For Lung Cancer Screening, a Small Dose of Hope

In In The News by Barbara Jacoby

By: Jane E. Brody


In 2011, a year after my husband Richard died of lung cancer, a major national study documented the potential ability to detect this disease when it might still be amenable to cure.

Having smoked up to a pack a day for 50 years, Richard knew his days were numbered even though he had quit smoking 15 years before his diagnosis of stage 4 cancer. Now there is guarded hope for the millions of other former and current smokers who are at high risk of developing one of the deadliest of cancers.

Through the Affordable Care Act and, if draft recommendations are adopted, soon through Medicare as well, many insured individuals will be eligible for a free CT exam that, for some at least, could be lifesaving.

Lung cancer is the third most common cancer among Americans, exceeded only by cancers of the prostate and breast. But it remains by far the leading cause of cancer deaths in both men and women, causing more deaths annually than breast and prostate cancers combined.

Despite treatment advances for many cancers, lung cancer has remained a stubborn killer, with only 16 percent of patients alive five years after diagnosis. This year an estimated 224,210 people in this country will learn they have lung cancer and more than 159,000 will die of the disease, according to the American Cancer Society.

The disease is aggressive and 70 percent of cases are diagnosed in advanced stages, which accounts for the low survival rate. Only 30 percent of lung cancers are discovered in stage 1 or 2, when surgery offers a potential cure, and only about half of those are cured.

Now, after years of research and one of the largest cancer screening trials ever mounted, there is genuine hope for reducing the toll exacted by this disease. A national study involving 53,454 current and former smokers believed to be healthy showed that annual screening by low-dose computed tomography, or LDCT, could prevent three lung cancer deaths for every 1,000 people screened.

Given the millions of people at risk, that could translate to a lot of lives saved. But it is by no means a miraculous solution to lung cancer mortality; for every 1,000 people screened, 14 still died of the disease. All told, of the 53,454 study participants screened with LDCT for three years, 1,076 received a lung cancer diagnosis, and within three years of follow-up 469 died of the disease.

For the benefits shown in the trial to be fully realized and for those benefits to outweigh potentially serious risks, screening would have to be limited to people at high risk of developing lung cancer. As calculated by Dr. Peter B. Bach of Memorial Sloan-Kettering Cancer Center and Dr. Michael K. Gould of Kaiser Permanente Southern California, screening high-risk individuals would prevent 15 times as many lung cancer deaths as screening those at low risk of developing the disease.

In addition, to maximize the ratio of benefit to risk, screening should only be done at venues with up-to-date equipment and thoroughly trained personnel who know whom to test, how to interpret the results, and when to follow up with additional tests and treatment if needed, Dr. Bach said. Such criteria resulted in a 20 percent higher survival rate in individuals screened annually for three years by LDCT than that achieved through screening by chest X-ray.

LastDecember, the United States Preventive Services Task Force advised that annual screening with LDCT be limited to adults between the ages of 55 and 80 who have at least a 30-pack-year smoking history and either still smoke or quit within the last 15 years. Pack-years are calculated by multiplying the number of packs of cigarettes smoked per day by the number of years a person smoked. A 30 pack-year history would result, for example, from smoking a pack a day for 30 years, or two packs a day for 15 years, or half a pack a day for 60 years.

The task force also recommended that screening be discontinued after a person had not smoked for 15 years or developed a health problem that “substantially limits life expectancy or the ability or willingness to have curative lung surgery.” A “Lung Cancer Screening Decision Tool” developed by Memorial Sloan-Kettering is available online.

Why shouldn’t everyone get a LDCT screening test? Although the test itself is noninvasive and the amount of radiation involved is very low (comparable to six months of natural background radiation), it is also associated with potentially serious risks.

Most common is the risk of a false-positive result. Up to half of lung nodules seen on LDCT turn out not to be cancer. Although in most cases, a repeat scan can rule out cancer, in others a lung biopsy, which can be risky, is required. In the national trial, major complications, including some deaths, occurred in 33 of every 10,000 persons from procedures used to determine whether nodules seen on LDCT were cancerous.

Follow-up tests can also uncover other possible unrelated problems that must be checked, leading to a spiral of additional procedures, any of which can have its own complications. Anxiety can also result from a suspicious finding, prompting a Brown University team to recommend counseling people beforehand about the potentially high rate of false positives and “significant incidental findings” associated with LDCT screening.

Then there is the cost, which could exceed $9 billion for Medicare alone and higher rates for everyone insured. The trial research team estimated that, compared with no screening, LDCT costs an additional $1,631 for a person to achieve an additional 0.0316 years of life, for a total of $52,000 per life-year gained or $81,000 for each quality-adjusted life-year.

Finally, “every screening program should offer help for smoking cessation,” Dr. Bach said. “Stopping smoking is far more important than screening.”

Laurie Fenton Ambrose, president of the Lung Cancer Alliance, an advocacy group, said screening provides a “teachable moment” and a chance to provide smoking cessation tools that can result in “a quit rate four times higher than in the general population.” She said her organization is working with hospitals to assure that every screening program follows best practices.