Since the government started lung cancer screening in July, some experts have argued that it would not be effective. More recently, however, the Korean Association for Lung Cancer (KALC) rebutted the critics’ arguments one by one.
KALC argued it was not true that “overdiagnosis would waste money and lung cancer screening provides insufficient evidence to reduce the mortality rate.” It then added that many studies have proved lung cancer screening reduces the death rate in the long term.
KALC held a news conference on Wednesday and refuted the claims of some physicians who opposed to the state lung cancer screening.
The government provides lung cancer screening every two years for a high-risk group -- people aged between 54 and 74 who have a history of smoking for more than 30 pack-years. The program aims to raise the survival rate of lung cancer patients by detecting the disease early.
However, the Excessive Diagnosis Prevention Society (EDPS) has pointed out that the effectiveness of lung cancer checkup has not been fully verified. It said the national lung cancer screening is likely to be “false positive” -- the screening shows it as lung cancer but the final test indicates it is not cancer -- so it requires an additional, unnecessary test, causing a waste of money.
Besides, there is only one NLST (National Lung Screening Trial) study in the U.S. that proved the effectiveness of lung cancer screening, and even this study has been in controversy in terms of the safety and efficacy, the group went on to say.
To counter this, KALC said there was plenty of evidence that showed the effectiveness of lung cancer screening.
“The U.S. NLST trial revealed that those who received CT screening had a 20 percent reduction in mortality risk compared to those who had X-ray tests. In a MILD study in Italy, the low-dose CT test group had 39 percent less death risk than those who didn’t have any test 10 years after the start of the study,” said Jang Seung-hun, director for PR affairs at KALC. “There are numerous studies overseas, which showed the effectiveness of lung cancer checkup.”
KALC presented various other studies, including NELSON of the Netherlands and Belgium and LUSI in Germany, to support its claim.
It also said a pilot screening program in Korea found that the proportion of patients who got a false positive was lower than that of U.S. patients, and the incidence of side effects in the final testing procedure was significantly small as well.
Kim Yeol, a professor at National Cancer Center, said only 14.6 percent of the patients in the local pilot program showed false positive, which was much lower than 26.6 percent shown in the NLST study in the United States. “We provided criteria stricter than that of the U.S. and focused on quality control, which allowed us to lower the rate of the false positive,” he said.
The pilot screening also showed that 68.4 percent of the patients had early detection of lung cancer (stage 1 and 1), three times higher than the average detection rate of 21 percent among the entire lung cancer patients registered with the government between 2012 and 2016, according to the NCC professor.
Kim also disclosed the result of the cost-effectiveness analysis of the pilot screening program, which was conducted by a research team led by Professor Jo Min-woo at the Preventive Medicine Department of Ulsan University College of Medicine. The analysis showed that it cost 26 million won ($22,389) to prolong life by one year with lung cancer screening, and another 28 million won to continue a healthy life, he added.
“The additional cost is lower than the recommended criteria by the World Health Organization and also lower than Korea’s gross national income per capita at around $30,000. So, it is cost-effective,” Kim said. “This means that the Korean economy can handle the extra cost for lung cancer screening.”
To raise the accuracy of lung cancer diagnosis, KALC has set up a two-stage strategy. Step one is to narrow down possible lung cancer cases with highly sensitive testing. The next is to filter out cases with low-risk lung cancer using a test with a high level of specificity.
KALC proposed that the government should develop a lung cancer prediction model to identify high-risk patients, to make lung cancer screening more effective.
Currently, the government selects people for the test based on risk factors such as smoking history and age. If a prediction model picks who to conduct the screening, it could raise the accuracy of lung cancer diagnosis, KALC said.
Another task is to find a biomarker for lung cancer. “The U.S. Center for Disease Control states guidelines for lung cancer screening. A recent paper in Europe also said lung cancer screening should be state-sponsored. We have plenty of evidence for lung cancer screening’s effectiveness,” Jang said. “To raise the efficiency of the screening, we will make various efforts.”