Fast DNA-sequencing machines are leading to simple blood tests for cancer.
Labs around the world are working toward developing cancer screening tests based on a simple blood draw. That’s possible because dying cancer cells also shed DNA into a person’s blood. Early on, the amount is vanishingly small—and obscured by the healthy DNA that also circulates. That makes it difficult to measure. But Lo says the objective is simple: an annual blood test that finds cancer while it’s curable.
Cancers detected at an advanced stage, when they are spreading, remain largely untreatable. In the United States, early detection is behind medicine’s most notable successes in applying technology to cut deaths from common cancers. Half of the steep decline in deaths from colorectal cancer is due to screening exams like colonoscopies.
Dr. Stegall’s Comments: The more pieces of information we can have about cancer activity in the body, the better. I use several excellent tests in my office, including ONCOblot and Onconomics Plus, which tell us about cancer activity in the body. The ONCOblot test measures a specific protein which has been shown to only be released by cancer cells, so this is a good screening test. It will also tell us the origin of the cancer. Onconomics Plus, informally known as the “Greek Test,” measures circulating tumor cells (CTCs), which are released by cancer cells into the blood stream and are the main way cancer ultimately spreads. This test is best utilized after a patient already has biopsy-proven cancer and wants to know the CTC level as well as which chemotherapy agents and natural substances were most successful against their cancer on lab testing. I find both of these tests to be quite valuable in personalizing treatment, as no two cancer cases are exactly alike.
Cancer Screening Tests Women Need to Know About
Along with giving Mother’s Day gifts and sending greetings this year, encourage the moms in your life to get up to date on cancer screening tests.
Screening tests look for cancer before a person has any signs or symptoms. Regular screenings can catch some cancers early, when they’re small, have not spread, and are easier to treat. With cervical and colon cancers, these tests can even prevent cancer from developing in the first place.
Sweeten the deal by offering to help your mom schedule her screening, drive her to and from appointments, and keep her company in the waiting room.
Dr. Stegall’s Comments: When we are dealing with a cancer diagnosis, the earlier the detection, the better. Survival rates for all cancers are significantly higher when the diagnosis is made early, before the cancer has spread to other parts of the body. Once metastasis occurs, survival rates drop sharply. For breast cancer screening, I feel that mammograms, ultrasounds, thermography, and monthly self-exams all have a valuable role to play depending on each woman’s unique situation. For colon cancer surveillance, a colonoscopy starting at age 50 (earlier if there is a significant family history of colon cancer) is an excellent idea.
I also encourage women to have a CA 125 level drawn on lab testing. CA 125 is a tumor marker which we commonly associate with ovarian cancer, but it can also be elevated in breast cancer. While CA 125 is not intended as a screening test, I still feel that it is valuable to check since elevations on lab testing in asymptomatic women can uncover early stage cancer before symptoms are present. Of note, elevations in CA 125 can be caused by other gynecological conditions as well (“false positives”), so this is not a perfect test. But I do feel that it has value in the setting of cancer screening.
Why Gene Tests for Cancer Don’t Offer More Answers – Despite progress, genetic profiling of tumors has a long way to go
Genetic tests for cancer have come a long way since they first entered the clinic in 1995. Back then, mutations in two genes—known as BRCA1 and BRCA2—hinted at the crucial role that genetics can play in treatment decisions. Women carrying one of those mutations (and having a family history of breast or ovarian cancer) were much more likely than the general population to develop tumors in their breasts or ovaries. Then, as now, some of these women opted to have their breasts and ovaries removed before any malignant growths could arise.
In the intervening decades, researchers have come to recognize that most cancers are driven largely by abnormalities in genes. Genetic analysis of tumors has, therefore, become standard practice for many malignancies—such as breast, lung and colon cancer—because the information may help guide therapy. Clinicians have amassed a modest arsenal of drugs able to counteract some of the most common mutations. Yet many patients learn that their cancers have mutations for which no drug exists.
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Dr. Stegall’s Comments: Although the majority of cancer research dollars today are spent on genetic testing, I feel that this is largely an exercise in futility. As I have mentioned before, I believe that cancer is a metabolic disease rather than a genetic disease. In other words, cancer forms when normal cells develop abnormal metabolism (energy production) as a result of environmental stressors such as harmful chemicals, toxins, and stressors. The genetic changes we see in cancer are the downstream effects of these metabolic changes, rather than the cause of cancer. This is why we have seen studies showing that the cancer cells from a patient’s tumor have different genetic changes. These changes in genes are chaotic and random, not predictable – which makes sense if we view genetic changes as symptoms rather than causes. So while I support further study into the genetics of cancer, and incorporate genetic characteristics into the blood testing I do, I remain convinced that we must also address the underlying metabolic cause.
