- An adenocarcinoma in situ is defined as a tumour of ≤ 3 cm with pure lepidic pattern but no lymphatic, vascular or pleural invasion and no tumor necrosis.
- Minimally invasive adenocarcinoma: a small (≤3 cm), solitary tumour with predominant alveolar epithelial appearance (lepidic growth), as in situ adenocarcinoma of the lung, with a zone of focal invasion of the stroma with a size inferior to 5 mm. It has no lymphatic, vascular or pleural invasion and no tumor necrosis.
- Invasive adenocarcinoma: Tumor of larger size or focus of invasion, or with lymphatic, vascular, pleural invasion or tumor necrosis.
For invasive adenocarcinomas, generally specify the pattern (mainly lepidic, acinar, papillary, micropapillary, solid predominant or "predominant subtype cannot be determined).
Lung adenocarcinoma, with lepidic pattern shown, wherein tumors cells cover alveolar walls.
Lung adenocarcinoma, with solid pattern.
Degree of differentiation
Lung adenocarcinomas may be classified as follows:
|Well differentiated||Solid pattern< 90% and mild/moderate atypia|
|Poorly differentiated||Solid pattern ≥ 90% and severe atypia|
- Tumor size
If the tumor has both lepidic and invasive components, specify the maximum dimension of each.
- Growth into adjacent structures
Notable adjacent structures possibly involved are:
- Parietal pleura
- Main bronchus
- Hilar soft tissues
- Organs of the mediastinum (specify where possible)
Staging of non-small-cell lung cancers (AJCC, 8th Ed.):
|T category||T criteria|
|TX||Primary tumor cannot be assessed, or tumor proven by the presence of malignant cells in sputum or bronchial washings, but not visualized by imaging or bronchoscopy.|
|T0||No evidence of primary tumor|
|Tis||Carcinoma in situ|
Squamous cell carcinoma in situ (SCIS)
Adenocarcinoma in situ (AIS): Adenocarcinoma with pure lepidic pattern, ≤3 cm in greatest dimension
|T1||Tumor ≤ in greatest dimension, surrounded by lung or visceral pleura, without bronchoscopic invasion more proximal than the lobar bronchus (i.e., not in the main bronchus).|
|T1mi||Minimally invasive adenocarcinoma: Adenocarcinoma (≤3 cm in greatest dimension) with a predominantly lepidic pattern and ≤5 mm invasion in greatest dimension.|
|T1a||Tumor ≤1 cm in greatest dimension. It also includes a superficial, spreading tumor of any size whose invasive component is limited to the bronchial wall and may extend proximal to the main bronchus (but these are uncommon)|
|T1b||Tumor >1 cm but ≤2 cm in greatest dimension|
|T1c||Tumor >2 cm but ≤3 cm in greatest dimension|
|T2||Tumor >3 cm but ≤5 cm or having any of the following features:
T2 tumors with these features are classified as T2a if ≤4 cm or if the size cannot be determined and T2b if >4 cm but ≤5 cm.
|T2a||Tumor >3 cm but ≤4 cm in greatest dimension|
|T2b||Tumor >4 cm but ≤5 cm in greatest dimension|
|T3||Tumor >5 cm but <7 cm in greatest dimension or directly invading any of the following: Parietal pleura (PL3), chest wall (including superior sulcus tumors), phrenic nerve, parietal pericardium; or separate tumor nodule(s) in the same lobe as the primary.|
|T4||Tumor >7 cm or tumor of any size invading one or more of the following: Diaphragm, mediastinum, heart, great vessels, trachea, recurrent laryngeal nerve, esophagus, vertebral body, or carina. Separate tumor nodule(s) in an ipsilateral lobe different from that of the primary.|
|N category||N criteria|
|NX||Regional lymph nodes cannot be assessed|
|N0||No regional lymph node metastasis|
|N1||Metastasis in ipsilateral peribronchial and/or ipsilateral hilar lymph nodes and intrapulmonary nodes, including involvement by direct extension.|
|N2||Metastasis in ipsilateral mediastinal and/or subcarinal lymph node(s)|
|N3||Metastasis in contralateral mediastinal, contralateral hilar, ipsilateral or contralateral scalene, or supraclavicular lymph nodes(s)|
|M category||M criteria|
|M0||No distant metastasis|
|M1a||Separate tumor nodule(s) in a contralateral lobe; tumor with pleural or pericardial nodes or malignant pleural or pericardial effusion (but note that in a few patients, effusions are negative for tumor in multiple microscopic examinations, and the fluid is non-bloody and is not an exudate, and in such cases the effusion should be excluded as a staging descriptor).|
|M1b||Single extrathoracic metastasis in a single organ (including involvement of a single nonregional node)|
|M1c||Multiple extrathroracic metastases in a single organ or in multiple organs.|
|When T is...||And N is...||And M is...||Then the stage group is...|
|Any T||Any N||M1a||IVA|
|Any T||Any N||M1b||IVA|
|Any T||Any N||M1c||IVB|
For non-small cell carcinoma (NSCLC) stages IB - IV, perform full next generation sequencing panel (DNA and RNA) with PDL-1 immunostaining if the treating physician approves. For advanced stage NSCLC that are not candidates for biopsy or re-biopsy, “liquid biopsy” on peripheral blood is a viable option.
- Lambe, Gerard; Durand, Michael; Buckley, Anne; Nicholson, Siobhan; McDermott, Ronan (2020). "Adenocarcinoma of the lung: from BAC to the future ". Insights into Imaging 11 (1). doi:10.1186/s13244-020-00875-6. ISSN 1869-4101.
- Barletta, Justine A.; Yeap, Beow Y.; Chirieac, Lucian R. (2010). "Prognostic significance of grading in lung adenocarcinoma ". Cancer 116 (3): 659–669. doi:10.1002/cncr.24831. ISSN 0008543X.
- . Protocol for the Examination of Specimens From Patients With Primary Non-Small Cell Carcinoma, Small Cell Carcinoma, or Carcinoid Tumor of the Lung. Version: Lung 184.108.40.206. Protocol Posting Date: June 2017. College of American Pathologists.
- Amin, Mahul (2017). AJCC cancer staging manual
(8 ed.). Switzerland: Springer. ISBN 978-3-319-40617-6. OCLC 961218414.
- For access, see the Secrets chapter.
- Copyright note: The AJCC, 8th Ed. is published by a company in Switzerland, and the tables presented therein are Public Domain because they consist of tabular information without literary or artistic innovation, and therefore do not fulfil the inclusion criterion of the Swiss Copyright Act (CopA) which applies to "literary and artistic intellectual creations with individual character" (see Federal Act on Copyright and Related Rights (Copyright Act, CopA) of 9 October 1992 (Status as of 1 January 2022)).