Lung Cancer (Bronchial Carcinoma): Classification

TNM classification

Category Status Brief description
T (tumor) Tis Carcinoma in situ
T1 Largest diameter <3 cm, surrounded by lung tissue or visceral pleura, main bronchus not involved
T1a(mi) Minimally invasive adenocarcinoma (adenocarcinoma with lepidic growth pattern < 3 cm in greatest extent with a solid portion < 5 mm in diameter)
T1a Largest diameter < 1 cm
T1b Largest diameter > 1 cm but < 2 cm
T1c Largest diameter > 2 cm but < 3 cm
T2 Largest diameter > 3 cm but < 5 cm or

  • Infiltration of the main bronchus regardless of distance from the carina but without direct invasion of the carina or
  • Infiltration of the visceral pleura or
  • Tumor-related partial atelectasis or obstructive pneumonia extending into the hilus, involving portions of the lung or the entire lung
T2a Largest diameter > 3 cm, but < 4 cm
T2b Largest diameter > 4 cm, but < 5 cm
T3 Largest diameter > 5 cm, but < 7 cm or

  • Infiltration of thoracic wall (including parietal pleura and superior sulcus), phrenic nerve, or parietal pericardium or
  • Additional tumor nodule in the same lobe of the lung as the primary tumor.
T4 Largest diameter > 7 cm or

  • With direct infiltration of diaphragm, mediastinum, heart, great vessels, trachea, recurrent laryngeal nerve, esophagus, vertebral body, or carina; or
  • Additional tumor nodule in another ipsilateral lobe of the lung.
N (lymph node) N0 No lymph node metastasis(s)
N1 Metastasis(s) to, or direct invasion of, ipsilateral, peribronchial, and/or ipsilateral hilar lymph nodes and/or intrapulmonary lymph nodes
N2 Metastasis(s) to ipsilateral mediastinal and/or subcarinal lymph nodes
N3 Metastasis(s) in contralateral mediastinal, contralateral hilar, ipsi or contralateral deep cervical, supraclavicular lymph nodes
M (metastasis) M0 No distant metastasis(s)
M1 Distant metastasis n)
M1a
  • Separate tumor nodule(s) in a contralateral lung lobe or
  • Pleura with nodular involvement or
  • Malignant pleural effusion or
  • malignant pericardial effusion
M1b A solitary distant metastasis(s) in a solitary extrathoracic organ
M1c Multiple distant metastases (> 1) in one or more organs

Classification of tumor stages

Stage Primary tumor Lymph node Distant metastases
0 Tis N0 M0
IA1 T1a(mi) T1a N0 N0 M0 M0
IA2 T1b N0 M0
IA3 T1c N0 M0
IB T2a N0 M0
IIA T2b N0 M0
IIB T1a – c N1 M0
T2a ,b N1 M0
T3 N0 M0
IIIA T1a – c N2 M0
T2a, b N2 M0
T3 N1 M0
T4 N0 M0
T4 N1 M0
IIIB T1a – c N3 M0
T2 a,b N3 M0
T3 N2 M0
T4 N2 M0
IIIC T3 N3 M0
T4 N3 M0
IVA any T each N M1a
each T each N M1b
IVB each T each N M1c

Specification of the category M1

Lung PUL Bone marrow MAR
Bone OSS Pleura PLE
Liver HEP Peritoneum PER
Brain BRA Adrenal ADR
Lymph node LYM Skin SKI
Other organs OTH

Classification of stage IIIA(N2) subgroups [2,3].

Subgroup Description
III A1 Incidental evidence of mediastinal lymph node metastases in a lymph node station on postoperative histologic examination of the resectate
III A2 Intraoperative evidence of lymph node metastasis in a lymph node station
III A3 Preoperative detection of lymph node metastases in one or more lymph node stations by staging using mediastinoscopy, fine needle biopsy, or PET
III A4 Bulky” (extensive) or fixed N2 metastases or metastases in multiple lymph node stations (mediastinal lymph nodes > 2-3 cm with extracapsular infiltration; involvement of multiple N2 lymph node locations; groups of multiple involved smaller (1-2 cm) lymph nodes

In small cell bronchial carcinoma, one has the following additional simplifying classification:

  • Very limited disease – stage I of the TNM system.
  • Limited disease (30%) – stage I-III of the TNM system.
  • Extensive disease (70%) – stage IV of the TNM system.

Classification of bronchial carcinoma according to histology

In addition to the TNM classification, the classification of bronchial carcinoma according to the histologic picture is of particular importance, as it determines the exact treatment recommendation:

  • Small cell lung cancer (SCLC; engl. : Small Cell Lung Cancer) [tumor doubling time: 10-50 days! ; approx. 80% are metastasized at diagnosis] (incidence: 13-15%)
  • Non-Small Cell Lung Cancer (NSCLC, English : Non-Small Cell Lung Cancer) [grow much slower than the SCLC].
    • Squamous cell carcinoma
    • Adenocarcinoma [see “New classification of adenocarcinoma” below; adenocarcinoma predominates in bronchial carcinoma]
    • Adenosquamous carcinoma
    • Large cell carcinoma
    • Bronchioalveolar carcinoma
    • Adenoid cystic carcinoma
    • Mucoepidermoid carcinoma

New classification of adenocarcinoma (considering the International Agency for the Study of Lung Cancer (ASLC) and the American Thoracic Society (ATS),2011):

  • Previnvasive lesion
    • Atypical adenomatous hyperplasia (AAH).
    • Adenocarcinoma in situ (AIS), (≤ 3 cm in size; previously classified as: “pure” bronchiolalveolar carcinoma): nonmucinous; mucinous; mixed nonmucinous/mucinous.
  • Minimally invasive adenocarcinoma (MIA).
    • Predominant lepidic adenocarcinoma (≤ 3 cm in size and ≤ 5 mm invasion): nonmucinous; mucinous; mixed nonmucinous/mucinous
  • Invasive adenocarcinoma
    • Lepidic predominant [previously classified as: nonmucinous bronchiolalveolar growth pattern, with ≥ 5 mm invasion]
    • Acinar predominant
    • Papillary predominant
    • Micropapillary predominant
    • Solid predominant with mucus formation
  • Variants of invasive adenocarcinoma
    • Invasive mucinous adenocarcinoma [previously classified as: mucinous brochiolalveolar carcinoma].
    • Colloid adenocarcinoma
    • Fetal adenocarcinoma (low and high malignant).
    • Enteric adenocarcinoma

Prognostic factors

According to the above classifications, the following prognostic criteria also result:

  • Histological type of carcinoma
  • Tumor stage; if the tumor affects both halves of the thorax, it is called “extensive disease” – in such cases, the patient can only be treated palliatively.

Furthermore, the following criteria must also be considered:

  • General condition of the affected person
  • Age
  • Gender
  • Immunology

Other prognostic factors

  • In stage I adenocarcinoma of the lung, solid predominant subtype is an independent predictor of early recurrence and, therefore, poorer postrecurrence survival.