Histological Patterns and Tumor Necrosis Have Significant Prognostic Implications in Stage I Lung Adenocarcinoma
Jimmy Lee, Ming-Yuan Lee, Chia-Chuan Liu, Chih-Hsun Shih, An-Chen Feng, Wan-Chen Tsai, Nei-Min Chu. Koo Foundation Sun Yat-Sen Cancer Center, Taipei, Taiwan
Background: Histomorphological patterns of lung adenocarcinoma have been found to play a distinctive role in its prognosis, based on which new classification and grading schemes have recently been proposed. The purposes of this study are to validate the recommendations, and try to analyze possible prognostic factors.
Design: We retrospectively reviewed histological slides of 172 patients with stage I lung adenocarcinoma who received surgery and follow-up at our institute. The respective percentages of the six histological subtypes, i.e. lepidic, papillary, acinar, micropapillary, and solid, were determined. The presence of lymphovascular invasion and/or necrosis was also reviewed.
Results: Of the 172 patients, 58(34%), 72(42%), and 42(24%) were stage T1a, T1b, and T2, respectively. Seven(5%) were minimally invasive carcinoma (invasive tumor <= 5mm). Thirty-five(20%) were lepidic predominant, 47(27%) papillary, 68(40%) acinar, 19(11%) solid, and 3(2%) micropapillary. The 5-year survival rate was 93% in lepidic predominant cases, and 45% in solid predominant cases. A 3-tier scoring system was applied, which stratified the patients into 3 subgroups with distinctive prognoses.
Tumor necrosis and lymphovascular invasion were present in 39(23%) and 37(22%) cases, respectively.Tumor necrosis, but not lymphovascular invasion, was found to be a major prognostic factor. The 5-year survival rate was 94% in cases without necrosis, and 54% in those with necrosis.
Finally, we performed a multivariant analysis on the histological patterns and found that only tumor necrosis was significantly associated with survival.
Conclusions: Our study confirms that histological patterns of stage I lung adenocarcinoma has a great impact on survival. A scoring system based on the two major predominant patterns may serve as a valuable tool in risk stratification. Finally, tumor necrosis is the most important prognostic factor for stage I lung adenocarcinoma.
Monday, March 19, 2012 9:30 AM
Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 291, Monday Morning