Copyright ©1999 Ceil Sinnex
RISK REDUCTION + SCREENING + EARLY DETECTION
+ PSYCHOSOCIAL ISSUES + CANCER POLITICS
RISK REDUCTION + SCREENING + EARLY DETECTION
Excerpts from Spring 1997 issue
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Excerpts from Autumn 1996 issue
Excerpts from Summer 1996 issue
Excerpts from Winter 1996 issue
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Autumn 1997: Early Detection of Ovarian and Endometrial Carcinoma,
Memorize These Words: 'Gynecologic Oncologist,'
Genetic Mutation Testing Risks
Summer 1997: I Had a Mastectomy After Genetic Testing,
Coley's Toxins, 3-Drug Cocktail Treatment
Spring 1997: Full text of an article on our Number One topic (by subscriber choice), the CA125-II blood test.
Expert Unpuzzles the CA125II Blood Test
By CEIL SINNEX
Copyright © 1997 Ceil Sinnex
The CA125-II blood test is best used for observing the trend of an ovarian-cancer patient's results over time, according to one of the test's co-developers.
"The key is that the absolute value of CA125-II is not very helpful," says Robert C. Bast Jr., M.D. "It's probably not helpful to compare one patient's results with another's."
Bast made the comment while fielding questions Ovarian Plus had obtained from 10 members of the Ovarian Problems Discussion Group on the Internet.
Because the CA125-II test is one of the few tools available for detection of ovarian cancer recurrences, the wait for results and the difficulty of interpreting the trends are sources of anxiety for survivors.
Every lab test produces some errors, or false results. The error rate for CA125-II has attracted special attention-perhaps because it tests for an unusually lethal disease.
The "normal range" for CA125-II tests is assumed for the purposes of this article to be under 35. However, Bast explains that several companies produce CA125-II assays (measurement methods); any company could possibly change its assay and its normal range, without notifying Bast and co-developer Robert C. Knapp MD.
It is therefore important for each patient to obtain her CA125-II results in writing, with the normal range stated. So that comparability may be assured, it is also recommended that the assay manufacturer and method be obtained in writing. The lab report should also show which generation of the test was used.
For example, a thorough lab report would state: "Centocor CA125-II radioimmunoassay sandwich method, normal below 35: 16."
CA125-II replaces the first generation of the test-CA125; but patients and doctors often are not routinely informed which generation is being used. It matters, because CA125-II may normally be several points higher or lower than CA125 was. The old CA125 is no longer manufactured in the United States, and Bast believes it unlikely old test kits are still being used.
My CA125 was rising slowly: 214 in August 1995, 236 a year later. It shot up to 400 only six weeks after that, but was down to 264 three weeks later. Both my gynecologic oncologist and medical oncologist think the 400 was an anomaly. What could account for this?
BAST: I agree with her doctors, because there's variation from day to day in the assay itself and also in the patient. The trend over time is the most important factor.
How can a patient find out exactly which CA125 test was done and by which company? I got a copy of the lab test results and the statement of normal range, but nothing more was included.
BAST: As a courtesy, labs should provide the information to the doctor, and to the patient upon request. She should ask the doctor, who needs to ask the lab.
CA125 was not a significant indicator for me at the time of diagnosis, when it was 61. So how accurate a predictor of recurrence is CA125 going to be for me?
BAST: Sixty-one is a modest elevation. If CA125 turns positive again, it may be an indicator of disease.
My results have gone from 61 to 17 post-chemotherapy, then 19, and 22. Should I worry about the upward trend?
BAST: Not unless it doubles outside a normal range. Day-to-day variation could account for this fluctuation.
Is it true that CA125 can elevate after chemotherapy as the tumor "breaks up"
BAST: Yes. There can be a transient increase before a decrease if the cancer is responding to chemotherapy.
Would you please give a simple explanation of what CA125 measures?
BAST: CA125 is a substance shed by cancer cells, also made by inflamed normal cells that line body parts. This substance is shed in body fluids and finds its way into the bloodstream.
When CA125 is rising, like mine (15, 19, 18, 20, 23.5) over a period of 16 months, and everyone says, "Don't worry," is there cause for concern?
BAST: That could occur from fluctuations in the test from day to day. CA125 may or may not always reflect illness.
What is exactly the function of this substance, CA125, in the body? Does having an elevated CA125 cause harm to the body, in and of itself?
BAST: No one knows what the normal function of the substance is. Having elevated CA125 does not cause harm to the body in and of itself, so far as we know.
Is there a correlation between the magnitude of the number and the disease activity?
BAST: For a patient whose CA125 was elevated at diagnosis, there's correlation between CA125 and their disease 90 percent of the time. It's the increase or decrease outside the normal range, rather than the absolute number, that's indicative.
I have heard of women with CA125 results as high as the 10,000 range. What is the meaning of these numbers in terms of the extent or progression of disease?
BAST: Aside from the fact that larger numbers usually indicate greater amounts of cancer, there's tremendous variation from person to person in how much CA125 is produced by the cancer and released to the bloodstream.
In what percentage of cases is CA125 elevated with a benign ovarian growth?
BAST: It depends on what kind of growth, but up to 20-25 percent in some studies.
Do certain types of ovarian cancer appear more sensitive to the test than others?
BAST: Serous ovarian cancers are more frequently positive than mucinous, but all types can sometimes be positive.
What's the difference between CA125 and CA125-II?
BAST: The designation II reflects a second-generation test that uses two different antibodies to capture the antigen. CA125-II has less variation from day to day than CA125 had.
Can doctors get labs to send a copy of their reports directly to the patient, and will the labs comply?
BAST: I think this comes down to the lab's and doctor's policy, but is not required by law.
During chemotherapy, my CA125s have risen from a low of 20 to 50. My doctor said my latest reading might be due to the fact I had diarrhea.. Can diarrhea increase CA125?
BAST: Not so far as I know.
Copyright (C) 1999 by Ceil Sinnex
Published by OVARIAN PLUS (TM)
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