Analyses of segmental lymph node metastases and intrapulmonary metastases of small lung cancer

[Progress in Survival Prognosis of Segmentectomy for Early-stage Non-small Cell Lung Cancer]

Surgery is currently the most appropriate treatment for early-stage non-small cell lung cancer (NSCLC). Increasing unilateral or bilateral multiple primary lung cancer being found, segmentectomy has attracted wide attention for its unique advantages in the treatment for such tumors. Ground glass opacity dominant early-stage NSCLC is associated with a good prognosis and can be cured by segmentectomy, however, the treatment of solid-dominant NSCLC remains controversial owing to the invasive nature. With the in-depth study on the lymph node metastasis pathway, radiological characteristics and molecular biology of NSCLC, a large part of solid nodules with certain characteristics can also be cured by segmentectomy. This paper reviews the research status and progress about the indication of segmentectomy.
.

Lobectomy does not confer survival advantage over segmentectomy for non-small cell lung cancer with unsuspected nodal disease

OBJECTIVE

Conversion to lobectomy is typically performed when positive lymph nodes are found during intentional segmentectomy. Our objective was to evaluate survival after lobectomy and segmentectomy in patients with unsuspected nodal metastases.

METHODS

The National Cancer Database was queried for patients with clinical T1N0, pathological N1/N2 non-small cell lung cancer (NSCLC) who underwent either lobectomy or segmentectomy. Survival differences between the 2 groups were evaluated using a propensity score model. Cox regression analysis was used to evaluate predictors of overall survival, including adjuvant treatment. Statistical analysis was done using SPSS version 21.0 (IBM Corp, Armonk, NY).

RESULTS

Between 2004 and 2015, unsuspected pathological N1 disease for clinical T1N0M0 NSCLC was found in 2.5% (228/9118) and 6.7% (8915/132,604) of patients who underwent segmentectomy and lobectomy, respectively. The incidence of unsuspected pathological N2 disease for clinical T1N0M0 NSCLC was 2.4% (224/9118) after segmentectomy and 3.9% (5192/132,604) after lobectomy. Using propensity matched pairs (227 pairs for N1 and 215 for N2), segmentectomy showed equivalent 5-year survival compared with lobectomy for the N1 group (41.9% vs 44.3%; P = .35), and N2 group (41.6% vs 37.2%; P = .99). In a multivariable model, adjuvant chemotherapy was associated with better survival of patients with unsuspected N1 (hazard ratio, 0.613; 95% confidence interval, 0.536-0.700; P < .001) and N2 (hazard ratio, 0.684; 95% confidence interval, 0.583-0.802; P < .001) nodal metastases.

CONCLUSIONS

Survival is similar between lobectomy and segmentectomy for clinical T1N0 and unsuspected pathological N1/N2 nodal metastases. The use of adjuvant chemotherapy significantly improves survival in patients with lymph node metastasis (N1/N2) independent of the type of anatomic lung resection.

Meta-analysis of segmentectomy versus lobectomy for radiologically pure solid or solid-dominant stage IA non-small cell lung cancer

OBJECTIVE

Whether segmentectomy can be used to treat radiologically determined pure solid or solid-dominant lung cancer remains controversial owing to the invasive pathologic characteristics of these tumors despite their small size. This meta-analysis compared the oncologic outcomes after lobectomy and segmentectomy regarding relapse-free survival (RFS) and overall survival (OS) in patients with radiologically determined pure solid or solid-dominant clinical stage IA non-small cell lung cancer (NSCLC).

METHODS

A literature search was performed in the MEDLINE, EMBASE, and Cochrane Central databases for information from the date of database inception to March 2019. Studies were selected according to predefined eligibility criteria. The hazard ratio (HR) and associated 95% confidence interval (CI) were extracted or calculated as the outcome measure for data combining.

RESULTS

Seven eligible studies published between 2014 and 2018 enrolling 1428 patients were included in the current meta-analysis. Compared with lobectomy, segmentectomy had a significant benefit on the RFS of radiologically determined pure solid or solid-dominant clinical stage IA NSCLC patients (combined HR: 1.46; 95% CI, 1.05-2.03; P = 0.024) and there were no significant differences on the OS of these patients (HR: 1.52; 95% CI, 0.95-2.43; P = 0.08).

CONCLUSIONS

Segmentectomy leads to lower survival than lobectomy for clinical stage IA NSCLC patients with radiologically determined pure solid or solid-dominant tumors. Moreover, applying lobectomy to clinical stage IA NSCLC patients with radiologically determined pure solid or solid-dominant tumors (≤2 cm) could lead to an even bigger survival advantage. However, there are some limitations in the present study, and more evidence is needed to support the conclusion.

Lymph node metastasis outside of a tumor-bearing lobe in primary lung cancer and the status of interlobar fissures: The necessity for removing lymph nodes from an adjacent lobe

The new Tumor Node Metastasis staging system does not recognize fissure status with respect to adjacent lobe invasion (ALI) in lung cancer. Furthermore, no specific surgical strategies have been recommended for lymph node dissections around adjacent nontumor-bearing lobes (NTBLs) according to fissure status. Therefore, this study was undertaken to investigate the necessity of removing additional adjacent lobe lymph nodes in patients with nonsmall cell lung cancer (NSCLC) for lesions limited to in the vicinity of the interlobar fissure.From August 2013 to March 2015, the records of 332 patients, who underwent systematic mediastinal lymph node dissection, were reviewed in this retrospective study. The bronchial lymph nodes had been subjected to pathological examination, and the status of the fissures was also recorded. A statistical analysis was performed to identify the significant predictors of lymph node metastasis.The patients were divided into a nonadjacent lobe invasion (NALI) group (n = 295) and an ALI group (n = 37). There was a significant difference in tumors with pN2 disease between the ALI and NALI groups (37.8% vs 8.8%, P = .001). ALI tumors had significantly more frequent pleural involvement than NALI tumors (62.2% vs 43.1%, P = .035). The frequency of N2 involvement among tumors invading across the complete fissure was higher than that of the tumors invading across the incomplete fissure (44.4% vs 14.3%, P = .015). However, the frequency of N1 involvement among tumors invading across the incomplete fissure was not statistically different than that of tumors not invading across incomplete fissure (32.1% vs 24.2%, P = .357). Regarding lymph node metastasis in NTBL, 15 (12.7%) patients had lymph node metastases in NTBLs. Pleural involvement was an independent predictor of lymph node metastasis in an NTBL.A greater frequency of N2 lymph nodes existed in NSCLC with invading adjacent lobe across complete fissure, extensive lymphatic resection within the hilum, and NTBL in tumors with pleural involvement are justifiable and necessary.

Outcomes and predictive factors for pathological node-positive in radiographically pure-solid, small-sized lung adenocarcinoma

OBJECTIVES

The indication of limited resection for radiographically pure-solid, small-sized lung adenocarcinoma is controversial. This study aimed to reveal the long-term outcome of standard surgical treatment and determine the predictive factors for pathological lymph node metastasis in optimal candidates undergoing limited surgical resection for pure-solid, small-sized lung adenocarcinoma.

METHODS

The medical records of 107 consecutive patients were retrospectively reviewed at our hospital between December 2002 and December 2013. Inclusion criteria were histopathological diagnosis of lung adenocarcinoma, radiographically pure-solid tumor, ≤ 2 cm tumor size measured using thin-section computed tomography, clinical N0M0, patients who underwent lobectomy with systematic or lobe-specific lymph node dissection, and R0 resection. Overall and disease-free survival curves were calculated using the Kaplan-Meier method. Clinicopathological factors predicting pathological node-positive metastasis were identified by univariate and multivariate analysis.

RESULTS

The 5-year overall and disease-free survival rates were 91.4% and 87.3%, respectively. Multivariate analysis demonstrated maximum standardized uptake value > 5 as the independent predictor of pathological node-positive metastasis (odds ratio 3.81; 95% confidence interval 1.25-12.3; p = 0.02). In all patients, the pathological node-positive rate was 16.7%; in patients who had a maximum standardized uptake value of ≤ 5, the rate was 7.9%.

CONCLUSION

The long-term outcome of standard surgical treatment was favorable. Maximum standardized uptake value was a significant predictor of pathological node-positive metastasis; however, diagnostic accuracy was not favorable. Therefore, the selection of optimal candidates is difficult, and limited surgical resection may not be applicable in pure-solid, small-sized lung adenocarcinoma.

Novel perspective to evaluate the safety of segmentectomy: clinical significance of lobar and segmental lymph node metastasis in cT1N0M0 lung adenocarcinoma

OBJECTIVES

The regularity of intrapulmonary lobar and segmental lymph node (LSN) metastasis in cT1N0M0 stage lung adenocarcinoma remains unclear. Thus, segmentectomy with uncertain LSN metastatic status remains a potential oncological risk. We aimed to facilitate more accurate determination of N staging and filter more suitable cases for segmentectomy.

METHODS

A prospective study was performed from March 2014 to September 2016. A total of 196 patients diagnosed with cT1N0M0 stage lung adenocarcinoma were enrolled and received lobectomy together with mediastinal lymph node dissection. The intrapulmonary LSNs were dissected and classified as adjacent LSN or isolated LSN. The metastatic status of the LSNs together with the TNM staging were analysed. A comparison of the metastatic probability of isolated LSN was carried out considering the metastatic status of adjacent LSN, imaging features, smoking history, pathological subtypes, size of the lesions and serum level of tumour markers (carcinoembryonic antigen and Cyfra21-1).

RESULTS

Among the 196 cases enrolled, 152 were confirmed as pN0, 36 as pN1, 6 as pN1 + N2 and 2 as skip pN2. When the LSNs had not been dissected, the false-negative rate for N staging was 9.0% (15 of 167). Patients with adjacent LSN metastasis (P < 0.001), solid nodule (P = 0.001), non-lepidic predominant invasive adenocarcinoma (P < 0.001), nodules with maximum diameter larger than 2 cm (P < 0.001) and those with elevated serum carcinoembryonic antigen level (>5 ng/ml) (P = 0.005) had a higher isolated LSN metastasis rate. No significant difference in isolated LSN metastasis rate was found between groups with or without smoking history (P = 0.90) and with different serum Cyfra21-1 levels (P = 0.14).

CONCLUSIONS

Dissection of intrapulmonary LSNs reduces the false-negative rate of lymph node metastasis. Solid nodule, non-lepidic predominant invasive adenocarcinoma, lung adenocarcinoma larger than 2 cm in maximum diameter or with elevated serum carcinoembryonic antigen level (>5 ng/ml) might not be suitable for segmentectomy. The lymph node sampling area during segmentectomy should include adjacent LSNs of the target segment. When metastasis to the adjacent LSNs is confirmed by fast-frozen pathology, segmentectomy would not be suitable.

Lymph node dissection during sublobar resection: why, when and how?

Appropriate lymph node (LN) assessment is a hallmark of surgical quality of curative intent operations for non-small cell lung cancer (NSCLC). Even in the era of extensive pre-treatment work-up including routine PET-scanning and brain imaging, and selective invasive LN evaluation, unexpected LN metastases are found at surgery in more than 10% of patients with a cT1aN0 tumor. Systematic lymphadenectomy minimizes the risk of leaving tumor-LN behind and thus the risk of an incomplete resection, and provides the most truthful pTNM, which is decisive in directing adjuvant chemotherapy. Removal of interlobar, hilar, and mediastinal LNs is necessary during sublobar resection, as it is during lobectomy. In addition, segmental LNs should be dissected at both the resected and nonresected lobar segments, because the lymphatic flow from the resected segment can go directly to the neighboring segmental LNs to join the lymphatic network at the roots of the lobar bronchi, especially for tumors in anteriorly located segments. Finally, several anatomical studies described direct lymphatic vessels from the lower lobes into the upper lobar bronchi LN rendering also advisable clearance of the upper lobar LN in case of lower lobe NSCLC. Given that intralobar LN dissection is impossible within the remaining lobe after wedge resection, omission of segmental and intralobar LN retrieval may also explain the high incidence of loco-regional recurrence observed after wedge resection. Thus, segmentectomy should be preferred to wedge resection as the recommended type of sublobar resection.

[Study on the Correlation Factors of 13, 14 Groups Lymph Node Metastasis of Non-small Cell Lung Cancer]

背景与目的

淋巴结转移是影响肺癌肿瘤-淋巴结-转移（tumor-node-matastasis, TNM）分期的重要因素之一，在非小细胞肺癌（non-small cell lung cancer, NSCLC）患者的手术中，13组、14组淋巴结因其隐藏于肺叶的深部而忽视做病理检测，影响术后病理分期准确性。本研究旨在探讨13组、14组淋巴结在NSCLC术中的阳性检出率及其对病理分期的影响。

方法

选取内蒙古医科大学附属医院100例NSCLC手术患者为研究对象，剖取胸内2组-12组、第13、14组淋巴结行病理检测，分析肿瘤的大小、部位、病理类型等因素与胸内淋巴结转移率的关系。

结果

100例患者胸内淋巴结转移率为47.0%，10组-12组、N2淋巴结、13组、14组淋巴结阳性率有统计学差异（P < 0.05）；不同T分期13组、14组淋巴结漏检率有统计学差异（P < 0.05）；周围型与中央型NSCLC的N1期漏检率无统计学差异（P>0.05）；不同病理类型肿瘤之间N1期漏诊率无统计学差异（P>0.05）。此外，发现有12例患者存在非肿瘤所在叶、段支气管旁淋巴结转移。

结论

临床上检测NSCLC 13组、14组与非肿瘤所在叶支气管旁淋巴结的转移情况十分必要，有利于获取术后准确的TNM分期，对于指导术后治疗意义重大。

The role of segmental nodes in the pathological staging of non-small cell lung cancer

Background

Segmental nodes are not examined routinely in current clinical practice for lung cancer, the role of segmental nodes in pathological staging of non-small cell lung cancer after radical resection was investigated.

Methods

A total of 113 consecutive non-small cell lung cancer patients who underwent radical resection between June 2009 and December 2011 were retrospectively reviewed. All the operations were performed by the same group of surgeons. N2 nodes, hilar nodes, interlobar nodes and some lobar nodes were collected during surgery. The removed lung lobes were dissected routinely along lobar and segmental bronchi to collect lobar nodes and segmental nodes. The collected lymph nodes were separately labeled for histological examination.

Results

The detection rates of hilar nodes, interlobar nodes, lobar nodes and segmental nodes were 61.1%, 85.0%, 75.2% and 80.5%, respectively. The metastasis rates of hilar nodes, interlobar nodes, lobar nodes and segmental nodes were 5.3%, 10.5%, 16.8% and 14.2%, respectively. There were 68 cases of N0 disease, 16 cases of N1 disease and 29 cases of N2 disease. If an analysis of segmental lymph nodes had been omitted, six patients (37.5% of N1 disease) would have been down-staged to N0, and two cases of multiple-zone N1 disease would have been misdiagnosed as single-zone N1 disease, one patient would have been misdiagnosed as N2 disease with skip metastases.

Conclusion

Segmental nodes play an important role in the accurate staging of non-small cell lung cancer, and routinely dissecting the segmental bronchi to collect the lymph nodes is feasible and may be necessary.

Reasonable extent of lymph node dissection in intentional segmentectomy for small-sized peripheral non-small-cell lung cancer: from the clinicopathological findings of patients who underwent lobectomy with systematic lymph node dissection

INTRODUCTION

Currently, randomized clinical trials to evaluate segmentectomy compared with lobectomy for peripheral cT1aN0M0 non-small-cell lung cancer (NSCLC) are ongoing. During segmentectomy, some lobar-segmental lymph nodes (LSNs) can be difficult to resect for anatomical reasons. The purpose of this study was to clarify the reasonable extent of dissection during intentional segmentectomy for peripheral cT1aN0M0 NSCLC.

METHODS

We reviewed the records of patients who underwent lobectomies and systematic lymph node dissections for cT1aN0M0 NSCLC from 1992 to 2009. Among them, a total of 307 patients whose primary nodule was located in the outer third peripheral lung field on thin-section computed tomography (TSCT), and who could be candidates for intentional segmentectomy were enrolled in this study. We analyzed the clinical and radiological factors, which may predict nodal metastasis, and the distribution patterns of lymph node metastases. In particular, we set out to evaluate the specific LSNs, which are difficult to resect on segmentectomy (isolated LSNs [iLSNs]).

RESULTS

Of all patients, 34 (11%) had lymph node metastases (pN1: 9, pN2: 25). The median tumor sizes and tumor disappearance rates (TDRs) on TSCT were significantly larger and lower, respectively, compared with those of the remaining 273 node-negative patients. All 34 node-positive patients had a solid-dominant component on TSCT (TDR < 0.25). Of these, nine patients (n = 5, station 11, n = 4, station 13) were iLSN positive, but all of them also had metastases to station 12 or mediastinal lymph nodes. No patients had solitary metastasis in iLSNs.

CONCLUSIONS

The reasonable extent of dissection for intentional segmentectomy for small (≤ 2 cm) peripheral NSCLC includes LSNs in the segments with tumors, and the hilar and mediastinal nodes. It may not be necessary to examine iLSNs. Systematic lymph node dissection might not be necessary for tumors with ground grass opacity on TSCT (TDR ≥ 0.25).

cT1aN0M0 lung adenocarcinoma treated with left S9+10 segmentectomy followed by completion lobectomy for a solitary metastasis (isolated tumor cells) in the neighboring segmental lymph node

A 47-year-old woman with a lung adenocarcinoma of 1.3 cm located in the left S9+10 was treated by S9+10 segmentectomy with sentinel node (SN) identification using radioisotopes. During segmentectomy, frozen section of the segmental nodes at S9+10 and S6, identified as SNs, did not show metastasis; however, postoperative immunohistochemical staining with cytokeratin revealed isolated tumor cells in the segmental node at S6. None of the other dissected nodes, including the hilar, interlobar, and mediastinal nodes, showed metastasis, even with immunohistochemical staining. Completion lobectomy was conducted 6 days after segmentectomy, and the resected specimens did not show further metastasis. The final pathological diagnosis was adenocarcinoma with pT1aN0(i+)M0 stage A. The present case was indicative of the importance of dissecting the segmental lymph node located not only at the tumor-bearing segment but also at the neighboring segment, especially the one located between the primary tumor and the lobar bronchi.

Sentinel nodes in lung cancer: review of our 10-year experience

Sentinel node (SN) identification in patients with lung cancer is useful not only to minimize lymph node dissection, but also to target the best lymph nodes for intraoperative frozen section during segmentectomy. Since 2000, we have identified the SN in lung cancer patients using radioisotope (RI). This review presents our data on SN identification, describing the following: the procedure, using a radioisotope tracer; the flow of Tc-99 tin colloid after the injection; the characteristics of patients whose SNs could not be identified; ex vivo SN identification; reliability of in vivo SN identification; the algorithm for reducing mediastinal lymph node dissection; the differences in SN identification between large and small radioisotope particles; SNs at segmental lymph nodes; SN navigation segmentectomy for clinical stage IA non-small cell lung cancer; and small metastasis in the SN.

Required area of lymph node sampling during segmentectomy for clinical stage IA non-small cell lung cancer

OBJECTIVE

To investigate the required area of lymph node sampling during segmentectomy, especially for segmental nodes at the nonresected segments, we examined the distribution of sentinel nodes in patients with non-small cell lung cancer who underwent segmentectomy.

METHODS

Ninety-four patients with clinical T1 N0 M0 non-small cell lung cancer were treated by using segmentectomy and dissection of lymph nodes with sentinel node identification using (99m)Tc-phytate. Anatomic locations of the segments were classified as either anterior or posterior, and correlations of anatomic location with the distribution of sentinel nodes at the segmental nodes were then examined.

RESULTS

Of the 94 patients, segmental nodes at both the resected and nonresected segments could be dissected in 42 patients. Segmental sentinel nodes were found at the resected segments in 27 (64%) of these 42 patients, a frequency that was significantly higher than that (12/42 [29%]) seen at the nonresected segments (P = .001). Seven (47%) of the 15 patients with tumors in the anteriorly located segments had segmental sentinel nodes at the nonresected segments, a frequency that was significantly higher than that (4/24 [17%]) seen in patients with tumors in the posteriorly located segments (P = .04).

CONCLUSION

The lymphatic flow from the anteriorly located segment can frequently go directly to the segmental lymph nodes of the posteriorly located segment, probably because the lobar bronchi locate at the posterior side in the thorax. Therefore segmental lymph nodes should be dissected at both the resected and nonresected segments during segmentectomy, especially for tumors in the anteriorly located segment.

Estudo comparativo entre lobectomia e segmentectomia estendida para o tratamento do carcinoma brônquico não de pequenas células em estágios iniciais

INTRODUÇÃO: O uso de ressecção menor que lobectomia para tumores em fase inicial continua em debate. MÉTODO: No período de 1995 até 2000 foram vistos 733 casos de carcinoma brônquico não de pequenas células. Após avaliação clínica e estadiamento cirúrgico, 191 pacientes foram submetidos a tratamento cirúrgico curativo, no qual, 63 com ressecção de tumores localmente avançados e 128 com tumores em estágio inicial (69 segmentectomias e 59 lobectomias). Utilizou-se como critério para indicar o tipo de ressecção o VEF1 pós-operatório mínimo de 800 ml. Foi utilizada segmentectomia estendida, onde a linha de ressecção ultrapassa a linha intersegmentar, incluído parênquima do segmento anexo. RESULTADOS: Entre 128 pacientes, houve 3 óbitos e 10 perdas de acompanhamento. Um total de 62 segmentectomias e 53 lobectomias foram estudadas. Havia 72 adenocarcinomas e 43 carcinomas epidermóide. A sobrevida em 5 anos dos pacientes submetidos à lobectomia foi de 80% (T1N0), 72,7% (T2N0), 50% (T1N1) e 31,8% (T2N1) e à segmentectomia foi de 80% (T1N0), 66,6% (T2N0), 41,1% (T1N1) e 30% (T2N1) (p>0,05). O tamanho do tumor e a presença de linfonodo interlobar positivo foram decisivos para o prognóstico (p<0,001), mas o tipo de ressecção não influenciou na sobrevida e na recidiva local ou à distância (p>0,05). CONCLUSÃO: A segmentectomia estendida pode ser uma opção para o tratamento de tumores em fase inicial em pacientes com reserva funcional limítrofe.

Video-assisted thoracoscopic surgery (VATS) segmentectomy for small peripheral lung cancer tumors: intermediate results

BACKGROUND

We investigated the feasibility and suitability of video-assisted thoracoscopic surgery (VATS) segmentectomy for curing selected non-small cell lung cancer (NSCLC) with this less invasive technique.

METHODS

We performed VATS segmentectomy for small (< 20 mm) peripherally located tumors and pathologically confirmed lobar lymph node-negative disease by frozen-section examination during surgery. Of the 34 patients who underwent this limited resection, 22 were treated with complete hilar and mediastinal lymph node dissection (intentional group), whereas 12 patients who were deemed to be high risk in their toleration for lobectomy underwent VATS segmentectomy with incomplete hilar and mediastinal lymph node dissection (compromised group). The surgical and clinical parameters were evaluated and compared with those of segmentectomy under standard thoracotomy to evaluate the technical feasibility of VATS segmentectomy.

RESULTS

We found that VATS segmentectomy could be performed safely with a nil mortality rate and acceptably low morbidity. The mean period of observation was relatively short at 656.7 +/- 572.1 and 783.4 +/- 535.8 days in the intentional and compromised groups, respectively. At the time of writing, all intentional patients remain alive and free of recurrence. There were two cases of non-cancer-related death in the compromised group. Clinical data indicated that VATS segmentectomy caused the same number or fewer surgical insults compared with segmentectomy under standard thoracotomy.

CONCLUSIONS

The present results are intermediate only; the rate of long-term survival and the advantages of the less invasive procedure still need further investigation. Nevertheless, we believe that VATS segmentectomy with complete lymph node dissection is a reasonable treatment option for selected patients with small peripheral NSCLC.

Computerized Tomographic Nodule Heterogeneity: Present and Future Impact on Indications for Sublobar Resections

With the advent of lung cancer screening, many nodules are being detected that are subsequently proven to be lung cancer. These nodules have different radiographic appearances and different biologic characteristics regarding their invasiveness and propensity for metastasis. These solid and part-solid nodules are now having surgeons reassess issues of lung sparing for early-stage lung cancer by not only considering smaller nodules as potentially appropriate for wedge resection or segmentectomies, but are also requiring surgeons to stratify these lesions by radiographic appearance. Data that argue for considering lesser resection of selected early-stage lung cancers, as well as the need for more prospectively accumulated facts that arise from trial designs like the original randomized Lung Cancer Study Group Trial, are discussed.

Intraoperative sentinel lymph node mapping in non-small-cell lung cancer improves detection of micrometastases

PURPOSE

Lymph node metastases are the most significant prognostic factor in localized non-small-cell lung cancer (NSCLC). Nodal micrometastases may not be detected with current standard histologic methods. We performed intraoperative technetium-99m ((99m)Tc) sentinel lymph node (SN) mapping in patients with resectable NSCLC. This study aimed to identify the first station of nodal drainage of operable lung cancers. Serial section histology and immunohistochemistry were used to validate the SN and to identify the presence of micrometastatic disease.

PATIENTS AND METHODS

One hundred patients with potentially resectable suspected NSCLC were enrolled. At thoracotomy, the primary tumor was injected with 0.25 to 2 mCi (99m)Tc. Intraoperative scintigraphic readings of both the primary tumor and lymph nodes were obtained with a hand-held gamma counter. Anatomic resection with a mediastinal node dissection was then performed.

RESULTS

Nine of the 100 patients did not have NSCLC (seven benign lesions and two metastatic tumors) and were excluded. Seventy-eight (86%) of 91 patients had a SN identified and a complete resection. Sixty-nine (88.5%) out of the 78 SNs were classified as true-positive with no metastases found in other intrathoracic lymph nodes without concurrent SN involvement. In nine patients, the SN was the only positive node. In seven of these nine patients, the SN was found to harbor only micrometastatic disease.

CONCLUSION

Intraoperative SN mapping with (99m)Tc is an accurate way to identify the first site of lymphatic tumor drainage in NSCLC. This method may also improve the precision of pathologic staging.

Interlobar lymph node metastases according to primary tumor location in lung cancer

Interlobar lymph node metastases were analyzed in consecutive 284 lung cancer patients with lobar-hilar and mediastinal lymph node dissection. Interlobar lymph node metastases were observed in 46 (16.2%) patients with no difference between right and left cases. On the right side, there was a significant difference in the frequency of inferior interlobar lymph node metastases between upper lobe and middle/lower lobe tumors (P=0.0004), but no difference in the frequencies of superior ones according to primary site. On the left, there was a significant difference in the frequency of interlobar lymph node metastases between upper lobe and lower lobe tumors (P=0.0021). In per-segment analyses, the frequency of inferior interlobar lymph node metastases in segments 1-3 and 6 was significantly lower than in the other total segments (P<0.0001) on the right, and that of interlobar lymph node metastases in the upper division segments (S1-3) was significantly lower than in the other total segments (P=0.0008) on the left. Even limited to one lobe, the patterns of interlobar lymph node metastases were different among the segments in the right lower lobe and the left upper lobe.

Analysis of lobar lymph node metastases around the bronchi of primary and nonprimary lobes in lung cancer: risk of remnant tumor at the root of the nonprimary lobes

STUDY OBJECTIVE

The details of lobar lymph node metastases at the root of nonprimary lobes (NPLs) in patients with lung cancer are still unclear.

DESIGN

A prospective study from February 1989 to November 2000. Lobar lymph nodes in primary lobes (PLs) and NPLs were evaluated regardless of the location of the primary tumor.

PATIENTS

Two hundred forty-eight patients who underwent surgery and had no involvement of the adjacent lobe by primary tumor were enrolled in this study.

MEASUREMENTS AND RESULTS

Lobar lymph node metastases were observed in 53 patients (21.4%), with frequencies not different among the primary sites. Thirty-seven patients had lobar lymph node metastases limited to the PL, and 16 patients had metastases in the NPLs. The frequencies of lobar lymph node metastases in NPLs were not affected by histologic type or T classification, but they were dependent on laterality and proximal lymph node metastases. On the right side, lobar lymph node metastases in NPLs were observed in 9.0% of all 155 patients, in 45.2% of 31 patients with lobar lymph node metastases, and in 34.3% of 35 patients with mediastinal lymph node metastases. They were significantly higher in the patients with interlobar/hilar lymph node metastases (12 of 28 patients) or with mediastinal metastases (12 of 35 patients) than in those without metastases on the right (p < 0.0001, respectively).

CONCLUSIONS

Lobar lymph node metastases in NPLs were frequent on the right side and became more frequent according to the prevalence of the proximal lymph node metastases, rather than the clinicopathologic properties of the primary tumor itself.