Putting the name of this imperious disease in the title of my homily places a weighty responsibility on me. Who am I to attempt to put forth relevant information and sensible opinions on this topic, the mere mention of which makes most normal folk distinctly uneasy? But I probably pay more attention to the news about cancer and its treatment than most of Gumshoe nation, and I will try hard to present a balanced and sober view of what’s going on, sometimes surveying the terrain from thirty thousand feet, and sometimes coming in for a closer look.
Let me start off with a very general observation: most of the news about cancer that appears in the media is about developments that will affect a relatively thin slice of the total population of cancer patients. The new drugs that we keep reading and hearing about are, initially at least, for a fairly small minority of cancer patients – usually those with rare cancers for which no other therapies are available, or for patients with advanced cancers who have failed previous courses of therapy. That’s not because the drug makers are preferentially targeting those patient classes, but because those are the patient classes for which it is feasible to gain regulatory approval for their new candidate drugs. I’ll explain in more detail later. What I want to do now is look broadly at the picture as a whole – what’s happening with incidence and mortality of the cancers as a class, and to what extent is cancer treatment changing. And, of course, where it is heading.
Some of you may be wondering if this piece is going to be good news, in which case you will read it to the last sentence, or dire warnings, in which case you will be inclined to chuck it in the trash along with the rest of the day’s dire warnings. On the whole, permit me to say that what you will take from this installment of the Doc Gumshoe is mostly bona fide good news, so please do read on.
However, just to get it over with, a bit of bad news: according to the Centers for Disease Control, it is predicted that the number of new cancer cases diagnosed each year in the US will rise in the next 20 years or so, from 1,735,000 this year to 2,387,000 in 2035. Why is this? The main reason is that here has been a huge decline in heart disease in our land. If heart disease rates had remained at their 1996 peak, there would have been about 10 million more deaths attributable to heart disease since then. But those 10 million individuals who avoided death from heart disease have not had immortality conferred on them. At some time, their sojourn on our planet comes to an end, and the vehicle that conveys them to the exit is, with increasing frequency, cancer.
What is unquestionably good news is that the rate of cancer deaths in the US has declined considerably. If the overall cancer death rate in 1990 had persisted, the result would have been about 2.4 million more cancer deaths between 1991 and 2015. Cancer deaths are projected to continue to decline, despite the increase in the number of cancer diagnoses due to the factors mentioned above. Overall, age-adjusted cancer mortality in the US declined by 26% from 1991 to 2015. And, whereas in the mid-1970s about 49% of cancer patients survived 5 years after diagnosis, by 2014 that 5-year survival rate had increased to 69%.
Globally, the picture is not nearly so rosy. The International Agency for Research on Cancer just published on September 12th the GLOBOCAN 2018 estimates of worldwide incidence and mortality for cancer. Data from local registries (which in some parts of the world capture information from only a small portion of the population) show that 18.1 million people were diagnosed with cancer in the previous year, and 9.6 million died of cancer. Cancer incidence is on the rise, and the predictions are that by 2030, as many as 30 million people will die of cancer annually, at least three-quarters of whom will be in lower income nations. As in the US, the rise in cancer incidence is largely propelled by increasing life expectancy, although the spread of unhealthy life-styles no doubt has something to do with it.
Although breast cancer is the most common type of cancer for women in most countries, in sub-Saharan Africa and parts of Asia, it is surpassed by cancer of the cervix. Lung cancer is now the commonest cancer globally, accelerated at least in part by the so-called “tobacco epidemic.” It is predicted to result in 2.1 million cancer diagnoses in 2018, and 1.8 million deaths.
Returning to data for the US, here’s a table that lists the estimated cancer statistics for 2017, showing the number of estimated new cases in males and females and the percentage of the total number of cases for each type of cancer. The last column shows the percentage of patients with each type of cancer who are estimated to survive at least five years beyond the diagnosis.
|Type of cancer||Estimated New Cases in Males – No. & % of Total||Estimated New Cases in Females – No. & % of Total||Estimated 5-year Survival – M & F|
|Lung & bronchus||116,990 14%||105,510 12%||18.3%|
|Colon & rectum||71,420 9%||64,010 8%||63.5%|
|Urinary bladder||60,490 7%||75%|