Average Prostate Volume and Dimensions at 70
While a definitive "normal" size can be challenging to state due to individual variation, medical research offers clear averages and trends. Most healthy adult prostates are about the size of a walnut, weighing 20–25 grams and having a volume of around 20–25 milliliters (mL or cc). However, the prostate typically experiences a second growth phase beginning in a man's mid-twenties and continuing throughout life. This means a 70-year-old's prostate will almost certainly be larger than it was in his youth.
Several studies provide specific mean volume data for this age group. For men aged 70–79, average prostate volumes are often cited between 35 and 50 cubic centimeters (cc), with some research indicating mean volumes in the mid-40s. It is important to remember that these are averages, and a man's prostate size is influenced by genetics, diet, and overall health.
Benign Prostatic Hyperplasia (BPH) and Size
At age 70, a significant number of men will have benign prostatic hyperplasia (BPH), a non-cancerous condition where the prostate's cells multiply and cause it to grow larger. The prevalence of BPH is high in older men, affecting up to 80% of men over 70. The size of enlargement due to BPH is highly variable. While some men may have slight growth, others may have a prostate many times its original size. Symptom severity does not always correlate with prostate size; some men with large prostates experience minimal symptoms, while others with smaller ones have significant issues.
Clinical Methods for Measuring Prostate Size in Millimeters
Urologists use several diagnostic tools to accurately measure the prostate and convert its dimensions into millimeters, providing a more precise evaluation than a digital rectal exam (DRE) alone. The volume is calculated from these measurements using a formula. Here are the common methods:
- Transrectal Ultrasound (TRUS): This is considered the most accurate method for measuring prostate size. A small probe is inserted into the rectum to create detailed images of the prostate. The urologist measures the prostate's length, width, and height in millimeters, then uses a standardized ellipsoid formula to calculate the volume in milliliters (cc).
- Magnetic Resonance Imaging (MRI): MRI provides highly detailed, multi-dimensional images of the prostate, allowing for precise measurement of its size and mapping of internal structures. It is often used in more complex cases or when cancer is suspected.
- Computed Tomography (CT) Scan: While not as precise for soft tissue as an MRI, a CT scan can also be used to evaluate prostate volume.
Comparison of Prostate Size and Volume Across Age Groups
The table below compares general prostate volume estimates across different age decades. It highlights how the average size steadily increases with age due to natural growth and the increasing prevalence of BPH.
| Age Group (Years) | Mean Prostate Volume (mL/cc) | Common Prostate Analogy | Associated Condition Trends |
|---|---|---|---|
| 40-49 | ~24-28 mL | Apricot | BPH prevalence starts to increase, but symptoms are often mild. |
| 50-59 | ~30-33 mL | Ping-pong ball | Histological BPH is present in about 50% of men in this decade. |
| 60-69 | ~35-37 mL | Lemon | BPH prevalence is significant, with symptoms becoming more common. |
| 70-79 | ~38-50+ mL | Tennis ball or larger | BPH prevalence is very high (around 80%), and symptoms can progress. |
| 80+ | >45+ mL | Varies, can be significantly larger | BPH is nearly universal, though symptoms and their severity vary. |
Understanding Symptom vs. Size
For a 70-year-old, focusing on the size in millimeters or volume in cubic centimeters is less important than evaluating the symptoms. Lower urinary tract symptoms (LUTS), which can include urinary frequency, urgency, and a weak stream, are the main concern related to BPH. The American Urological Association Symptom Score (AUA-SS) is a tool used by doctors to quantify the impact of LUTS on a patient's quality of life. A moderate score can prompt a urologist to recommend treatment, even if the prostate is only slightly enlarged. Conversely, a man with a very large prostate but no bothersome symptoms may not require immediate treatment.
Conclusion: Age-Related Growth is Expected
In summary, while there is no single "normal" size in millimeters for a prostate at age 70, an increase in size from younger years is a natural and expected part of the aging process. The average volume for a man in his 70s is typically in the range of 35 to 50 mL or greater. Precise measurements are determined by a urologist using tools like transrectal ultrasound. More critical than the exact size is the presence and severity of urinary symptoms. Management decisions are based on the impact the enlarged prostate has on a man's quality of life, not just its dimensions.
For more information on prostate health, please consult your healthcare provider or visit reputable medical resources.
