Prostate, part of male reproductive system, located at the base of bladder, is responsible for production of seminal fluid that helps nourish and transport sperm. It’s similar to shape and size of a walnut and can be felt during rectal examination. It’s one of the most commonly detected cancer after skin cancer and is second most cause of mortality in US. It is one of the most common cancers in men. 
Prostate cancer usually grows slows in the initial phases and may remain limited to prostate without any major symptoms but it may spread as well. The earlier it is detected the better the prognosis.
Signs and Symptoms of Prostate Cancer
There are no evident symptoms evident in earlier stages. In later stages, they might vary from a variety of symptoms like
- Decreased force or trouble in urinating
- Blood in urine or semen
- General bone, pelvic and lower back pains can also be troublesome
- Erectile dysfunction.
Most common reason to visit a doctor is usually erectile dysfunction, but since its most common in old age, there is a debate about screening for prostate regularly. Decisions about prostate-cancer screening should be based on the preferences of an informed patient. 
Risk Factors of Prostate Cancer
Prostate cancer is a disease of older men, >64 years. Black population is more affected than the others. There are a lot of incidences of occurrence of prostate cancer if there is a history of it in the family. Also, family association with breast cancer – BRCA 1 and 2 can also be considered as a risk factor. 
Tests and Diagnosis of Prostate Cancer
Regular screening can result in early detection and treatment of asymptomatic cancers could extend life, as compared with treatment at the time of clinical diagnosis. Most common and largely practiced is the digital rectal examination, which was the primary screening test for prostate cancer. Some of the other tests that are recommended are :
Prostate Specific antigen test (PSA test)- It is specific tumour marker for prostate cancer. A little amount if found in blood is normal, but a large amount can indicate inflammation, infection or cancer.
Prostate Imaging: Ultrasound and MRI are the most common methods. But MRI gives a better soft tissue resolution as compared to Ultrasound.
Biopsy: If cancer is suspected past these tests, Biopsy is performed where tissue samples are obtained from prostate via rectum.
Stages of Prostate Cancer
Once Diagnosis of prostate cancer is confirmed, staging is performed to determine the extent of spread and treatment course for future. Some tests can be performed to determine the spread like bone scan, MRI (Magnetic Resonance Imaging) , CT (Computerized tomography) and PET (Positron emission tomography). 
Stage I. This is an early stage, where cancer is limited to a small area in prostate. Under microscopic examination cells are not aggressive
Stage II Cancer in this stage can either be small or extended to both sides of prostate. It may also be considered aggressive.
Stage III. Cancer is seen to be spread in the nearby tissues.
Stage IV. Nearby organs, such as the bladder, lymph nodes, bones, lungs or other organs are affected by cancer.
Treatment of Prostate Cancer
There are 3 main kind of treatments available and your practitioner chooses from them depending on the extent of your cancer. Expectant management, Radiotherapy and Radical prostectomy are the options available.
Clinical researches are being conducted to explore other options for treatment and management of the cancer. 
 Screening for Prostate Cancer,Richard M. Hoffman, M.D., M.P.H, N Engl J Med 2011; 365:2013-2019 – November 24, 2011 – DOI: 10.1056/NEJMcp1103642, http://www.nejm.org/doi/full/10.1056/NEJMcp1103642
 Management of Prostate Cancer,N Engl J Med 2008; 359:2605-2609 December 11, 2008 DOI:10.1056/ NEJMclde0805491, http://www.nejm.org/doi/full/10.1056/NEJMclde0805491