Episode 024: Lung Cancer Series, Pt. 2: Fundamentals of histology and staging

Lung Cancer Histology and Staging *Workup for a nodule that is concerning: **Ensure there is a dedicated CT scan of the chest to evaluate **Try to obtain old imaging; the rate of change is important **Can get PET, but even if a lesion if not FDG-avid, but growing quickly we should consider biopsy anyway **Referral to pulmonary medicine, who can assist with biopsy and also regional lymph node evaluation (important – more below) **PFTs are often ordered because it provides information about lung function in anticipation of possible surgery for treatment Lung Cancer Histology: *Non-small cell lung cancer (NSCLC) **Umbrella term for a variety of cancers **Increased risk in smokers **More common types: ***Adenocarcinoma (~50% of all lung cancers) ****Most common overall; cancer of the mucus producing cells ****IHC: TTF-1, NapsinA, CK7 positive ***Squamous Cell Carcinoma (22.7%) ****More often seen in patients with a smoking history ****IHC: p63 positive and cytokeratin pearls ***Remaining ~15% are the other types of lung cancer / mixed histologies **Small cell lung cancer (SCLC) ***Neuroendocrine tumor with very different pathology ***Much more aggressive than NSCLC ***Oncologic emergency ***IHC: Chromogranin and synaptophysin positive IHC pearls: TTF-1 usually means lung cancer (but can be negative in squamous cell lung cancer). This will be important in the future (we promise :]) *Staging for NSCLC: **Nodal evaluation: lymph node evaluation is part of the workup for NSCLC **Single digit = central/mediastinal nodes (higher risk) **Double digit = peripheral/hilar/intrapulmonary lymph nodes (lower risk) **“R” vs. “L” is direction *Pearl: Why is this important? If there is nodal involvement, systemic therapy is going to be necessary *Putting it all together: **T: Tumor size: T1-4 **N: Nodal involvement ***N0: no nodal involvement ***N1: Nodes closest to the primary tumor (double digits) ****Ipsilateral peribronchial, hilar, intrapulmonary ***N2: Further away (single digit) ****Ipsilateral mediastinal and/or subcarinal LN ***N3: Contralateral any node or supraclavicular LN **M: Metastasis – in lung cancer, patients with certain patterns of metastatic disease are still curable! ***M0: no mets ***M1a: Contralateral lobe, pleural effusion or pericardial effusion à these are generally still curable! ***M1b: single site of metastatic disease à these are generally still curable! ***M1c: multiple sites of metastatic disease à these are generally not curable *Staging for SCLC: **Limited stage - meaning it can fit in “one radiation field” **Extensive stage - does not fit in “one radiation field” *Once lung cancer is diagnosed: **Go to NCCN to learn the flow of ongoing management **Complete staging (if not already done): ***CT C/A/P (don’t necessarily need if a PET scan is done) ***PET Scan ***MRI brain à in general this is needed, but there are some exception to this (see NCCN) **Referral to pulmonary for nodal evaluation References: NCCN.org https://doi-org.proxy.library.vanderbilt.edu/10.1016/j.semcancer.2017.11.019-Article about IHC markers for lung cancer Please visit our website (TheFellowOnCall.com) for more information Twitter: @TheFellowOnCall Instagram: @TheFellowOnCall Listen in on: Apple Podcast, Spotify, and Google Podcast