Adenocarcinoma in situ and minimally invasive adenocarcinoma in lungs of smokers: image feature differences from those in lungs of non-smokers

Haruto Sugawara,Osamu Abe,Yasushi Yatabe,Hirokazu Watanabe,Akira Kunimatsu,Masahiko Kusumoto,Shun-Ichi Watanabe

doi:10.1186/s12880-021-00705-1

Abstract

PurposeWe aimed to examine the characteristics of imaging findings of adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA) in the lungs of smokers compared with those of non-smokers.Materials and methodsWe included seven cases of AIS and 20 cases of MIA in lungs of smokers (pack-years ≥ 20) and the same number of cases of AIS and MIA in lungs of non-smokers (pack-years = 0). We compared the diameter of the entire lesion and solid component measured on computed tomography (CT) images, pathological size and invasive component diameter measured from pathological specimens, and CT values of the entire lesion and ground-glass opacity (GGO) portions between the smoker and non-smoker groups.ResultsThe diameters of AIS and MIA on CT images and pathological specimens of the smoker group were significantly larger than those of the non-smoker group (p = 0.036 and 0.008, respectively), whereas there was no significant difference in the diameter of the solid component on CT images or invasive component of pathological specimens between the two groups. Additionally, mean CT values of the entire lesion and GGO component of the lesions in the smoker group were significantly lower than those in the non-smoker group (p = 0.036 and 0.040, respectively).ConclusionAIS and MIA in smoker’s lung tended to have larger lesion diameter and lower internal CT values compared with lesions in non-smoker’s lung. This study calls an attention on smoking status in CT-based diagnosis for early stage adenocarcinoma.

Highlights

Invasive adenocarcinoma (MIA) and adenocarcinoma in situ (AIS) are subtypes of lung adenocarcinoma as defined by the 2015 WHO classification [1]
Tumor diameter and internal density Tumor diameter measured from computed tomography (CT) images and pathological specimens of the non-smoker group were 14.6 ± 4.7 mm and 12.4 ± 4.5 mm, respectively, which were significantly smaller than those of the smoker group (17.1 ± 4.0 mm for CT images, p = 0.036 and 16.3 ± 5.5 mm for pathological specimens, p = 0.008)
There was no significant difference in the size of the solid component measured on CT images or the diameter of the invasive component on pathological specimens between the nonsmoker and smoker groups

Summary

Introduction

Invasive adenocarcinoma (MIA) and adenocarcinoma in situ (AIS) are subtypes of lung adenocarcinoma as defined by the 2015 WHO classification [1]. These lesions have been shown to have significantly better prognoses than those of invasive adenocarcinoma [2, 3]. With the presence of emphysema or interstitial lung disease, histological patterns of lung cancer tend to differ from those of non-smokers; imaging findings have shown to be different [9, 10]. Previous reports have shown that CT-based diagnoses of malignant tumors are more difficult in the emphysematous lung compared with the normal lung [11]. This study aimed to examine the characteristics of imaging findings of AIS and MIA in smokers’ lungs compared with those in nonsmokers’ lungs

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Conclusion