Prostate gland secretes a chemical called as prostate specific antigen (PSA) which can be measured in the blood. The normal range is 0- 4 ng/ml. If this value is higher and there is no other apparent cause for it, would warrant a prostatic biopsy, which may then detect an early cancer. Notably, PSA is a highly sensitive test, that lack absolute specificity – meaning, non-malignant causes can also give rise to it such as benign enlargement, urinary infection etc; hence, caution in its interpretation needs to be exercised. PSA density and Free PSA are further test which can increase specificity.
DIAGNOSIS AND STAGING
Biopsy is imperative for diagnosis and sub-typing. Whenever a prostate cancer is suspected a digital rectal examination (which is a finger test to feel the prostatic surface through the rectum) is done, and gives a fair idea about chance of a malignancy and the local stage. An MRI scan of the pelvis can further help judge the local stage.
For reasons unknown, prostate cancer has a predilection to spread to the bones and hence a bone scan becomes an imperative part of staging. Simply put, there are 4 stages of this cancer: –
Stage 1 – Microscopic disease detected only on biopsy and PSA of less than 10
Stage 2 – Gross disease but with in the prostate, or PSA >10
Stage 3 – Gross disease spreading outside the prostate, and any PSA level
Stage 4 – Spread to other parts such as surrounding lymph nodes, bladder, rectum, bones, etc
SUBTYPES OF PROSTATE CANCER
Prostate cancer is a spectrum of disease varying from an indolent cancer with median survivals more than 20 yrs – even in stage 4 and without treatment, to very aggressive ones with median survivals ranging in a year or two only, even with best treatment. Thankfully, aggressive variety is far less common than indolent ones.
Gleason score (in the name of Dr Donald Gleason) is the pathological scoring system to grade the aggressiveness of the disease on the prostatic biopsy on a scale of 2 to 10 (10 being the most aggressive) and is the utmost essential information to plan therapy.
For stage 1 and 2 – encompasses localized disease amenable to surgical ablation and cure from the disease. An immense degree of development has been witnessed in surgical techniques in the recent years which mainly includes robotic arm – facilitating superior surgical maneuverability in the tightly packed anatomy of prostate and thence outcomes esp. in the hands of the expert robotic surgeon. Those who do not wish to undergo surgery or are poor surgical candidates can be offered curative radiotherapy with arguably equal results.
For Stage 3 – Surgical techniques offer poorer results in this stage and radiotherapy (RT) with androgen (hormonal) deprivation remains the standard of care. With latest techniques such as IGRT (image guidance) offer superior results with minimal side effects, if any.
For Stage 4 – As said earlier, prostate cancer is dependant on male hormone (androgens), until even late stages of tumor progression and hence androgen ablation (castration) is the mainstay of stage 4 disease. This can be achieved by surgical removal of testis or injections to stop hormone secretion from them. However, over a period of time, the disease do become independent of hormonal deprivation when 2nd line hormonal therapy, chemotherapy and sometimes even immunotherapy is utilized to abate the disease and improve survivals. Surely, plenty of newer agents are making headway into the armamentarium of us physicians, which have facilitated not only better survivals but also quality of life.
Prostate cancer is frequently called “The curse of men”, no matter manliness is not synonymous with godliness, as some may believe.