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What’s Behind the Biggest One-Year Decline in Cancer Deaths?

February 05, 2020

The American Cancer Society recently announced that the cancer death rate in the United States fell 2.2 percent from 2016 to 2017 — the largest single-year decline in cancer mortality ever reported.

The cancer death rate declined by 29 percent from 1991 to 2017. Experts attributed the decline in part due to the reduced smoking rates and to advances in lung cancer treatment.

Cancer remains the second-leading cause of death nationally after heart disease in both men and women. The American Cancer Society predicts that this year there will be 1,806,590 new cancer cases in the United States and 606,520 cancer deaths. In Connecticut this year, we expect about 20,300 new cancer diagnoses and approximately 6,390 deaths. Lung cancer accounts for about a quarter of all cancer deaths and kills more people than breast, prostate, colorectal and brain cancers combined.

Three factors might help explain the decrease in lung cancer mortality:

• A continued decreased prevalence of tobacco use, now down to approximately 16 percent.
• A lung-cancer screening strategy with low-dose computed tomography, otherwise known as a low-dose CT scan. Studies have demonstrated that an earlier diagnosis in current or former smokers ages 55-74 with a 30 pack-year history of smoking — a pack year is an average of a pack of  cigarettes a day for one year — decreases mortality by 20 percent. Approximately 75 percent of screened patients who are diagnosed will have early stage 1 disease, which is highly curable. For those diagnosed without screening, approximately 75 percent have stage 3 or 4 disease, which carries a much more serious prognosis. Unfortunately, data suggests that only about 3 percent to 4 percent of eligible patients have this screening performed, even though it is now covered by most health insurance. Hartford HealthCare provides lung cancer screening at all of its hospital imaging facilities.
• New therapies, including targeted therapy and immunotherapy, have provided meaningful responses and remissions for patients with advanced lung cancer, providing hope for longer-term survival.

For patients with advanced melanoma, an aggressive form of skin cancer, mortality has similarly decreased due to advances in immunotherapy.

As more Americans put on excess pounds, the rate of obesity-related cancers is increasing. These include malignancies of the liver, kidneys, pancreas and uterus, cancers of the breast in postmenopausal women, and colon and rectal cancers in adults younger than 55.

Studies have found that obesity, unhealthy diets and a lack of physical activity are associated with metabolic and hormone abnormalities and with chronic inflammation, which may help explain the link to cancer.

Over the past decade, mortality rates dropped 1.5 percent per year in women and 1.8 percent per year in men. This exciting decrease in mortality is driven by continued decreases in death rates for the four major cancer sites: lung, breast, prostate and colon/rectum.

Death rates for female breast cancer have declined 40 percent from peak rates in 1989, while deaths from prostate and colorectal cancers have each dropped about 52 percent from their peak, a result of improvements in early detection and treatment.

The five-year relative survival rate for all cancers diagnosed during 2009 through 2015 was 67 percent overall, 68 percent in whites, and 62 percent in blacks. This represents a substantial improvement over data from just a couple decades ago. Further treatment advances with new personalized regimens of targeted therapies, chemotherapy, immunotherapy and innovative radiation and surgical techniques will likely continue this trend in lowered mortality rates.

Dr. Andrew L. Salner is Medical Director of Hartford HealthCare Cancer Institute at Hartford Hospital. For more information about the Cancer Institute, click here.