The origin and development of malignant prostate cancer is not fully understood yet. Evidence seems point to a condition of precancerous prostate cells as the precursor to the disease. This condition, or high-grade prostatic intraepithelial neoplasia (PIN), occurs when the cells lining the prostate begin to have microscopic changes, which then appear to lead to the development of prostate cancer cells.
Metastasized prostate cancer is cancer which has spread beyond the first layer of cells, where it initially developed, and into nearby tissue. A malignant prostate cancer is classified as carcinoma if it begins in the lining layer of an organ. Adenocarcinoma of the prostate is the most common malignant prostate cancer, but on rare occasions, other types of malignant prostate cancer can occur in some men. The different types of prostate cancer can be categorized as follows:
- Adencarcinoma – This cancer starts in the glandular cells which line the ducts of the prostate gland and is the most typical of prostate cancer types. Over 95% of men diagnosed with prostate cancer, have adencarcinoma. Second to melanoma, adenocarcinoma of the prostate is the most common malignant cell growth in men who are over age 65.
- Small-cell carcinoma – This cancer is similar to small-cell carcinoma of the lung. Made up of small, round cells called neuroendocrine, this malignant prostate cancer begins from nerve-like cells. Although rare, it is particularly aggressive and difficult to cure. It is rare for small-cell carcinoma to be diagnosed initially, because it generally does not cause prostate specific antigen (PSA) levels to increase, so when found, it is usually advanced. If a patient with large, local cancer also has a low PSA level, he should be assessed for small-cell carcinoma. When this type of cancer is discovered, it is usually in men who were first diagnosed with adenocarcinoma of the prostate that was not cured or controlled by radiation, surgery or chemotherapy. In such cases, the malignant prostate cancer usually returns as a large mass in the pelvis, or it has metastasized to other critical organs like the liver. The main treatment for this type of malignant prostate cancer is chemotherapy.
- Squamous cell carcinoma – This cancer is quite rare and found in only .5% to 1% of men who have been diagnosed with malignant prostate cancer. It begins in the non-glandular cells. It too does not cause PSA levels to rise and is extremely aggressive. Characterized by a high degree of malignancy, when found, it is usually metastasized to the liver, lungs and bone. A combination of treatment therapies, such as radiotherapy and chemotherapeutic drugs, is typically used to control the disease and prolong survival time.
- Transitional cell carcinoma- This metastatic prostate cancer is similar to the bladder cancer found in men, but is different from the cancer that found in the interior part of the prostate gland, called the transition zone. It develops from tumors in the bladder, the prostate’s ducts and the part of urethra that stretches through the prostate. Most often treatment is removal of both the prostate and the bladder.
- Other rare types of cancer: other rare types of prostate cancer also exist such as sarcomas and other epithelial tumors, such as rhabdomyosarcoma and leiomyosarcoma of the prostate.
Prostate Cancer Staging
Your doctor will analyze the information from your digital rectal examinations (DRE), diagnostic imaging tests, biopsy, prostate specific antigen (PSA) level, and Gleason score to decide which, if any, other tests is needed for prostate cancer staging. Staging is the process in which all diagnostic information are pulled together to determine how much malignant prostate cancer is present within the prostate gland and whether it has metastasized to nearby tissues or other areas in your body. Men with a low PSA level, normal DRE results and low Gleason scores may not need other tests because most likelihood that metastatic prostate cancer is low.
The stage of cancer is an indication of long term results and important in determining the appropriate treatment options. The more malignant prostate cancer that is in your body, the greater possibility that it is aggressively spreading and the less likely that the treatments are going to be effective. Some doctors believe that if the metastatic prostate cancer is in the worst stage, then it is better to hold off on aggressive therapies, because they would not be effective anyway, while other doctors would argue that the best approach to an aggressive cancer is an aggressive treatment, if there is to be any chance of prolonging the survival of a cancer patient.
The Four Stages of Malignant Prostate Cancer
| Stage | Characteristics | Prostate Cancer Gleason Score | Prostate Cancer PSA Test Level |
| Stage I | Malignant prostate cancer found incidentally or because of elevated PSA | 2 to 4 | Under 10 |
| Stage II | Malignant prostate cancer found because of abnormal digital rectal exam. The cancer is still confined to prostate | 5 to 10 | Under 20 |
| Stage III | Metastatic prostate cancer in to tissues outside of prostate | 2 to 10 | Any Level |
| Stage IV | Metastatic prostate cancer in other critical areas such as lymph nodes or bone | 2 to 10 | Any Level |
- Stage I – Malignant prostate cancer is unexpectedly found during surgery for prostate enlargement, or transurethral resection. This kind of discovery of prostate cancer used to occur 10% to 15% of the time, but now with earlier testing and more advanced screening methods, it is very rare. Men with stage 1 prostate cancer typically have low prostate cancer Gleason scores (2 to 4) and less than 5% of cancerous tissue, meaning the cancer is contained within the prostate and has not spread to lymph nodes or other places in the body.
- Stage II – Malignant prostate cancer is found because of because of a nodule or irregularity found on the prostate exam. The cancer is still fairly small and most often confined to the prostate. Men with prostate cancer at stage 2 will have a Gleason score for prostate cancer from 5 to 10, with cancer that is still contained within the prostate gland and has not spread to the lymph nodes or elsewhere, and one of the following occurred:
- The cancer has an intermediate or high Gleason Score of 5 or higher, or more than 5% of the tissue contained cancer and was discovered during a transurethral resection.
- The cancer was not found during a DRE or seen on transrectal ultrasound, but discovered because of a high PSA level.
- Stage III – Metastatic prostate cancer is discovered growing in the fat surrounding the prostate, the seminal vesicles or base of the bladder. Although it has begun to grow beyond the prostate, it has not yet spread into the lymph nodes or bone. Men with this stage cancer can have any prostate cancer Gleason score.
- Stage IV – Also called late stage prostate cancer, this malignant prostate cancer has metastasized to other vital areas of the body, such as the lymph nodes or the bones. Prostate cancer at this stage has one or more of the following characteristics:
- Prostate cancer cells have spread to outside tissues, other than the seminal vesicles. The cancer has spread beyond the prostate, and into the bladder’s external sphincter, the rectum, and/or the wall of the pelvis.
- Prostate cancer cells have metastasized to the lymph nodes.
- Prostate cancer cells have spread to further areas in the body.
This categorizing or prostate cancer staging helps your doctors to identify the best treatment choices for your particular situation. If the biopsy of your prostate indicates malignant prostate cancer cells, your doctor may want to do more tests to positively determine how widespread they are and at what stage the malignant prostate cancer is at. This staging is critical in determining that treatment options that help can control any metastasized prostate cancer and best increase the outlook of your survival.
