The prostate gland is a small, walnut-shaped organ that is part of the male reproductive system. Situated just below the bladder and in front of the rectum, it encircles the top portion of the urethra, the tube that carries urine and semen out of the body. Its primary function involves producing a fluid that contributes to semen, nourishing and transporting sperm during ejaculation. The size of this gland indicates a man’s prostate health.
Normal Prostate Size and Age
A healthy adult prostate measures around 3-4 cm in width, 2-3 cm in height, and 4-5 cm in length. Its average volume is 20 to 30 cubic centimeters (cc) or milliliters (mL), weighing approximately 20-25 grams in younger men. Prostate size is not static and changes over a man’s lifetime. The prostate undergoes two growth phases, with the second beginning around age 25 and continuing throughout adulthood.
What is considered “normal” varies significantly with age. For instance, by age 40, the prostate might grow to the size of an apricot, and by age 60, it can reach the size of a lemon or even a tennis ball. While the prostate generally enlarges with age, some men may experience stable or slightly decreasing prostate size. Prostate volumes up to 40 cc can still be considered within normal limits for older men; by age 60, many prostates exceed 30 grams, with some reaching 50-100 grams or more.
Measuring Prostate Size
Healthcare professionals use various methods to assess prostate size. One common approach is the Digital Rectal Exam (DRE), where a doctor inserts a gloved, lubricated finger into the rectum to feel the prostate. While simple and cost-effective, DRE has limitations for precise measurement and can underestimate prostate size, particularly for volumes greater than 30 mL.
Transrectal Ultrasound (TRUS) is a more accurate method for determining prostate volume and dimensions. This procedure involves inserting a small ultrasound probe into the rectum to create detailed images of the prostate. TRUS is used to evaluate benign prostatic hyperplasia (BPH) and provides volume measurements close to the actual prostate volume.
Magnetic Resonance Imaging (MRI) offers more detailed imaging and is used for prostate size assessment, especially in prostate cancer staging. MRI is more accurate than TRUS for estimating prostate volume, though both methods may underestimate actual prostate weight compared to surgical specimens. The ellipsoid formula, which multiplies the height, width, and length of the prostate by 0.52, is often used to calculate prostate volume from these imaging measurements.
What an Enlarged Prostate Means
A prostate larger than the typical range often indicates benign prostatic hyperplasia (BPH), a common condition associated with aging. BPH is characterized by the non-cancerous enlargement of the prostate gland, which can compress the urethra that passes through it. This compression can lead to various urinary symptoms, though symptom severity does not always directly correlate with the degree of prostate enlargement.
While BPH is a common cause of prostate enlargement, other conditions can also lead to an increase in prostate size. Prostatitis, an inflammation of the prostate gland, can cause swelling and pain. This condition can be acute, with sudden, serious symptoms, or chronic, with symptoms that come and go. Unlike BPH, prostatitis can affect men of any age and may be caused by bacterial infections.
Prostate cancer, although less common than BPH, is another condition that can cause prostate enlargement. It involves the growth of abnormal cells within the prostate tissue. While prostate cancer usually grows slowly and early stages often have no symptoms, it can share similar urinary symptoms with BPH as it progresses. Having an enlarged prostate due to BPH does not increase the risk of developing prostate cancer.
When to Consult a Doctor
Consult a doctor for prostate concerns if you experience certain symptoms, regardless of your prostate’s perceived size. These symptoms can include a frequent or urgent need to urinate, particularly at night, and difficulty initiating urination. A weak or interrupted urine stream, dribbling after urination, or a sensation that the bladder has not fully emptied also warrant medical attention.
Other signs that should prompt a doctor’s visit include pain or burning during urination, blood in the urine or semen, or painful ejaculation. Frequent pain or stiffness in the lower back, hips, pelvic, or rectal area, or upper thighs are also reasons to consult a healthcare professional. Early diagnosis and regular check-ups, especially for men over 50 or those with a family history of prostate issues, are important for managing prostate health. Only a medical professional can accurately assess prostate size and determine the underlying cause of any symptoms.