Novel approaches to locally advanced unresectable non-small cell lung cancer

A meta-analysis comparing the efficacy and safety of gemcitabine plus cisplatin induction chemotherapy in patients with locoregionally advanced NPC

PURPOSE

Nasopharyngeal carcinoma (NPC) is a malignant tumor endangering human health. Gemcitabine or cisplatin chemotherapy has been regarded as effective treatment for patients with locoregionally advanced NPC. However, the effect of gemcitabine plus cisplatin concurrent chemoradiotherapy (CCRT) remained controversial among the studies. Therefore, we conducted this meta-analysis to assess the efficacy and safety of induction chemotherapy by gemcitabine and cisplatin (GP regimen) in patients with locoregionally advanced NPC.

METHODS

A systematic literature search was performed using PubMed, Web of Science, and Embase to evaluate the survival benefit and toxicity profiles of patients with locoregionally advanced NPC who were treated with CCRT. A random-effects model or a fixed-effects model was used to pool the data according to the heterogeneity among the included studies.

RESULTS

A total of five studies with 1286 patients met the inclusion criteria and were included in this meta-analysis. Pooled estimate showed that GP regimen was associated with significant improvements in OS (HR = 0.57, 95% CI 0.45, 0.73; P < 0.001), DFS (HR = 0.56, 95% CI 0.47, 0.66; P < 0.001), and DRFS (HR = 0.51, 95% CI 0.36, 0.73; P < 0.001), but not in LRFS (HR = 0.54, 95% CI 0.25, 1.19; P = 0.126) and ORR (RR = 1.30, 95% CI 0.54, 3.09; P = 0.556). Moreover, the incidence of adverse events of all grades (RR = 1.15, 95%CI 0.11, 1.38; P = 0.063) or grade 3-4 (RR = 0.96, 95%CI 0.57, 1.29; P = 0.385), was comparable between GP regimen and control treatments.

CONCLUSION

Our meta-analysis indicated that the patients with locoregionally advanced NPC could benefit from the regimen of gemcitabine plus cisplatin induction chemotherapy.

Effect of compound K, a metabolite of ginseng saponin, combined with gamma-ray radiation in human lung cancer cells in vitro and in vivo

Pretreatment of NCI-H460 human lung cancer cells with compound K produced by intestinal bacteria enhances gamma-ray radiation-induced cell death. Increases in apoptosis induced by combined treatment are made apparent in the observation of nuclear fragmentation, loss of mitochondrial membrane potential (Deltapsi), and activation of caspase 3. Apoptosis induced by compound K and gamma-ray radiation is associated with reactive oxygen species (ROS) generation. Furthermore, compound K, in combination with gamma-ray radiation, has an enhanced effect in the regression of NCI-H460 tumor xenografts of nude mice. These results suggest that compound K has possible application for cancer therapy when used in combination with gamma-ray radiation.

Enhancement of antitumor activity of cisplatin in human lung cancer cells by tumor suppressor FUS1

FUS1 is a novel tumor suppressor gene located in the human chromosome 3p21.3 region. We previously showed that restoration of FUS1 function in 3p21.3-deficient human non-small-cell lung cancer (NSCLC) cells significantly inhibited tumor cell growth in vitro and in vivo. In this study, we evaluated the combined effects of the tumor suppressor FUS1 and the chemotherapeutic drug cisplatin on tumor cell growth and apoptosis induction in NSCLC cells, and explored the molecular mechanism of their mutual action. Exogenous expression of FUS1 by nanoparticle-mediated gene transfer sensitized the response of NSCLC cells to cisplatin, resulting in a 4- to 6-fold increase in tumor-suppressing activity. A systemic treatment with a combination of FUS1-nanoparticles and cisplatin in a human H322 lung cancer orthotopic xenograft mouse model dramatically enhanced the therapeutic efficacy of cisplatin. We also found that the FUS1-enhanced chemosensitivity is associated with the downregulation of MDM2, accumulation of p53 and activation of the Apaf-1-dependent apoptosis pathway. Our results demonstrated an important role of FUS1 in modulating chemosensitivity of lung cancer cells, and suggested that a proper combination of molecular therapeutics such as the proapoptotic tumor suppressor FUS1 and the conventional chemotherapeutic drugs such as cisplatin may be an efficient treatment strategy for human lung cancer.

Synergistic tumor suppression by coexpression of FUS1 and p53 is associated with down-regulation of murine double minute-2 and activation of the apoptotic protease-activating factor 1-dependent apoptotic pathway in human non-small cell lung cancer cells

FUS1 is a novel tumor suppressor gene identified in human chromosome 3p21.3 region. Loss of expression and deficiency of posttranslational modification of FUS1 protein have been found in a majority of human lung cancers. Restoration of wild-type FUS1 in 3p21.3-deficient human lung cancer cells exhibited a potent tumor suppression function in vitro and in vivo. In this study, we evaluated the combined effects of FUS1 and tumor suppressor p53 on antitumor activity and explored the molecular mechanisms of their mutual actions in human non-small cell lung cancer (NSCLC) cells. We found that coexpression of FUS1 and p53 by N-[1-(2,3-dioleoyloxyl)propyl]-NNN-trimethylammoniummethyl sulfate:cholesterol nanoparticle-mediated gene transfer significantly and synergistically inhibited NSCLC cell growth and induced apoptosis in vitro. We also found that a systemic treatment with a combination of FUS1 and p53 nanoparticles synergistically suppressed the development and growth of tumors in a human H322 lung cancer orthotopic mouse model. Furthermore, we showed that the observed synergistic tumor suppression by FUS1 and p53 concurred with the FUS1-mediated down-regulation of murine double minute-2 (MDM2) expression, the accumulation and stabilization of p53 protein, as well as the activation of the apoptotic protease-activating factor 1 (Apaf-1)-dependent apoptotic pathway in human NSCLC cells. Our results therefore provide new insights into the molecular mechanism of FUS1-mediated tumor suppression activity and imply that a molecular therapy combining two or more functionally synergistic tumor suppressors may constitute a novel and effective strategy for cancer treatment.

Prophylactic cranial irradiation with combined modality therapy for patients with locally advanced non-small cell lung cancer

Central nervous system (CNS) metastasis is a significant problem for many patients with non-small cell lung cancer (NSCLC). The earlier data reported a high incidence of CNS metastasis in patients with locally advanced NSCLC who were treated with radiotherapy alone. However, poor control of both thoracic and extracranial systemic disease dominated the results of the early trials. The risk for CNS metastasis as the first site of failure remains a significant concern for patients who have completed modern combined modality therapy. With improvements in the treatment of thoracic and systemic disease, there is renewed interest in prophylactic cranial irradiation (PCI). The results from the Radiation Therapy Oncology Group (RTOG) trial of PCI to prevent CNS relapse in patients with locally advanced NSCLC are anticipated.

Potential clinical application of antioncogene ribozymes for human lung cancer

Non-small-cell lung cancer frequently contains oncogenetic defects (mutations in ras, retinoblastoma, and p53 genes) that contribute to disease pathophysiology. Recent studies and clinical trials have focused on gene therapy approaches that either replace the function of defective tumor-suppressor genes such as p53 or inactivate mutant oncogenes such as ras. Ribozymes are RNA molecules with highly specific intrinsic enzymatic activity against target RNA sequences, which can discriminate mutant sequences that differ by a single base from their wild-type counterparts. Following binding to the RNA substrate by base-pair complementation, the ribozyme cleaves the target RNA irreversibly, then releases itself for new rounds of subsequent cleavage, resulting in significantly improved target:effector stoichiometry as compared with antisense oligonucleotides of the same specificity. Transcript-specific ribozymes have been used extensively for experimental oncogene inactivation. Ribozymes are effective for targeting mutant ras, p53, or the multidrug-resistant gene product for lung cancer cells in vitro. However, their in vivo effect is not well defined against this malignancy. We recently characterized the antitumor properties of an anti-K-ras ribozyme specific for the K-ras codon 12 mutation (GGT-->GTT). When delivered as a transgene by an adenoviral vector (ADV), the K-ras ribozyme (KRbz) suppressed growth of lung tumor xenografts expressing the relevant mutation, whereas the corresponding antisense sequence lacking catalytic activity did not. Multiple intratumoral (3-5) injections of KRbz-ADV were effective in producing complete tumor regressions of preexisting tumor xenografts. Clinical trials are under consideration to examine the applicability of this anti-K-ras ribozyme for treatment of non-small-cell lung cancers expressing the relevant mutation.

A phase II trial of concurrent chemoradiation therapy followed by consolidation chemotherapy with oral etoposide and cisplatin for locally advanced inoperable non-small cell lung cancers

We report a phase II study to evaluate the survival rate, response rate and toxicity of concurrent chemoradiation therapy (CCRT) followed by consolidation chemotherapy (CT) with oral etoposide and cisplatin for patients with locally advanced inoperable non-small cell lung cancer (NSCLC). Fifty-four patients with locally advanced inoperable NSCLC who had received no prior therapy were enrolled into this trial between May 1995 and December 2000. Treatment consisted of two cycles of concurrent CT and four cycles of consolidation CT with oral etoposide (50 mg/m2) on days 1-14 during the CCRT courses and on days 1-21 during the consolidation CT courses, plus cisplatin (75 mg/m2 i.v.) on day 1 of a 28-day cycle. Conventional radiotherapy (1.8 Gy/fraction, 63 Gy over 7 weeks) was delivered from day 1 of the CT. Fifty-two patients were evaluable for response. Twelve patients (22%) achieved complete responses, and 32 patients (60%) achieved partial responses, for an overall response rate of 82% with a median duration of response of 9.1 months. Forty-three per cent developed grade 4 haematological toxicity, 11% grade 3 or 4 oesophagitis and 7% grade 3 or 4 lung toxicity. There were two treatment-related deaths, one from radiation pneumonitis and the other from sepsis. After a median follow-up duration of 50 months (range 20-85), the median overall survival time was 15.3 months (95% CI, 9.7-20.8), and the 1-, 2-, 3-, and 5 year overall survival rates were 62, 40, 30 and 16%, respectively. The duration of median progression-free survival was 12.3 months (95% CI, 7.4-17.3), and the 1-, 2-, 3-, and 5-year progression-free survival rates were 47, 40, 29 and 23%, respectively. Thus, concurrent conventional chest radiotherapy with oral etoposide plus cisplatin followed by consolidation CT led to an encouraging survival rate and prolongation of the time to progression, with moderate toxicity in patients with locally advanced inoperable NSCLC.

Translational research in lung cancer

Recent research advances in cancer and molecular biology have furthered our understanding of the etiology and natural history of lung cancer. Through translational research, a growing understanding of the molecular changes that underlie cancer progression has contributed to the development of novel molecular approaches for early detection, further defining prognosis, refining treatment schedules, identifying new therapeutic targets, and identifying patients at risk for treatment-related toxicity from aggressive therapy, such as pneumonitis and esophagitis. In this article, we review progress in molecular/gene screening and prognosis, and we present a clinical study, based on preclinical research, in which we apply low-dose radiosensitizing paclitaxel for locally advanced non-small-cell lung cancer (NSCLC); this resulted in superior local tumor control while keeping treatment toxicity low. We also review progress made in identifying cytokines: interleukin [IL]-1alpha, IL-6, and transforming growth factor [TGF] beta as markers for lung cancer treatment-related radiation pneumonitis. Finally, we summarize different targeted therapy approaches and discuss their application to clinical trials. Irrespective of the slow progress toward clinical improvements, we have gained much knowledge through translational research using new molecular and biologic technology. We believe that knowledge of lung cancer biology will continue to provide the foundation for future improvements in lung cancer treatment.

Carboplatin plus paclitaxel and sequential radiation followed by consolidation carboplatin and paclitaxel in patients with previously untreated locally advanced NSCLC. A Hoosier Oncology Group (HOG) phase II study

Chemoradiation is standard treatment for patients with unresectable locally advanced non-small cell lung cancer (NSCLC). However, local and distant relapse rates remain high. It has been postulated that the addition of consolidation chemotherapy might further decrease the systemic relapse rate. We performed this phase II study to evaluate the toxicities and activity of two cycles of paclitaxel and carboplatin administered prior to and following thoracic radiation in patients with locally advanced, inoperable NSCLC. From April to December 1997, 25 patients were entered on study. Twenty-three patients were eligible and received paclitaxel 225 mg/m(2) intravenously over 3 h followed by carboplatin at an AUC (6) on days 1 and 22. Radiation consisted of 60 Gy given over 6 weeks beginning on day 43. Patients with non-progressive disease received two additional cycles of consolidation carboplatin and paclitaxel. Four of 23 patients progressed during induction chemotherapy. There were seven PR's and 11 had SD after induction chemotherapy. Following radiation, the response changed to 11 PR, four SD, and three had progressive disease. Of the 15 patients eligible to receive consolidation chemotherapy, three were excluded due to a poor performance status. Twelve patients were treated with consolidation chemotherapy with further improvement in two patients (SD to PR, PR to CR). All 12 patients who received consolidation chemotherapy developed grade 3 or 4 neutropenia, including three patients with neutropenic fever. The overall response rate was 52.1%. The median survival, 1-, and 2-year survival was 10.5 months, 45, and 17%, respectively. In conclusion, consolidation chemotherapy was associated with significant hematologic toxicity without an obvious improvement in survival in comparison to other studies utilizing chemoradiation alone.

Failure-specific prognostic factors after continuous hyperfractionated accelerated radiotherapy (CHART) or conventional radiotherapy in locally advanced non-small-cell lung cancer: a competing risks analysis

The aim of this study was to identify possible failure-specific prognostic factors in non-small-cell lung cancer. Clinical outcome was analysed in 549 patients participating in the randomized controlled trial of CHART vs conventional radiotherapy. Local failure and distant failure with or without concurrent local relapse were subjected to a competing risk analysis using an accelerated failure-time model with a log-logistic hazard function. Randomization to CHART (2 P = 0.005), increasing age (2 P = 0.036) and female sex (2 P = 0.09) was all associated with a prolonged interval to failure. Advanced clinical stage was associated with a decreased interval to failure (2 P = 0.004) and a significantly increased risk (2 P = 0.009) of failing in distant rather than in local position. From this model, prognostic indices for local and distant failure were estimated for each individual patient. Competing risk analysis allows identification of patients with different failure patterns, and may provide a means of stratifying patients for intensified local or systemic therapy.

Dose and fractionation concepts in the primary radiotherapy of non-small cell lung cancer

At present, radiotherapy alone or in combination with chemotherapy offers the only chance of cure of medically inoperable or locally advanced unresectable non-small cell lung cancer. The radiobiological basis and clinical results of current dose and fractionation concepts in the primary radiotherapy of NSCLC are briefly reviewed. Whenever possible, focus is given to the results of randomized phase III trials. With the exception of early disease treated to doses higher than 60 Gy, the prognosis of inoperable localized NSCLC is very poor. Local recurrence is the major cause of failure after radiation therapy calling for intensified local treatment. Dose-escalation using conventional fractionation or moderate hypofractionation is promising but randomized trials are presently not available. Dose-escalated hyperfractionation theoretically offers advantages, however, there appears currently no strong evidence from randomized trials supporting this approach in NSCLC. The highly accelerated CHART regimen significantly improved survival by 9% compared to standard radiotherapy. Nevertheless, even when treated with CHART, about 80% of all patients will eventually develop local recurrence and 60% distant metastases. Many trials on combined radiochemotherapy have used radiotherapy regimens that are not optimal from a current perspective. Because of the high rate of both, local recurrence and distant metastases, future research should be directed to further intensify radiotherapy as well as to integrate such protocols with systemic treatment in carefully selected patients. Since toxicity is expected to increase, state-of-the-art 3D conformal radiation techniques need to be part of clinical trials testing such strategies.

Photodynamic Therapy for Patients with Advanced Non–Small-Cell Carcinoma of the Lung

Patients with advanced non-small-cell lung carcinoma (NSCLC) have poor prognoses and experience negative sequelae of disease. Patients often suffer from dyspnea and/or hemoptysis, with overall pulmonary compromise. Patients with advanced, inoperable disease have limited options for treatment. This study summarizes our early experience and findings using photodynamic therapy (PDT) as an effective modality in the palliation of hemoptysis, dyspnea, and physical airway obstruction in cases of inoperable lung cancer. A retrospective review was conducted for the first 10 patients diagnosed with stage III/IV obstructive NSCLC who underwent PDT at our institution. Endobronchial lesions were identified by bronchoscopy. Treatments were initiated 48 hours after intravenous injection of 2 mg/kg of the photosensitizing agent porfimer sodium (Photofrin, QLT PhotoTherapeutics, Vancouver, BC). The porfimer sodium was then activated by illumination with a 630 nm wavelength light using a Coherent argon ion laser through a flexible bronchoscope. Repeated bronchoscopies were performed 1-3 days following initial PDT for evaluation and airway debridement. In 8 cases, a second treatment of PDT was administered within 72 hours of the first injection. One patient received a third treatment several months later. Three patients also received endobronchial stents after PDT. Overall, all 10 patients responded to PDT. Physical airway obstruction was reduced in all patients, with a noted improvement in bronchoscopic luminal diameter. Acute hemoptysis resolved in all 7 symptomatic patients. Median survival was 5.5 months post-PDT, while median survival postdiagnosis was 10.5 months. Three patients are alive at the time of this review at 5-21 months following therapy. Patients with unresectable late-stage NSCLC have few options for treatment. Our early experience with PDT indicates effective relief of hemoptysis, dyspnea, and airway obstruction and improves their quality of life.

Innovative treatments for non-small cell lung cancer

Lung cancer remains the most frequent and most lethal cancer worldwide. Non-small cell lung cancer (NSCLC) comprises the vast majority of the histological types. Surgery remains the standard therapy for early stage disease but for advanced stage disease, modern treatment is unsatisfactory. However, during the past ten years, improvements in response and survival have been seen with the use of newer chemotherapy regimens. Early studies of neo-adjuvant (pre-operative) chemotherapy for resectable stage III patients have shown promising results. For patients with non-resectable NSCLC platinum-based doublets are now established as first-line treatment, either alone or in combination with radiotherapy. Innovative non-platinum based combinations are actively being evaluated. The most promising non-platinum agents at this time include gemcitabine, paclitaxel, docetaxel, irinotecan and vinorelbine. These agents appear to be effective as single agents and in combinations and also have improved toxicity profiles. Several other systemic approaches are under active evaluation; the most promising areas include anti-angiogenesis agents, immunotoxins, interleukins, vaccines and molecular therapy.

Topoisomerase I Inhibitors in the Combined Modality Therapy of Lung Cancer

Locally advanced non small-cell lung cancer (NSCLC) represents 30%-40% of all pulmonary malignancies. Despite the fact that the disease is confined to the chest, most patients will eventually succumb to their dis-ease. Therefore, the management of NSCLC is undergoing rapid evolution with hope of improving overall survival. The arrival of a new generation of chemotherapeutic agents, including the taxanes, gemcitabine, and topoisomerase inhibitors such as irinotecan and topotecan, offers the hope of real advances against this malignancy. Irinotecan and topotecan are camptothecin derivatives that are felt to exert their cytotoxic effects by targeting topoisomerase I. It is believed that topoisomerase I inhibitors stabilize a DNA-topoisomerase I cleavable complex, and interactions between this complex and the replication machinery may lead to cell death. There is a significant volume of in vitro and in vivo data demonstrating that these topoisomerase I inhibitors also act as radiosensitizers. Early clinical data with topotecan suggests that it is a more active agent in small-cell lung cancer than it is in NSCLC despite a common mechanism of action with irinotecan. With the increasing data that exist on the improved outcome with concurrent chemoradiation treatment for malignancies including lung cancer and head and neck cancers, there is an impetus to pursue the addition of other drugs that can radiosensitize tumors and further improve local control. Irinotecan is undergoing early clinical trials in the combined modality setting in several different disease sites. This paper will review the in vitro and in vivo data on the ability of irinotecan and topotecan to render tumors more susceptible to ionizing radiation. It will then focus on the experience with both drugs and thoracic radiation in the treatment of NSCLC, in which irinotecan has yielded acceptable toxicity results and response rates in excess of 60% in early trials. It is hoped that newer treatment strategies, such as the combination of radiation and topoisomerase I inhibitors in lung cancer, will have a significant impact on cure rates in the future.