Thursday, November 4, 2010

Use of Scans May Become Less Scant

Today the Washington Post reported that a federal study (National Cancer Institute) had found that the use of CT scans could reduce deaths from lung cancer by 20% in former and current smokers.  The article stated:
The participants were randomly assigned to receive three annual screenings with either low-dose helical CT scans, which are also known as spiral CT scans, or a standard chest X-ray. The CT scans use X-rays to obtain multiple images of the chest. Most hospitals can perform the scans. The subjects were then followed for up to another five years to see who developed lung cancer. Those who were diagnosed received standard treatment. A total of 354 deaths from lung cancer occurred among the subjects who underwent CT scans, compared with 442 among those who got the chest X-rays - a 20.3 percent reduction in lung cancer mortality.
To date, there has not been an effective screening test for lung cancer and it is believed that the higher mortality rates for lung cancer derive from finding the disease in later stages rather than through early screening.  Similarly, ovarian cancer is not easily detected in early stages because there is no good screening test.  Testing CA-125 levels is not very accurate.  And having your standard gynecological exam is not a great way to find ovarian cancer, as I well know given that I had one about 4 months before my tumor was found with a CT scan, already at stage 3.

I have given a lot of thought to why CT scans are not used more frequently to screen for ovarian cancer.  There are probably a lot of reasons.  First, ovarian cancer is still fairly rare. A woman in this country has a lifetime risk of less than 2% of developing ovarian cancer .  Second, CT scans for ovarian cancer, typically  full abdominal with contrast on a multidetector CT scanner (MDCT)  have side effects from the radiation (possibly leading to cancer) and allergies to the contrast agents (ranging from a rash to anaphylaxis-an inability to breathe).  Third, and probably the most important factor for those of the cynical bent, CT scans cost a lot of money because the machines are expensive (approximately $900,000 or more for an MDCT) and insurance will not pay the fees which can be thousands of dollars (after all the machines don't pay for themselves).

Perhaps there will be research on CT scans as screening for ovarian cancer like the research of the study on lung cancer screening reported today.  It will not do any good for me just as the new screening results for lung cancer will not help my good friend who has stage 4 lung cancer. But these scans may help others including my own daughter and granddaughter.

1 comment:

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