In medicine, staging lung cancer is an assessment of the extent to which lung cancer has spread from its original source. Like most cancers, staging is an important determinant of treatment and prognosis. In general, advanced cancer stages are less able to receive treatment and have a poorer prognosis.
Initial evaluation of non-small cell lung cancer staging using TNM classification. It is based on the size of t umor, lymph node involvement n main ode, and far m etastasis. After this, using the TNM descriptors, the groups were assigned, ranging from occult cancer, through stages 0, IA (one-A), IB, IIA, IIB, IIIA, IIIB to IV (four). This stage group helps with treatment options and prognostic estimates.
There are several methods by which this judgment is made. They are broadly classified into non-invasive techniques, which commonly involve lung medical imaging such as computer tomography (CT) scans and PET scans, and invasive techniques such as biopsies and operation. Invasive techniques provide additional information because tissue samples can be seen microscopically to confirm the presence of cancer cells (as opposed to tissue enlargement due to other causes such as infection) and to determine the type of lung cancer and its quality.
Staging can also be categorized as clinical or as a pathological/surgical presentation. Clinical staging is performed before definitive surgery. This is based on the results of imaging studies (such as CT scans) and biopsy results (ie clinical staging excluding biopsy results, an "invasive technique.") Pathological staging is also called surgical staging and reflects not only the results of a non-surgical biopsy, but is evaluated either intra- or post-operative and based on the combined results of surgical and clinical findings, including surgical sampling of the thoracic lymph node.
Video Lung cancer staging
Lung cancer
Lung cancer is responsible for 1.3 million deaths worldwide every year, and is the most common cause of cancer-related deaths in men and the second most common among women. The most common cause of lung cancer is long-term exposure to tobacco smoke. Non-smoker lung cancer, which accounts for about 15% of cases, is often associated with a combination of genetic factors, radon gas, asbestos, and air pollution. The main types of lung cancer are non-small cell lung carcinoma and small cell lung carcinoma, both distinguished histologically as well as by how they are treated; Non-small cell lung carcinomas are primarily treated with surgery if feasible, whereas small cell lung carcinomas are more frequently treated with chemotherapy and radiation.
The diagnosis of lung cancer is based on chest x-rays and computer tomography (CT) scans, and confirmed by biopsy. Biopsy is usually done via bronchoscopy or CT-guided biopsy. Treatment and prognosis depends on the histological type of cancer, stage, and patient performance status. Treatments include surgery, chemotherapy, and radiotherapy.
Maps Lung cancer staging
Pattern development
Lung cancer can start in different parts of the lung. From there it spreads in a fairly predictable pattern. Usually, if lung cancer spreads, first go to the near-by lymph nodes, followed by further lymph nodes located between the lungs in the space called mediastinum. In mediastinum, lung cancer tends initially to remain on the side where the original tumor begins. After crossing the mediastinal midline, it indicates a more advanced disease, surgery that can not be operated on. Lung cancer can also spread to distant organs, for example, the liver or adrenal gland, which is the most advanced stage of a disease called stage IV.
Staging
Staging is the process of determining how much cancer there is in the body and where it is located. The stage of lung cancer is very important because treatment options are often very complex, even for doctors with a lot of experience in the field, and the choice depends on the stage of the disease. The ultimate goal is to describe the degree or severity of a person's cancer, and to unify the cancer that has the same prognosis and treatment.
Staging information obtained before surgery, for example with x-rays and ultrasound endoscopy, is called clinical staging and surgical staging known as pathological staging.
Clinical staging is performed by combining imaging and sampling (biopsy), or otherwise expressed, non-invasive (radiological) and invasive (biopsy) methods.
Pathological staging is more accurate than clinical staging, but clinical staging is the first and sometimes the only type of staging. For example, if the clinical stage reveals stage IIIB or IV, surgery is not helpful and no pathological staging information is to be obtained (appropriately).
A lung cancer biopsy can be taken for two different reasons:
- Diagnosis: To find out if the abnormalities seen on chest x-ray or CT scan are indeed lung cancer, and what type of histology it is (small cell or non-small cell).
- Staging: To find out whether structures, such as the lymph nodes in the mediastinum, have been attacked by cancer or not.
However, it is often possible, with proper planning, to obtain diagnostic and staging information with a single biopsy procedure.
There are a variety of staging methods available, each with advantages and disadvantages. Many cancer care centers review newly-diagnosed patients on interdisciplinary chest radiographs in which radiologists, oncologists, surgeons, lung experts, pathologists and EUS specialists (endosonographers) discuss the relative merits of available modalities and make choices with consensus.
TNM classification
System staging TNM lung cancer are:
- T Tumors
- T1a: The primary tumor is <= 2Ã, cm in the largest dimension.
- T1b: The primary tumor is & gt; 2 but <= 3Ã, cm in the largest dimension.
- T2a: The primary tumor is & gt; 3 and <= 5 cm in the largest dimension.
- T2b: The primary tumor is & gt; 5 and <= 7Ã, cm in the largest dimension.
- T3 size: Primary tumor is & gt; 7 cm in the largest dimension;
- T3 inv: Primary tumor invades the chest wall, diaphragm, phrenic nerve, mediastinal pleura, or pericardium;
- T3 centered: The primary tumor is & lt; 2 cm to the carina or there is atelectasis throughout the lung;
- T3 Satellite: Primary tumors are associated with separate tumor nodules in the same pulmonary lobe;
- T4 inv: Tumors attack the heart, large vessels, trachea, recurrent laryngeal nerves, esophagus, or spine;
- T4 ipis: Tumor of any size with additional tumor nodules in different ipsilateral lobes;
- N lymph nodes
- N1: Nodal metastasis in ipsilateral lymph nodes or lymph node hilum;
- N2: Metastatic nodal in ipsilateral mediastinal/subkinal lymph nodes;
Method
The American Joint Committee on Cancer (AJCC) and the International Union Against Cancer (UICC) recommend the TNM staging, which is a two-step procedure. Their TNM system, which they now develop together, first classifies cancer with several factors, T for tumors, N for nodes, M for metastasis, and then grouping these TNM factors into the overall stages as shown in their table.
AJCC has provided a web poster version accessible from this copyright-protected TNM descriptor and group group, where readers are directed to accurate, detailed, up to date information; In addition, both the National Cancer Institute (NCI) and the National Comprehensive Cancer Network (NCCN) reprint this descriptor and grouping table with AJCC permission, and extensively discuss the staging modalities and treatment options, providing clear assistance to experts in care decisions best. The NCCN Line "outlines a step-by-step treatment decision from diagnosis through all phases of care and survival."
Although the TNM classification is an internationally agreed system, it has evolved gradually through different editions; the date of publication and adoption for the use of the AJCC edition is summarized in the table in this article; previous editions are available from AJCC for web downloads. Therefore, it is important when reviewing treatment reports or prognosis to recognize that the criteria used in the TNM system vary over time, sometimes substantially, according to different editions. The literature report usually reflects the performances used when the research is started and done, rather than when it is finally published. The date of publication and adoption for the use of the AJCC edition is summarized here to assist the reader in understanding which era the literature uses.
As in every edition of the TNM staging system, used from 2010 January 1 (7th edition) made significant changes to the scheme used for non-small cell lung carcinoma, small cell lung carcinoma and bronchus-pulmonary carcinoid tumors. The revisions are based on a detailed analysis and consensus process by AJCC and UICC which sees the overall viability of 81,015 patients. Changes have been reviewed in detail, including extensive presentations (with some tables and detailed discussions) of prognostic data for 6 and 7 editions, looking at individual T, N and M descriptors, and in the whole stage group. This table uses a limited excerpt of a copyrighted TNM system to show the concept of change, as well as the similarity, between editions.
Consequently, a certain stage may have a very different prognosis depending on the staging edition used, regardless of changes in the method or diagnostic treatment, an effect called "phase migration." The technology used to assign patients to certain categories has also changed, and it can be seen that increasingly sensitive methods tend to cause individual cancers to be moved to a higher stage, so it is not appropriate to compare the cancer forecasts with historical expectations for that stage.
Finally, of course, a more important consideration is the effect of improving treatment over time as well.
Of great importance in history, Dr. Clifton Mountain, a Texas surgeon, made a significant contribution to the TNM staging system, especially in non-small cell lung carcinomas, and such literature often refers to the "Mountain" performance.
VA Classification
In small cell lung carcinomas, the TNM classification is often used in conjunction with additional categorization, the Veterans Administration Lung Cancer Study system. The VA scheme has two stages. Limited stage disease is limited to areas that can be tolerated by one area of ​​radiotherapy ("port"), but excludes cancers with pleural and pericardial effusion. All other small cell lung cancers are a broad stage in this scheme. There are several shifts over time in the sense of this definition.
Staging modality
CT and PET scans
Mainstay non-invasive staging is a chest CT scan followed by metabolic imaging with a PET scan. CT scans show abnormalities such as pulmonary nodules or enlarged lymph nodes while PET scans reveal an increase in metabolism as occurs in structures that contain cancer cells that grow rapidly. PET/CT combines the benefits of functional assessment with PET and anatomic assessment with CT. PET/CT is a significant improvement for staging patients with lung cancer with a management impact in the order of 40% and discordant findings compared to conventional imaging in half of patients. PET/CT also has high inter-and intra-reporter agreements. The main benefit of PET is to identify distant metastatic disease, thereby demonstrating the futility of locoregional approaches such as surgery or curative radiotherapy.
According to the American College of Chest Physicians (ACCP) Guidelines for Non-Invasive Staging for Lung Cancer (2007), the sensitivity and specificity collected from CT scans to identify mediastinal lymph node metastases were 51% and 85%, respectively and for PET scanning 74% (95% CI, 69 to 79%) and 85% (95% CI, 82 to 88%), respectively. In other words, a person relies on non-invasive staging results alone, between 21 and 31 percent of patients will be reduced (cancer is higher than seen) and between 12 and 18 percent of patients will be overstated (cancer is actually at an early stage rather than apparently). In certain clinical situations, confirmation of mediastinal node status results with sampling will be required.
PFT
Pulmonary function tests (PFT) are not a formal part of staging but may be useful in treatment decisions. Patients with lung cancer resulting from air pollution (work or smoking) are more likely to have other lung disorders such as COPD, which limits their respiratory reserves. Patients with restricted respiratory reserves have a higher risk for postoperative complications if surgical treatment is performed; they may not be able to tolerate reduced lung capacity after partial removal of the lungs.
Brain MRI
PET scans need to be specifically modulated to detect metastases in the brain, which in turn show a fairly uniformly active absorption of normal brain activity. In practice, CT scans or MRIs are used to detect brain metastases. Although MRI has a slightly higher detection rate and can find smaller metastases, contrasting CT scans can be a great choice because of factors such as incompatible metal prosthetic, claustrophobia, or noise intolerance.
Mediastinum staging
Almost half of lung cancers have mediastinal disease at diagnosis. If the cancer involves one of the mediastinal lymph nodes, these lymph nodes are designated N2 if they are on the same side as the original tumor, and N3 if they are on the other side. N2, and especially the N3 lymph nodes, affects the clinical stage is very significant. The American Thoracic Society has standardized the nomenclature of lymph nodes in the chest. There are fourteen numbered nodal stations. Lymph nodes considered to be in the mediastinum are stations 1-9, which are potential sites of N2 or N3, whereas stations 10-14 are hilar and peripheral nodes, and thus potential N1 locations.
There are many modalities that allow staging of mediastinal lymph nodes. In the following table is composed from the most up to the least invasive.
​​â € <â €
​​â € <â €
This section focuses on the emerging role of different types of endoscopic ultrasound and biopsy that play in the diagnosis and staging of lung cancer, with an emphasis on the most common type of lung cancer, non-small cell lung cancer (NSCLC). These techniques have been reviewed extensively and have reached substantial consensus in such guidelines from the NCCN.
Ultrasound endoscopy (EUS) is an endoscopic technique in which a miniature ultrasound probe is passed through the mouth to the upper gastrointestinal tract to investigate organs and structures close to the esophagus, stomach, or duodenum, such as the lungs. In 1993, Wiersema published the first description of EUS to diagnose and trigger lung cancer, performed by advancing the fine needle through the esophagus into adjacent lymph nodes. A number of subsequent studies show that this general methodology is effective, extremely safe, minimally invasive, and well tolerated. With these advantages, many people think that EUS along with endobronchial ultrasound (EBUS) improve diagnosis and staging of lung cancer.
Endoscopic ultrasound (EUS)
A meta-analysis was published in 2007, based on 1,201 cancers in 18 high quality clinical trials carefully selected by established criteria from the literature, systematically checking the performance of EUS guided by EUS in NSCLC staging. Two scenarios are considered: regulation of enlarged lymph nodes in CT (suggestive but not cancer diagnostic), and external scenarios of absence of enlarged lymph nodes in CT (suggestive but not diagnostic with no cancer). Overall, in both settings, minor complications were reported in 0.8% of procedures; no major complications were recorded. EUS-FNA in enlarged discrete mediastinal lymph nodes has excellent collected sensitivity (8 studies) of 90% (95% CI, 84-94%) and a specificity of 97% (95% CI, 95 to 98%). EUS-FNA in the setting of no mediastinal lymph nodes on CT had a collected sensitivity (4 studies) of 58% (95% CI, 39 to 75%) and a specificity of 98% (95% CI, 96 to 99%). Although this sensitivity (58% in CT-negative disease) may be at first consideration disappointing, if the EUS performed as a staging test it can help avoid more invasive staging procedures, or surgery, if positive (for the presence of cancer). In other words, EUSs that have positive results (indicating cancer) will avoid unnecessary surgery, whereas non-cancerous outcomes may be mis-negative, and may require excision biopsy techniques for confirmation, such as VATS or mediastinoscopy.
The ACCP guidelines recommend invasive staging for patients with or without enlargement of mediastinal lymph nodes on CT regardless of PET scan findings. If needle technique is used (such as EUS-NA, TBNA, EBUS-NA, or TTNA) non-malignant results should be further confirmed by mediastinoscopy as described above.
EUS is believed to reach the 5, 7, 8 and 9 lymph nodes. In the mediastinum superior the slightly to right trachea of ​​the esophagus makes it often possible to reach the left side of the 2nd and 4th lymph nodes and, more rarely, the right-sided paratracheal lymph nodes. In general, EUS is most appropriate for the evaluation of posterior inferior mediastinum while mediastinoscopy or EBUS is best for anterior mediastinum superior. The feasibility of EUS-FNA aorto-lung space (subaortic) lymph nodes (station 5) is a major advantage of EUS. The evaluation of these stations has traditionally required medied medication (Chamberlain procedure). EUS can easily take samples of celiac lymph nodes, which can not be reached by other mediastinum staging methods. In one recent study, an unexpected incidence of celiac lymph node metastasis (11%) was noted. EUS can also be used for potential biopsies of left adrenal metastases, while the right adrenal gland is largely inaccessible.
The utility potential of EUS-FNA in mediastinal recovery in patients who have undergone chemotherapy and radiotherapy for N2 or N3 disease is under investigation. The underlying idea is that initially advanced cancer, previously too broad for surgery, may have responded to chemotherapy and radiation so that now they may be operative candidates. Instead of immediately proceeding to a thoracotomy based on CT or PET results, which may lead to "open and closed" thorax surgery, recovery, including invasive staging, may invalidate non-responders, missed only imaging tests. If early mediastinal staging includes mediastinoscopy, most surgeons try to avoid recurrent mediastinoscopy after radiation treatment due to scarring. Although recovery with PET and CT scans may help target biopsies, the concept is that negative PET mediastinum should be sampled. In N2 disease, EUS-FNA and EBUS-FNA appear to offer the best risk-benefit ratios in these patients.
Endobronchial ultrasound (EBUS)
As mentioned in the table, EUS can not reliably access right-sided paratracheal lymph node stations 2R and 4R and may not be optimal for left paratracheal lymph node stations as well. The adaptation of the endoscopic ultrasound scope originally designed for the gastrointestinal tract is known as endobronchial ultrasound (EBUS). Instruments are inserted into the trachea rather than the esophagus. There are two types of EBUS bronchus available: radial catheter probe and EBUS convex probe (CP-EBUS), but only the latter are our concern here. The initial experience with mediastinal stage by CP-EBUS appears to be very promising with sensitivity ranging from 92 to 96 percent in 4 series of 70 to 502 patients.
​​â € <â €
Many patients will, if given a choice, prefer an instrument inserted into the esophagus (EUS) above one that is inserted into the trachea (EBUS). In addition, many patients with suspected lung cancer will have other smoking-related illnesses, such as emphysema or COPD, which make procedures such as bronchoscopy (EBUS) at higher risk than the upper endoscopic through the esophagus (EUS). An active and emerging field of research concerns the value of EUS and EBUS merging in one session, one specialist following another, or - even more convenient - multiple trained operators performing one or the other - or both - as necessary.
EUS-FNA and EBUS-FNA are complementary techniques. EUS has the highest yield in the posterior inferior mediastinum, and the strongest EBUS for superior anterior mediastinum. Some lymph node stations can only be accessed by one method and not another (for example, stations 2 and 4 L and 3 which are difficult or impossible to see by EUS, stations 5 and 8 can not be biopsied by EBUS). Together, EBUS and EUS include all mediastinum (except perhaps station 6) and complete mediastinal staging should be possible with a combination of these two procedures. This combination can conceptually eliminate the need for most of the surgical mediastinoscopies and is in fact more comprehensive.
When combined, this approach has been called "complete medical mediastinoscopy." EUS-FNA with EBUS may allow near-complete, minimally invasive mediastinal staging in patients with suspected lung cancer
References
External links
- Vilmann P, Larsen SS. Biopsy guided endoscopic ultrasonography in the chest: slight loss, many advantages. Respiras J. 2005 Mar, 25 (3): 400-1. Review
- Ultrasound Endoscopy Resources
Source of the article : Wikipedia
0 Comments