Document 1Q2BX3kDBoKN07orZ7zzN7yao

Centennial Article Commentary C Of fl/lEDI g "A System for the Clinical Staging of Lung Cancer"--A Commentary Theresa C. McLoud1 Each month the American Journal of Roentgenologywill republish online one of the 100 most-cited articles from its first century. A corresponding commentary in the print journal by a contemporary radiologistwill provide a current perspective. For a full list of these articles, see page 3 of the January 2006 issue of the AJR or go to www.ajronline.org. Keywords: cancer, cardiopulmonary imaging, chest imaging, lung disease DOI:10.2214/AJR.05.1968 Received November 8, 2005; accepted without revision November 17, 2005. department of Radiology, Massachusetts General Hospital and Harvard Medical School, Founders 216, Fruit St., Boston, MA 02114. Address correspondence to T. C. McLoud. AJR 2006; 187:269-270 0361-803X/06/1872-269 American Roentgen Ray Society his seminal article by Mountain et al. [1] is the first description of the Tapplication of the TNM classifica tion scheme to the clinical staging MDCT systems with automated bolus injec tion of contrast material provide detailed im ages of both local tumor extent (the T factor) and nodal metastases (the N factor). The in of lung cancer. This original study cotrnosdisutcetdion of the American Thoracic Society of 2,155 proven cases of lung cancer. The CT map of nodal stations has permitted accu staging was based on results of physical ex rate CT localization of abnormal nodes [4]. amination findings, radiographic studies, en However, CT has important limitations in doscopic studies, mediastinoscopy, and thora staging of the primary tumor. Sensitivity and centesis. More than 300 survival curves were specificity for both chest wall involvement plotted for various characteristics of the pri and mediastinal invasion can be less than 65% mary tumor, spread to the regional lymph [5-8]. These are critical areas that may deter nodes, and distant metastases in various com mine surgical versus nonsurgical manage binations. Various TNM sets were then as ment. In the 1990s, many studies compared signed to stage groups to indicate prognosis. CT findings with the gold standard of medi The TNM system (which was already in astinoscopy or surgery for staging of lymph place at the time of the article by Mountain node metastases. Those studies showed that, et al. [1]) uses common language to provide regardless of the threshold size of lymph node a basis for categorizing extent of disease. chosen, CT findings in isolation could not be This classification by Mountain et al. [1] taken as clear evidence of malignant nodal in meets several important clinical objectives volvement. About 20% of all nodes deemed by aiding the clinician in the planning of malignant based on CT criteria will be benign treatment and making a quantitative estimate [3, 5-8]. CT, however, continues to play an of prognosis. It makes possible comparison important and necessary part in the evaluation of the results of different treatments. The of patients with lung cancer. TNM staging classification is applicable to MRI plays an important role in the evalua non-small cell lung cancer (NSCLC) and tion and staging of superior sulcus (or Pan has been in universal use since 1986. It was coast's) tumors. Direct multiplanar imaging modified in 1997 to more accurately group and large differences in signal intensity be patients with similar prognosis and treat tween tumor and soft tissue allow better as ment options and in particular to identify pa sessment of invasion into the root of the neck, tients who would benefit from surgery [2]. chest wall, and vertebral bodies [6, 9-11]. Since the introduction of this classification, Because of the limitations of CT and MRI, imaging has played an important role in the the search for a better noninvasive technique clinical staging of lung cancer. At the time of for staging of lung cancer has led to the ap the original publication by Mountain et al. [1], plication of 18F-FDG PET for imaging both only standard chest radiography and conven the mediastinum for nodal disease and the re tional tomography were available for chest im mainder of the body for distant metastases. A aging, and assessment of distant metastatic dis meta-analysis has confirmed that PET is sig ease was generally limited to nuclear medicine nificantly more accurate than CT in the de studies such as bone scintigraphy. tection of nodal mediastinal metastases, with CT has now become the most important di a sensitivity and specificity of 79% and 91%, agnostic imaging procedure for the regional respectively, for PET versus 60% and 77% staging of lung cancer [3]. Helical CT and for CT [12]. The development of fusion im- AJR:187, August 2006 269 McLoud aging with PET/CT has permitted more pre cise localization of lymphadenopathy, allow ing accurate separation of N1 from N2 disease and N2 from N3 disease. PET is suf ficiently sensitive that a patient with negative mediastinal PET results may proceed di rectly to surgical resection of the primary tu mor without a staging mediastinoscopy [13]. PET has also been shown to be more sensi tive than conventional imaging in the detec tion of extrathoracic metastases--except brain metastases because of the high glucose uptake of the normal brain [13]. One of the major benefits of PET is its ability to mini mize unnecessary thoracotomies [14]. In conclusion, the TNM classification sys tem for the staging of lung cancer has led to important advances in the determination of prognosis and treatment of patients with this disease. Imaging, particularly CT and PET, has become an important tool for the determi nation of the extent of disease and appropriate clinical staging. The original work by Moun tain et al. [1] provided an important frame work for the appropriate management of pa tients with lung cancer. References 1. Mountain CF, Carr DT, Anderson WAD. A system for the clinical staging of lung cancer. AJR 1974; 120:130-138 2. Mountain CF. Revisions in the international system for staging lung cancer. Chest 1997; 111:1710-1717 3. Spiro SG, Porter JC. State of the art. Lung cancer: where are we today? Current advances in staging and nonsurgical treatment. Am J Respir Crit Care Med 2002; 166:1166-1196 4. Tisi GM, Friedman PH, Peters RM, et al. American Thoracic Society: Clinical staging of primary lung cancer. Am Rev Respir Dis 1983; 127:659-664 5. Quint LE, Francis IR. Radiologic staging of lung cancer. J Thorac Imaging 1999; 14:235-246 6. Webb WR, Gatsonis C, Zerhouni EA, et al. CT and MR imaging in staging non-small cell bron chogenic carcinoma: report ofthe Radiologic Diag nostic Oncology Group. Radiology 1991; 178:705-713 7. Dales RE, Stark RM, Raman S. Computed tomog raphy to stage lung cancer: approaching a contro versy using meta-analysis. Am RevRespir Dis 1990; 141:1096-1101 8. McLoud TC, Bourgouin PM, Greenberg RW, et al. Bronchogenic carcinoma: analysis of staging in the mediastinum with CT by correlative lymph node mapping and sampling. Radiology 1992; 182:319-323 9. Shiotani S, Sugimura K, Sugihara M, et al. Diagno sis of chest wall invasion by lung cancer: useful cri teria for exclusion ofthe possibility ofchest wall in vasion with MR imaging. Radiat Med 2000; 18:283-290 10. McLoud TC, Swenson SJ. Lung carcinoma. Clin Chest Med 1999; 20:697-713 11. Heelan RT, Demas BE, Caravelli JF, et al. Superior sulcus tumors: CT and MR imaging. Radiology 1989; 170:637-641 12. Dwamena BA Sonnad SS, Angobaldo JO, Wahl RL. Metastases from non-small cell lung cancer: mediastinal staging in the 1990s--meta-analytic comparison of PET and CT. Radiology 1999; 213:530-536 13. Marom EM, McAdams HP, Erasmus JJ, et al. Stag ing non-small cell lung cancer with whole-body PET. Radiology 1999; 212:803-809 14. van Tinteren H, Hoekstra OS, Smit EF, et al. Effec tiveness of positron emission tomography in the preoperative assessment of patients with suspected non-small cell lung cancer: the PLUS Multicentre Randomized Trial. Lancet 2002; 359:1388-1393 270 AJR:187, August 2006