Looking Backward – And a Peek in the Other Direction

Doc Gumshoe looks at the state of cancer treatment... and some of the interesting drug approvals from 2018

By Michael Jorrin, "Doc Gumshoe", January 31, 2019

Chances are not many of us observed New Year’s Eve with celebratory toasts to the glorious year gone by.   Rather, we bid goodbye to 2018 and hoped 2019 would be a better year – for ourselves, our near and dear, our country, and our planet.   However, as I wade through the volumes of healthcare-related stuff that land in my in-box every day, I do find news that is unquestionably positive.  

Let’s lead off with this item:

The cancer death rate in the US has been declining steadily for 25 years

Cancer continues to be the second most frequent cause of death in the US, after heart disease, but the death rate is dropping.   The death rate from cancer rose to a high of 215.1 deaths per 100,000 population in 1991. But by 2016, 25 years later, it had dropped to 156 per 100,000 population, a decline of a bit over 27%.   This decline, starting in 1992, has continued at a steady pace and is expected to continue as time goes on. 2016, by the way, is the most recent year from which the data have been collected and analyzed.   The data were compiled by the American Cancer Society from several registries and published in an article in CA: A Cancer Journal for Clinicians on January 8, 2019. (Siegel R. 2019;69;7-24).

If cancer death rates had remained at their 1991 peak, this would have resulted in about 2,629,200 more deaths during those 25 years – more than 100,000 per year.   Over a ten year period from 2007 to 2016 the decline in the death rate was somewhat different in men and in women. In women the cancer death rate declined by approximately 1.4% per year, while in men it dropped by 1.8% per year.

The decline in the cancer death rate was in sharp contrast to what we had seen through most of the 20th century, when cancer death rates were rising, seemingly inexorably, every year.   This increase was primarily driven by the increase in smoking and tobacco use, which affected both sexes and persons of all ages, and caused major increases in lung cancer incidence.   And it is the reversal of that smoking trend that has mostly brought about the decrease in cancer deaths, although improved medical treatment for cancer has certainly played a major part.

The highest death rates in both men and women are due to cancers of the lung and bronchus, which account for 24% of the cancer deaths in men and 23% in women.   However, in terms of incidence, these are not the most frequent cancers. In men, the most frequent cancer is cancer of the prostate, accounting for about 20% of all cancers.   And in women, the most frequent cancer is breast cancer, which accounts for about 30% of cancer incidence. But both of these cancers have a relatively high survival rate. The 174,600 cases of prostate cancer estimated to occur this year are expected to cause 31,620 deaths, for a survival rate of a bit over 80%.   In women, the 268,600 predicted cases of breast cancer are expected to lead to 41,760 deaths, for a survival rate of about 84%.

This contrasts sharply with cancers like pancreatic cancer, the incidence of which in men is 29,940 cases with a predicted death rate of 23,800 – a survival rate of about 20%.   And in women, the 26,830 cases of pancreatic cancer are predicted to lead to 21,950 deaths, for a survival rate of 18%.

The survival rates for lung and bronchial cancers are not as bad as that, but by no means are they rosy.   In men, 116,440 cases of lung cancer are expected to cause 76,650 deaths, for a survival rate of about 33%, and in women the predicted incidence and mortality rates are 111,710 and 66,010, meaning that the expected survival rate will be about 40%.

All told, the survival rates for women are somewhat higher than for men.   The total predicted new cases annually of cancer in men is 870,970, and the predicted cancer deaths total 321,970, for a survival rate of about 63%.   In women, those figures are 891,480 and 285,210, suggesting a survival rate of about 68%.

Those numbers for incidence and survival are predicted based on current statistics.   The survival rate percentage calculation is based on the assumption that, for example, a man who has had prostate cancer and dies from any cause other than that specific cancer is a prostate cancer survivor; similarly for all the other cancers mentioned.    That assumption is likely flawed to some degree. A person who has lived with lung cancer for several years and dies due to a heart attack should perhaps not be counted as a lung cancer survivor. But the numbers certainly provide a good picture of expectations: for example, a woman is likely to survive breast cancer, but not pancreatic cancer.

Another way of looking at the probability of surviving cancer is to consider the five-year survival statistics.   These are more easily and more precisely measured – we don’t have to wait until the patient dies to decide whether he/she survived a particular form of cancer.   We only need to check at the five year-mark after the diagnosis. Five-year survival numbers at first glance are a great deal more optimistic than the ultimate survival statistics given above.   For example, for all stages of these cancers combined, the five-year survival rates are highest for prostate cancer (98%), skin melanomas (92%), and breast cancer in women (90%). As expected, these rates are lowest for pancreatic cancer (9%), liver cancer (18%), esophageal cancer (19%), and lung cancer (19%).   

It should be noted that those five-year survival rates should not be taken as cure rates.   A man who has is still alive five years after a diagnosis of prostate cancer has not necessarily been cured.   Perhaps the cancer is merely indolent. These rates are partly indicative of the aggressiveness of a particular form of cancer, as well as being partly indicative of the likelihood of effectiveness of treatment for that cancer.   For example, the five-year survival rate for prostate cancer lumps in the men who have opted for definitive treatment, such as prostatectomy, with the men who have opted for “watchful waiting.”

Despite all the caveats mentioned above, the overall picture is positive.   The five-year survival rate for all cancers is about 67%, which is pretty close to the predicted total survival rates of 63% in men and 68% in women.   The Doc Gumshoe take on this is that all in all, we have about a two out of three chan