At the start of every year the American Cancer Society issues the latest cancer statistics. This year the data were released in two publications, both of which are found at the end of this article. Some of the salient features of the data are discussed below.
I’ll start with prostate cancer which seems to eternally trouble the ACS. Since the cessation of routine PSA testing in men, there has been a nonsignificant increase in the incidence of prostate cancer. The current recommendation from the United States Preventive Services Task Force is that PSA testing only be done after a discussion of its pros and cons with each patient. That a government task force has to advise that doctors talk to their patients before instituting diagnosis or treatment defines the condition of modern medicine.
In the last few iterations of these annual compilations of cancer data the use of age adjusted mortality was abandoned. It’s far and away the best way to present mortality statistics. The death of a 90 year old from cancer does not carry the same burden as does the demise of a 50 year old. Adjusting for age eliminates this problem. Below are age adjusted mortality curves for various malignancies in both men and women.
These two figures convey the most important data from both reports. Observe that the most striking finding is the decline in lung cancer mortality. This reduction is entirely the result of the cessation of cigarette smoking as the treatment of lung cancer has not improved over the span shown in the graphs. A similar poorly treated cancer is that in the stomach. Note that stomach cancer which was the leading cause of cancer death in1930 has now almost vanished. The reason for this observation is still opaque.
Next look at colon and rectum. Starting around 1985 mortality started to decline in both men and women. This fall in death rates is likely the result of screening for colon cancer and the widespread use of colonoscopy which allows the identification and removal of premalignant polyps.
Breast cancer mortality requires more analysis of the data above. Despite the widespread use of mammography as a diagnostic tool in the mid 60s, age adjusted mortality did not decline until about 1990. The Canadian National Breast Screening Study has repeatedly failed to show a difference in mortality between women screened with mammography compared to those using self examination. The most likely explanation for the decline in breast cancer deaths since 1990 is better treatment rather than better screening. Nevertheless women seem to want mammography as soon as possible, though the current recommendation is (except in special cases) not to start until age 50. The current reports emphasize that there are risks from long term screening in addition to the problem of over diagnosis. Mammograms may identify lesions that are of no clinical significance leading to diagnostic procedures that are of no value.
Back to prostate cancer. Observe that mortality was lower in 1930 than it is today and that it increased to more than twice the 1930 rate by the early 90s. It then declined plateauing to its current level around 2010. The reason for this up and down curve is unclear. It’s hard to invoke either screening or changes in treatment as the agent of this phenomenon.
An interesting statistic, though I can’t explain it, is the difference among the states (Puerto Rico is included) in cancer mortality expressed as deaths per 100,000 population. Mississippi has the dubious distinction of being first with a mortality rate of 225.9 for men and 148.5 for women. The death rate for women in Oklahoma is a bit higher – 149.6. Mississippi is the poorest state in the union. It would be the second poorest were Puerto Rico to be admitted as a state; yet the island commonwealth has the lowest death rates in the US – 132.1 for men and 86.4 for women. Thus, wealth is not an explanation. The next lowest mortality rates are from Hawaii – 151.4 for men and 105.5 for women.
Finally, the table below shows the leading causes of death in 2020 compared to 2019. Note that almost every cause of death increased. Total deaths were up more than half a million. These increases were doubtless due to the COVID-19 epidemic. Though the explanation requires some further examination. More than 350 thousand deaths were attributed to COVID. This attribution is doubtless an overestimate. Note that the only cause of death to decrease was chronic lower respiratory diseases. Deaths from this class were likely attributed to COVID. The government induced overreaction to the viral epidemic almost certainly degraded medical care such that delayed or omitted medical care allowed death rates from all causes to spike.
I’ve just touched on all the data reported in the two publications below. Download them and peruse them at your leisure to get a true understanding of where we are with respect to cancer.
