Houston, Texas, USA: Tumors that spread, or metastasize, in the body shed cells into blood that doctors can scrutinize for insights into what a patient’s cancer might do. Analyzing these so-called circulating tumor cells (CTCs) isn’t part of routine care yet, in part because they’re so hard to pick out of the millions of normal cells in a blood sample. Still, scientists are making progress in this area. And in June, a research team reported that treatment decisions made on the basis of CTC testing had increased lifespans in men with an aggressive type of metastatic prostate cancer.
Doctors usually treat metastatic prostate cancer with drugs that interfere with how a man’s body makes or uses testosterone, which is the male hormone (or androgen) that accelerates the tumor’s spread. If the standard hormone-blocking treatments aren’t effective, then doctors have two other options: they can either give chemotherapy drugs known as taxanes, or shift to other hormone blockers that act specifically on the cancer cell’s androgen receptor. Known as androgen receptor signaling (ARS) inhibitors, these alternative hormone blockers include an agent called enzalutamide and another called abiraterone. But neither of them will work if the androgen receptor has a genetic mutation called AR-V7 that also makes the tumors grow very aggressively.
With mounting evidence showing that the mutation doesn’t affect a man’s response to taxanes, researchers began to wonder if screening for AR-V7 in CTCs could guide them to the most appropriate treatment. That’s what a team at the Memorial Sloan Kettering Cancer Center in New York set out to investigate.
Here’s what they did
They began by collecting blood samples from 142 men with metastatic prostate cancer who weren’t responding to standard hormonal therapy. After their CTCs were screened for the AR-V7 protein, the men were treated either with ARS inhibitors or taxanes at their doctor’s discretion. The treating doctors had no knowledge of each patient’s AR-V7 status.
Half the men wound up being treated with ARS inhibitors and the other half with taxanes. And as it turns out, the men who tested negative for AR-V7 lived longer when treated with ARS inhibitors; their median survival was 19.8 months, compared to 12.8 months among the taxane-treated men. Conversely, the men who tested positive for AR-V7 lived longer when given taxanes: their median survival was 14.3 months, compared to 7.3 months among the men treated with ARS inhibitors.
The results mark a significant advance for AR-V7 as a guide to more effective, personalized treatment, and also for CTCs as “liquid biopsies” that doctors can easily sample for important prognostic information.
“The research adds to an expanding body of knowledge related to AR-V7 in prostate cancer,” said Dr. Marc Garnick, the Gorman Brothers Professor of Medicine at Harvard Medical School and Beth Israel Deaconess Medical Center. “Hopefully the utility and availability of this test will become more widespread, and further enhance our ability to select the best treatments for specific patients based on the molecular characteristics of their disease.”
Prostate cancer – National Cancer Institute
Prostate cancer is a disease in which malignant (cancer) cells form in the tissues of the prostate.
Prostate cancer is the most common cancer and the second leading cause of cancer death among men in the United States. Prostate cancer usually grows very slowly, and finding and treating it before symptoms occur may not improve men’s health or help them live longer. In the United States, 1 out of every 5 men will be diagnosed with prostate cancer in his lifetime according to the National Cancer Institute.
Prostate cancer prevention
Cancer prevention is action taken to lower the chance of getting cancer. By preventing cancer, the number of new cases of cancer in a group or population is lowered. Hopefully, this will lower the number of deaths caused by cancer.
To prevent new cancers from starting, scientists look at risk factors and protective factors. Anything that increases your chance of developing cancer is called a cancer risk factor; anything that decreases your chance of developing cancer is called a cancer protective factor.
Some risk factors for cancer can be avoided, but many cannot. For example, both smoking and inheriting certain genes are risk factors for some types of cancer, but only smoking can be avoided. Regular exercise and a healthy diet may be protective factors for some types of cancer. Avoiding risk factors and increasing protective factors may lower your risk but it does not mean that you will not get cancer. Different ways to prevent cancer are being studied.
Prostate Cancer Screening
Screening is looking for cancer before a person has any symptoms. This can help find cancer at an early stage. When abnormal tissue or cancer is found early, it may be easier to treat. By the time symptoms appear, cancer may have begun to spread.
Scientists are trying to better understand which people are more likely to get certain types of cancer. They also study the things we do and the things around us to see if they cause cancer. This information helps doctors recommend who should be screened for cancer, which screening tests should be used, and how often the tests should be done.
It is important to remember that your doctor does not necessarily think you have cancer if he or she suggests a screening test. Screening tests are given when you have no cancer symptoms. Screening tests may be repeated on a regular basis.
If a screening test result is abnormal, you may need to have more tests done to find out if you have cancer. These are called diagnostic tests.
Prostate Cancer Treatment
Prostate cancer is a disease in which malignant (cancer) cells form in the tissues of the prostate. Signs of prostate cancer include a weak flow of urine or frequent urination. Tests that examine the prostate and blood are used to detect (find) and diagnose prostate cancer. Certain factors affect prognosis (chance of recovery) and treatment options.
Tests that examine the prostate and blood are used to detect (find) and diagnose prostate cancer.
The following tests and procedures may be used:
- Physical exam and history : An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken.
- Digital rectal exam (DRE): An exam of the rectum. The doctor or nurse inserts a lubricated, gloved finger into the rectum and feels the prostate through the rectal wall for lumps or abnormal areas.
Digital rectal exam (DRE). The doctor inserts a gloved, lubricated finger into the rectum and feels the rectum, anus, and prostate (in males) to check for anything abnormal.
- Prostate-specific antigen (PSA) test : A test that measures the level of PSA in the blood. PSA is a substance made by the prostate that may be found in an increased amount in the blood of men who have prostate cancer. PSA levels may also be high in men who have an infection or inflammation of the prostate or BPH (an enlarged, but noncancerous, prostate).
- Transrectal ultrasound : A procedure in which a probe that is about the size of a finger is inserted into the rectum to check the prostate. The probe is used to bounce high-energy sound waves (ultrasound) off internal tissues or organs and make echoes. The echoes form a picture of body tissues called a sonogram. Transrectal ultrasound may be used during a biopsy procedure.
Transrectal ultrasound. An ultrasound probe is inserted into the rectum to check the prostate. The probe bounces sound waves off body tissues to make echoes that form a sonogram (computer picture) of the prostate.
- Transrectal magnetic resonance imaging (MRI): A procedure that uses a strong magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body. A probe that gives off radio waves is inserted into the rectum near the prostate. This helps the MRI machine make clearer pictures of the prostate and nearby tissue. A transrectal MRI is done to find out if the cancer has spread outside the prostate into nearby tissues. This procedure is also called nuclear magnetic resonance imaging (NMRI).
- Biopsy: The removal of cells or tissues so they can be viewed under a microscope by a pathologist. The pathologist will check the tissue sample to see if there are cancer cells and find out the Gleason score. The Gleason score ranges from 2-10 and describes how likely it is that a tumor will spread. The lower the number, the less likely the tumor is to spread.
A transrectal biopsy is used to diagnose prostate cancer. A transrectal biopsy is the removal of tissue from the prostate by inserting a thin needle through the rectum and into the prostate. This procedure is usually done using transrectal ultrasound to help guide where samples of tissue are taken from. A pathologist views the tissue under a microscope to look for cancer cells.
Certain factors affect prognosis (chance of recovery) and treatment options.
The prognosis (chance of recovery) and treatment options depend on the following:
The stage of the cancer (level of PSA, Gleason score, grade of the tumor, how much of the prostate is affected by the cancer, and whether the cancer has spread to other places in the body).
The patient’s age.
Whether the cancer has just been diagnosed or has recurred (come back).
Treatment options also may depend on the following:
- Whether the patient has other health problems.
- The expected side effects of treatment.
- Past treatment for prostate cancer.
- The wishes of the patient.
Most men diagnosed with prostate cancer do not die of it.