetes. Many newer therapeutic agents, specifically antiangiogenesis agents, are associated with HTN. Understanding the risk factors, pathophysiology, and clinical measures of HTN in the general population and the unique needs of the cancer patient with HTN will improve the individualized management of these patients.
Hypertension is considered a common but manageable problem. The Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC) defines HTN as a systolic blood pressure (SBP) of 140–159 mmHg or a diastolic blood pressure (DBP) of 90–99 mmHg. The generally accepted target blood pressure is 120/80 mmHg. A pressure of 140/90 mmHg indicates the need for antihypertensive treatment in otherwise healthy individuals. This target is 130/80 mmHg for patients with additional risk factors, specifically cardiovascular disease (CVD), chronic renal disease, or diabetes.
The JNC guidelines further define levels of HTN and are widely used to determine management. It is important to note that these parameters are based on the average of two or more properly measured readings (sitting for at least 5 minutes at rest with feet on floor and arms supported at heart level) at each of two or more visits after an initial screening visit, and are applied to adults who are not acutely ill and are not taking antihypertensive medications.
Newly diagnosed cancer, recurrence or progression of cancer, and certainly the administration of treatment require clinicians to further characterize HTN in the oncology population. Furthermore, clinical measures of blood pressure (BP) are often taken after walking a patient back to an examination room or intake area. Additional factors that may affect BP measures include smoking within 15 minutes of a BP check, time of day (ie, circadian rhythm, as BP values are higher in the early morning, lower during sleep or rest), the presence of pain, and “white coat” syndrome.
Boggia et al found average ambulatory readings from patients, taken over a 24-hour period, were lower than clinic readings by between 10/5 and 20/10 mmHg. Thus multiple measures representing variable times of day and settings are most helpful in determining a 24-hour average BP. Several studies support a 24-hour average BP > 135/85 mmHg as being linked to adverse cardiovascular events.
More recently, several epidemiological studies have suggested microalbuminuria (30–300 mg/d) as a strong predictor of cardiovascular events and death in hypertensive patients. Institution of antihypertensive therapy is an effective tool for reduction of albuminuria and secondary adverse events. The National Institutes of Health and National Cancer Institute (NCI) common terminology criteria for adverse events (CTCAE) are the most commonly used criteria for classification of adverse events in oncology clinical trials. The criteria specific to grading of HTN in the oncology population focus on changes in blood pressure measures from baseline.