Prostate cancer / Prostate carcinoma
Prostate cancer is the most common cancer in men in Germany and the third leading cause of death due to cancer, after lung and colon cancer. Each year about 65,000 Germans are diagnosed with prostate cancer. Glandular tissue of the prostate can degenerate and form this malignant tumor.
The causes of prostate cancer are still not fully understood. Particular risk factors include: increasing age; family history as well as certain diets and lifestyles.
Complaints include pain on urination or ejaculation, or blood in the urine. The disease does usually not show any symptoms in its early stages. In Germany, men are advised to undergo regular screening tests from the age of 45.
maintrac® for prostate cancer
Nowadays, questions have been raised about rushing into taking biopsies of the prostate, and the subsequent need for surgical removal of the prostate or use of radiotherapy. This is firstly because metastases can develop due to cancer cells finding their way into the blood stream during the surgical intervention. Secondly, the therapy may have rather serious side effects, with slow-growing tumors posing a low risk, especially in older patients. In the early stages of the disease, when the cancer is still limited to the prostate, it may be more beneficial to avoid treatment in favor of close monitoring of the tumor. This procedure is known as “active surveillance”, or „watch and wait“. maintrac® can contribute in this particular situation to longterm-monitoring with cell counts being carried out every 3 to 6 months depending on the specific circumstances.
If lymph nodes are already affected, or distant metastases are detected, then local radiation therapy and surgical interventions in many cases no longer suffice. Since prostate cancer growth is stimulated by the hormone testosterone, it can be of benefit to involve hormone therapy in the treatment process. The aim of the hormone treatment is to lower testosterone levels. Drugs which bind with the androgen receptor, the receptor for testosterone, blocking the effects of testosterone, are called anti-androgens. With maintrac®, the androgen receptor status of the circulating tumor cells can be determined. This can be useful for the primary oncologist when making a decision for or against an anti-androgen therapy. If this form of therapy does not prove very effective (castration-resistant tumor), then chemotherapy can also be considered. Whether the medicines used achieve the desired effect can be tested in advance on the circulating tumor cells by using maintrac® analysis.
Therapy-relevant characteristics in prostate cancer
In addition to prostate-specific antigen (PSA) and prostate-specific membrane antigen (PSMA) testing, maintrac® allows for determination of androgen receptors (AR) and B7-H3 on circulating tumor cells.
- Both PSA and PSMA count towards prostate-associated markers. PSA is a protein which is mainly expressed by prostate cells. In tumors of unknown origin, it can give an indication of which organ is affected. It can also be used for follow up in cases of prostate carcinoma, or can support long-term monitoring in cases of the “watch-and-wait” approach. PSMA is a membrane-bound glycoprotein which is also present on the circulating tumor cells (originating from the prostate carcinoma), and can be used similarly to PSA. Since the PSMA-PET/CT (positron emission tomography/computer tomography) only gives results if the tumor expresses PSMA, a determination of PSMA on the circulating tumor cells with maintrac® should be carried out beforehand. This marker also serves as a suitable target antigen for innovative therapeutic approaches (lutetium PSMA).
- The androgen receptor is activated by the steroid hormones, testosterone and dihydrotestosterone, and gives an indication of the growth behavior of the tumor cells in response to androgens. The AR is an important prognostic parameter in cases of prostate carcinoma. In patients showing hormone-receptor-positive status, AR is considered an indication that the patient may respond to hormone-blocking therapy, and as such, he may have greater chances of survival.
- B7-H3 binds to receptors on lymphocytes, which regulate the immune response. Until now, this has been demonstrated for dendritic cells, T-cells activating monocytes and carcinoma cells. It is believed that the presence of B7-H3 leads to cell-death or paralysis of immune cells which fight against the tumor. As such, its determination can give an indication of whether the body’s own immune response will be inhibited by the presence of B7-H3.