Diagnosis of visceral pleural invasion in resected lung cancer using a jet stream of saline solution

[Place and role of the pleura in non-small cell lung cancer dissemination]

INTRODUCTION

The pleural involvement (PLI) in non-small cell lung cancer (NSCLC) has a poor prognosis, even though it might be very heterogeneous.

PATIENTS AND METHODS

A multicentric retrospective descriptive study was performed over 2329 patients who were operated for NSCLC between 1979 and 2010. The patients with PLI were classified in P(Parietal)PLI and V(visceral)PLI and then each subdivided : VPLI to peripheric (VPLI-P) and fissural (VPLI-F) and PPLI to mediastinal (PPLI-M) and costal (PPLI-C). Characteristics and survival were compared between the subgroups as well as with patients without PLI (WPLI, n=1439).

RESULTS

The sex-ratio was 2.8 (males: n=1713). The PLI patients were significantly younger, with a less sex-ratio, less R0 resections (96% versus 98.7%, P=0.000076), and less N0 (60% vs 70%, P<10(-6)) as their 5-year survival (45.7% vs 55.5%, P<10(-6)). The PLI was related to the size of NSCLC (P<10(-6)) and N2 involvement (P=0.0020). It was less frequent after neoadjuvant treatment (36.2% vs 39.1% P=0.03). In the VPLI-F or PPLI-M, pneumonectomies were more frequent (P<10(-6)). In VPLI-P (n=196/561), there were more pN1 and pN2 (P=0.0065) with a 5-year survival of 42.9% vs 54.4%, P=0.013. In multivariate analysis, the PLI was not an independent prognostic factor contrary to age, sex, type of resection, pT and pN.

CONCLUSION

The pleura play a major role in NSCLC dissemination. Its involvement affects pN, the type of surgical resection and justifies the use of neoadjuvant treatment.

Commonly encountered difficulties in pathologic staging of lung cancer

CONTEXT

Lung cancer is the leading cause of cancer mortality worldwide. Despite technological, therapeutic, and scientific advances, most patients present with incurable disease and a poor chance of long-term survival. For those with potentially curable disease, lung cancer staging greatly influences therapeutic decisions. Therefore, surgical pathologists determine many facets of lung cancer patient care.

OBJECTIVE

To present the current lung cancer staging system and examine the importance of mediastinal lymph node sampling, and also to discuss particularly confusing and/or challenging areas in lung cancer staging, including assessment of visceral pleura invasion, bronchial and carinal involvement, and the staging of synchronous carcinomas.

DATA SOURCES

Published current and prior staging manuals from the American Joint Committee on Cancer and the International Union Against Cancer as well as selected articles pertaining to lung cancer staging and diagnosis accessible through PubMed (National Library of Medicine) form the basis of this review.

CONCLUSIONS

Proper lung cancer staging requires more than a superficial appreciation of the staging system. Clinically relevant specimen gross examination and histologic review depend on a thorough understanding of the staging guidelines. Common sense is also required when one is confronted with a tumor specimen that defies easy assignment to the TNM staging system.

Visceral pleural invasion in lung cancer: recognizing histologic parameters that impact staging and prognosis

Visceral pleural involvement (VPI) is a critical component in the staging of non-small cell lung carcinoma (NSCLC). Tumors < or =3 cm that involve the visceral pleura are classified as T2 lesions, underscoring the prognostic significance of this histologic parameter. Accurate staging of small NSCLCs depends on appropriately assessing the presence or absence of VPI. Elastic stains can be instrumental in detecting disruptions of the visceral pleural elastic layer by tumor, a finding that has prognostic and staging implications similar to tumor that is present on the visceral pleural surface.

Prognostic value of visceral pleural invasion in resected non-small cell lung cancer diagnosed by using a jet stream of saline solution

OBJECTIVE

Visceral pleural invasion caused by non-small cell lung cancer is a factor in the poor prognosis of patients with that disease. We investigated the relationship between the diagnosis of visceral pleural invasion by using a jet stream of saline solution, which was previously reported as a new cytologic method to more accurately detect the presence of visceral pleural invasion, and prognosis.

METHODS

From January 1992 through December 1998, 143 consecutive patients with peripheral non-small cell lung cancer that appeared to reach the visceral pleura underwent a surgical resection at the Department of Thoracic Oncology, National Kyushu Cancer Center. The surface of the visceral pleura in patients undergoing lung cancer resection was irrigated with a jet stream of saline solution. The diagnosis of visceral pleural invasion was determined by means of either a pathologic examination or by means of a jet stream of saline solution. In addition, a cytologic examination of the pleural lavage fluid obtained immediately after a thoracotomy was evaluated.

RESULTS

Forty-nine (34%) resected tumors were identified as having visceral pleural invasion. The diagnosis of visceral pleural invasion in 31, 6, and 12 patients was determined by using a jet stream of saline solution alone, pathologic examination alone, or both, respectively. The visceral pleural invasion and positive findings of intrapleural lavage cytology were linked. Although there was no significant difference between the incidence of distant metastases in the patients with visceral pleural invasion and those without visceral pleural invasion, the incidence of local recurrence, especially regarding carcinomatous pleuritis (malignant pleural effusion, pleural dissemination, or both), in the patients with visceral pleural invasion was significantly higher than in those without visceral pleural invasion. The recurrence-free survival of patients with visceral pleural invasion was significantly shorter than that of patients without visceral pleural invasion (P =.004), even patients with stage I disease (P =.02). There was also a significant difference between the patients with or without visceral pleural invasion in the overall survival (P =.02). Visceral pleural invasion was independently associated with a poor recurrence-free survival on the basis of multivariate analyses (P =.03), as were sex (P =.03), age (P = 002), and the stage of the disease (P <.0001).

CONCLUSIONS

This study confirmed that the jet stream of saline solution method in addition to ordinary pathologic examination was useful for detecting visceral pleural invasion, which is considered to be one of the causes of local recurrence, especially in carcinomatous pleuritis.

Visceral pleura invasion and pleural lavage tumor cytology by lung cancer: a prospective appraisal

BACKGROUND

Despite an early-stage diagnosis, lung cancer presenting with visceral pleura invasion (VPI) or malignant pleural lavage cytology (PLC) has a poor prognosis. The purpose of this study was to correlate VPI to malignant PLC.

METHODS

One hundred forty-three consecutive patients scheduled for surgical lung resection having undergone preresectional pleural lavage cytology were reviewed. There were 121 malignant and 22 nonmalignant lesions. All cases were studied by pathology, histology, previous transthoracic puncture, VPI, and presence of pleural lymphatic involvement.

RESULTS

PLC was positive (n = 13) or suspected (n = 5) for malignant cells in, respectively, 10.7% and 4.1% of patients with lung cancer. There was no positive PLC in cases of nonmalignant disease. PLC was positive only in pT2 tumors and almost always when the tumor was exposed on the pleural surface, thus possibly exfoliating within the pleural space (12/17 patients, 70.6%; p < 0.01). Positive PLC was obtained whatever the histology but did not appear related to previous transthoracic puncture or involvement of pleural lymphatics by tumor cells.

CONCLUSIONS

VPI and positive PLC are linked, and the appearance of tumor cells within the pleural cavity can be explained by tumor desquamation. The role that visceral pleura involvement and parietal pleura reabsorption play in lung cancer is of paramount importance and deserves further research. A better understanding of their relationship could have major implications in the therapeutic management of non-small cell lung cancer.

Cytologically malignant margins of wedge resected stage I non-small cell lung cancer

BACKGROUND

We have developed a novel test for the surgical margin of pulmonary malignant tumor using a cytologic technique (the run-across method in which a glass slide is run across the staple site), and we have assessed whether this method is useful in predicting margin relapse and prognosis.

METHODS

From April 1996 to March 1999, 15 lesions of stage I non-small cell lung cancer (NSCLC) (maximum diameter ranged from 10 to 35 mm with a median of 20 mm) from 15 patients with cardiopulmonary impairment were excised without additional proximal resections. The surgical margin was examined using the run-across method. There were 8 male 7 female patients whose ages ranged from 51 to 80 years. One patient underwent video-assisted thoracic surgery and 14 underwent thoracotomy. The preoperative diagnoses of the patients were 13 adenocarcinomas, 2 squamous cell carcinomas, and 1 undiagnosed lesion (1 adenocarcinoma). The follow-up period ranged from 37 to 63 months.

RESULTS

The rate of positive cytology was 47% in comparison with the rate of positive histology of 20%. There were 4 patients with margin relapse (3 of them contained negative histology margins) at a rate of 57% among the positive cytology patients in comparison with 0% among the negative cytology patients (p = 0.03). In a comparison of survival between the negative cytology group and the positive cytology group, there were no statistically significant differences.

CONCLUSIONS

The run-across method is also useful in confirming complete resection. A positive cytology margin could lead to margin relapse even if a non-small cell lung cancer is resected with a negative histology margin.

Diagnosis of visceral pleural invasion by lung cancer using intraoperative touch cytology

BACKGROUND

Invasion to the visceral pleura is an important component of lung cancer staging and an independent prognostic factor. However, the accuracy of pathologic examination depends on how the sections are made, and the pathologist may miss the most invaded part of the pleura. Therefore, we have designed "touch" cytology in an effort to more accurately diagnose the pleural invasion by lung cancer.

METHODS

Immediately after thoracotomy, the surface of the visceral pleura just above the tumor was gently touched by a glass slide without scrubbing in 100 patients who simultaneously underwent pleural lavage cytology or cytology of the subclinical pleural effusion.

RESULTS

Seventeen percent of the tumors were diagnosed as invading the visceral pleura by touch cytology. Lavage cytology was found to be positive in 7%. In reference to the pathologic examination of the tumor specimen, touch cytology was found to be positive in all of p3, 5 out of 6 of p2, 5 out of 30 of p1, and 5 out of 62 of p0 cases. Touch cytology correctly diagnosed all the positive cases detected by lavage or effusion cytology.

CONCLUSIONS

This study suggests that our method is useful in detecting the visceral pleural invasion and raises a possibility that pathologic p0 and p1 lung cancers include a subset of patients with tumor cells exposed on the pleural surface.

Visceral pleura invasion by non-small cell lung cancer: an underrated bad prognostic factor

BACKGROUND

Visceral pleura invasion (VPI) by non-small cell lung cancer is a factor of poor prognosis. A tumor of any size that invades the visceral pleura is classified as T2. Few studies have been conducted concerning the prognostic significance of VPI relative to other staging factors.

METHODS

Between April 1984 and December 1996, 1,281 patients with T1 (n = 430) and T2 (n = 851) non-small cell lung cancer underwent curative surgical resection. Adjuvant radiation therapy was performed in 455 patients. There were 176 women and 1,105 men aged 30 to 86 years (mean, 60.9 years). Five hundred nineteen pneumonectomies, 742 lobectomies, and 20 segmentectomies were performed. In all patients, a complete mediastinal lymph node dissection was performed. International staging was stage IA and B (n = 697); stage II A and B (n = 247), and stage III A (n = 337). The patients were divided into two groups according to the existence of VPI (group I without, group II with). Both groups were compared with regard to the size of the tumors, histology, associated lymph node involvement, survival rates, and cause of death. Univariate and multivariate analyses were conducted.

RESULTS

VPI (group II) was identified in 19.1% of the resected specimens: group I, n = 1036; group II, n = 245. The VPI was present in only 10% of non-small cell lung cancer 3 cm or less in size, reaching 33% of patients with non-small cell lung cancer larger than 5 cm (p = 0.0001). Squamous non-small cell lung cancer were significantly less accompanied by VPI (13.5%) than the other histologic categories. The VPI was associated with a higher frequency of N2 involvement (group I = 24.6%, group II = 33.4%, p = 0.01) and N2 involvement was more extensive (two or more N2 involved stations: group I = 8.2%, group II = 15.6%, p = 0.003). Actuarial survival rates were 51.8% at 5 years and 33.8% at 10 years in group I (median, 66 months), and 34.6% at 5 years and 27.9% at 10 years in group II (median, 30 months) (p = 0.000002). Long-term survival rates significantly decreased for larger tumors. Even in patients with N2 stage tumors, the difference of survival curves between the two groups was statistically significant. Cancer-related deaths were more frequent in group II and were mainly caused by distant metastases. By multivariate analysis, visceral pleura invasion proved to be a significant independent factor of poor prognosis.

CONCLUSIONS

The VPI is a factor of poor prognosis. Its frequent association with extensive N2 involvement supports the hypothesis that exfoliated tumor cells are drained through the pleural lymphatics by the mediastinal lymphatic pathways and then into the bloodstream. The VPI is an important prognostic factor and, as such should stimulate more studies to better select the patients who could benefit from adjuvant therapy.

Fine-needle aspiration cytologic technique for lung cancer has a high potential of malignant cell spread through the tract

BACKGROUND

Fine-needle aspiration cytologic technique (FNAC), a method to detect malignancy for undetermined pulmonary nodules, may have a high potential to spread malignant cells from the tumor to the pleural cavity.

OBJECTIVE

The authors assessed malignant cell spread through the needle tract following FNAC for peripheral lung carcinoma.

MATERIALS AND METHODS

Lung lobes resected from 20 patients during the treatment of lung carcinoma were examined. The visceral pleura over the lung carcinoma was irrigated by heparinized saline solution to clean the surface, and then irrigated before FNAC and irrigated following FNAC to collect cells on the visceral pleura. FNAC was performed once for each tumor. Papanicolau's method was employed for cytologic examination.

RESULTS

There were 15 specimens of adenocarcinoma, 4 specimens of squamous cell carcinoma, and 1 specimen of atypical carcinoid. The maximum diameter of the specimens ranged from 10 to 60 mm (median, 25 mm). Pleural indentation was observed in 15 samples. All results of FNAC were positive and matched the histologic diagnosis. Pre-FNAC specimens revealed a positive malignancy rate of 10% (2 of 20), but post-FNAC specimens had a rate of 60% (12 of 20; p = 0.002) CONCLUSION: FNAC has the potential to spread malignant cells to the pleural space. Further study is needed to determine the clinical significance of the spread of malignant cells in the pleural space.

Lymphatic drainage of carbon particles injected into the pleural cavity of the monkey, as studied by video-assisted thoracoscopy and electron microscopy

OBJECTIVES

The aim of this study was to clarify the dynamics of lymphatic drainage of the pleural cavity to understand the mechanism of malignant pleural effusion.

METHODS

We injected carbon particles into the pleural cavity of monkeys subjected to general anesthesia. We then observed the parietal pleura with a video-assisted thoracoscope and scanning and transmission electron microscopes to examine the regions of the parietal pleura where the carbon particles had been absorbed.

RESULTS

The video-assisted thoracoscope showed that the carbon particles had gone directly to the costal, mediastinal, and diaphragmatic pleura by 10 to 15 minutes after injection. From the scanning and transmission electron microscopes, we found that the parietal pleura in the costal and mediastinal regions consisted of 3 elements: a layer of small mesothelial cells, the macula cribriformis, and lymphatic lacunae. Stomata (3-5 microm in diameter) were found between the small mesothelial cells. The macula cribriformis was composed of densely packed collagen fibrils and had many foramina (3-10 microm in diameter). Intrapleurally injected carbon particles were carried into the lymphatic lacunae via the stomata and vesicles of the mesothelial cells and the foramina of the macula cribriformis. The lymphatic lacunae filled with carbon particles were richly distributed in both the anterior costal pleura and the mediastinal pleura.

CONCLUSION

We suggest that the mesothelial stomata and the macula cribriformis are structures essential to the absorption of macromolecules and cellular elements from the pleural cavity into the lymphatic system.