February
04, 2020| By Jean-Marc Fix | Region: North
America Life/Health VP, Actuarial Research & Development, Stamford
When the Cancer Statistics, 2020 report was
released a few weeks ago, the press rightfully basked in the great news: In
the U.S. there were 2.9 million fewer cancer deaths than there would
have been if the historically increasing cancer rates had remained level
instead of decreasing since 1991.1 The report also said
that the U.S. saw the largest single-year drop in cancer death rates
ever - a 2.2% drop. Let’s reflect on the causes of this decline, and
the likelihood of it continuing in the future.
Cancers With Greatest
Impact on Mortality Rates
Cancer is the second most common cause of death
overall in the U.S., close behind heart disease, and is the first or
second for most age and gender groups.2 It is therefore
critical to our understanding overall mortality. Drops in cancer deaths rates
have been led by drops in the four of the largest killers: lung,
colorectal (CRC), breast, and prostate cancers. Deaths rates for these
four are about half of what they were at their peaks (except for female breast
cancer which reduced only by about a quarter).3
Lung cancer is still the primary killer-cancer
responsible for about one out of five deaths for both men and women. This
highlights the importance of controlling the smoking epidemic, and victories on
this front have led to the significant - and so far recently
accelerating - drops we have enjoyed since the early 1990s for men
and the early 2000s for women. There is still much room for progress
especially for women but prevalence of smoking can only drop so far. In
addition, we see worrying signs with the inroads of vaping and non-traditional
smoking at the younger ages.4
As for the other top cancers, we see a slowdown
of improvement rates for both CRC and breast cancer, and a significant
reduction of the improvement rate for prostate cancer - all since the early 2010s.
Melanoma death rates have improved very significantly since 2013/2014,
most likely due to the introduction of new therapies. On the other hand,
several cancers associated with the human papillomavirus (HPV) infection
have increased. What will an increasing use of the HPV vaccination mean
for this group of cancers?
Strategies to Improve
Impact of Therapies
So, what will the future bring us? In the short
term, an ongoing decrease in smoking will continue to drive down deaths from
lung cancer and through that, cancer deaths overall. In the long term, five
different strategies will vie for impact:
·
Control of risky
behaviors at the population level - Less impact of smoking, less sun exposure,
beginning recognition by the general public that obesity is a risk factor
for cancer
·
Treatment or vaccination
against infections leading to cancers like hepatitis C and human
papillomavirus, not to forget HIV and hepatitis B (see recent Gen Re blog explaining hepatitis)
·
Increasing impact of
precision medicine, especially through pharmacogenomics
·
Better understanding of
immunotherapy (e.g., vaccines targeted to a person’s own specific cancer
cells), the addition of combination therapies and new technologies to fight
multi-drug resistant cancer (e.g., nano-particles)
·
Better understanding of
epigenetics and the microbiome (e.g., using markers from the microbiome to
tag cancer cells to prevent them from dodging the immune system)5
Developing Immune
System Therapies
I want to spend a minute highlighting the
consequences of our ability to read genetic-like code and increasingly write
and manufacture custom proteins. I will grossly oversimplify a very complex
subject: To be successful, cancer cells evolve multiple mutations, among which
are the abilities to capture “energy” efficiently, spread and evade our immune
system. Until recently, our treatment options had been to capitalize on that
energy differential between normal and cancer cells that renders them slightly
more vulnerable to toxic agents, like radiation or chemotherapy. The price to
pay was lots of collateral damage including hair loss, vomiting, weight loss
and depression. Recent developments have allowed us to take advantage of the
defense system our body has evolved over million of years: our killer
immune system.
One technology based on our existing immune
system is designing custom vaccines, particular to a specific tumor, that
highlights the cancer cells to our immune system. Another technology is
creating custom immune cells tailored to recognize the cancer signatures:
CAR-T cell treatment where we engineer (the C in chimeric) the
recognition “nose” (the AR in antigen receptor) of a T-cell or of our
immune system. Those are not without danger: if we pick a signature that is not
specific enough to the cancer, the immune system will destroy all other cells
that coincidentally have that same signature. There are many challenges but an
immune therapy for cancer in some form or a combination of forms will open possible
new venues for research and for success.6
The Contributions of
Care & Follow-Up Data in Research
We need to keep in mind that not all progress in
fighting cancer will come from medical advances. Better access to care and
better follow-up through electronic health records - and hopefully better
research because of that communication - should bring some positive
dividends.7 Challenges will remain numerous, foremost the
heterogeneity of the processes classified under the umbrella of “cancer” today.
While maximizing the impact of testing - as we have seen with the changes
in recommended mammograms and prostate cancer - “watchful waiting” will
continue to be a tight rope we walk between increasing awareness and
increasing costs.
As we have seen with the impact of key drugs in
melanoma treatment, access to care will continue exacerbate socio-economic
differences. Finally, we are now recognizing the issues associated with two
vulnerable populations: survivors of cancer and the elderly.
Regardless of the challenges remaining, our
understanding of the genetic code and human ingenuity have provided for many
potential roads forward. One thing for sure is that we have only begun to
harvest the rewards of that revolutionary understanding.
Endnotes
1. Rebecca L. Siegel, et al.,
“Cancer Statistics, 2020,” CA: A Cancer Journal for Clinicians
2020;70:7-30, 8/20/2020, American Cancer Society, https://acsjournals.onlinelibrary.wiley.com/doi/full/10.3322/caac.21590.
2. Ibid. Table 7, Ten Leading Causes of Death
in the United States by Age and Sex, 2017.
3. Ibid. at Note 1. Figure 7, Trends
in Cancer Mortality Rates by Sex Overall and for Selected Cancers,
United States, 1930 to 2017.
4. Andrea S. Gentzke, et al., Vital
Signs: Tobacco Product Use Among Middle and High School Students —
United States, 2011–2018 MWWR, February 15, 2019 /
68(6);157–164, https://www.cdc.gov/mmwr/volumes/68/wr/mm6806e1.htm.
5. S. McDowell, et. al., Cancer research
insights from the latest decade, 2010-2020. 12/30/19, https://www.cancer.org/latest-news/cancer-research-insights-from-the-latest-decade-2010-to-2020.html.
6. C. Rodríguez Fernández, Four new
technologies that will change cancer treatment, Labiotech.eu., 10/15/19, https://www.labiotech.eu/features/cancer-treatments-immuno-oncology.
7. Louis J. DeGennaro,
Leukemia & Lymphoma Society, Advances in cancer research and treatment
in 2020, December 2019, https://www.lls.org/blog/advances-in-cancer-research-and-treatment-in-2020-my-predictions.
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