Medical City, Dallas, Texas USA
Sometimes location and timing is everything. Since I can’t attend all of the great thoracic surgery conferences and events, sometimes I just have to wait for something closer to home. But then again, “home” is a relative concept.
As a locum tenens provider, I travel around the country working in various hospital surgical programs on short-term contracts. It’s an interesting and always changing life but one that allows me to pursue my love of thoracic surgery to the fullest.
For the next few weeks, Medical City in Dallas, Texas is my home, as part of the cardiothoracic surgery service. It’s a return trip so it was nice to renew my acquaintance with the surgeons and staff of the CVICU and step-down units.
Today, as part of an ongoing continuing medical education program series, Dr. Mitchell Magee, of Southwest Cardiothoracic Surgeons gave an hour-long lecture entitled, “Lung cancer staging and evolving less invasive surgical treatment alternatives.” The focus of the talk was the changes in lung cancer classification and staging in the 7th edition guidelines. These revisions were proposed to replace previous versions which were based on a very small, select sample of patients at a single site. In comparison, the new revisions are based on over 100,000 patients worldwide.
T, N, M
T – tumor
N – nodes
M – metastasis
This classification system has been in use since the 1940’s and has been revised several times to reflect our growing knowledge. The latest revisions (7th edition) were released in 2012 after several years of research and debate. (For more on this process, see “The science behind the 7th edition Tumour, Node, Metastasis staging system for lung cancer” by Marshall et al, 2012).
Dr. Magee discussed the most recent revisions and how these changes affect both the treatment recommendations and prognoses for our patients. After reviewing these changes, he talked a bit about obtaining sufficient diagnostic information for accurate staging, including the role of EBUS, the new CT scan screening guidelines and the gold standard, mediastinoscopy. He also discussed some of the limitations of PET/CT and other non-invasive diagnostic imaging.
As part of these changes in the subclassification of tumors, 10 stages have been downstaged (meaning that previously in-operable cases may now be eligible for resection) and seven classifications have been upstaged – meaning that the cancers are now considered more advanced.
For example, patients with two separate tumors in the same lobe of the lung has been upstaged to T3. Two different tumors in the same lung, but a different lobe is now T4 classification.
Some of the classifications have changed to make findings more specific. For example, T1 staging has now been subdivided into T1a and T1b.
Any invasion of the pleura, including microscopic – is now T2 staging.
He concluded the presentation with a short overview of the history of surgical resection for lung cancer, and the evolution of surgical techniques from open thoracotomies with pneumonectomies to lung sparing procedures utilizing more minimally invasive techniques.
Despite these changes, the hallmarks of a successful cancer operation remain unchanged – the right operation for the individual patient, and the need to respect oncological principles, like surgical margins, and a through lymph node dissection.
Lymph node dissection/ node sampling
Node sampling remains a crucial part of the cancer staging process despite the advent of less invasive imaging studies due to it’s infaliable accuracy. (There is either tumor tissue in the node or there isn’t, where as PET scan results can be false positive or false negative).
For this reason, tissue samples remain the gold standard of treatment and are the most accurate way to predict and prognosticate the extent of disease.
General rules regarding lymph node sampling are:
– More nodes are better. The minimum acceptable number of nodes for accurate staging is at least SIX for at least THREE different stations.
A good way to remember the relationship between node stations and node status is that bode stations are determined by distance from mediastinum; meaning that node station 14 is more peripheral that node 2.
N1 nodes are stations 10 – 14
N2 nodes are the single digit nodes (2, 4, 7 etc.)
References and additional suggested readingBaltayiannis N, Chandrinos M, Anagnostopoulos D, Zarogoulidis P, Tsakiridis K, Mpakas A, Machairiotis N, Katsikogiannis N, Kougioumtzi I, Courcoutsakis N, Zarogoulidis K. (2013). Lung cancer surgery: an up to date. J Thorac Dis. 2013 Sep;5(Suppl 4):S425-S439. Review. Free pdf. Nice review article discussing the importance of staging for determining optimal treatment for lung cancer, as well as the impact of the latest revisions to the (7th edition) TNM classification system.
IASLC Staging Handbook in Thoracic Oncology – a site-specific guide on the new TNM classification of thoracic malignancies. This publication is published in coordination with the 7th editions of the TNM Classification of Malignant Tumors/UICC and AJCC Cancer Staging Manual.
Goldstraw P, Crowley J, Chansky K et al. (2007). The
IASLC lung cancer project: proposals for the revision of the
TNM stage groupings in the forthcoming (seventh) edition of
the TNM classification of malignant tumours. J Thorac Oncol
2007; 2: 706-714. Figure 1. Powerpoint slides TNM classification revisions for the 7th edition.
Quick and easy summary of the 7th edition classifications for Lung cancer staging – 7th edition Lung cancer staging pdf from the American Joint Commission on Cancer.
Lung cancer screening guidelines – screening questions for patients to determine if they need lung cancer screening.
Li S, Zheng Q, Ma Y, Wang Y, Feng Y, Zhao B, Yang Y. (2013). Implications of False Negative and False Positive Diagnosis in Lymph Node Staging of NSCLC by Means of (18)F-FDG PET/CT. PLoS One. 2013 Oct 25;8(10):e78552. doi: 10.1371/journal.pone.0078552. Incidence of false negatives/ positives and who is most at risk for false findings.
About Dr. Magee
Dr. Mitchell Magee is Surgical Director of Thoracic Oncology and the Minimally Invasive Therapy Institute for Lung and Esophagus at Medical City Dallas. While his partner, Dr. Dewey focuses exclusively on cardiac surgeries like cardiac bypass, valve replacement, TAVR, LVADS and cardiac transplantation, Dr. Magee is the thoracic arm of the two surgeon Southwest Cardiothoracic Surgeons practice. This means Dr. Magee is able to devote his time to a sizable portion of all of the esophageal tears, empyemas, mediastinal masses and lung pathology that a city the size of Dallas has to offer.
Dr. Magee is also part of the CLEAR Clinic at Medical City – which is the lung cancer screening center at the Medical City Dallas facility.
Southwest Cardiothoracic Surgeons
7777 Forest Lane, A307
Dallas, TX 75230