This work examines methods to differentiate between multiple primary lung cancer (MPLC) and intrapulmonary metastases (IPM), emphasizing the challenge of accurate diagnosis due to the increasing incidence of MPLC. The Martini and Melamed criteria, though widely used, have been criticized for potential misclassifications. This work proposes to apply the Comprehensive Histologic Assessment method incorporating nonmucinous lepidic component and complex glandular patterns and confront the results to those generated by the Martini and Melamed criteria.
A cohort of 43 patients with two or more lung adenocarcinomas, diagnosed from 2016 to 2023, was assessed using both the Martini and Melamed criteria and the Comprehensive Histologic Assessment incorporating nonmucinous lepidic component and complex glandular patterns. Descriptive statistics were performed, revealing that both diagnostic methods resulted in similar proportions of MPLC and IPM diagnoses, but agreement between the two methods was observed in only 72.2% of cases. The cases that diverged involved comparisons between nodules with more than a four-year gap between them, as well as nodules located in the same lobe. Therefore, it is suggestable that the time interval between two nodules and the localisation of two nodules might not be reliable indicators for the classification of MPLC and IPM. The challenge of classification also becomes apparent when three or more nodules are present in the same patient, indicating the necessity for additional investigations. Limitations include the small sample size and the potential for interobserver variability in the histologic assessments.
Future research aims to correlate these findings with molecular data assessed using Next-Generation Sequencing methodology to identify the most precise criteria for distinguishing MPLC from IPM. Additionally, expanding the study's methodology to different lung cancer types and additional cohorts is proposed for further investigation.