Prostate Cancer

Affiliated Hospital of Weifang Medical University

Excluding skin cancer, adenocarcinoma of the prostate is the cancer diagnosed most commonly in men and is the second leading cause of cancer-related mortality in men.

prostate-specific antigen (PSA)

EPIDEMIOLOGIC CONSIDERATIONS

The projected incidence of adenocarcinoma of the prostate is 180,400 new cases in 2000, and the disease is expected to result in 31,900 deaths .

A number of risk factors for prostate cancer have been identified, age being the most important.

ANATOMY OF THE PROSTATE GLAND

The normal prostate gland consists of a transitional zone, a central zone, and a peripheral zone.

It is oriented with the broad base superiorly, the midsection, and the narrow apex inferiorly.

HISTOLOGIC FEATURES OF PROSTATIC NEOPLASIA

Almost all prostate cancers are adenocarcinomas.

The earliest recognizable prostatic lesion is prostatic intraepithelial neoplasia (PIN).

MOLECULAR BIOLOGICAL FEATURES OF PROSTATIC

NEOPLASIA At a genetic level, the process of

prostatic carcinogenesis is complex, with multiple genetic lesions implicated in the progression from PIN to localized cancer, locally advanced cancer, and metastatic cancer.

SCREENING FOR PROSTATE CANCER

The availability of PSA as a diagnostic tool, coupled with increased awareness of the disease, has produced a marked increase in the number of new cases diagnosed.

CLINICAL PRESENTATION Common Symptoms and Signs

Before the availability and frequent application of PSA determinations, the most common presentation of prostate cancer was with symptoms of urinary obstruction or bony pain.

Digital Rectal Examination

Digital rectal examination (DRE), an essential component of evaluation for prostate cancer, typically reveals a hardened nodule, although either diffuse induration of the gland or a normal gland may be present.

Prostate-Specific Antigen

PSA is relatively specific to prostatic tissues and has been highly useful for diagnosing and following up the clinical course of prostate cancer.

INTERPRETING PSA TEST RESULTS

Interpretation of the PSA determination must include both the degree of elevation and the results of other examinations, particularly findings of the DRE.

INCREASING THE SPECIFICITY AND SENSITIVITY OF PSA

TESTING Fewer than 50% of patients with a PSA

between 4 and 10ng/ml will prove to have prostate cancer on subsequent biopsy.

DIAGNOSIS

The diagnostic procedure of choice for localized prostate cancer is transrectal biopsy, often directed by transrectal ultrasonography

TNM Staging Classification

Histopathologic grade (G) GX Grade cannot be assessed G1 Well differentiated (slight anaplasia) G2 Moderately differentiated (moderate

anaplasia) G3 Poorly differentiated or

undifferentiated(marked anaplasia)

Primary tumor (T) TX Primary tumor cannot be assessed T0 No evidence of primary tumor T1 Clinically inapparent tumor not palpable nor visible by

imaging T1a Tumor incidental histologic finding in 5% or less of tissue

resected T1b Tumor incidental histologic finding in more than 5% of

tissue resected T1c Tumor identified by needle biopsy (e.g., because of

elevated PSA level) T2 Tumor confined within prostatea T2a Tumor involves one lobe T2b Tumor involves both lobes T3 Tumor extends through the prostate capsuleb T3a Extracapsular extension (unilateral or bilateral) T3b Tumor invades seminal vesicle(s) T4 Tumor is fixed or invades adjacent structures other than

seminal vesicles: bladder neck,external sphincter, rectum, levator muscles, and/or pelvic wall

Regional lymph nodes (N) NX Regional lymph nodes cannot be

assessed N0 No regional lymph node metastasis N1 Metastasis in regional lymph node or

nodes Distant metastasis (M) MX Distant metastasis cannot be assessed M0 No distant metastasis M1 Distant metastasis M1a Nonregional lymph node(s) M1b Bone(s) M1c Other site(s)

StageI T1a N0 M0 G1 Stage II T1a N0 M0 G2–4 T1b N0 M0 Any G T1c N0 M0 Any G T2 N0 M0 Any G Stage III T3 N0 M0 Any G Stage IV T4 N0 M0 Any G Any T N1 M0 Any G Any T Any N M1 Any G

Assessment of Risk for Extracapsular Spread

Extracapsular spread of prostate cancer affects the choice of local treatment modality and has a negative impact on prognosis.

Assessment of Lymph Node or Distant Metastasis

Most commonly, prostate cancer spreads to bone or pelvic lymph nodes. Frequently, the pattern of bony metastasis is blastic and is visualized readily by bone scintigraphy.

TREATMENT Localized Disease

The principle goal of therapy for localized prostate cancer is cure.

Several curative options exist, but lack of randomized comparisons among them complicates selection of the appropriate treatment for any given patient.

RADICAL PROSTATECTOMY

Usually, radical prostatectomy is reserved for patients who have T1 or T2 disease and are suitable candidates for major surgery.

PSA level is being used to assess outcome and should remain undetectable after radical prostatectomy.

RADIOTHERAPY

External-beam radiotherapy is a second curative modality for localized prostate cancer.

Often, radiotherapy series include patients with more extensive local disease than do surgical series, rendering problematic comparison of the outcome and complications of therapy.

INTERSTITIAL BRACHYTHERAPY

Radioactive seed implantation using 125I or 103Pd is another promising treatment option for patients with localized prostate cancer.

CRYOSURGERY

Cryosurgical ablation of the prostate involves use of cooling probes that cause necrosis of prostatic tissue through freezing.

Metastatic Prostate Cancer

Metastatic prostate cancer is considered incurable. Control of tumor growth, palliation of symptoms, and maintenance of quality of life are important goals of therapy.

ORCHIECTOMY

Orchiectomy removes the major source of male testosterone production.

CYTOTOXIC CHEMOTHERAPY

The role of cytotoxic chemotherapy for patients after progression on androgen blockade is being reevaluated, but recent studies suggest that significant palliation may be derived and objective responses can be obtained. Tannock et al.

Most patients with disease relapse have osseous disease only, which renders response assessment difficult.

Trials using posttherapy PSA decline as an end point have identified several active agents that are undergoing further testing.

INVESTIGATIONAL APPROACHES

Because no curative therapy for metastatic prostate cancer exists, the need for better treatment is urgent.

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