Taxanes as radiosensitizers for head and neck cancer

Impact of Radiation Dose on Survival for Esophageal Squamous Cell Carcinoma Treated With Neoadjuvant Chemoradiotherapy

Purpose: Radiation dose used in the neoadjuvant chemoradiotherapy (NCRT) for patients with locally advanced esophageal squamous cell carcinoma (ESCC) varies in different trials and clinical practice. Methods and Materials: Data from patients diagnosed with ESCC receiving NCRT followed by esophagectomy were retrospectively collected from February 2013 to December 2017. Lower dose (LD) radiotherapy was defined as ≤45 Gy, and >45 Gy was considered as higher dose (HD). Survival rates were calculated by the Kaplan-Meier method and compared with long-rank test. Multivariate Cox regression analyses were performed to identify variables associated with survival. Results: A total of 118 patients treated with NCRT were included in our analysis: 62 patients received LD radiotherapy, and 56 patients received HD radiotherapy. The median follow-up time was 24.3 months (0.67-65.3 m). Two-years overall survival (OS) rates were 75.0 and 79.0% in HD and LD group, respectively (P = 0.360), and complete pathological remission (pCR) rates in two groups were 42.9 and 30.6%, respectively (P = 0.17). The incidences of toxic effects including post-operative complications were not significantly different between two groups. Multivariate analysis showed that tumor T stage, M1a disease, smoking history, and pCR rate were significantly associated with OS. Conclusions: In ESCC patients treated with NCRT followed by surgery, higher radiation dose was not significantly associated with a higher pCR rate and longer survival. Lower radiation dose might be a preferable time-dose fraction scheme. Our finding needs to be further validated by randomized trials.

A Phase I/II Study of Nab-Paclitaxel, Cisplatin, and Cetuximab With Concurrent Radiation Therapy for Locally Advanced Squamous Cell Cancer of the Head and Neck

Nab-paclitaxel might impact efficacy of radiation for head and neck (H&N) cancer. Nab-paclitaxel, cisplatin, cetuximab, and radiation were evaluated in patients with locally advanced head and neck cancer in this phase I/II trial. Median follow-up was 24 months for 34 patients. The maximum tolerated dose of nab-paclitaxel was 20 mg/m² with 20 mg/m² cisplatin and 250 mg/m² cetuximab. The 2-year progression-free survival (PFS) was 60% (95% confidence interval (CI) 0.42, 0.78), local control 71% (95% CI 0.55, 0.87), and overall survival 68% (95% CI 0.50, 0.86). This is the first study evaluating these agents with radiation in humans, with similar 2-year PFS as historic control.

Oroxylin a could be a Promising Radiosensitizer for Esophageal Squamous Cell Carcinoma by Inducing G2/M Arrest and Activating Apoptosis

To evaluate the radiosensitization of Oroxylin A on esophageal carcinoma cell as well as the optimal scheduling of Oroxylin A and radiotherapy (RT). Cell proliferation was estimated by a CCK8 assay. Radiosensitization was evaluated by a clonogenic survival assay. The progressions of Cell apoptosis and Cell cycle were investigated by flow cytometry. Expressions of survivin and cell cycle regulators were evaluated by Western blot analysis. A dose-dependent cell survival reduction was found in response to radiation with or without Oroxylin A. The apoptosis rates were remarkably dose-dependent higher in combination groups than in either Oroxylin A or radiation alone group. Besides, Oroxylin A could obviously radiosensitize ESCC cells by arresting tumor cells in G2/M phase and regulating cyclin B1 and Cdc 2 protein expression. Oroxylin A could be a promising radiosensitizer for esophageal squamous cell carcinoma by inducing G2/M phase blocking and activating cell apoptosis.

Systematic analysis of pemetrexed-based chemoradiotherapy for patients with locally advanced or metastatic esophageal cancer

PURPOSE

This systematic analysis was conducted to evaluate the efficacy and safety of pemetrexed-based chemoradiotherapy in treating patients with locally advanced or metastatic esophageal cancer.

METHODS

Clinical studies evaluating the efficacy and safety of pemetrexed based regimens on response and safety for relevant patients were identified using a predefined search strategy. Pooled response rates (RRs) were calculated.

RESULTS

For pemetrexed-based regimens, 4 clinical studies including 47 patients with locally advanced or metastatic esophageal cancer were considered eligible for inclusion. Systematic analysis showed that, in all patients, the pooled RR was 51% (24/47) . Major adverse effects of grade III/IV were esophagitis, neutropenia, thrombocytopenia, anemia anorexia, fatigue, diarrhea, dysphagia and vomiting. No treatment related death occurred with pemetrexed-based treatment.

CONCLUSION

This systematic analysis suggests that pemetrexed based radiotherapy is associated with reasonable activity and good tolerability in treating patients with locally advanced or metastatic esophageal cancer.

Fenofibrate increases radiosensitivity in head and neck squamous cell carcinoma via inducing G2/M arrest and apoptosis

Radiation therapy is an important treatment for head and neck squamous cell carcinoma (HNSCC). However, how to promote radiation sensitivity in HNSCC remains a challenge. This study aimed to investigate the radiosensitizing effects of fenofibrate on HNSCC and explore the underlying mechanisms. HNSCC cell lines CNE-2 and KB were subjected to ionizing radiation (IR), in the presence or absence of fenofibrate treatment. Cell growth and survival, apoptosis and cell cycle were evaluated. In addition, CNE-2 cells were xenografted into nude mice and subjected to IR and/ or fenofibrate treatment. The expression of cyclinB and CDK1 was detected by Western blotting. Our results showed that fenofibrate efficiently radiosensitized HNSCC cells and xenografts in mice, and induced apoptosis and G2/M arrest via reducing the activity of the CDK1/cyclinB1 kinase complex. These data suggest that fenofibrate could be a promising radiosensitizer for HNSCC radiotherapy.

Phase II study of docetaxel (Aisu®) combined with three- dimensional conformal external beam radiotherapy in treating patients with inoperable esophageal cancer

OBJECTIVE

This study was designed to investigate treatment efficacy and side effects of concomitant Aisu® (docetaxel) with three-dimensional conformal external beam radiotherapy for the treatment of inoperable patients with esophageal cancer.

METHODS

Inoperable patients were treated with three-dimensional conformal external beam radiotherapy (5/week, 2 GY/day, and total dose 60GY) plus docetaxel (30-45 mg/m2, iv, d1, 8).

RESULTS

Twenty eight patients met the study eligibility criteria and the response rate was evaluated according to RICIST guidelines. Among 28 patients, 2 achieved CR, 22 PR, 3 SD and 1 patient was documented PD. Mild gastrointestinal reaction and bone marrow suppression were also documented. All treatment related side effects were tolerable.

CONCLUSION

Three-dimensional conformal external beam radiotherapy combined with docetaxel is an active and safe regimen for inoperable patients with esophageal cancer.

Weekly paclitaxel and carboplatin induction chemotherapy followed by concurrent chemoradiotherapy in locally advanced squamous cell carcinoma of the head and neck

OBJECTIVE

To perform a phase II trial evaluating dose dense induction chemotherapy for locally advanced head and neck cancer.

PATIENTS AND METHODS

Thirty-five patients received 6 weekly doses of carboplatin (area under the curve=2) and paclitaxel (135 mg/m) followed by concurrent weekly paclitaxel (40 mg/m) and carboplatin (area under the curve=1) and daily radiation (66-72 Gy).

RESULTS

There was 1 induction death from neutropenic sepsis and 1 sudden death during chemoradiotherapy. The overall response rate with induction was 79%. With >40 months of follow-up, the 36-month overall survival was 67% and squamous cell carcinoma of the head and neck survival 84%. Patients undergoing biopsy of the primary tumor site after the therapies had 17/18 (94%) pathologic complete response rate. The locoregional relapse rate was 40% (24 mo 28%) and distant relapse rate was 8% with only 1 distant site.

CONCLUSIONS

Therapy was active but patients must be carefully selected and monitored. Compared with the historical controls, dose dense and intense induction chemotherapy decreased distant failure rate without compromising the locoregional control.

Concurrent chemoradiotherapy with weekly paclitaxel and carboplatin for locally advanced head and neck cancer: Long-term follow-up of a Brown University Oncology Group Phase II Study (HN-53)

BACKGROUND

A phase II study was conducted using concurrent paclitaxel, carboplatin, and external beam radiotherapy (RT) in patients with advanced head and neck cancer.

METHODS

Forty-three patients (stage III, n = 12; stage IV, n = 31) were treated with 8 cycles of weekly paclitaxel (60 mg/m(2)), carboplatin (area under the curve [AUC] = 1), and RT (1.8 Gy daily; total dose, 66-72 Gy). Patients with initially palpable lymph nodes underwent neck dissection.

RESULTS

The overall clinical response rate was 91% (65% complete, 26% partial). Severe mucositis occurred in 37 (90%) patients, necessitating hospitalization in 13 (31%) patients. With a median follow-up of 49 months, the locoregional and distant failure rates were 26% and 21%, respectively.

CONCLUSIONS

Concurrent paclitaxel, carboplatin, and RT for advanced head and neck cancer results in high complete response rates. Long-term follow-up has revealed the curative potential of this regimen, though the doses used resulted in unacceptable toxicity.

Anti-angiogenic drugs: from bench to clinical trials

Angiogenesis, the generation of new capillaries through a process of pre-existing microvessel sprouting, is under stringent control and normally occurs only during embryonic and post-embryonic development, reproductive cycle, and wound repair. However, in many pathological conditions (solid tumor progression, metastasis, diabetic retinopathy, hemangioma, arthritis, psoriasis and atherosclerosis among others), the disease appears to be associated with persistent upregulated angiogenesis. The development of specific anti-angiogenic agents arises as an attractive therapeutic approach for the treatment of cancer and other angiogenesis-dependent diseases. The formation of new blood vessels is a complex multi-step process. Endothelial cells resting in the parent vessels are activated by an angiogenic signal and stimulated to synthesize and release degradative enzymes allowing endothelial cells to migrate, proliferate and finally differentiate to give rise to capillary tubules. Any of these steps may be a potential target for pharmacological intervention. In spite of the disappointing results obtained initially in clinical trials with anti-angiogenic drugs, recent reports with positive results in phases II and III trials encourage expectations in their therapeutic potential. This review discusses the current approaches for the discovery of new compounds that inhibit angiogenesis, with emphasis on the clinical developmental status of anti-angiogenic drugs.

Silatecan DB-67 is a novel DNA topoisomerase I–targeted radiation sensitizer

The silatecan 7-tert-butyldimethylsilyl-10-hydroxy-camptothecin (DB-67) represents a new generation of camptothecin derivatives that exhibits a potent in vitro DNA topoisomerase I (TOP1)–mediated DNA-damaging activity, improved blood stability, and holds significant promise for the treatment of human cancers. In this study, we characterize the role of TOP1 in mediating the radiosensitization activity of DB-67. As examined by clonogenic survival assay, DB-67 exhibited potent radiosensitization activity at a concentration 10-fold lower than camptothecin in the human glioma D54-MG and T-98G cells, which harbor wild-type and mutant p53, respectively. Analyzed by the single-hit multitarget model, DB-67 induced radiosensitization by obliterating the “shoulder” of the radiation survival curve in the D54-MG cells. The in vivo targeting of TOP1 by DB-67 was investigated by immunoblot analysis. In a dose-dependent manner, DB-67 specifically stimulates covalent linking of TOP1 to chromosomal DNA at concentrations 10-fold lower than camptothecin in the D54-MG cells. The potency of in vivo targeting of TOP1 by DB-67 correlates well with its cytotoxicity and radiosensitization activity. Furthermore, DB-67 exhibited substantially less cytotoxicity and radiosensitization activity in the TOP1 mutant Chinese hamster lung fibroblast DC3F/C-10 cells than in their parental DC3F cells. Together, our data show that DB-67 exhibits potent cytotoxicity and radiosensitization activity by targeting TOP1 in mammalian cells and has great potential for being developed to treat human cancers.

Radiobiology of radioimmunotherapy: targeting CD20 B-cell antigen in non-Hodgkin's lymphoma

The radiobiology of radioimmunotherapy is an important determinant of both the toxicity and the efficacy associated with the treatment of B-cell non-Hodgkin's lymphoma with radiolabeled anti-CD20 monoclonal antibodies. The properties of the target, CD20, and the mechanisms of action of both the monoclonal antibodies and the associated exponentially decreasing low-dose-rate radiotherapy are described. The radiation dose and dose-rate effects are discussed and related to both the tumor responses and normal organ toxicity. Finally, the use of either unlabeled or radiolabeled anti-CD20 monoclonal antibodies as a component of combined modality therapy (including the sequential or concurrent use of sensitizers) and future directions of the field are discussed.

Expression of ErbB2 enhances radiation-induced NF-kappaB activation

Her-2/neu (ErbB2) oncogene, the second member of the epidermal growth factor receptor (EGFR) family, encodes a transmembrane tyrosine kinase receptor in Her-2-positive tumors. Accumulating evidences demonstrate that signaling networks activated by EGFR and transcription factor NF-kappaB are associated with cell response to ionizing radiation (IR). The present study shows that overexpression of ErbB2 enhanced NF-kappaB activation induced by IR in human breast carcinoma MCF-7 cells transfected with ErbB2 genes (MCF-7/ErbB2). Stable transfection of dominant-negative mutant IkappaB (MCF-7/ErbB2/mIkappaB) or treatment with anti-ErbB2 antibody, Herceptin, inhibited NF-kappaB activation and radiosensitized MCF-7/ErbB2 cells. Consistent with NF-kappaB regulation, basal and IR-induced Akt, a kinase downstream of ErbB2, was activated in MCF-7/ErbB2 cells and inhibited by Herceptin. To identify specific genes affected by ErbB2-mediated NF-kappaB activation, a group of IR-responsive elements Cyclin B1, Cyclin D1, Bcl-2, Bcl/XL, BAD and BAX were evaluated. Basal levels of prosurvival elements Cyclin B1, Cyclin D1, Bcl-2 and Bcl/XL but not apoptotic BAD and BAX were upregulated in MCF-7/ErbB2 cells with striking enhancements in Bcl-2 and Bcl/XL. IR further induced Cyclin B1 and Cyclin D1 expression that was reduced by Herceptin. Bcl-2 kept a high steady level after Herceptin+IR treatment and, in contrast to control MCF-7/Vector cells, Bcl/XL was inhibited in MCF-7/ErbB2 cells by Herceptin+IR treatment. However, all four prosurvival proteins were downregulated by inhibition of NF-kappaB in MCF-7/ErbB2/mIkappaB cells. These results thus provide evidence suggesting that overexpression of ErbB2 is able to enhance NF-kappaB response to IR, and that a specific prosurvival network downstream of NF-kappaB is triggered by treatments using anti-ErbB2 antibody combined with radiation.

Radiobiology of radioimmunotherapy with 90Y ibritumomab tiuxetan (zevalin)

Radioimmunotherapy represents a significant advance over unlabeled immunotherapy for the treatment of patients with B-cell non-Hodgkin's lymphoma. The efficacy of radioimmunotherapeutic agents depends in large part on the basic biological effects associated with their components, monoclonal antibodies and radionuclides, separately and in combination. The radiobiological effects associated with yttrium 90-labeled ibritumomab tiuxetan (Zevalin; Biogen Idec Inc, Cambridge, MA) include the induction of apoptosis and cell-cycle redistribution (eg, arrest of cells in the G(2)/M phase of the cell cycle). Because of dose-rate effects, tumor cells may, in some cases, be more susceptible to the low-dose-rate radiation used in radioimmunotherapy than to the high-dose-rate radiation used in external beam radiotherapy. The efficacy of radioimmunotherapy may potentially be optimized through a variety of approaches, including the use of agents that increase the expression of certain tumor antigens (thus facilitating improved biodistribution of radiolabeled monoclonal antibodies) or that sensitize tumor cells to radiation.

Comparison of antiangiogenic activities using paclitaxel (taxol) and docetaxel (taxotere)

Tumor growth requires a competent vascular supply and angiogenesis has been considered as a potential target for the treatment of several cancers. The two clinically approved taxanes, paclitaxel and docetaxel, are novel antimitotic agents that are under extensive investigation in clinical trials. Both taxanes have demonstrated significant activity against many solid tumors, but little is known about the effect of paclitaxel and docetaxel on endothelial cell function and angiogenic processes. The purpose of our study was to examine and compare the effects of these drugs on angiogenic processes in vitro and in vivo. These processes include: proliferation, migration and differentiation of cultured human umbilical vein endothelial cells (HUVEC) (in vitro), capillary sprouting of rat aortic ring explants (ex vivo) and HT1080 tumor growth in vivo. Our results demonstrate that endothelial cells are 10-100-fold more sensitive to these drugs than tumor cells. Additionally, comparison of the taxanes demonstrated that angiogenesis is blocked by both drugs primarily via inhibition of proliferation and differentiation (tube assay) and induction of cell death. Docetaxel, however, appears to be more potent at inhibiting angiogenesis, with an IC(50) concentration 10x less than that of paclitaxel. We conclude that these important findings should be taken in account in clinical trials where tumor angiogenesis is being targeted.

Concurrent radiation therapy and paclitaxel or docetaxel chemotherapy in high-risk breast cancer

PURPOSE

Evidence supports the inclusion of the taxanes in the treatment of breast cancer. A recent randomized trial has shown a survival advantage to the addition of paclitaxel in the adjuvant treatment of node-positive patients. Several studies have suggested diminished local control if adjuvant radiation is delayed, while in vitro and in vivo studies have demonstrated a benefit of concurrent administration of taxanes with radiation. For these reasons, we began in 1995 to administer radiation therapy concurrently with the taxanes in advanced breast cancer. This retrospective review examines the feasibility of such treatment.

METHODS AND MATERIALS

Forty-four patients were treated with concurrent radiation and either paclitaxel (29 patients) or docetaxel (15 patients). One patient received both paclitaxel and docetaxel. Eighteen patients were treated for recurrent disease, 9 had received prior radiation. Toxicity was assessed by the RTOG scale for acute and late effects.

RESULTS

Concurrent radiation and taxane chemotherapy was well tolerated. Nine patients (20%) experienced Grade 3 acute skin toxicity. This was more likely with docetaxel than paclitaxel (p = 0. 04). Among patients undergoing breast conservation, there were no Grade 3 toxicities. With a median follow-up of 11 months, 1 patient has developed breast fibrosis.

CONCLUSION

Concurrent administration of both paclitaxel and docetaxel with radiation resulted in acceptable toxicity. Overall, the acute skin toxicity seen with docetaxel was more pronounced. However, among patients undergoing breast conservation the taxanes were both well tolerated. Further study is necessary to assess the impact of concurrent treatment on long-term outcome.

Integration of taxanes into primary chemotherapy for squamous cell carcinoma of the head and neck: promise fulfilled?

Chemotherapy has become integrated into the treatment of head and neck cancer in not only the palliative but now also the primary setting. Organ preservation is possible using induction chemotherapy, and improved survival results have been confirmed for concomitant chemoradiotherapy. The taxanes, paclitaxel and docetaxel, appear to be as active as any other drugs in head and neck cancer. When used in combination in the induction, recurrent, or metastatic settings, response rates rival those of the standard cisplatin/5-fluorouracil regimen. At least one ongoing study will help to establish superiority of cisplatin/paclitaxel versus cisplatin/5-fluorouracil in the recurrent or metastatic setting, and another between cisplatin/5-fluorouracil and doctaxel/cisplatin/5-fluorouracil in the induction setting. Both paclitaxel and docetaxel are being extensively studied as radiosensitizers. They are relatively well tolerated and have good efficacy but have not yet been adequately studied in comparison with other regimens. In conclusion, the taxanes have significantly expanded our effective treatment options in both the primary and recurrent or metastatic settings.