Evaluation of p53 alterations in occult lymph node metastases

Systematic review and meta-analysis of the prognostic impact of lymph node micrometastasis and isolated tumour cells in patients with stage I-IIIA non-small cell lung cancer

Lymph node micrometastases could be one of the reasons for the high recurrence rate after complete surgical resection in stage I-IIIA non-small cell lung cancer (NSCLC). The standard evaluation of a single haematoxylin and eosin (H&E) slide of a paraffin-embedded section of a lymph node is insufficient for the detection of micrometastases, and there is a need for additional histopathological evaluation. The association of lymph node micrometastases with survival remains as yet unresolved. The aim of this systematic review and meta-analysis is to investigate if lymph node micrometastases and isolated tumour cells in patients with stage I-IIIA NSCLC, detected with multiple sectioning and/or immunohistochemistry (IHC) and/or reverse transcriptase polymerase chain reaction (RT-PCR), are associated with overall survival (OS) and disease-free survival (DFS) after surgical resection. We performed a meta-analysis of time-to-event outcomes based on 15 articles using ancillary techniques to detect micrometastases. We extracted the OS and DFS every 3-6 months after surgery, for patients with and without occult lymph node micrometastasis, from the survival curves published in each article. These data were used to reconstruct OS and DFS for 'micrometastasis' and 'no micrometastasis' groups. Based on all included studies that used IHC, serial sectioning, or RT-PCR, we found a 5-year OS of 55% (micrometastasis) vs. 75% (no micrometastasis), and a 5-year DFS of 53% (micrometastasis) vs. 75% (no micrometastasis). Patients with stage I-IIIA NSCLC with lymph node micrometastases detected by ancillary histopathological and molecular techniques have a significantly poorer OS and DFS compared to patients without lymph node micrometastases.

Detection of occult tumor cells in regional lymph nodes is associated with poor survival in pN0 non-small cell lung cancer: a meta-analysis

BACKGROUND

patients of pN0 non-small cell lung cancer (NSCLC) with occult tumor cells (OTCs) in regional lymph nodes (LNs) are reported to have controversial prognostic outcomes.

METHOD

We pooled pN0 NSCLC patients with OTCs in LNs and compared with those without OTCs. Patient characteristics, hazard ratios (HRs) and 95% confidence intervals (CIs) for overall survival (OS) and/or disease-free survival (DFS) were analyzed. HR greater than 1 conferred an increased hazard for patients with OTCs.

RESULTS

Eighteen articles were finally enrolled in the meta-analysis and 15 studies provided sufficient data for extracting HRs for OS, resulting to 5 articles available for DFS analysis. The combined HRs of OS was 2.22 (95% CI, 1.87 to 2.64) and 2.4 (95% CI, 1.71 to 3.36) for analysis of DFS. The similar trend was obtained in the subgroup analyses regarding detection methods and study type. Interestingly, even in the analysis of mean numbers of LNs dissection (MLND) intraoperatively, both subgroups (LNs/Pts. <12 and ≥12) illustrated significant HRs of OS (HR: 3.13, 95% CI, 2.17 to 4.52 in LNs/Pts. <12 subgroup and HR: 2.09, 95% CI, 1.63 to 2.68 in LNs/Pts. ≥12). The combined HR of OS in this section was 2.37 (95% CI, 1.63 to 2.68). No publication bias was detected in all the meta-analysis sections. The prognosis of patients with OTCs is inferior to those without OTCs in the terms of OS and DFS regardless of detection methods, study types and MLND.

CONCLUSIONS

The prognosis of patients with OTCs is inferior to those without OTCs in the terms of OS and DFS regardless of detection methods, study types and MLND.

Clinical significance of micrometastasis in lung and esophageal cancer: a new paradigm in thoracic oncology

In the past decade, detection of micrometastatic disease in different clinical samples including pleural lavage, lymph node, bone marrow, and blood has become a rapidly growing area of interest in research of non-small cell lung cancer and esophageal cancer. The results of these studies support the concept that, just as in many other solid malignancies, systemic spread may happen at an early stage in non-small cell lung cancer and esophageal cancer. Such systemic spread is often occult (micrometastases) at the time of primary diagnosis, which may have adverse effects on survival. Improved staging can be expected with information on micrometastases, and a subgroup of patients who will benefit most from adjuvant therapy might be identified. Although reliable and standard methods need to be developed before detection of micrometastasis is incorporated in the routine clinical practice, we suggest that it be considered an important correlate in clinical trials in non-small cell lung cancer and esophageal cancer.

Molecular assessment of lymph nodes in patients with resected stage I non-small cell lung cancer: preliminary results of a prospective study

OBJECTIVES

Routine histologic examination of resected lymph nodes in patients with stage I non-small cell lung cancer may underestimate the incidence of advanced disease. The presence of occult lymph node metastases may predict a higher risk of recurrence after intended curative resection. The purpose of this study was to determine the prognostic significance of TP53 and K-ras mutations in histologically determined negative lymph nodes from patients with stage I non-small cell lung cancer who underwent intended curative surgical resection.

METHODS

Between July 1995 and March 1998, clinical data and tissue samples of primary tumors and lymph nodes were collected in a prospective fashion from 102 patients undergoing resection for non-small cell lung cancer (stage I, n = 55; stage II, n = 32; stage IIIA, n = 15). TP53 and K-ras mutations were detected by direct sequencing. If molecular alterations were found in the primary tumor, the corresponding lymph nodes were examined for these same TP53 (by oligonucleotide hybridization) and K-ras (by allele-specific ligation) mutations.

RESULTS

TP53 mutations were found in 47 of 94 primary tumors (50%), and K-ras mutations were present in 26 of 55 adenocarcinomas (47%). A total of 134 lymph nodes from 32 patients with stage I disease were analyzed. In 9 cases (28%) the same TP53 or K-ras mutations were found in tumor and lymph node specimens, suggesting occult metastasis. On the basis of nodal location, 7 patients had their disease upstaged by a single stage and 2 patients by two stages. All 28 patients with stage II or III disease had pathologically determined positive nodes that were confirmed as positive by molecular analysis. Standard histopathologic assessment of regional lymph nodes failed to detect metastases at levels below 0.9% tumor-specific mutant TP53 clones per node. No statistically significant difference in disease-specific or overall survival was observed between patients with stage I disease with and without molecular lymph node metastases.

CONCLUSIONS

Occult lymph node metastases are present in a significant percentage of patients with stage I non-small cell lung cancer. These data suggest that molecular analysis allows a more accurate assessment of staging. However, larger studies are needed to determine the clinical role of molecular staging.