If a biopsy reveals prostate cancer, also known as adenocarcinoma of the prostate, important variables related to prognosis include:

• Cancer Grade
• Cancer Stage
• Pre-treatment PSA
• Tumor volume on the biopsy.

Grading & Staging

Prostate cancer grade refers to its degree of aggressiveness. The prostate cancer grading system is known as the Gleason score. Gleason is a pathologist who devised a system that scales from 2 (the least aggressive form of prostate cancer) up to 10 (the most aggressive form). The majority of men with prostate cancer have Gleason 5 –7 lesions. The higher the Gleason score is, the more aggressive the cancer.

Prostate cancer stage is determined on the basis of DRE (Digital Rectal Exam). Most men have a normal DRE and are stage T1c (PSA detected cancer)

T1c (PSA detected)
T2a (small nodule)
T2b (larger nodule)
T3 (very large nodule with probable extension outside of the prostate)
T4 (prostate cancer growing into adjacent organ such as the bladder)

The pretreatment PSA provides some information with regard to prognosis. The lower the PSA, the better the prognosis. However, pre-treatment PSA does not adequately stage the individual patient.

Tumor volume, or percent of the biopsy involved with cancer, can also provide some prognostic information. A lower amount of tumor in a biopsy specimen can often correlate with the amount of tumor in the prostate gland. However, there can be some degree of sampling error on routine prostate biopsy and the individual patient tumor volume, in and of itself, may not always accurately predict outcome. Together, Gleason score (grade of the cancer), tumor stage, pre-treatment PSA and biopsy tumor volume can provide a good deal of information with regard to curability and treatment outcome.

Prostate Cancer Grading System (Gleason score 2 – 10)

Estimated reduction of life expectancy in men 65 to 75 years of age based on tumor grade (JAMA. 274:626, 1995)

Prostate Cancer Staging System (based primarily on rectal exam)

Indicators of overall prognosis

Additional prognostic information may be obtained by consideration of the percentage of tissue involved with cancer on the biopsy specimen. In general, the greater the percentage of tissue containing tumor is, the larger is the malignancy within the prostate gland. The correlation between tumor volume on the biopsy and size of the cancer within the prostate is most accurate when viewed or calculated in a large cohort. For the individual patient however, biopsy tumor volume may not accurately depict the size of the cancer within the prostate gland due to sampling error. The biopsy needle, for example, may only sample the portion of the tumor mass.

Fortunately, the majority of prostate tumors detected through PSA-based screening efforts are confined to the prostate at the time of diagnosis. However many tumors still are found in more advanced stages. Initially, prostate cancers will grow through the capsule or the rind of the prostate into the surrounding soft tissue. The tumor can spread along the ejaculatory ducts and involve the seminal vesicles. Next, the cancer can invade the lymph system and spread to the lymph nodes in the pelvis. When prostate cancer is in its most advanced stages, it will spread to the bones and then on to the lung, liver, brain and elsewhere.

The routine staging evaluation includes a thorough history and physical examination. A baseline bone scan is often obtained to check for spread to the bony skeleton. Bone scans are rarely positive in patients with PSA levels of less than ten and a Gleason score of less than, or equal to, six. A CAT scan or MRI of the abdomen and the pelvis is obtained to evaluate the pelvic lymph nodes. Either of these studies will only document lymph nodes at least one cm. in maximum diameter. Again, most men diagnosed with localized prostate cancer will have normal or negative studies. Other staging studies include an endorectal coil MRI of the prostate gland. Although this type of imaging tool can confirm gross evidence of spread beyond the prostate gland, it is not sensitive or accurate enough to detect microscopic spread outside of the prostate gland. A prostascint scan is a type of nuclear medicine imaging study, which attempts to locate cancer cells that have spread to other parts of the body. This test is best reserved for patients who have suffered a prostate cancer relapse after definitive local therapy, whether it was radiation or surgery. By itself, the prostascint scan is not very sensitive, but its diagnostic capability improves when obtained with a CAT scan of the abdomen and pelvis.

Once the metastatic evaluation has been competed, patients are grouped into three main categories: (1) localized cancer, (2) locally advanced cancer, (3) metastatic cancer.

Radiation | Surgery | Therapy for Localized Prostate Cancer | Treatment of Metastatic Prostate Cancer