Min Jae Cha, Presenter: Nothing to Disclose

Ho Yun Lee MD, Abstract Co-Author: Nothing to Disclose

Jaehun Kim, Abstract Co-Author: Nothing to Disclose

Kyung Soo Lee MD, PhD, Abstract Co-Author: Nothing to Disclose

Joungho Han, Abstract Co-Author: Nothing to Disclose

Young Mog Shim MD, Abstract Co-Author: Nothing to Disclose

Eunju Lee, Abstract Co-Author: Nothing to Disclose

In the novel international multidisciplinary classification of lung adenocarcinoma proposed by IASLC/ ATS/ERS, the micropapillary pattern(MP) has been added as a new histologic subtype. It has been demonstrated that tumors classified as MP according to the predominant histopathologic subtype have a poor prognosis. Our aim was to analyze whether there are characteristic CT features of MP in lung adenocarcinomas, to seek for quantitative CT and PET parameters as predictors of MP, and to determine if such parameters show any correlation with the proportion of MP within a whole tumor.

We identified 1586 patients from surgical database who underwent complete surgical resection of lung adenocarcinoma. 141 patients were excluded due to poor image quality, lack of pathologic slides, or extensive combined inflammation. Among total 1445 cases, 267(18%) showed presence of MP(MP+). Of 267 cases with MP+, 24(4%) showed both micropapillary and solid patterns. We performed comprehensive imaging analyses such as CT morphology,attenuation, tumor mass(density X volume), tumor uniformity and entropy representing tumor heterogeneity; measurement of SUVmax of MP+ to compare with those of 100 MP-negative(MP-) adenocarcinomas. Correlations between the extent of MP and imaging parameters were assessed.

Means ± standard deviation in SUVmax were 4.2 ± 3.1 in MP- tumors and 7.5 ± 4.4 in MP+ tumors (P< .001); that of tumors with both micropapillary and solid patterns was 8.3 ± 3.9. Ill-defined tumor margin was seen in 21% of MP+ tumors, whereas it was seen in none of MP-. MP+ tumors showed significantly lower entropy, representing decreased tumor heterogeneity. Multiple logistic regression analysis disclosed that a combination of ill-defined tumor margin, high SUVmax, and low tumor entropy was the most powerful imaging indicator of MP+ adenocarcinoma. SUVmax and tumor mass were closely correlated with the proportion of MP within a whole tumor (r=.577 and -.247, respectively; both Ps< .05).

Characteristic CT features and quantitative imaging biomarkers appear to be the predictors of MP+ and to help patient stratification by indicating the proportion of MP within the whole tumor in lung adenocarcinomas.

Imaging parameters may help to identify MP+ adenocarcinomas.

Cha, M, Lee, H, Kim, J, Lee, K, Han, J, Shim, Y, Lee, E, The Micropapillary Pattern in Lung Adenocarcinomas: Its Proportion, Characteristic Imaging Features, and Quantitative Bioimaging Marker Study Results.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12029553.html