Men may require more frequent lung cancer screenings

Women may go longer between lung cancer screenings than men, according to study results presented at the European Lung Cancer Conference.

The U.S. Preventive Services Task Force (USPSTF) recommends annual lung cancer screening with low-dose CT in adults aged 55 to 80 years who have a 30 pack-year smoking history and currently smoke or have quit within the past 15 years.

However, research shows the clinical and radiological presentation of lung cancer differs in women and men, particularly in Asia.

“Less frequent screening would reduce radiation exposure, but previous studies of longer screening intervals produced varied results,” Mi-Young Kim, MD, radiologist at the Lung Cancer Center at Asan Medical Center in Seoul, Korea, said in a press release. “This may have been caused by differences in the clinical and radiological presentation of lung cancer in women and men.”

Researchers retrospectively evaluated potential gender-related differences in 46,766 consecutive patients who underwent CT screening at Asan Medical Center.

Of those, 282 patients developed lung cancer, including 186 patients diagnosed from the initial CT scan and 96 patients diagnosed from subsequent scans.

Researchers analyzed CT screening intervals, stage and cancer pathology to identify gender-related differences in those 96 patients (men, n = 85).

Eighty-seven percent of men reported as smokers. Common cancer types in men included adenocarcinoma (42%), squamous cell carcinoma (35%) and small cell lung cancer (18%). All women had adenocarcinoma.

“Most female patients were nonsmokers (82%), who have a lower risk for lung cancer, while 87% of men were smokers,” Kim said. “We included all patients screened for lung cancer in a 17-year period, but the number of women patients was low, and further studies are needed to confirm the sex differences we found.”

Women demonstrated a longer mean time interval of screening CT than men (5.6 ± 3.1 years vs. 3.6 ± 2.4 years; P = .02).

However, men had a higher stage of disease. Fewer men than women presented with stage I lung cancer (49% vs. 82%).

Minimum CT screening interval to detect stage I lung cancer appeared longer in women than in men (5 years vs. 1 year).

Pathological analyses showed that men most commonly developed solid nodules (72%), whereas women most commonly developed ground glass opacity nodules (45%).

“Because ground glass opacity nodule is the most common feature of lung cancer in women and all cases are adenocarcinoma, the growth rate of cancers might be low,” Kim said.

The researchers recommended a 3-year interval screening for women and a 1-year interval for men to optimally detect most stage I lung cancer.

“Our study suggests that the annual follow-up interval for CT is too frequent for women, and scans every 2 to 3 years might be suitable,” Kim said. “By reducing the number of unnecessary CT scans, we can decrease radiation exposure and increase cost effectiveness.” – by Kristie L. Kahl

Reference:

Kim MY, et al. Abstract 18PD. Presented at: European Lung Cancer Conference; May 5-8, 2017; Geneva, Switzerland.

Disclosures: The researchers report no relevant financial disclosures.