Lymph node metastasis has been reported in 22.4% [1]

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1 GENERAL THORACIC Peripheral Lung Adenocarcinomas: 10 mm or Less in Diameter Daizo Kondo, MD, Katsuo Yamada, MD, Yasuhiko Kitayama, MD, and Shoji Hoshi, MD Departments of General Thoracic Surgery and Pathology, Shizuoka Saiseikai General Hospital, Shizuoka, Japan Background. Few reports have been published regarding peripheral lung adenocarcinomas that are 10 mm or less in diameter. This is considered to be the smallest tumor size detectable by present diagnostic modalities. Methods. Clinicopathologic studies were performed in 57 patients with peripheral lung adenocarcinomas of 10 mm or less in diameter. Outcomes were compared with two other groups that consisted of 32 patients with adenocarcinomas between 11 and 15 mm in diameter and 35 patients with adenocarcinomas between 16 and 20 mm in diameter. Tumors were curatively resected between 1992 and Results. The mean age was 61.7 years. The following three features were more frequent: female sex (78.9%), nonsmokers (77.2%), and cases with carcinoma detected by computed tomography despite negative chest radiography (96.5%). Negative lymphatic invasion (94.7%) was significantly higher. Three cases showed lymphatic invasion that was classified as types E or F, according to Noguchi s classification. There were no cases of lymph node metastasis, pleural involvement, or intrapulmonary metastasis. Well-differentiated type was in 93.0%. Types A and B, which are noninvasive alveolar replacementtype adenocarcinomas, were significantly dominant (86.0%). The 5-year postoperative survival rate was 97.3%, which was significantly better than in the other two groups (75.5%, 78.1%). Conclusions. Histopathologic features of most peripheral lung adenocarcinomas of 10 mm or less in diameter were types A and B. Types A and B were considered fundamentally indicated for thoracoscopic wedge resections. However, the other types required the standard operation. (Ann Thorac Surg 2003;76:350 5) 2003 by The Society of Thoracic Surgeons Lymph node metastasis has been reported in 22.4% [1] to 44.0% [2] of cases of lung adenocarcinomas that are 20 mm or less in diameter. Metastasis has even been reported in approximately 17.0% [3, 4] of stage ct1 N0 M0 cancers. Therefore, adenocarcinomas less than 20 mm do not necessarily correlate to early stages of lung cancer. In 1995, Noguchi and colleagues [5] proposed a new histologic classification for small adenocarcinomas of the lung. In this classification, small adenocarcinomas are divided into two groups and six distinctive structural patterns on the basis of tumor growth patterns. One group is pulmonary adenocarcinoma in which the tumors show a growth pattern involving the replacement of alveolar lining cells. This group includes type A (localized bronchioloalveolar carcinoma), type B (localized bronchioloalveolar carcinoma with foci of collapse of alveolar structures), and type C (localized bronchioloalveolar carcinoma with foci of active fibroblastic proliferation). Another group is the nonreplacement-type adenocarcinomas, which includes type D (poorly differentiated adenocarcinoma), type E (tubular adenocarcinoma), and type F (papillary adenocarcinoma with compressive and destructive growth). It has been concluded that types A and B are thought to be in situ peripheral adenocarcinomas, whereas type C Accepted for publication Feb 12, Address reprint requests to Dr Kondo, Department of General Thoracic Surgery, Shizuoka Saiseikai General Hospital, Oshika 1-1-1, Shizuoka , Japan; d130893@siz.saiseikai.or.jp. appears to be an advanced stage of types A and B. Conversely, types D, E, and F are small advanced adenocarcinomas. Since the introduction of spiral computed tomography (CT) in the early 1990s, smaller diameter lung cancers are being diagnosed [6]. We performed surgical resections in 57 patients with small peripheral lung adenocarcinomas that were 10 mm or less in diameter and were mainly diagnosed by CT. The aim of the present study was to compare clinicopathologic features of small peripheral lung adenocarcinomas of 10 mm or less in diameter with tumor groups of 11 to 20 mm in size. Thus, we herein discuss the significance of limited operations. Material and Methods Subjects consisted of 57 patients without preoperative treatment who had a peripheral lung adenocarcinoma of 10 mm or less in diameter (group 1). They were selected from 414 patients who underwent resection of a primary lung cancer in the Department of General Thoracic Surgery at Shizuoka Saiseikai General Hospital between April 1, l992, and June 30, Group 1 was compared with group 2, which consisted of 32 patients with an adenocarcinoma of 11 to 15 mm in diameter that was curatively resected during the same period. Group 1 was also compared with group 3 of 35 patients with an adenocarcinoma of 16 to 20 mm in diameter. Patients who visited to the outpatient clinic routinely 2003 by The Society of Thoracic Surgeons /03/$30.00 Published by Elsevier Inc PII S (03)

2 Ann Thorac Surg KONDO ET AL 2003;76:350 5 LUNG ADENOCARCINOMAS: 10 MM OR LESS underwent chest radiography (CxR) and thoracic CT scanning for lung cancer screenings. Noncalcified pulmonary nodules were examined by thin-slice CT (TSCT). Thin-slice CTs were reexamined after 1 month and again after 3 months if no changes were found. After 6 months up to June l998, TSCT was repeated if there were again no changes. When nodule enlargement was observed, CTguided transcutaneous needle lung biopsy, thoracoscopic biopsy, or open lung biopsy was indicated. Between July l998 and February 2001, patients with nodules that had a ground-glass opacity (GGO) appearance on TSCT underwent a TSCT examination again after 3 months. Furthermore, when a reduction in tumor size did not occur, a lung biopsy was performed. Since March 2001, CTguided transcutaneous needle biopsies were not performed for a nodule with GGO appearance, because of questionable diagnostic characteristics. Also, this policy was followed to eliminate the risk of postoperative cancer tissue remnants related to the unresectability of the pulmonary biopsy site by wedge resection. The surgical principle for lung adenocarcinomas less than 10 mm in size was altered according to our experience in previous cases. Between April l992 and June l998, all patients with lung cancers underwent a lobectomy with systematic lymphadenectomy. Because six of eight cases were type A or B, intraoperative histopathologic examination by frozen section was performed. Therefore, segmentectomy with systematic lymphadenectomy was indicated for types A or B. Of the 28 patients with type A or B lung cancer, 4 were misdiagnosed as type C by intraoperative frozen-section histopathologic examination. All 31 patients with pure GGO on TSCT, which were experienced before February 2001, were classified as type A or B. Therefore, intraoperative histopathologic examination by frozen section was discontinued after March Cases with pure GGO since underwent wedge resection without lymphadenectomy. As a result, 23 of the 57 patients in group 1 underwent lobectomy with systematic lymphadenectomy, previously described by Naruke and colleagues [7]. Thirteen of the 57 patients underwent segmentectomy with systematic lymphadenectomy, and the remaining 21 underwent a wedge resection without nodal sampling. Of the 13 patients who underwent segmentectomy, 11 were performed as intentionally limited operations. The remaining two cases were because of low pulmonary function. Of the 21 patients who underwent a wedge resection, 17 were intentionally limited operations, 2 owing to low pulmonary function, and 2 because of other impaired conditions. Resected specimens were all fixed with formalin, cut into 5-mm to 10-mm slices, and evaluated by conventional hematoxylin and eosin staining. All patients in this study were followed at an outpatient clinic by thoracic surgeons. They were scheduled for the following testing: CT of the chest, upper abdomen, and brain; bone scintigraphy; and serum tumor markers (carcinoembryonic antigen). Examinations were scheduled every 3 months for 6 months after the operation. Thereafter, tests were scheduled every 6 months for 5 years after the operation. After 5 years, thoracic CT was 351 taken every 6 months. None of the patients were lost to follow-up. Clinical records of each patient were reviewed for age, sex, smoking history, symptoms, diagnostic technique for detection of tumor, and maximum tumor diameter on TSCT. The grade of tumor differentiation and the presence of lymph node metastasis were determined according to the TNM classification system of the International Union Against Cancer [8]. Furthermore, lymphatic invasion, pleural involvement, intrapulmonary metastasis, and the subtype of the small lung adenocarcinoma according to Noguchi s histologic classification [5] were evaluated. Lymphatic invasion was defined as tumor cells that were identified in the lymphatic vessel lumen. Pleural involvement was determined when the tumor had invaded into the elastic layer of the visceral pleura. Intrapulmonary metastasis was defined as an independent mass that was isolated from the primary malignancy with histopathologic features identical to the primary tumor. Statistical analysis was performed using StatView software (Abacus Concepts, Berkeley, CA). Intergroup comparisons of each factor were performed by the F test, 2 test, and Fisher s exact test. Survival rate was determined by the Kaplan-Meier method, and the determination of significance was made by the log-rank test. A p value less than 0.05 was considered as the level of significance. Results Clinical Characteristics The data are listed in Table 1. The mean age in group 1 was 61.7 years. Subjective symptoms were observed in only one case. There was no statistically significant difference in age and symptoms among the three groups. Group 1 consisted of a significantly larger number of women (45 cases, 78.9%) than the other two groups (50.0% in group 2 and 57.1% in group 3; p 0.005, p 0.03, respectively). Nonsmokers were prevalent in all groups, especially in group 1 with 44 cases (77.2%), which was significantly higher than the other two groups. Tumors were detected by CxR in only two cases (3.5%). The other 55 cases (96.5%) were diagnosed by CT. The number of cases in which only CT (not detected on CxR) detected the tumor was based on the tumor diameter. The smaller diameter tumors were more likely to be detected by CT only and not by CxR. The percentage of cases that were detected by CT and not CxR in group 2 was 65.6%. The percentage of cases in group 3 was 14.3%. There was a significant difference (p ) among the three groups. Histopathologic Findings The results are shown in Table 2. Specimens were incomplete in three cases of group 3. This resulted in unclear evaluations as follows: differentiation in one case, Noguchi s classification in three cases, and lymphatic invasion in two cases. Concerning tumor differentiation, welldifferentiated adenocarcinoma was found in 53 of 57 GENERAL THORACIC

3 GENERAL THORACIC 352 KONDO ET AL Ann Thorac Surg LUNG ADENOCARCINOMAS: 10 MM OR LESS 2003;76:350 5 Table 1. Patient Characteristics Characteristic Group 1 Group 2 Group 3 p value 1vs2 1vs3 2vs3 Number of patients Age (y) Median (range) 61.7 (31 85) 63.9 (46 85) 65.7 (43 84) Sex Male Female Tumor size (mm) Median (range) 6.9 (3 10) 12.4 (11 15) 18.2 (16 20) Symptoms Symptomatic Asymptomatic Smoking history Smokers Nonsmokers Diagnostic technique CxR CT CT computed tomography; CxR chest roentgenography. cases (93.0%) in group 1, which was not significant versus the 26 of 32 cases (81.3%) in group 2. However, there was a significant difference (p ) versus the 13 of 34 cases (38.2%) in group 3. As to Noguchi s classification, the frequency of types A, B, and C alveolar replacementtype lung adenocarcinoma was high in all groups: 50 of 57 cases (87.7%) in group 1, 29 of 32 cases (90.6%) in group 2, and 23 of 32 cases (71.9%) in group 3. Particularly, types A and B were more frequent with 86.0% (49 cases) in group 1, which was significantly different from group 2 with 34.4% (11 cases; p ) and group 3 with 28.1% (9 cases; p ). Systematic lymphadenectomy was performed in 36 cases of group 1, 24 cases of group 2, and 33 cases of group 3. Those cases underwent evaluation of lymph node metastasis. There was no metastasis in group 1, which was significant (p ) against group 3 (8 of 33 cases, 24.2%). Lymphatic invasion was positive in 3 of 57 cases (5.3%) in group 1, which was significant against group 2 (7 of 32 cases, 21.9%; p ) and group 3 (13 Table 2. Pathologic Features Variable Group 1 Group 2 Group 3 p Value 1vs2 1vs3 2vs3 Differentiation Well Moderately and poorly Noguchi s classification Types A and B (A/B) 49 (39/10) 11 (8/3) 9 (5/4) Types C, D, E, and F (C/D/E/F) 8 (1/0/3/4) 21 (18/2/0/1) 23 (14/2/6/1) Lymph node metastasis N N1, 2, and 3 (1/2/3) 0 1 (1/0/0) 8 (1/4/3) Lymphatic invasion Negative Positive Pleural involvement Negative Positive Intrapulmonary metastasis Negative Positive 0 0 3

4 Ann Thorac Surg KONDO ET AL 2003;76:350 5 LUNG ADENOCARCINOMAS: 10 MM OR LESS Fig 1. Postoperative survival curves for 124 cases with peripheral lung adenocarcinomas of 20 mm or less in diameter. There are significant differences between groups 1 (dashed line) and 2(solid line; p 0.013) and between groups 1 and 3 (dotted line; p 0.006). of 33 cases, 39.4%; p ). The three cases with lymphatic invasion in group 1 consisted of one case of type E and two cases of type F. Pleural involvement was not found in group 1, while it was detected in 5 of 35 cases (14.3%) in group 3 (p 0.003). Intrapulmonary metastasis was not observed in either group 1 or group 2, but it was detected in 3 of 35 cases (8.6%) in group 3 (not statistically significant). Prognosis Regarding the observation period, there was a statistically significant difference (p ) between groups 1 (880 days) and 3 (1,377 days). To date, there have not been any recurrences in group 1, but one patient died of an accidental cause. The recurrence of cancer was observed in two cases in group 2 and in eight cases in group 3. Postoperative 5-year survival was obtained in 97.3% of patients in group 1, 75.4% in group 2, and 78.1% in group 3. This indicated that group 1 had a significantly better prognosis than the latter two groups (p and p 0.006, respectively), as shown in Figure 1. Comment The percentage of women with small-sized lung adenocarcinomas has been reported as 52.2% [3] and 58.3% [9], which are equivalent to the percentages found in groups 2 and 3. However, the 78.9% found in group 1 was significantly higher than those. The risk of smoking in lung adenocarcinoma has remained low when compared with other histologic types of lung cancer, although it is now increasing in the United States and Japan. The risk of death as a result of lung adenocarcinoma for smokers has been reported to be 19.2 times higher than for nonsmoker men and 8.2 times higher than for nonsmoker women in the United States [10]. In Japan, the risk of morbidity from lung adenocarcinoma in smokers is reported to be as low as 1.5 to 2.0 times [11, 12]. The present study showed that the percentage of nonsmokers was high, especially the 77.2% found in group 1. Although it is 353 outside the scope of the present study, second-hand smoke exposure in nonsmokers and other risk factors, except for smoking, remain to be investigated in lung adenocarcinoma. Several reports have recently been published to emphasize the usefulness of detecting early stages of lung cancer with CT. The accuracy of CT for detecting lung cancer has been reported to be 4 to 10 times higher than CxR, and lung cancers were diagnosed by CT in stage IA in 60% to 80% [13 15]. The present study demonstrated that 55 of 57 cases with peripheral lung adenocarcinomas of 10 mm or less in diameter were diagnosed by CT, but not CxR. All of these cases were stage IA cancers. Thus, CT examination is indispensable in detecting early stages of peripheral lung adenocarcinoma. As to histopathologic findings, the percentage of alveolar epithelium replacement-type adenocarcinoma (equivalent to types A, B, and C of Noguchi s classification) was high in peripheral lung adenocarcinomas of 20 mm or less. Noguchi and associates [5] reported a value of 74.2%. We found it to be 84.3% in the present study. However, the frequency of types A and B, equivalent to bronchioloalveolar carcinoma in the World Health Organization classification [16] and carcinoma in situ by Noguchi and coworkers [5], was different between the report by Noguchi and associates [5] and the present study. The former was 14.4% for tumor sizes less than 20 mm, and the latter was 86.0% (49 of 57 cases) in group 1. It appears significant that cancers detected at the size of 10 mm or less in diameter will almost always be carcinoma in situ. Nevertheless, alveolar epithelium nonreplacement-type adenocarcinoma (types D, E, and F) was found in 7 of 57 cases in group 1, and three of the seven cases demonstrated positive lymphatic invasion. Therefore, even if the cancer size is less than 10 mm, we could not consider it to be an early stage cancer. Lung cancers classified in group 1 were CT-visible and CxR-invisible lung cancers in most cases. The group was different from the other groups in patient characteristics and pathologic features. Therefore, it is likely that this cancer group has a distinctly different tumor entity from the traditional CxR-visible lung cancer. Many cancers in group 1 are type A or B, which are slow-growing and remain within a 10-mm diameter for a long time. These would often fall into the category of overdiagnosis. The fact that type C is minimal in group 1 suggests that the type A or B becomes type C, which is rapidly growing and more aggressive so that it grows rapidly to more than 10 mm. This may also suggest that the size would change tumors to type C. Furthermore, of the seven cases with types E and F in group 1, two cases coexisted with types A and B. Noguchi and colleagues [5] reported that types D, E, and F are thought to be de novo adenocarcinomas because stepwise progression has not been observed in these types. They are few in frequency, rapidly growing, and more aggressive so that even CT cannot frequently detect these tumors that are within the size category of less than 10 mm. There have been many reports [1, 4, 9, 17 21] regarding limited operations of non small-cell lung cancer. Most of GENERAL THORACIC

5 GENERAL THORACIC 354 KONDO ET AL Ann Thorac Surg LUNG ADENOCARCINOMAS: 10 MM OR LESS 2003;76:350 5 these authors have discussed the indications for a limited operation from the size of the cancer or the results in detecting lymph node metastasis before and during the operation. Some authors have reported occult micrometastasis in the lymph nodes using immunohistochemical staining. Micrometastasis was observed in 35.7% [22] in pn0 adenocarcinoma and in 20.4% [9] in pn0 small-sized adenocarcinoma, and their postoperative prognosis was poor. Even if a limited operation is performed because of the absence of metastatic lymph nodes before and during the operation, considerable risks will remain because of residual metastatic lesions that cannot be completely removed. A prospective study of the operative results of limited resections of lung cancer has been recently reported in Japan. The authors concluded that extended segmentectomy with lymph node dissection is an alternative method as a standard operation for non small-cell lung cancer less than 2 cm in diameter confirmed as N0 by intraoperative lymph node examination of frozen sections [17]. It is known that if systematic lymphadenectomy was performed for those cases, segmentectomy had the same radical cure rate as lobectomy. However, 86% of group 1 were occupied with types A and B, which did not require lymphadenectomy. Postoperative stage of group 1 was stage IA in all cases; however, positive lymphatic invasion was observed in 5.3% of cases. The most important factor for discrimination of small advanced adenocarcinoma, which is known to be the poorest of all prognoses, will be more dependent on Noguchi s classification rather than tumor size and stage. Types A and B lung adenocarcinoma are theoretically expected to be completely removed by limited operations without lymphadenectomy as previously reported [9]. It is important to diagnose types A and B before the operation. In our experience, the diagnostic ability of intraoperative histopathologic examination by frozen section was poor when using Noguchi s classification. An early stage of localized bronchioloalveolar carcinoma is recognized as a hazy, increased-density area, or GGO, on CT scans [23, 24]. Peripheral lung adenocarcinomas demonstrating pure GGO with 10 mm or less in diameter are highly suspected of types A and B as mentioned above. Such cases may be fundamentally suitable to undergo thoracoscopic wedge resections with minimal invasion. If histopathologic results of the resected specimen show type C, D, E, or F, a standard operation must then be added. However, this circumstance will not be common. On the other hand, because tumors without the appearance of pure GGO have the possibility of being types C, D, E, and F, the standard operation may currently be adequate. Lymph node sampling is not necessary in wedge resections for types A and B because these types never have metastasis caused by in situ carcinoma. Consequently, lymph node sampling makes thoracoscopic surgery hazardous for future cancers because of the resultant adhesions. Also, systematic lymph node dissection may be adequate for types C, D, E, and F, because lymph node sampling has a low curative potential. As to the surgical treatment of non small-cell lung cancers that are 10 mm or less in diameter, Miller and associates [25] recently reported that a standard operation is suitable because of lymph node metastases and recurrence of cancers. However, cases with tumors that were not detected on CxR, yet detected on CT, were uncommon (13%). Accordingly, types A and B were thought to be uncommon. The present study revealed different findings from the results reported by Miller and colleagues [25]. In conclusion, peripheral lung adenocarcinomas with a diameter of 10 mm or less are common in women and nonsmokers. Most cases were detected by CT. Histopathologic findings showed types A and B of Noguchi s classification in 86%, which was different from the adenocarcinomas of 11 mm or more in diameter. Types A and B adenocarcinomas that demonstrate pure GGO on TSCT would be fundamentally indicated for thoracoscopic partial lung resections. However, type C and nonalveolar replacement-type adenocarcinoma (types D, E, and F) must be resected by the standard operation, even if the tumor is less than 10 mm in diameter. References 1. Watanabe S, Oda M, Go T, et al. Should mediastinal nodal dissection be routinely undertaken in patients with peripheral small-sized (2 cm or less) lung cancer? Retrospective analysis of 225 patients. 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6 Ann Thorac Surg KONDO ET AL 2003;76:350 5 LUNG ADENOCARCINOMAS: 10 MM OR LESS cancer with mobile spiral computed tomography scanner. Lancet 1998;351: Altorki N, Kent M, Pasmantier M. Detection of early-stage lung cancer: computed tomographic scan or chest radiograph? J Thorac Cardiovasc Surg 2001;121: Henschke CI, McCauley DI, Yankelevitz DF, et al. Early Lung Cancer Action Project: overall design and findings from baseline screening. Lancet 1999;354: Histological typing of lung and pleural tumours. World Health Organization International Histological Classification of Tumours. Berlin: World Health Organization, Yoshikawa K, Tsubota N, Kodama K, Ayabe H, Taki T, Mori T. Prospectivstudy of extended segmentectomy for small lung tumors. Ann Thorac Surg 2002;73: Ginsberg RJ, Rubinstein LV. Randomized trial of lobectomy versus limited resection for T1 N0 non-small cell lung cancer. Lung Cancer Study Group. Ann Thorac Surg 1995; 60: Pastorino U, Valente M, Bedini V, Infante M, Tavecchino L, Ravasi G. Limited resection for stage I lung cancer. Eur J Surg Oncol 1991;17: Read RC, Yoder G, Schaeffer RC. Survival after conservative 355 resection for T1 N0 M0 non-small cell lung cancer. Ann Thorac Surg 1990;49: Suzuki K, Nagai K, Yoshida J, Nishimura M, Nishiwaki Y. Predictors of lymph node and intrapulmonary metastasis in clinical stage I A non-small cell lung carcinoma. Ann Thorac Surg 2001;72: Izbicki JR, Passlick B, Hosch SB, et al. Mode of spread in the early phase of lymphatic metastasis in non-small-cell lung cancer: significance of nodal micrometastasis. J Thorac Cardiovasc Surg 1996;112: Kuriyama K, Seto M, Kasugai T, et al. Ground-glass opacity on thin-section CT. Value in differentiating subtypes of adenocarcinoma of the lung. AJR Am J Roentgenol 1999;173: Jang HJ, Lee KS, Kwon OJ, Rhee CH, Shim YM, Han J. Bronchioloalveolar carcinoma: focal area of ground-glass attenuation at thin-section CT as an early sign. Radiology 1996;199: Miller DL, Rowland CM, Deschamps C, Allen MS, Trastec VF, Pairolero PC. Surgical treatment of non-small cell lung cancer 1 cm or less in diameter. Ann Thorac Surg 2002;73: GENERAL THORACIC Internet Discussion Forum Each month, we select an article from The Annals of Thoracic Surgery for discussion within the Surgeon s Forum of the CTSNet Discussion Forum Section. The articles chosen rotate among the six dilemma topics covered under the Surgeon s Forum, which include: General Thoracic Surgery, Adult Cardiac Surgery, Pediatric Cardiac Surgery, Cardiac Transplantation, Lung Transplantation, and Aortic and Vascular Surgery. Once the article selected for discussion is published in the online version of The Annals, we will post a notice on the CTSNet home page ( with a FREE LINK to the full-text article. Readers wishing to comment can post their own commentary in the discussion forum for that article, which will be informally moderated by The Annals Internet Editor. We encourage all surgeons to participate in this interesting exchange and to avail themselves of the other valuable features of the CTSNet Discussion Forum and Web site. For August, the article chosen for discussion under the Pediatric Cardiac Surgery Dilemma Section of the Discussion Forum is: Does Right Ventricular Outflow Tract Damage Play a Role in the Late Genesis of Late Right Ventricular Dilatation After Tetralogy of Fallot Repair? Yves d Udekem d Acoz, MD, Agnes Pasquet, MD, Laurent Lebreux, MD, Caroline Ovaert, MD, Françoise Mascart, MD, Annie Robert, ScD, PhD, and Jean E. Rubay, PhD, MD Tom R. Karl, MD The Annals Internet Editor UCSF Children s Hospital Pediatric Cardiac Surgical Unit 505 Parnassus Ave, Room S-549 San Francisco, CA Phone: (415) Fax: (212) karlt@surgery.ucsf.edu 2003 by The Society of Thoracic Surgeons Ann Thorac Surg 2003;76: /03/$30.00 Published by Elsevier Inc