Clinical Features of Prostate Cancer

written by Dr Loh Chit Sin on 7 April 2011

Prostate cancer is today the most common cancer in American men. Prevalence increases with age and there is great geographical variation in prevalence. For more than half a century, the mortality from prostate cancer did not alter much since Huggins’ and Hodges’ discovery of androgen deprivation in 1941. Most cancers present with obstructive or metastatic symptoms and median survival from metastatic disease had remained about 18 months to 2 years. Few cases presented early and incidental carcinomas diagnosed from prostatectomy done for bladder outlet obstruction were the commonest form of early prostate cancers diagnosed. Most of these were transitional zone tumours which follow a more indolent course. The introduction of PSA assay and improved imaging had enable urologists to diagnose more and more early organ-confined prostate cancer. The incidence of the disease exploded due largely lead-time bias although this is beginning to fall in the USA. As a proportion, early prostate cancers form the majority of the new cases in the West and radical prostatectomy became the most commonly performed urological operation in many countries and remains so. PSA assay lacks specificity in the lower range although specificity improves with increasing levels. Most cases of elevated PSA levels require further evaluation. In cases in which the natural life expectancy exceeds 10 years, systematic trucut needle biopsy, usually transrectally, is carried out. Prevalence of prostate cancers these cases is about 30% in the West although it appears to be lower in Malaysia.

Early organ confined prostate cancer is curable and the gold standard treatment is radical prostatectomy, despite its associated risks of incontinence (5%) and incontinence (50%). Nowadays, the surgery can be carried out through keyholes with the assistance of and opearting robot which offers reduced blood loss, post-operative pain and complications. Radical external beam therapy is an alternative for some patients but results are comparable to surgery in selected cases. Treatment using intensity modulated radiotherapy protocol (IMRT) offers a higher radiation dose with reduced collateral damage and is still currently the minimum standard of care for external beam radiation treatment. In selected cases, radioactive seeds implantation (low dose rate brachytherapy) offers treatment results as good as surgery but with minimum invasiveness and complications. More accurate preoperative staging of the disease locally is found wanting in the management of early prostate cancers as post-treatment relapse still occurs in patients who undergo radical curative treatment. There are good correlations between preoperative tumour grade plus PSA levels and pathological staging and prognosis. Post-operative PSA assay is a very sensitive tool for determination of residual disease or relapse particularly after radical prostatectomy. In general, consensus has not been reached on the best management of biochemical relapse after curative treatment. There is better consensus on management of locally advanced and metastatic diseases that is based principally on hormonal deprivation. Increasingly, the trend is now for early hormonal deprivation. The outlook for hormone escape disease used to be quite bleak but recent advances in immunotherapy and new drugs has offered hope for these patients.