Each January, the American Cancer Society publishes its analysis of cancer statistics for the U.S. They provide a sense of what is doing better and what is doing worse with regard to cancer; when you see figures cited in the lay press, they are usually derived from this source. Herewith the admittedly biased Neugut take on this year’s ACS report:
1. The headline result is always the overall cancer mortality rate. That has declined by one-third since about 1990 when cancer mortality in the U.S. peaked. The lion’s share of this decline has primarily been attributable to advances in prevention and screening. Decreases in the use of tobacco have led to reduced lung cancer mortality as well as other tobacco-related malignancies, while breast screening and colorectal screening have had significant impacts on those two cancers, and there has probably been some improvement in prostate cancer mortality as well, from prostate screening.
What is of interest in this report is that the ACS believes that treatment advances are also now having a more significant impact on the overall cancer mortality rate as well. Most important has been the use of adjuvant chemotherapy for breast and colorectal cancer as well as for some other malignancies. Immunotherapy has made major improvements in metastatic melanoma, a formerly devastating disease. And certainly there have been improvements in the treatment of various hematologic malignancies, but since each of these tumors is relatively uncommon, these improvements don’t really significantly affect the overall cancer mortality statistics. Another notable advance has been the development of tyrosine kinase inhibitors, such as imatinib (Gleevec), for chronic myelogenous leukemia, which has been a game-changer.
2. A major and very important new finding is that cervical cancer incidence rates have now decreased by two-thirds among women in their 20s. This apparently reflects the success of the new human papillomavirus (HPV) vaccine and its utilization among children and adolescents. This bodes well for the future in the prevention of other HPV-related malignancies (anal, penile, vulvar and vaginal cancers). This topic deserves its own future article.
3. Lung cancer incidence rates continue to fall as the impact of reduced tobacco use bears fruit. Other tobacco-related malignancies (squamous cell carcinoma of the esophagus, for example) have had similar declines.
4. Breast cancer and uterine cancer rates are continuing to rise. Two factors appear to be at play here. One is continuing increases in the average body mass index of women, which is a major risk factor for these two malignancies. But more important has been the dramatic increase in the age at first pregnancy of women in the U.S., which has been rising since the 1970s from about 21 to recently reaching a median of age 30. It is not surprising that such a profound demographic change will have scrambled the statistics for these hormone-related malignancies.
The bottom line is that there has been impressive success over the past three decades in the reduction of cancer mortality. Certainly, the largest share of these improvements has come from advances in prevention and screening/early detection rather than treatment advances. While there are indeed some striking and impressive successes in treatment, they have mostly been for less common cancers—Hodgkin lymphoma, testicular cancer, childhood malignancies—or have made only marginal improvements in survival for other cancers. The result is that if one talks about “cancer” as an overall entity (something that I think is usually not a profitable thing to do), it gives a distorted picture of reality.
To take a broader view, the reductions in mortality for other diseases have also mostly come from prevention rather than treatment. The sensational improvements in cardiovascular and cerebrovascular mortality over the past three decades are also not primarily the result of cardiac transplants or stents, impressive and glorious though they may be as technological feats, but from the more impressive efforts that have gone into hypertension and hyperlipidemia control, tobacco cessation, increases in physical activity and efforts to reduce obesity and caloric intake. Interestingly, cardiovascular disease has now regained its primacy as the No. 1 cause of mortality in the U.S.
Of course, some cancers continue to be elusive in terms of demonstrating significant progress from either an incidence or mortality point of view. Prominent in this sphere are pancreatic cancer and glioblastomas. A significant advance for either of these on a prevention, early detection or treatment level would be a welcome addition to a future edition of the ACS report.
Alfred I. Neugut, MD, PhD, is a medical oncologist and cancer epidemiologist at Columbia University Irving Medical Center/New York Presbyterian and Mailman School of Public Health in New York.
This article is for educational purposes only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment, and does not constitute medical or other professional advice. Always seek the advice of your qualified health provider with any questions you may have regarding a medical condition or treatment.
