Stromal invasion and micropapillary pattern in 212 consecutive surgically resected stage I lung adenocarcinomas: histopathological categories for prognosis prediction
- 1Institute of Clinical Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan
- 2Department of Pathology and Laboratory Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
- 3Department of Surgery, Taipei Veterans General Hospital, Taipei, Taiwan
- 4Department of Internal Medicine, National Yang-Ming University Hospital, I-Lan, Taiwan
- 5Institute of Clinical Medicine, Taipei Medical University Shuang-Ho Hospital, New Taipei City, Taiwan
- Correspondence to Dr Teh-Ying Chou, Department of Pathology and Laboratory Medicine, Taipei Veterans General Hospital, Taipei 11217, Taiwan;
- Accepted 13 June 2012
- Published Online First 19 July 2012
Background and Aim It is of importance to search for prognostic indicators supplementing the tumour–node–metastasis stage for surgically resected early-stage lung adenocarcinomas. The roles of stromal invasion and micropapillary pattern in categorising histopathology and predicting the prognosis of stage I lung adenocarcinomas are explored.
Methods We retrospectively examined 212 consecutive surgically resected stage I lung adenocarcinomas to propose a new histopathology-based categorical classification. Category A tumours have pure lepidic growth pattern without stromal invasion (ie, adenocarcinoma in situ). Stromal invasion in the form of central fibrotic focus is absent in category B tumours and present in category C tumours. Category B is subclassified into B1, which has areas of lepidic growth, and B2, which does not. Category C is subclassified into C1, which has invasive tumour cells in the periphery of central fibrotic focus, and C2, which has invasive tumour cells in the centre of central fibrotic focus. Based on the absence or presence of micropapillary pattern, the C2 tumours are further subclassified into C2a and C2b, respectively.
Results The 5-year recurrence-free probabilities for categories B1 (17 cases), B2 (10 cases), C1 (nine cases), C2a (114 cases) and C2b (62 cases) are 100%, 78.8%, 100%, 67.5% and 53.1%, respectively (p<0.001).
Conclusions Based on stromal invasion and micropapillary pattern, the histopathological categorical classification proposed here provides a concise and precise scheme for outcome prediction in early-stage lung adenocarcinomas.
Competing interests YCY and TYC collected and reviewed the pathology slides of cases and prepared the manuscript, YCW, LSW and WHH provided the clinical and follow-up data, YCY and CYC executed the statistical analysis, TYC designed the study and submitted the manuscript.
Funding Parts of this study were supported financially by grants NSC96-2320-B-010-033 and NSC99-2320-B-010-023-MY3 from the National Science Council, grants V96C1-078 and V99ER2-012 from Taipei Veterans General Hospital, grant ‘Center of Excellence for Cancer Research at Taipei Veterans General Hospital’ (DOH101-TD-C-111-007) from the Department of Health and grant ‘Aim for the Top University Plan’ from the Ministry of Education, Taiwan.
Patient consent Obtained.
Ethics approval The study protocol followed the guidelines of the TVGH Institutional Review Board.
Provenance and peer review Not commissioned; externally peer reviewed.