I’m going to open with the journey that led to this post. It started with this post by John Horgan questioning the U. S. Prevention Services’s updated guidelines on early breast cancer screening. Basically, his conclusion is that the new guidance may actually lead to more deaths which appears to be the inference derived from the service’s own data. That led to this post of his on cancer mortality which in turn led to the graph at the top of the page from Our World in Data.
I wish the graph had been updated to the present day. Twelve years can be an eternity. I also wish the graph had been adjusted for age. As a pathologist buddy of mine observes everybody dies of something. If heart disease doesn’t get you cancer will.
Several things jumped out at me from the graph and I wanted to reflect on those. The most obvious is that less smoking has resulted in an enormous difference in the mortality due to lung cancer. It probably has reduced mortality due to other forms as well. But that isn’t the only thing.
Note that death rates for several forms of cancer (pancreas, leukemia) were increasing until the mid-1960s and have plateaued since then. I would speculate that the adoption of Medicare/Medicaid resulted in a decline in cancer deaths.
Several cancers (breast cancer in women, prostate cancer in men, colo-rectal cancer) show sharp declines in mortality in the 1990s. In the cast of prostate cancer I can only speculate the approval of the PSA test was instrumental. There may be a similar factor in breast cancer in women. Routine colonoscopies may be related to the declines in mortality from that cause. All of those would seem to contradict Mr. Horgan’s observations.
Mortality due to liver cancer, stomach cancer, and uterine cancer has been decreasing for a long time—over the last century. Mortality due to liver cancer in men, bucking the trends, has actually increased since 1980. I have no explanation for that. I would suspect it is behavioral or environmental.
American Cancer Society has a up to 2020 chart in their Facts and Figures pdf. Gather that while lung cancer rates are still dropping, not much change in the other types. Agree medicaid/medicare has done a lot to get people treated as well as effective chemotheraphies.
Liver cancer declining from 1930 might be from the effects of Prohibition. Perhaps also stomach cancer. If liver cancer has reversed in men, it might be that alcohol use has returned and exceeded pre-Prohibition levels.
We have good success with a few cancers. Childhood cancers do well now. However, for a lot of cancers we have seen no or minimal advances. Some of that is due to no improvements in treatments and some due to an increase in disease prevalence. Liver cancer increasing is probably due hepatitis and obesity which are risk factors. While I understand the reasoning behind his concern that reducing the breast cancer screening age might increasing mortality its probably less of a risk for breast cancer. Interventions would incur in younger people and interventions keep getting more focused. Your friend’s observation is also true. If fewer people are dying from heart disease they have to die of something.
One of the big issues is cost. Pharma companies are now turning out very expensive drugs, costs running $50,000 to nearing $1 million that only extend life a few months or maybe a bit longer, often with significant side effects.
https://www.mskcc.org/news/what-s-behind-rise-liver-cancer-deaths-and-what-can-be-done-about-it
Steve
Another factor for liver cancer could be obesity.
I speculate we will see a reduction of cancer due to Wegovy and Mounjaro in next decade or two (obesity is likely the 2nd largest lifestyle factor in cancer, behind smoking).
On the other hand, cancer due to smoking will likely make a come back due to an increase in smoking via cannabis.
As to the various cancers that have been decline for a century or more; my guess is its related to improvements in hygiene and nutrition.