Would you allow patients to self-refer for a CT lung cancer screening? Would you screen a never-smoker? What size nodule would trigger a follow-up exam? What is your lower age limit and lower pack-year limit for screening?
These are just a few of the questions tackled during an interactive lung cancer screening session at the recent Radiological Society of North America meeting, and that highlight the uncharted waters physicians face in the wake of the pivotal National Lung Screening Trial.
The NLST demonstrated a 20% reduction in lung cancer mortality when low-dose CT screening was used, compared to chest X-ray, among 53,000 asymptomatic current or former heavy smokers. However, CT produced more than three times the number of positive results and a higher false-positive rate than radiography.
Without a clear plan to manage abnormal findings or a firm handle on cost, policymakers and payors are hesitant to back reimbursement for widespread lung cancer screening. Results of the ongoing NLST cost-effectiveness analysis are expected early next year. Based on already published data, however, a crude back-of-the-envelope estimate puts the incremental cost-effectiveness ratio at $38,000 per life-year gained, NLST investigator Dr. William Black told attendees.
“That actually is a pretty good deal compared to a lot of things we do in medicine, and in fact most people would put the threshold for acceptability somewhere between $50,000 to $100,000 per life-year gained,” he said. “So it certainly is feasible”
Dr. Black pointed out that low-dose CT saved one lung cancer death per 346 persons screened in NLST, which again is very favorable compared to the rate of 1 per 2,000 patients for mammography.
Although the session provided just a small snapshot in time, audience responses suggest there is much work ahead. A full 77% of attendees were not using low-dose CT to screen for lung cancer and 72% reported not being familiar with the recently published National Comprehensive Cancer Network guidelines for lung cancer screening.
One-quarter of the audience had no lower age limit for screening, and 34% said they did not provide either decision support or obtain informed consent.
Radiologist and NLST collaborator Dr. Caroline Chiles said informed consent in NLST helped prepare patients for the potential risks of a screen, the likelihood of a positive result and that a positive result didn’t mean they had lung cancer.
“It made a huge difference once they got that letter saying they had a positive screen, because at that point you don’t want everyone rushing out to a surgeon to get that nodule resected,” she added.
What attendees and panelists could agree on is the need for smoking cessation to be included in any future lung cancer CT screening program, with 60% of attendees saying they already do so.
Dr. Chiles pointed out that 16.6% of participants in the NELSON lung screening trial quit smoking compared with 3%-7% in the general public, but that participants were less likely to stay non-smokers. She also cited a recent MMWR that found 70% of adult smokers want to quit smoking, but only about half had been advised by a health professional to quit.
“We really have to think of lung cancer screening as being a teachable moment,” she said.
She suggested physicians visit www.smokefree.gov for help in guiding their patients. Dr. Black also noted that the NLST team is working on a lung cancer screening fact sheet for physicians and patients that will be ready in a few weeks and made available on the Internet.