Educating Clinicians About LDCT May Increase Early Diagnosis

By providing general practitioners with direct access to low-dose computed tomography (LDCT), a greater number of symptomatic lung cancers were diagnosed in a favorable stage, according to results of a Danish study published in PLoS One.

In Denmark, a fast-track referral system was introduced that allows general practitioners to refer patients who they believe might have lung cancer to undergo screening within the next 72 hours.

“Only 25% of Danish lung cancer patients are diagnosed that way,” said study author

Louise Mahncke Guldbrandt, PhD, of Aarhus University, Aarhus, Denmark. “For the rest of the patients, there is only the use of a conventional x-ray and approximately 20% of patients will have a false negative x-ray prior to a lung cancer diagnosis.”

In this study, the researchers were testing if a technological and organizational upgrade would increase the use of the fast-track referral system. The study included 266 general practitioners who were randomized into two groups. One group was offered direct access to a chest LDCT with continuing medical education on lung cancer diagnosis.

Over a period of 19 months, general practitioners referred 649 patients to direct CT, with 648 actually performed. Most patients were referred to CT with coughing as their most prominent symptom. General practitioners referred 335 patients to the lung cancer fast track during the study period; 33 lung cancers were diagnosed as a result. Of all patients referred for LDCT, 2.3% were diagnosed in a favorable stage and about half of the patients required further work-up.[[{"type":"media","view_mode":"media_crop","fid":"30073","attributes":{"alt":"Louise Mahncke Guldbrandt, PhD","class":"media-image media-image-right","id":"media_crop_9344098226312","media_crop_h":"0","media_crop_image_style":"-1","media_crop_instance":"3140","media_crop_rotate":"0","media_crop_scale_h":"0","media_crop_scale_w":"0","media_crop_w":"0","media_crop_x":"0","media_crop_y":"0","style":"height: 225px; width: 150px; border-width: 0px; border-style: solid; margin: 1px; float: right;","title":"Louise Mahncke Guldbrandt, PhD, study author","typeof":"foaf:Image"}}]]

Of the study group, 133 practitioners had access to direct CT, of whom 91(68.4%) used this route. Although one general practitioner referred as many as 40 patients to LDCT, the median number of referrals was two. The researchers found no difference between those who referred patients and those who did not in terms of age, sex, or type of clinic.

“We did hope for more patients with lung cancer to be diagnosed this way,” Guldbrandt told Diagnostic Imaging. “The positive predictive value for lung cancer in the existing fast-track is 10% and the patients referred to LDCT are different from the patients referred to the fast-track as these patients are more obviously ill and, therefore, there are more patients with advanced disease. The ones referred to LDCT were the not as obviously ill and, therefore, the proportion of cancer was lower.”

Less than half of the general practitioners (48.1%) participated in the CME meeting about lung cancer diagnosis. However, the referral rate was 61% higher among general practitioners who worked in a clinic where at least one practitioner participated in the CME meeting compared with clinics where no one participated.

The researchers do not yet know if the study intervention will reduce mortality from lung cancer.

“Early stage identification is beneficial only if the proportion of late stage cancers is reduced and this will be analyzed in a randomized controlled trial,” Guldbrandt said.