Clinical impact of minimal micropapillary pattern in invasive lung adenocarcinoma: prognostic significance and survival outcomes.
Micropapillary subtype has recently been established to be a distinct marker for poor prognosis in lung adenocarcinomas. According to the current classification of lung adenocarcinomas, all subtypes are listed semiquantitatively in 5% increments. In other words, a minimal amount of the micropapillary pattern, precisely <5% of the entire tumor is disregarded. Therefore, we sought to assess the prognostic significance and survival outcomes in patients with a micropapillary pattern proportion of <5% of the entire tumor. A total of 525 patients with lung adenocarcinoma were classified into 3 subgroups according to the presence and proportion of micropapillary subtype: (1) ≥5% of the micropapillary pattern (n=114); (2) <5% of the micropapillary pattern (n=115); and (3) absence (<1%) of the micropapillary pattern (n=296). Sex, TNM stage, lymph node status (N status), tumor size, and predominant subtype demonstrated a significant difference among the 3 subgroups. Overall survival (OS) and disease-free survival (DFS) were significantly different among the 3 subgroups (P=0.009 and 0.001 for OS and DFS, respectively). Furthermore, OS was significantly better in patients without the micropapillary pattern (<1%) than in those with <5% (P=0.034). At multivariate analyses, age (P=0.005) and N status (P=0.005) were independent prognostic factors influencing OS. In conclusion, our results demonstrated that even a small proportion of the micropapillary pattern, specifically <5% of the entire tumor has a significant prognostic impact on OS. N status remained an independent prognostic factor that negatively influenced OS.
*Department of Radiology and Center for Imaging Science ‡Department of Pathology ∥Department of Thoracic Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul †Department of Radiology, Medical Research Institute, Pusan National University Hospital, Pusan National University School of Medicine, Busan §Department of Pathology, Kyungpook National University Hospital, Kyungpook National University School of Medicine, Daegu, Korea.
Geewon
G
Lee
Ho Yun
HY
Lee
Ji Yun
JY
Jeong
Joungho
J
Han
Min Jae
MJ
Cha
Kyung Soo
KS
Lee
Jhingook
J
Kim
Young Mog
YM
Shim
D000230:Adenocarcinoma / Q000401:mortality* / Q000473:pathology*; D000231:Adenocarcinoma, Papillary / Q000401:mortality / Q000473:pathology; D000328:Adult; D000368:Aged; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008175:Lung Neoplasms / Q000401:mortality* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies