Thursday, October 27, 2011

What is this 1 in 8 business?

1 in 8 is the most over used and misused breast cancer statistic ever. And now it is popping up again. First of all those who have the 1 in 8 chant going in terms of chances of getting breast cancer in your lifetime should understand that the risk greatly increases as you get older. Breast cancer is much rarer in your 30s and 40s.

This is from the National Cancer Institute's website:

"The estimated probability of being diagnosed with breast cancer for specific age groups and for specific time periods is generally more informative than lifetime probabilities. Estimates by decade of life are less influenced by changes in life expectancy and incidence rates. The SEER report estimates the risk of developing breast cancer in 10-year age intervals. These calculations factor in the proportion of women who live to each age. In other words, they take into account that not all women live to older ages, when breast cancer risk becomes the greatest.
A woman’s chance of being diagnosed with breast cancer is:
  • from age 30 through age 39 . . . . . . 0.43 percent (often expressed as "1 in 233")
  • from age 40 through age 49 . . . . . . 1.45 percent (often expressed as "1 in 69")
  • from age 50 through age 59 . . . . . . 2.38 percent (often expressed as "1 in 42")
  • from age 60 through age 69 . . . . . . 3.45 percent (often expressed as "1 in 29")
These probabilities are averages for the whole population. An individual woman’s breast cancer risk may be higher or lower, depending on a number of factors, including her family history, reproductive history, race/ethnicity, and other factors that are not yet fully understood."

But now this 1 in 8 odds is popping up in terms of the number of women who can really can attribute their annual mammogram to saving their lives:

"In an analysis published this week in the Archives of Internal Medicine, researchers at Dartmouth estimate that only about 1 in 8 women whose breast cancer was identified during a routine mammogram actually owe their lives to the screening."

This is from an article which covers the debate on the benefits of annual mammograms again. First of all, do we need to cover this topic again and again and again? Give it a rest. And how can you tell a woman whose breast cancer was found in a mammogram that she would have found it early enough to save their lives? My tumor was found on an annual mammogram when I was 45. I probably would not have found it myself. I had a physical with a breast exam about a month before my bad mammogram and nothing was detected. So would I have been able to feel it a year later? I already had one positive lymph node. 

But I digress, 1 in 8 is a misused statistic. And what it also says is that 7 of 8 women will not get breast cancer.

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