CARCINOMA PROSTATE

The risk of carcinoma of the prostate increases with age, being increasingly detectable from 50-80 years. Though the cause is unknown, several factors influence the risk. Geographical (Sweden and USA), racial (blacks) and occupational (rubber workers) factors and altered oestrogen and androgen levels are some of the risk factors.



Adenocarcinoma arising from the glandular acini is the most common. Sarcomas, and squamous cell, transitional cell and small cell carcinomas are other tumours. Apart from these, metastases to prostate are seen from the bladder, lung, colon and lymphomas. Grossly, multifocal lesions and invasion of the prostatic capsule are the characteristic features of this disease. It most commonly metastasises to bone, with dense osteoblastic or osteolytic lesions, and less frequently to the liver and lung with paraneoplastic syndromes.

Early prostatic carcinoma is usually asymptomatic and can be detected by routine rectal examination. Induration or non tender nodularity are the frequent findings. The presence of symptoms indicates advanced disease. Urinary symptoms like sudden onset of urinary tract obstruction, poor urine flow, urgency and terminal haematuria, back pain or paraplegia may be due to extradural secondaries. Acute and chronic prostatitis, nodular hyperplasia and benign adenomas have to be clinically differentiated from prostatic carcinoma.

The histological diagnosis is established by transperitoneal needle biopsy or by transrectal fine-needle aspiration cytology (FNAC). Routine investigations like urine analysis, complete blood picture, renal and liver profile, serum alkaline phosphatase, serum calcium and phosphorus levels, chest X-ray, and X-ray of bony secondary sites are carried out (Fig. 14.6). Ultrasonography, CT scan, isotope bone scan and lymphangiogram are optional. Estimation of acid phosphatase levels in serum is not considered very specific for carcinoma prostate. Prostate-specific antigen (PSA) is more sensitive and useful. Carcinoembryonic antigen is increased in a few cases.

Routine and careful examination of the prostate after 50 years of age is essential for prevention and early diagnosis of carcinoma prostate. Surgery, radiotherapy and hormonal manipulation are modalities of treatment.In cases diagnosed incidentally at histology during transurethral resection of suspected benign prostatic hyperplasia, random multiple needle biopsies are carried out. If no further foci are detected, patients are kept on follow-up without any further treatment.A tumour which is palpable but is confined to the prostate (single nodule of less than 2 cm) is managed with radical prostatectomy. However, few patients with carcinoma are diagnosed early and are fit for surgical treatment. Tumours with multifocal lesions or those localised to the periprostatic area are managed by radical prostatectomy or radiotherapy. This group of patients needs pelvic lymphadenectomy for pathological staging before prostatectomy, as radical treatment depends on the stage of the disease. The increased incidence of impotency, lymphoedema, pulmonary embolism are limiting factors of radical surgery.

External radiotherapy is widely employed in the management of carcinoma prostate, either alone or as adjuvant to radical prostatectomy. Interstitial implant irradiation using I-125, Ir-192, Au-198, P-32 isotopes is also used. Neither hormonal therapy nor chemotherapy has improved survival in early stages of carcinoma prostate.In advanced stages transurethral resection of the prostate is done to relieve the bladder outlet obstruction as a purely palliative measure. Orchidectomy is also effective. Radiotherapy is useful in isolated painful bony secondaries, spinal cord compression, pelvic pain syndromes and haematuria. Endocrine therapy is the mainstay of treatment of symptomatic prostatic malignancy. Orchidectomy, luteinising hormone-releasing hormone (LH-RH) agonists and oestrogens result in dramatic improvement. Long-acting oestrogen chlorotriamisene (TACE), progestins, flutamide (anti-androgen), aminoglutethamide and diethylstilbesterol diphosphate can be used. Chemotherapy is given for hormone-resistant cases. Multi-drug chemotherapy has not shown superior results over single-agent therapy. Adriamycin, 5-fluorouracil, methotrexate, cyclophosphamide, cisplatin and DTIC are used.

Survival is directly related to stage: stages I and II-70%, stage III-56% and stage IV-25% at 5 years. Well differentiated carcinomas have better prognosis. Grades I, II, III and IV carry 5-year survival of 60%, 35%, 15% and 5%, respectively. Involvement of seminal vesicles is associated with poor prognosis.

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