The prostate is a small, walnut-sized gland that forms part of the male reproductive system, situated just beneath the bladder and in front of the rectum. Its primary function is to produce the fluid that nourishes and transports sperm, which forms a significant component of semen. The gland surrounds the urethra, the tube that carries urine out of the body, which is why changes in its size directly influence urinary function. Prostate size does not remain constant throughout a man’s life, making the question of a “normal” size at age 70 a common inquiry.
Normal Prostate Dimensions at Age 70
Determining the “normal” size of the prostate in a 70-year-old man is based on a range, not a single fixed number. The average prostate volume for men in this age group falls between 30 and 50 cubic centimeters (cc), which is equivalent to 30 to 50 milliliters (mL). For comparison, a healthy prostate in a younger adult is around 20 to 25 cc. This progressive increase reflects the natural, age-related growth of the organ over time.
Clinical data suggests the median prostate volume for men in their 70s is closer to 40-45 mL, but significant individual variation exists. A prostate size exceeding 30 cc is considered notable, especially when evaluating treatment options for enlargement. However, size alone does not dictate whether a man will experience symptoms or require medical intervention.
Understanding Age-Related Prostate Enlargement
The underlying process for this increase in size is known as Benign Prostatic Hyperplasia (BPH), which is a non-cancerous growth of the prostate’s glandular and stromal tissue. This condition is common, affecting approximately 80% of men by the time they reach 80 years of age, meaning most men in their 70s have some degree of enlargement. The proliferation of cells is driven by hormonal changes that occur over decades.
The hormone Dihydrotestosterone (DHT) is the main factor stimulating this growth within the prostate. DHT is a potent androgen derived from testosterone through the action of the enzyme 5-alpha-reductase, which is highly active within the prostate cells. Although serum testosterone levels may decline with age, the local concentration and effect of DHT remains sufficient to promote cellular reproduction.
The growth typically occurs in the transition zone of the prostate, the region immediately surrounding the urethra. As the tissue expands, it compresses the urethra, leading to obstruction of urinary flow. BPH is not prostate cancer, nor does having BPH increase the risk of developing prostate cancer. The two conditions are separate, though both become more prevalent with advancing age and can co-exist.
Methods for Measuring Prostate Volume
Healthcare providers use several methods to assess prostate size and volume. The initial and most common screening method is the Digital Rectal Examination (DRE), where a physician manually feels the prostate through the rectal wall to estimate its size and check for abnormal masses. While the DRE is quick and can reliably identify prostates over 30 cc, it provides only a rough, subjective estimate of the volume.
For a more precise measurement, the gold standard is the Transrectal Ultrasound (TRUS). This procedure involves inserting a small ultrasound probe into the rectum to generate detailed images of the prostate. The physician measures the prostate’s length, width, and height, which are then used in the prolate ellipsoid formula to calculate the volume in cubic centimeters.
In complex cases or for detailed assessment, Magnetic Resonance Imaging (MRI) may be used, as it offers the most accurate visualization and measurement of the gland and surrounding structures. Accurate volume measurement is valuable for determining the most appropriate treatment, as certain medications, such as 5-alpha-reductase inhibitors, are more effective for prostates exceeding a specific size threshold.
Symptoms That Warrant a Doctor’s Visit
Prostate size is less important than the presence and severity of symptoms experienced by the individual. Many men with significantly enlarged prostates remain asymptomatic, while others with only mild enlargement can experience bothersome urinary problems. These issues are collectively known as Lower Urinary Tract Symptoms (LUTS) and are the primary reason for seeking medical consultation.
Storage symptoms are a common group of LUTS, including increased frequency, a sudden urge to urinate, and nocturia (waking up to urinate multiple times during the night). The other category involves voiding or obstructive symptoms, resulting directly from the compressed urethra. These include difficulty starting the urine stream (hesitancy), a weak or interrupted flow, and the sensation of incomplete bladder emptying.
Any man in his 70s experiencing these LUTS, particularly if they are interfering with sleep or daily activities, should schedule an appointment with a healthcare provider. Evaluation is necessary not only to confirm that BPH is the cause but also to rule out other potential causes, such as infection or bladder issues. Addressing these symptoms can significantly improve quality of life, regardless of the prostate’s measured volume.