I have been confused and, frankly, suspicious about cancer stats for years. I was hoping that either health professionals or statisticians on the board could help me make sense of it all.
Just to keep things simple, I'm going to stick to breast cancer statistics for now.
A local hospital just took out an ad in the paper for Breast Cancer Awareness Month. They listed the following statistics (all stats here are from Canada).
Quote:
Sounds like about one in four women diagnosed will die of breast cancer. Then it goes on:
Quote:
Now, that sounds like one in three diagnosed will die of the disease.
What really throws me off is the very common statement that breast cancer death rates are steadily declining, and that over 80% of women diagnosed with breast cancer become successful breast cancer survivors. That made no sense to me at all, until I read that someone who lives five years or more after diagnosis is considered a "cancer survivor." The Canadian Cancer Society says that the 5 year survival rate for breast cancer is 86%, so I thought that was probably what they were talking about. (Of course, the CCS also says that the mortality rate for breast cancer is 23 per 100,000 cases, and I have no idea where that fits in.)
So I am assuming that when health experts talk about a declining breast cancer rate, what they really mean is that women are taking longer to die from breast cancer, and a greater number take more than 5 years. When they say that early diagnosis means a greater chance of survival, I assume that the earlier you find the cancer, the more likely it is that you will die more than 5 years later, since the cancer was found at an earlier date. If that is the way the statistic is used, doesn't that mean that a woman can die of breast cancer and still be counted as a breast cancer survivor, as long as she died five years and one day after her initial diagnosis?
And what about the differing statistics on death rates? Is it one in four, one in three, 23 per 100,000, or are all the stats being manipulated in one way or another?
Is there more to it? What am I missing here?
Just to keep things simple, I'm going to stick to breast cancer statistics for now.
A local hospital just took out an ad in the paper for Breast Cancer Awareness Month. They listed the following statistics (all stats here are from Canada).
Quote:
Women diagnosed with breast cancer in last year - 22,000 Women who will die of BC in same year - 5,300 |
Quote:
One in nine women will develop breast cancer in her lifetime. One in 27 women will die of it. |
What really throws me off is the very common statement that breast cancer death rates are steadily declining, and that over 80% of women diagnosed with breast cancer become successful breast cancer survivors. That made no sense to me at all, until I read that someone who lives five years or more after diagnosis is considered a "cancer survivor." The Canadian Cancer Society says that the 5 year survival rate for breast cancer is 86%, so I thought that was probably what they were talking about. (Of course, the CCS also says that the mortality rate for breast cancer is 23 per 100,000 cases, and I have no idea where that fits in.)
So I am assuming that when health experts talk about a declining breast cancer rate, what they really mean is that women are taking longer to die from breast cancer, and a greater number take more than 5 years. When they say that early diagnosis means a greater chance of survival, I assume that the earlier you find the cancer, the more likely it is that you will die more than 5 years later, since the cancer was found at an earlier date. If that is the way the statistic is used, doesn't that mean that a woman can die of breast cancer and still be counted as a breast cancer survivor, as long as she died five years and one day after her initial diagnosis?
And what about the differing statistics on death rates? Is it one in four, one in three, 23 per 100,000, or are all the stats being manipulated in one way or another?
Is there more to it? What am I missing here?