Question

Public health relevance of Prostate cancer

please describe as detailed as possible

Answer 1

Prostate cancer remains an important public health concern in Western countries and an emerging malignancy in developing nations. Prostate cancer incidence is dependent on efforts to detect the disease.

99% of prostate cancers are adenocarcinomas, mainly occurring in the peripheral part of the prostate gland.

Symptoms
The general clinical symptoms (which cannot be distinguished from those caused by benign prostatic hyperplasia) are urinary frequency, nocturia and urgency caused by obstruction of the urethra. In some cases, initial symptoms come from painful skeletal metastases.

Many men with prostate cancer often have no symptoms.

Epidemiology

Prostate cancer is one of the most common male cancers worldwide with over 650,000 men diagnosed each year.

Significant geographical variation in incidence has been observed worldwide. The highest incidence rates have been observed in developed countries including the United States (particularly among Afro-Caribbean males) and Western Europe, while the lowest rates are seen among men in Asian and African countries

However, recent prostate cancer incidence rates and geographical variations should be interpreted in the context of the availability of PSA testing and screening behaviour. Prevalence of latent prostate cancer is high (15-30% of men over 50 years will have a prostatic adenocarcinoma that, while meeting the histopathologic criteria for malignancy is thought to have a low potential for growth and metastasis)

As a result PSA screening may result in amplifying the incidence of prostate cancer. However, studies have shown similar strong geographical variations prior to the introduction of PSA testing.

In the UK Prostate cancer is the most common cause of cancer of men, accounting for 1 in 4 of all new male cancers diagnosed.

In the UK there were 26,798 new cases of prostate cancer diagnosed in 20033.

In 2004 there were 10,209 deaths in the UK from prostate cancer.

Prostate cancer increases significantly with age with very few cases diagnosed in men <50 years and >70% of cases occurring in males aged >65 years.

The incidence rate for prostate cancer among men aged 65-69 years is 449/100,000 men, rising to 757/100,000 men in men aged 75-79 and 970/100,000 men in men aged >85 years.

The lifetime risk of developing prostate cancer is 1 in 13.

Mortality rates for prostate cancer increase significantly with age.

Risk Factors
The main known risk factors are age, ethnicity, family history and diet.

Age - is considered one of the most important risk factors for prostate cancer. Approximately 70% of all diagnosed prostate cancers occur among men aged > 65 years and the majority of men will have some form of prostate cancer after age 80.

Ethnicity - Higher rates are observed among Afro-Caribbean American males compared to Caucasian American males. Low rates have been observed among males in Japan and China.

Family History - Men with a family history of prostate cancer in a first degree relative have a 2-3 fold increased risk of developing disease. Risk is further increased if the affected relative is young or if more than one relative affected

Screening and Prevention
There are 3 main diagnostic tests for prostate cancer

Digital Rectal Examination (DRE)
Overall detects less than 50% of prostate cancers and is more likely to detect advanced prostate cancer .

Trans-Rectal Ultrasound scan (TRUS).

Prostate-Specific Antigen test (PSA) - blood test that measures PSA enzyme.
However, a number of important factors limit the effectiveness of PSA testing as part of a population screening programme.

Low specificity - only an estimated 25-35% of men with abnormally high PSA levels will have prostate cancer.

Low sensitivity - up to 20% of all men with prostate cancer will have normal PSA levels.

PSA levels may be raised by infection, certain drug or recent prostate biopsies.

The PSA test has not been standardised, there is inter-laboratory variability, and levels of PSA need to be adjusted for a number of factors including age, the ratio of PSA serum concentration to gland volume and the free total PSA ratio

As it can be mostly undetected in individual unless in late STAGE that is in a malignant stage . So public education is much important