Role of Computed Tomography in Lung Cancer Staging
Purpose of Review: Computed tomography has always been an important imaging technique in lung cancer staging but, due to its well-known limitations, additional imaging and/or invasive tests are usually performed. Purpose of this review is to determine whether new developments in CT and in the other staging techniques have changed the role of CT.
Recent Findings: Despite important technical improvements and the availability of new CT applications, the recent literature confirms the limitations of CT in staging patients with NSCLC. Most attention was given however to other invasive and noninvasive staging techniques and their accuracy in comparison with CT. It was shown that FDG-PET is very useful in the preoperative patient with NSCLC and that it is, especially in N-staging, more accurate than CT. Also combining CT or FDG-PET with EUS-FNA biopsy seems to be a good approach in some indications. Finally, the first reports on the use of integrated PET-CT scanners in lung cancer staging were published and very promising results were shown.
Summary: Computed tomography stays nevertheless the routine imaging procedure for staging patients with NSCLC although performing a PET scan in addition to this CT examination seems to be a good approach that can reduce but certainly not always avoid invasive staging procedures. Mediastinoscopy is still generally considered the standard of care when tissue needs to be obtained from suspicious nodes on FDG-PET and/or CT, although minimally invasive biopsy techniques could replace to a large extent this more invasive technique in the near future.
Lung cancer is a common disease and is the leading cause of death in many countries. Non-small cell lung cancer (NSCLC) accounts for approximately 80% of these cancers, with small cell lung cancer (SCLC) accounting for the remainder. Once the pathologic diagnosis of lung cancer is made, staging becomes the most important task. This staging is most applicable to NSCLC and is based on the TNM classification. Indeed, because SCLC spreads early and widely, the implication of staging on the management of this tumor is, except in rare cases of surgically operable limited SCLC, the choice between chemotherapy and radiation for limited disease and chemotherapy alone for extensive disease. On the other hand in NSCLC, an important aim of staging is to help to define whether the patient is eligible for surgery or not, because surgery offers the best chance for a cure. In both groups staging is, of course, also very important to predict survival and for follow-up during therapy. At this moment, several imaging techniques and invasive tests are available to determine the extent of the primary mass, to examine eventual spread of tumor to the mediastinal lymph nodes, and to look for the presence of distant metastases. However, despite the formulation of international guidelines, the routine clinical practice of these staging procedures remains variable. Reasons for this variability are not only the variable local availability of and experience with the several staging procedures but also the continuous technical improvement of the existing techniques and the development of new ones.
Despite its well-known limitations, CT stays the routine imaging procedure for staging patients with NSCLC in most institutions. CT helps to determine resectability of the tumor and to assess intra- and extra thoracic cancer spread. The success of CT is related to the fact that this technique provides very detailed imaging information of the tumor and that it can depict invasion of this tumor in the fissure, the chest wall, or the mediastinum. In addition CT may show definitely that the tumor is too extensive for resective surgery. However, despite the continuously improving image quality, there are still a lot of cases where CT may leave this in doubt. Moreover, although CT provides the most detailed morphologic information about the presence and enlargement of mediastinal lymph nodes, it is not a good predictor of spread of tumor to these lymph nodes. Often the technique is also not able to reliably exclude extra-thoracic metastases. In nearly all cases, TNM staging can only be performed adequately when CT is combined with another imaging technique and/or followed by a more invasive test. A discussion on the role of CT in staging NSCLC and on potential new insights that may have occurred during the past year should therefore not only concentrate on CT but also on the developments within the other staging techniques. This review discusses recent developments in the locoregional (T and N) and distal (M) staging of NSCLC especially concentrated on the current and future role of CT in comparison with other staging techniques.
Purpose of Review: Computed tomography has always been an important imaging technique in lung cancer staging but, due to its well-known limitations, additional imaging and/or invasive tests are usually performed. Purpose of this review is to determine whether new developments in CT and in the other staging techniques have changed the role of CT.
Recent Findings: Despite important technical improvements and the availability of new CT applications, the recent literature confirms the limitations of CT in staging patients with NSCLC. Most attention was given however to other invasive and noninvasive staging techniques and their accuracy in comparison with CT. It was shown that FDG-PET is very useful in the preoperative patient with NSCLC and that it is, especially in N-staging, more accurate than CT. Also combining CT or FDG-PET with EUS-FNA biopsy seems to be a good approach in some indications. Finally, the first reports on the use of integrated PET-CT scanners in lung cancer staging were published and very promising results were shown.
Summary: Computed tomography stays nevertheless the routine imaging procedure for staging patients with NSCLC although performing a PET scan in addition to this CT examination seems to be a good approach that can reduce but certainly not always avoid invasive staging procedures. Mediastinoscopy is still generally considered the standard of care when tissue needs to be obtained from suspicious nodes on FDG-PET and/or CT, although minimally invasive biopsy techniques could replace to a large extent this more invasive technique in the near future.
Lung cancer is a common disease and is the leading cause of death in many countries. Non-small cell lung cancer (NSCLC) accounts for approximately 80% of these cancers, with small cell lung cancer (SCLC) accounting for the remainder. Once the pathologic diagnosis of lung cancer is made, staging becomes the most important task. This staging is most applicable to NSCLC and is based on the TNM classification. Indeed, because SCLC spreads early and widely, the implication of staging on the management of this tumor is, except in rare cases of surgically operable limited SCLC, the choice between chemotherapy and radiation for limited disease and chemotherapy alone for extensive disease. On the other hand in NSCLC, an important aim of staging is to help to define whether the patient is eligible for surgery or not, because surgery offers the best chance for a cure. In both groups staging is, of course, also very important to predict survival and for follow-up during therapy. At this moment, several imaging techniques and invasive tests are available to determine the extent of the primary mass, to examine eventual spread of tumor to the mediastinal lymph nodes, and to look for the presence of distant metastases. However, despite the formulation of international guidelines, the routine clinical practice of these staging procedures remains variable. Reasons for this variability are not only the variable local availability of and experience with the several staging procedures but also the continuous technical improvement of the existing techniques and the development of new ones.
Despite its well-known limitations, CT stays the routine imaging procedure for staging patients with NSCLC in most institutions. CT helps to determine resectability of the tumor and to assess intra- and extra thoracic cancer spread. The success of CT is related to the fact that this technique provides very detailed imaging information of the tumor and that it can depict invasion of this tumor in the fissure, the chest wall, or the mediastinum. In addition CT may show definitely that the tumor is too extensive for resective surgery. However, despite the continuously improving image quality, there are still a lot of cases where CT may leave this in doubt. Moreover, although CT provides the most detailed morphologic information about the presence and enlargement of mediastinal lymph nodes, it is not a good predictor of spread of tumor to these lymph nodes. Often the technique is also not able to reliably exclude extra-thoracic metastases. In nearly all cases, TNM staging can only be performed adequately when CT is combined with another imaging technique and/or followed by a more invasive test. A discussion on the role of CT in staging NSCLC and on potential new insights that may have occurred during the past year should therefore not only concentrate on CT but also on the developments within the other staging techniques. This review discusses recent developments in the locoregional (T and N) and distal (M) staging of NSCLC especially concentrated on the current and future role of CT in comparison with other staging techniques.
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