Dr. Roach: Should screening test for stomach cancer have broader use?
Dear Dr. Roach: I read with interest your recent column regarding the benefit of a colonoscopy for detecting colon cancer. I am 58 and started experiencing frequent light nausea about two months ago, a few days after getting my first Moderna vaccine. My doctor had me get a blood test. It was generally normal except the liver’s enzyme activity level was very high. That led to a second, liver-focused blood test, an abdominal ultrasound, an abdominal CT scan, followed by a colonoscopy and endoscopy. The last test’s biopsy determined that I have stomach cancer, and a liver biopsy, torso PET scan, chemotherapy and immunotherapy are next.
If the cancer has spread to the liver, which appears likely, then I have stage IV stomach cancer, which may be fatal. I am not aware of any family history of stomach cancer. Why aren’t endoscopies a recommended test for all age 50+ individuals, as colonoscopies are? I might have a much better survival prognosis if they were. Has any doctor found a way to beat stage IV stomach cancer?
Dear M.S.: I am very sorry to hear about your diagnosis, and wish you well with your treatment. The prognosis for stage IV stomach cancer is not good, but recent advances with immunotherapy and chemotherapy should give you hope.
Successful screening for cancer requires two factors: a cancer that is detectable at a time when it can be successfully treated, and a screening test that is safe and accurate at detecting early cancer.
Some cancers are initially very slow-growing. The best examples are cervical and colon cancer, where screening clearly saves lives. They normally grow for five to seven years before they become invasive and spread both locally and to distant organs. This allows screening tests (Pap smear and HPV testing for cervical cancer, colonoscopy or stool cards for colon cancer) to have a good chance of finding the cancer while it can be easily cured.
Unfortunately, cancers are highly variable from one person to another. Some breast cancers may be detectable and treatable for 10 years before they spread, but other breast cancers are so aggressive that they have already spread by the time the most sensitive test can find them. Stomach cancer in a 50-year-old is detectable for an average of about three years before causing symptoms, which makes early detection possible but difficult.
The best-studied screening test for stomach cancer has been an endoscopy, which is relatively invasive and has some potential for harm. In some countries where there is much more stomach cancer, such as Korea and Japan, recommendations are to have endoscopy every two years for people over 50. Unfortunately, there are no good trials showing that screening for stomach cancer reduces the likelihood of death, probably because stomach cancer is relatively uncommon in North America, and a successful trial requires many subjects. Screening is recommended for people at high risk, including some people with familial cancer syndromes like FAP and Lynch syndrome.
Cancer screening may be about to change dramatically with the development of a blood-based cell-free DNA test, which has shown great promise in early diagnosis of many kinds of cancers, including stomach cancer. Further evidence is necessary before these should be used for general screening.
Readers may email questions to ToYourGoodHealth@med.cornell.edu.