Have cancer cases increased from 1 in 20 people in the early 1900s to 1 in 3 people, according to the latest available data? It depends: While there does not appear to be widespread cancer data from the early 1900s for comparison, the current probability of cancer varies by geographical area. In addition, cancer-detection technology has radically changed since 1900, which would affect the incidence rate. A spokesperson for the Union for International Cancer Control (UICC) told Lead Stories that today, it is estimated that 1 in 5 people worldwide will develop cancer during their lifetime, although the figure in men and women in the U.S. and U.K. is closer to 1 in 3 people.
The claim appeared in a Facebook post (archived here) published on October 17, 2021. It featured a graphic that read:
THE WAR ON CANCER HOAX
Billions of dollars have been invested in cancer research. And yet, instead of cancer rates falling, they have skyrocketed. In the early 1900s, 1 in 20 people developed cancer. Today, it's 1 in 3. That's pathetic! Are they researching how to cure cancer, or how to give everyone cancer?
This is what the post looked like on Facebook on October 20, 2021:
(Source: Facebook screenshot taken on Wed Oct 20 16:12:14 2021 UTC)
The post does not specify the geographical area it is meant to refer to, so Lead Stories primarily relied on global statistics from the International Agency for Research on Cancer (IARC), the World Health Organization's cancer agency that promotes international collaboration on cancer research. Statistics from the U.S. and the United Kingdom are also noted in this fact check.
The post's claim that 1 in 20 people developed cancer in the early 1900s appears to be unsubstantiated, as there is not adequate data to confirm or deny such a statistic, and the post cites no source. According to the IARC, the first attempts at gathering population-based cancer cases data in the early 1900s were not successful due to a lack of collaboration from doctors. It was not until 1926 in Hamburg, Germany, that nurses successfully assembled what is considered the world's first population-based cancer registry.
Eric Grant, a communication and media manager for the UICC, said in an email to Lead Stories on October 20, 2021:
For the number of cases, the International Agency for Research on Cancer (IARC) estimates that globally, 1 in 5 people develop cancer during their lifetime, and 1 in 8 men and 1 in 11 women die from the disease. These new estimates (2020) suggest that more than 50 million people are currently living within five years of a past cancer diagnosis. In 2020, there were an estimated 19.3 million cases and 10 million cancer deaths.
Grant went into further detail about cancer incidence and mortality figures in a subsequent email:
... we can say that the rise/decrease in incidence/mortality is depends on the cancer and regions. Some cancers have seen a drop in incidence, and certainly the more we vaccinate against HPV, the more cervical cancer incidence should drop. As fewer people smoke or engage in other behaviors that are risky for cancer, that also would positively impact incidence.
There have also been improvements in detecting cancers earlier and treating them more efficiently, particularly in high-income countries, to the point that several are no longer death sentences. Breast cancer incidence, for instance, has been on the rise, but the survival rate for localized breast cancer, when it is detected in the early stages and treated efficiently, can now be as high as 95%.
However, the U.S. National Cancer Institute reported that based on IARC data, cancer rates are generally the highest in countries with a top-ranked standard of living, although incidence rates for certain cancers do not follow that trend. To that point, Grant clarified in a follow-up email that cancer risk varies by country:
While globally, as I sent to you, 1 in 5 people are estimated to get cancer in their lifetime, in the US, 1 in 2 women and 1 in 3 men are expected to develop cancer in their lifetime, with similar figures for the UK per the British Journal of Cancer.
Despite the questionable statistics used in the post, an article from the International Journal of Cancer, the official journal of the UICC, does suggest that cancer has become more ubiquitous over time:
Cancer has afflicted humanity from pre-historic times though its prevalence has markedly increased in recent decades in unison with rapidly aging populations and, in the last half-century, the increasing risky health behavior in the general population and the increased presence of carcinogens in the environment and in consumer products.
The IARC predicts that cancer incidence will continue to increase. However, that does not mean that investments in cancer research are for naught: For example, according to data from the American Cancer Society, cancer mortality rates in the U.S. have continued to decrease and the five-year relative survival rate has improved.
