The study adds support for lung cancer screening and provides reassurance for patients whose cancer is caught early.
Diagnosing lung cancer early through CT screening dramatically improves survival, a US study has found.
Patients diagnosed early had a 20-year survival rate of 80%, compared to an average five-year survival rate in the US of 18%, according to the study presented at the annual meeting of the Radiological Society of North America.
In Australia, figures from the Australian Institute of Health and Welfare show that the average five-year survival rate after lung cancer is 20%.
The study included 1200 patients who were initially screened as part of a lung cancer study and who were later diagnosed with early-stage lung cancer.
The researchers found that after 20 years, the lung cancer survival rate was 100% for the 139 participants with nonsolid cancerous lung nodules, as well as the 155 people with partly solid nodules.
Survival was 73% for the 991 with solid cancers, and 86% for clinical Stage IA participants regardless of the cancer’s consistency, they said. Participants with pathologic Stage IA lung cancers with an average diameter of 10mm or less had a 20-year lung cancer survival of 92%.
Ultimately, anyone interested in being screened needs to know that if they are unfortunate enough to develop lung cancer, it can be cured if found early.
Dr Claudia Henschke
“This confirms our previous estimates of lung cancer survival rates and adds further evidence of the high curability of lung cancer diagnosed by screening,” the researchers wrote in the abstract.
“No lung cancer deaths were identified in part-solid and nonsolid cancers. Lung cancer consistency is an important predictor of lung cancer survival and should be considered in updated staging criteria as has already been accepted in the pathologic criteria.”
“The key finding is that even after this long a time interval they are not dying of their lung cancer,” lead author and professor of diagnostic, molecular and interventional radiology Dr Claudia Henschke said in a statement.
“And even if new lung cancers were found over time, as long as they continued with annual screening, they would be OK,” said the director of the Early Lung and Cardiac Action Program at Mount Sinai in New York.
Dr Henschke said that while screening did not prevent cancers from occurring, it was an important tool in identifying lung cancers at an early stage when they could be surgically removed.
“Ultimately, anyone interested in being screened needs to know that if they are unfortunate enough to develop lung cancer, it can be cured if found early.
“Symptoms occur mainly in late-stage lung cancer. Thus, the best way to find early-stage lung cancer is by enrolling in an annual screening program.”
Dr Henschke told The Medical Republic that the US Preventive Services Task Force’s recommendations for annual lung cancer screening should be expanded to include a broader population than only adults aged 50-80 with a 20 pack-year smoking history, who currently smoke or have quit within the past 15 years.
“We do think they should be expanded, especially for the category of people who have quit for more than 15 years,” she said.
“The risk of lung cancer declines very slowly and for many of these people, their risk remains quite high, substantially higher than those who are the lower end of the eligible range.
“In addition, current guidelines do not take into account increased susceptibility for women and minorities.”
Dr Henschke said that while there were risks with any medical test, low-dose CT scans were low-risk.
“The risks are quite low and continue to decrease as scanners continue to be developed with lower radiation dose, and protocols for management continue to improve as to decrease the false positive rates.
“I think the more important concern is the negative effect of not enrolling in a screening program when at risk because of inflated concerns regarding risk.”
Dr Henschke’s team began tracking lung cancer patients in 1992, and since then they have enrolled more than 87,000 people to their International Early Lung Cancer Action Program. The participants were aged 40 or older, and were current, former, and never smokers.
In 1992, the team’s paper in the NEJM showed that early CT screening could detect clinical stage I lung cancer in a high proportion of persons when it was still curable by surgery.
“In a population at risk for lung cancer, such screening could prevent some 80% of deaths from lung cancer,” they wrote.
That 1992 study also showed an 80% lung cancer-specific survival rate among 484 people with lung cancer diagnosed on CT, regardless of the stage at diagnosis or type of treatment.
Among the 412 people with clinical stage I lung cancer, the estimated 10-year survival rate was 88%, and among the 302 people with clinical stage I lung cancer who underwent surgical resection within one month after the diagnosis, the rate was 92%.
