Screen-detected multiple primary lung cancers in the ITALUNG trial

Abstract

Occurrence of multiple primary lung cancers (MPLC) in individuals undergoing low-dose computed tomography (LDCT) screening has not been thoroughly addressed. We investigated MPLC in subjects recruited in the ITALUNG randomized clinical trial. Cases of cytologically/histologically proven MPLC detected at screening LDCT or follow-up CT were selected and pathologically re-evaluated according to the WHO 2015 classification. Overall 16 MPLC were diagnosed at screening LDCT (n=14, all present at baseline) or follow-up CT (n=2) in six subjects (4 in one subject, 3 in two and 2 in three subjects), representing 0.43% of the 1,406 screenees and 15.8% of the 38 subjects with at least one screen-detected primary lung cancer. MPLC included 9 adenocarcinomas in three subjects and a combination of 7 different tumour histotypes in three subjects. MPLC, mostly adenocarcinomas, are not uncommon in smokers and ex-smokers with at least one LDCT screen detected primary lung cancer.

Keywords: Multiple primary lung cancer; adenocarcinoma; low-dose CT screening; lung cancer.

Figure 1

Case I (Table 1). Four primary adenocarcinomas in a 70-year-old smoker, which were all detected at baseline LDCT screening round. They appeared as a spiculated lung nodule in the right upper lobe (RUL) (A), a ground glass opacity in the same lobe (B), a small solid nodule in the right lower lobe (RLL) (arrow in C) and a ground glass opacity with a small solid component in the left upper lobe (LUL) (D). Haematoxylin and eosin histologic staining (original magnification ×200) demonstrate an invasive adenocarcinoma, acinar predominant (E) in the RUL lesion corresponding to (A), an invasive adenocarcinoma, lepidic predominant (F) in the RUL lesion corresponding to (B) and an invasive adenocarcinoma, acinar predominant (G) in the RLL lesion corresponding to (C). Papanicolaou stain (original magnification ×40) of fine needle aspiration biopsy shows papillary pattern of uniform malignant cells with irregular nuclei consistent with adenocarcinoma (H) in the LUL lesion corresponding to (D).

Figure 2

Case II (Table 1). Adenocarcinoma and small cell lung cancer in a 61-year-old smoker both detected at baseline LDCT screening round. They appeared as a rounded lung nodule in the RUL and a subpleural small solid nodule (arrow) in the LUL (A). Haematoxylin and eosin histologic staining demonstrate invasive adenocarcinoma, acinar predominant (original magnification ×200) (B) in the RUL lesion and small cell lung carcinoma (original magnification ×100) (C) in the LUL lesion.