Good news on cancer shows why the battle against smoking matters. A lot.

There’s good news out on declining deaths caused by one of the nation’s leading killers. But experts warn that the country will need to work hard to sustain a sharp drop in cancer mortality rates — mostly due to smokers quitting their nasty habit. That’s because other factors like rising obesity may undo the recent favorable results.

The findings reported by the American Cancer Society were heartening, as the New York Times reported:

“The cancer death rate in the United States fell 2.2% from 2016 to 2017 — the largest single-year decline in cancer mortality ever reported … Since 1991, the rate has dropped 29%, which translates to approximately 2.9 million fewer cancer deaths than would have occurred if the mortality rate had remained constant.”

The battle against cancer has benefited significantly by the steady decline of cigarette smoking. This has resulted in notably fewer lung cancers, the leading killer of Americans with the disease, claiming 1 in 4 of the nation’s cancer deaths. Experts say they also are seeing improvements in lung cancer treatment, especially with costly drug regimens targeted at late-stage patients. (By the way, it is worth looking at a social media string by Dr. Vinay Prasad, a hematologist-oncologist and published skeptic of medical studies on cancer, to avoid Big Pharma hype about cancer mortality and drug therapies).

Reductions in lung cancer’s harms, statistically speaking, can create a disproportionate effect on overall cancer mortality rates.

But experts noted that improved therapies also helped patients with skin cancers and spreading or metastatic forms of the disease.

Gains against cancer are important because of its outsized role in Americans ill health, the New York Times reported:

“Cancer remains the second leading cause of death after heart disease in both men and women nationally. The American Cancer Society predicts that in 2020 there will be about 1,806,590 new cancer cases and 606,520 cancer deaths. Lung cancer kills more people than breast, prostate, colorectal and brain cancers combined. ‘We are still dealing with the effects of cigarette smoking from the 1960s and 70s in today’s population,’ said Dr. Otis Brawley, an oncologist at Johns Hopkins University and former chief scientific officer at the American Cancer Society. Because there is a lag between exposure and cancer diagnosis, people who stopped smoking may develop lung cancer years later. But these rates should continue to go down, Dr. Brawley said.”

Even as they were cheered by the decline in cancer mortality rate, particularly with lung cancer, experts expressed concern because they did not see similar progress with colorectal, breast, and prostate cancer. “The rising rate of obesity among Americans, as well as significant racial and geographic disparities, likely explain why the decline in breast and colorectal cancer death rates has begun to taper off, and why the decrease in rates of prostate cancer has halted entirely,” the New York Times reported.

The Washington Post reported this:

“The [cancer society] report said a slight rise in breast cancer incidence rates since 2004 — about 0.3% per year — is partly the result of fertility rate declines and increased obesity. Those factors also may be contributing to an increase in uterine cancer. The cancer society also said survival has improved since the mid-1970s for all of the most common cancers except cervical and uterine cancers. In those cases, treatment breakthroughs for advanced disease have not materialized.”

In my practice, I not only see the harms that patients suffer while seeking medical services, but also the clear benefits they may enjoy by staying health and far away from the U.S. health care system. It is fraught with medical error, preventable hospital acquired illnesses and deaths, and misdiagnoses.

If you don’t smoke, please don’t start. If you smoke, talk to your doctor and make the challenging effort to stop. The vaping fad is too new to know much about its long-term cancer risks. But the data on using e-cigarettes as a burning tobacco alternative and a way to stop smoking is far from a slam dunk. No one argues that vaping is good for you — just that it is less harmful and another possible way to quit smoking. That’s a dubious health argument, akin to asking whether it’s “better” to die in a car or plane crash. Neither, thank you. And, by the way, it always has been clear that marijuana smoking isn’t beneficial to the lungs.

Besides refraining from smoking, growing evidence shows health benefits from patients controlling their weight and alcohol use. This can be done with healthful diet, sensible exercise, adequate sleep, and stress management.

While obesity is a significant problem of its own and a risk factor in many cancers, the causes of these disease cases can be more complex than, say, the proven and direct tie between cigarette smoking and lung cancer. Shaming those with weight problems, including suggesting that they will “give themselves” cancer, isn’t helpful in helping them lose pounds, nor in supporting those with cancer — and they need all the goodwill we can offer.

We’ve got a lot of work to do to battle cancer and to slash its injury and deaths even more.