Cite this page: Bychkov A. AJCC / TNM staging. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/lungtumorstaging.html. Accessed June 3rd, 2020.
Pathologic TNM staging of carcinomas of the lung, AJCC 8th edition
Definition / general
Applicable to carcinomas of the lung, including non small cell and small cell carcinomas and bronchopulmonary carcinoid tumors, does not apply to sarcomas or other rare tumors of the lung
WHO has defined new entities of adenocarcinoma in situ and minimally invasive adenocarcinoma, which are assigned to Tis and T1mi categories, respectively
T, N and M categories code the anatomic extent of lung cancer and predict overall survival of patients with non small cell and small cell carcinomas
The 8th edition AJCC / TNM classification has provided a more comprehensive stratification of tumors based on subdivision of T, N and M categories and also adopted the newly introduced histological entities of lung carcinoma
pTX: 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
pT0: no evidence of primary tumor
pTis: carcinoma in situ, squamous cell carcinoma in situ, adenocarcinoma in situ (pure lepidic pattern and ≤ 3 cm)
pT1mi: minimally invasive adenocarcinoma (≤ 3 cm with a predominantly lepidic pattern and ≤ 5 mm of invasion)
pT1a: tumor ≤ 1 cm or rarely a superficial, spreading tumor of any size with invasive component limited to the bronchial wall that may extend proximal to the main bronchus
pT1b: tumor > 1 cm but ≤ 2 cm
pT1c: tumor > 2 cm but ≤ 3 cm
pT2: tumor > 3 cm but ≤ 5 cm or involves the main bronchus regardless of distance to the carina without involvement of the carina, invades visceral pleura (PL1 or PL2) or is associated with atelectasis or obstructive pneumonitis that extends to the hilar region involving part or all of the lung
pT2a: tumor > 3 cm but ≤ 4 cm or has 1 of the above features and size cannot be determined
pT2b: tumor > 4 cm but ≤ 5 cm
pT3: tumor > 5 cm but ≤ 7 cm or directly invades parietal pleura (PL3), chest wall (including superior sulcus tumors), phrenic nerve or parietal pericardium or presence of a separate tumor nodule in the same lobe
pT4: tumor > 7 cm or tumor of any size invading diaphragm, mediastinum, heart, great vessels, trachea, recurrent laryngeal nerve, esophagus, vertebral body or carina or presence of a separate tumor nodule in an ipsilateral different lobe
Tumor size has important prognostic relevance; each centimeter increase in size, from less than 1 cm to up to 5 cm, yields a significantly different prognosis
A CT detected a ground glass nodule in the upper lung. Surgical resection revealed a 2 cm adenocarcinoma with pure lepidic pattern and no stromal invasion. What is the pT category?
Board review answer #1
The pTis category for adenocarcinoma in situ was added in the AJCC / TNM 8th edition staging scheme. By definition, this is a localized, small (≤ 3 cm) adenocarcinoma with growth restricted to neoplastic cells along pre-existing alveolar structures (lepidic growth) and lacking stromal, vascular, alveolar space or pleural invasion. Radiologic equivalent is a pure ground glass nodule on CT. In contrast, minimally invasive adenocarcinoma (pT1mi) is defined as a lepidic predominant adenocarcinoma measuring up to 3 cm with an invasive component measuring up to 0.5 cm.
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