Céline Mascaux

The role of RAS oncogene in survival of patients with lung cancer: a systematic review of the literature with meta-analysis

The proto-oncogene RAS, coding for a 21 kDa protein (p21), is mutated in 20% of lung cancer. However, the literature remains controversial on its prognostic significance for survival in lung cancer. We performed a systematic review of the literature with meta-analysis to assess its possible prognostic value on survival. Published studies on lung cancer assessing prognostic value of RAS mutation or p21 overexpression on survival were identified by an electronic search. After a methodological assessment, we estimated individual hazard ratios (HR) estimating RAS protein alteration or RAS mutation effect on survival and combined them using meta-analytic methods. In total, 53 studies were found eligible, with 10 concerning the same cohorts of patients. Among the 43 remaining studies, the revelation method was immunohistochemistry (IHC) in nine and polymerase chain reaction (PCR) in 34. Results in terms of survival were significantly pejorative, significantly favourable, not significant and not conclusive in 9, 1, 31, 2, respectively. In total, 29 studies were evaluable for meta-analysis but we aggregated only the 28 dealing with non-small-cell lung cancer (NSCLC) and not the only one dealing with small-cell-lung cancer (SCLC). The quality scores were not statistically significantly different between studies with or without significant results in terms of survival, allowing us to perform a quantitative aggregation. The combined HR was 1.35 (95% CI: 1.16–1.56), showing a worse survival for NSCLC with KRAS2 mutations or p21 overexpression and, particularly, in adenocarcinomas (ADC) (HR 1.59; 95% CI 1.26–2.02) and in studies using PCR (HR 1.40; 95% CI 1.18–1.65) but not in studies using IHC (HR 1.08; 95% CI 0.86–1.34). RAS appears to be a pejorative prognostic factor in terms of survival in NSCLC globally, in ADC and when it is studied by PCR.

Role of Bcl-2 as a prognostic factor for survival in lung cancer: a systematic review of the literature with meta-analysis

The role of the anti-apoptotic protein Bcl-2 in lung cancer remains controversial. In order to clarify its impact on survival in small and non-small cell lung cancer (NSCLC), we performed a systematic review of the literature. Trials were selected for further analysis if they provided an independent assessment of Bcl-2 in lung cancer and reported analysis of survival data according to Bcl-2 status. To make it possible to aggregate survival results of the published studies, their methodology was assessed using a quality scale designed by the European Lung Cancer Working Party (including study design, laboratory methods and analysis). Of 28 studies, 11 identified Bcl-2 expression as a favourable prognostic factor and three linked it with poor prognosis; 14 trials were not significant. No differences in scoring measurement were detected between the studies, except that significantly higher scores were found in the trials with the largest sample sizes. Assessments of methodology and of laboratory technique were made independently of the conclusion of the trials. A total of 25 trials, comprising 3370 patients, provided sufficient information for the meta-analysis. The studies were categorised according to histology, disease stage and laboratory technique. The combined hazard ratio (HR) suggested that a positive Bcl-2 status has a favourable impact on survival: 0.70 (95% confidence interval 0.57–0.86) in seven studies on stages I–II NSCLC; 0.50 (0.39–0.65) in eight studies on surgically resected NSCLC; 0.91 (0.76–1.10) in six studies on any stage NSCLC; 0.57 (0.41–0.78) in five studies on squamous cell cancer; 0.75 (0.61–0.93) and 0.71 (0.61–0.83) respectively for five studies detecting Bcl-2 by immunohistochemistry with Ab clone 100 and for 13 studies assessing Bcl-2 with Ab clone 124; 0.92 (0.73–1.16) for four studies on small cell lung cancer; 1.26 (0.58–2.72) for three studies on neuroendocrine tumours. In NSCLC, Bcl-2 expression was associated with a better prognosis. The data on Bcl-2 expression in small cell lung cancer were insufficient to assess its prognostic value.

The role of EGF-R expression on patient survival in lung cancer: a systematic review with meta-analysis

The prognostic value of epidermal growth factor receptor (EGF-R) for survival of patients with lung cancer remains controversial. The authors performed a systematic review of the literature in order to clarify its impact. Published studies were identified using an electronic search in order to aggregate the available survival results, after a methodological assessment using a scale specifically designed by the European Lung Cancer Working Party (ELCWP). To be eligible, a study had to have dealt with EGF-R assessment in lung cancer patients on the primary site and to have analysed survival according to EGF-R expression. Among the 16 eligible studies, 14 assessed any nonsmall-cell lung cancer (NSCLC) subtype, one adenocarcinoma only and one squamous-cell carcinoma only. The overall median quality score was 56.3%, with no significant difference either between studies assessable or not assessable for meta-analysis or between studies with significant and nonsignificant results. One individual trial reported a survival benefit for patients with EGF-R expression, three a survival disadvantage and 12 no statistically significant difference. Eleven studies (2,185 patients) provided sufficient data to allow a meta-analysis of the survival results. EGF-R expression positivity was determined according to the cut-off as determined by the authors. The meta-analysis showed that EGF-R expression was not a statistically significant prognostic factor for survival in NSCLC. In the subgroup of studies using immunohistochemistry, statistical tests reached a significant level against EGF-R. Epidermal growth factor receptor might be a poor prognostic factor for survival in nonsmall-cell lung cancer. The amplitude of the impact is small, however, and may be subject to publication bias.

The role of microvessel density on the survival of patients with lung cancer: a systematic review of the literature with meta-analysis

In order to determine whether angiogenesis is a prognostic marker in lung cancer, we performed a systematic review of the literature to assess the prognostic value on survival of microvessel count in patients with lung cancer. Published studies were identified by an electronic search in order to aggregate survival results, after a methodological assessment using a quality scale designed by the European Lung Cancer Working Party. To be eligible, a study had to deal with microvessel count assessment in lung cancer patients on the primary site and to provide survival analysis according to microvessel count expression. Microvessel count has been assessed on surgical samples by immunohistochemistry using factor VIII in 14 studies, CD34 in 10 and CD31 in eight. Respectively 1866, 1440 and 1093 non-small cell lung cancer patients were considered. The overall median quality scores were respectively 52, 59 and 59% for studies assessing microvessel count via factor VIII, CD34 and CD31, without significant difference between studies evaluable or not for meta-analysis nor between studies with significant or non significant results. Seven ‘factor VIII’ studies, nine ‘CD34’ and seven ‘CD31’ provided sufficient data allowing a meta-analysis on survival and were evaluable for results aggregation. This showed that a high microvessel count in the primitive lung tumour was a statistically significant poor prognostic factor for survival in non small cell lung cancer whatever it was assessed by factor VIII (HR: 1.81; 95% CI: 1.16–2.84), CD34 (HR: 1.99; 95% CI: 1.53–2.58) or CD31 (HR: 1.80; 95% CI: 1.10–2.96). Variations in survival among the individual studies can be explained in addition to patients selection criteria by the heterogeneous methodologies used to stain and count microvessels: different antibody clones, identification of ‘hotspots’, Weidner or Chalkey counting method, cut-off selection. Microvessel count, reflecting the angiogenesis, appears to be a poor prognostic factor for survival in surgically treated non small cell lung cancer but standardisation of angiogenesis assessment by the microvessel count is necessary.

Prophylactic cranial irradiation in small cell lung cancer: a systematic review of the literature with meta-analysis

PurposeA systematic review of the literature was carried out to determine the role of prophylactic cranial irradiation (PCI) in small cell lung cancer (SCLC) .MethodsTo be eligible, full published trials needed to deal with SCLC and to have randomly assigned patients to receive PCI or not. Trials quality was assessed by two scores (Chalmers and ELCWP).ResultsTwelve randomised trials (1547 patients) were found to be eligible. Five evaluated the role of PCI in SCLC patients who had complete response (CR) after chemotherapy. Brain CT scan was done in the work-up in five studies and brain scintigraphy in six. Chalmers and ELCWP scores are well correlated (p < 0.001), with respective median scores of 32.6 and 38.8 %. This meta-analysis based on the available published data reveals a decrease of brain metastases incidence (hazard ratio (HR): 0.48; 95 % confidence interval (CI): 0.39 - 0.60) for all the studies and an improvement of survival (HR: 0.82; 95 % CI: 0.71 - 0.96) in patients in CR in favour of the PCI arm. Unfortunately, long-term neurotoxicity was not adequately described .ConclusionsPCI decreases brain metastases incidence and improves survival in CR SCLC patients but these effects were obtained in patients who had no systematic neuropsychological and brain imagery assessments. The long-term toxicity has not been prospectively evaluated. If PCI can be recommended in patients with SCLC and CR documented by a work-up including brain CT scan, data are lacking to generalise its use to any CR situations.

A systematic review of the role of etoposide and cisplatin in the chemotherapy of small cell lung cancer with methodology assessment and meta-analysis

PURPOSE Cisplatin (CDDP) and etoposide (VP16) are considered major standard cytotoxic drugs for small cell lung cancer (SCLC). The present systematic review had as its objective the evaluation of their role, as components of chemotherapy regimens, on survival. METHODS Published randomised clinical trials (from 1980 to 1998) were selected comparing, in SCLC patients, chemotherapy regimens, given as first-line therapy. One arm (the experimental arm) had to include CDDP and/or VP16, while another had to omit the same drug(s). Trials quality was assessed by two published scores (Chalmers and European Lung Cancer Working Party (ELCWP)). For each individual trial, the hazard ratio (HR) of the survival distributions was estimated on the basis of reported statistics or, if not available, by extracting, from the survival graphical representations, the data required to construct the difference between expected and observed numbers of events as calculated in the log-rank statistic. A combined hazard ratio was obtained by the Peto method (a value < 1 meaning a benefit for CDDP and/or VP16). RESULTS Thirty-six trials eligible for our systematic review were identified, classified into four groups (I-IV): group I, 1 trial testing a CDDP-based regimen (without VP16) against another arm not including either CDDP or VP16; group II, 17 trials testing a VP16-based regimen (without CDDP) against a regimen without VP16 and CDDP; group III, nine trials comparing a regimen including CDDP and VP16 with a regimen using neither drug; and, finally, group IV, nine trials comparing a regimen based on both drugs with a regimen based on VP16 only. Overall, Chalmers and ELCWP scores correlated well (r(S) = 0.76, P < 0. 001) and had respective median scores of 50.3 and 63.7%. The number of eligible patients did not have a significant impact on the scores as well as the trials group, the trial positivity (a positive trial defined as showing itself a statistically significant survival benefit for the experimental regimen), overall or in categories, and the year of publication. Combined hazard ratios with 95% confidence intervals were: 0.70 (0.41-1.21) for group I, 0.72 (0.67-0.78) for II, 0.57 (0.51-0.64) for III, and 0.74 (0.66-0.83) for IV, showing a survival benefit in favour of regimens including etoposide alone or in combination with cisplatin, justifying with high significance levels the use of each of these drugs. Overall survival benefits could also be shown for regimens including CDDP (HR = 0.61; confidence interval (CI), 0.57-0.66), as well as for those including VP16 (HR = 0. 65; CI, 0.61-0.69). Robustness of these results has to be confirmed with appropriate randomised trials.

Ki-67 expression and patients survival in lung cancer: systematic review of the literature with meta-analysis.

Among new biological markers that could become useful prognostic factors for lung carcinoma, Ki-67 is a nuclear protein involved in cell proliferation regulation. Some studies have suggested an association between Ki-67 and poor survival in lung cancer patients. In order to clarify this point, we have performed a systematic review of the literature, using the methodology already described by our Group, the European Lung Cancer Working Party. In total, 37 studies, including 3983 patients, were found to be eligible. In total, 49% of the patients were considered as having a tumour positive for the expression of Ki-67 according to the authors cutoff. In all, 29 of the studies dealt with non-small-cell lung carcinoma (NSCLC), one with small-cell carcinoma (SCLC), two with carcinoid tumours and five with any histology. In terms of survival results, Ki-67 was a bad prognosis factor for survival in 15 studies while it was not in 22. As there was no statistical difference in quality scores between the significant and nonsignificant studies evaluable for the meta-analysis, we were allowed to aggregate the survival results. The combined hazard ratio for NSCLC, calculated using a random-effects model was 1.56 (95% CI: 1.30–1.87), showing a worse survival when Ki-67 expression is increased. In conclusion, our meta-analysis shows that the expression of Ki-67 is a factor of poor prognosis for survival in NSCLC.

Activity of chemotherapy and immunotherapy on malignant mesothelioma: a systematic review of the literature with meta-analysis

The role of chemotherapy for unresectable malignant mesothelioma is unclear. The aims of the present study were to evaluate the methodological quality of published papers relative to chemotherapy or immunotherapy in malignant mesothelioma and to aggregate, for trials having a similar methodology, the response rates in order to identify the most active chemotherapeutic drugs and regimens. The literature relative to this topic, published between 1965 and June 2001 was reviewed. A methodological qualitative evaluation was performed according to the European Lung Cancer Working Party scale, specifically designed for phase II trials. A study was considered as potentially positive if the upper limit of the 95% confidence interval (CI) of the response rate was greater than 20% and positive if the lower limit of the 95% CI was > 20%. Eighty-three studies (88 treatment arms) were eligible for the systematic review. Fifty-three arms were considered as positive or potentially positive. No statistically significant difference in the methodological quality was observed between negative and positive studies. Studies were aggregated in four groups according to the presence of cisplatin and/or doxorubicin in the treatment regimen. The combination of cisplatin and doxorubicin had the highest response rate (28.5%; P < 0.001). Cisplatin was the most active single-agent regimen. Our systematic qualitative and quantitative overview of the literature suggests that the most active chemotherapeutic regimen, in term of objective response rate, is the combination of cisplatin and doxorubicin and the best single-agent is cisplatin. The combination of these two drugs can be recommended as control arm for future randomised phase III trials.

Evolution of microRNA expression during human bronchial squamous carcinogenesis

MicroRNAs, negative post-transcriptional regulators of gene expression, are involved in cancer. Their role in early bronchial carcinogenesis was analysed in 60 biopsies obtained by fluorescence bronchoscopy (six per stage: normal tissue of nonsmokers, normal normofluorescent and hypofluorescent bronchial tissue of smokers, hyperplasia, metaplasia, mild, moderate and severe dysplasia, in situ carcinoma and invasive squamous cell carcinoma (SQCC)). In total, 69 microRNAs were found to be differentially expressed in the course of bronchial carcinogenesis. Among them, some microRNAs showed a linear evolution of their expression level, such as miR-32 and miR-34c, whose expression progressively decreased from normal bronchial tissues of nonsmokers to SQCC. Others behaved differently at successive stages, such as miR-142-3p or miR-9, or are only altered from a specific stage, such as miR-199a or miR-139. MicroRNAs globally followed a two-step evolution, first decreasing (a reverse of their increase during embryogenesis) during the earliest morphological modifications of bronchial epithelium, and thereafter increasing at later stages of lung carcinogenesis. Moreover, microRNA expression was very efficient for the prediction of the histological classification between low- and high-grade lesions and between in situ and invasive carcinoma. The present data show, for the first time, that microRNAs are involved in bronchial carcinogenesis from the very early steps of this process and, thus, could provide tools for early detection of lung cancer.

The role of HER-2/neu expression on the survival of patients with lung cancer: a systematic review of the literature

C-erbB-2 prognostic value for survival in patients with lung cancer remains controversial. We performed a systematic review of the literature to clarify its impact. Studies were identified by an electronic search in order to aggregate the survival results, after a methodological assessment using the scale of the European Lung Cancer Working Party. To be eligible, a study had to deal with c-erbB-2 assessment in lung cancer patients and to analyse survival according to c-erbB-2 expression. In total, 30 studies were eligible: 24 studies dealt with non-small-cell lung carcinoma (NSCLC), five with adenocarcinoma and one study dealt with small-cell carcinoma. In all, 31% of the patients were positive for c-erbB-2. According to c-erbB-2 expression, 13 studies were ‘negative’ (significant detrimental effect on survival), one ‘positive’ (significant survival improvement) and 16 not significant. Significant studies had a better subscore relative to analysis and results report than nonsignificant studies. In total, 86% of the significant studies and only 56% of the nonsignificant studies were evaluable for the meta-analysis. This suggests a possible bias in our aggregated results. For NSCLC, the hazard ratio was 1.55 (95% CI: 1.29–1.86) in favour of tumours that do not express c-erbB-2. In conclusion, the overexpression of c-erbB-2 might be a factor of poor prognosis for survival in NSCLC, but there is a potential bias in favour of the significant studies with an overestimation risk of the magnitude of the true effect of c-erbB-2 overexpression.