Evaluation of high-risk pulmonary nodules and pathologic correlation in patients enrolled in a low-dose computed tomography (LDCT) program.

BACKGROUND: The American Cancer Society estimates that lung cancer is responsible for 155,870 deaths: 84,590 in men and 71,280 in women. In an effort to reduce lung cancer mortality, many major medical societies have recommended annual low-dose CT screenings for high-risk individuals. The Centers for Disease Control and Prevention (CDC) has recommended yearly lung cancer screening with LDCT for people who are classified as high-risk individuals.
METHODS: In February 2014, our institution implemented a low-dose program. We analyzed patients seen between the dates of February 21, 2014 and June 1, 2017. Our studied population consisted of 639 total patients. We established a prospective database examining multiple parameters such as evolution of change in lung-RADS classification, histology of tumors, follow up rates, and overall success of the program. The eligibility criteria used at our institution mirrored the patient eligibility criteria posted on the American College of Radiology's Lung Cancer Screening website. In order for an individual to be evaluated within our low-dose CT screening program, the individual must be between the ages of fifty-five and eighty, be asymptomatic, have a thirty-pack years or greater history of smoking, and be a current smoker or have quit within the last 15 years. The patients were then assessed in a standardized fashion for radiographic risk of nodules according to the ACR Guidelines.
RESULTS: Six hundred and thirty-nine total patients were evaluated over the course of the study and there were 759 total scans conducted. As a major goal was to identify frequency of pulmonary nodules, we noted that 43.9% (333/759) of scans showed the presence of pulmonary nodules. These nodules were found in 207 out of 639 patients (32.4%). Using the guidelines given by the American College of Radiology, we classified 36 out of 639 patients as high-risk individuals [4A, B, X (5.63%)]. We also studied the evolution of nodules over the time period of the study with respect to Lung-RADS and found that the most common change seen was migrating from lung-RADS 1 to lung-RADS 2. Within the study period, we found malignancies in eight patients (1.25%). These malignancies included one squamous cell carcinoma, five adenocarcinomas, one non-small cell carcinomas, and one lymphoma. We found five of the eight malignancies to be stage III (62.5%) and the remaining to be either stage I or stage II.
CONCLUSIONS: This is one of the few studies that examined the correlation of lung-RADS risk stratification and histopathologic nature of nodules. In addition to demonstrating the merits of the low-dose CT screening program, our study has demonstrated, amongst the large number of patients, very low rates of migration from low lung-RADS classification to a higher risk category, the finding of more advanced stages of malignancies, and a preponderance of adenocarcinoma within the eight malignancies found.