Prostate carcinoma
المؤلف:
James Carton
المصدر:
Oxford Handbook of Clinical Pathology 2024
الجزء والصفحة:
3rd edition , p268-270
2025-04-02
592
Definition
• a malignant epithelial tumour arising in the prostate.
Epidemiology
• The most common malignant tumour in men, accounting for about 25% of all male cancers.
• about 1 in 8 men will develop prostate cancer in their lifetime.
• Prevalence rising due to longer life expectancy and increased detection rates.
• a less prominent cause of cancer- related deaths, as many cases behave in a relatively indolent fashion.
Aetiology
• Racial background and genetic factors are important, with a 5- to 10- fold increased risk in men with two or more affected first- degree relatives.
• Dietary association with animal products, particularly red meat.
Carcinogenesis
• arises from a precursor lesion known as prostatic intraepithelial neoplasia (PIN), characterized by neoplastic transformation of the epithelium lining of the prostatic ducts and acini.
• Harbour mutations in a number of genes, including GST-pi, PTEN, AMACR, p27, and E-cadherin (note these are not classical tumour suppressor genes or oncogenes).
Presentation
• The vast majority of prostate cancers are diagnosed early following investigation of a raised serum prostate- specific antigen (PSA) level.
• More advanced localized disease may be present with a suspicious- feeling prostate on digital rectal examination or lower urinary tract symptoms.
• Rarely, patients present with symptoms of metastatic disease.
Diagnosis
• Patients with raised PSA are usually referred for MRI of the prostate to identify suspicious areas that may be targeted for biopsy.
• Prostate biopsy may be performed via a transperineal or transrectal route. The transperineal route carries a much lower risk of introducing infection into the prostate gland.
Histopathology
• The most common type of prostate cancer is acinar adenocarcinoma, in which the malignant epithelial cells form glandular structures.
• One of the key diagnostic features of prostate cancer is the abnormal architecture of the malignant glands which are crowded and show infiltration between benign glands and ducts.
• Malignant epithelial cells have enlarged nuclei with prominent nucleoli and denser amphophilic cytoplasm.
• Malignant glands often have intraluminal crystalloids (dense crystal- like structures), amorphous pink secretions, or blue- tinged mucin.
Gleason scoring
• Prostate cancers are graded using the Gleason scoring system.
• Gleason scores are expressed in the format x +y =z and are based on the two most common Gleason patterns present in the tumour.
• Gleason patterns range from 1 to 5 and are based on the architectural growth of the tumour.
• in practice, patterns 1 and 2 are never diagnosed, and so all prostate cancers have a Gleason score of between 6 and 10.
• Gleason pattern 3 is composed of well- formed discrete glandular units (Fig. 1).
• Gleason pattern 4 is composed of poorly formed, fused, or cribriform glands (Fig. 2).
• Gleason pattern 5 is composed of solid sheets, cords, or single cells showing no glandular differentiation.
Immunohistochemistry
• Prostate cancer cells are typically positive for PSA and CK7 whilst being negative for CK20.
• Basal cell markers (e.g. p63 or cytokeratin 5, are often used to confirm a morphological diagnosis of prostate cancer by demonstrating absence of basal cells around the cancer glands).
Fig1. Gleason pattern 3 prostate adenocarcinoma composed of individual well- formed glandular acini (see Plate 33).
Fug2. Gleason pattern 4 prostate adenocarcinoma composed of fused poorly formed glands (see Plate 34).
Prognosis
• The Gleason score is a powerful prognostic indicator, with a higher score associated with a worse outcome.
• Other important factors include the serum PSA level and the stage of the disease.
Prostate cancer screening
• Screening using serum PSA is a controversial subject.
• at present, most countries do not operate an organized prostate screening programme.
• Current evidence suggests that screening would result in overdiagnosis and overtreatment of many men with prostate cancers that are unlikely to behave in an aggressive manner.
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