Gemcitabine and radiation therapy in non-small cell lung cancer: state of the art

Revealing the impact of modified modules flexibility on gemcitabine prodrug nanoassemblies for effective cancer therapy

Prodrug nanoassemblies combine the advantages of prodrug strategies and nanotechnology have been widely utilized for delivering antitumor drugs. These prodrugs typically comprise active drug modules, response modules, and modification modules. Among them, the modification modules play a critical factor in improving the self-assembly ability of the parent drug. However, the impact of the specific structure of the modification modules on prodrug self-assembly remains elusive. In this study, two gemcitabine (GEM) prodrugs are developed using 2-octyl-1-dodecanol (OD) as flexible modification modules and cholesterol (CLS) as rigid modification modules. Interestingly, the differences in the chemical structure of modification modules significantly affect the assembly performance, drug release, cytotoxicity, tumor accumulation, and antitumor efficacy of prodrug nanoassemblies. It is noteworthy that the prodrug nanoassemblies constructed with flexible modifying chains (OD) exhibit improved stability, faster drug release, and enhanced antitumor effects. Our findings elucidate the significant impact of modification modules on the construction of prodrug nanoassemblies.

Investigation of Lung Cancer Cell Response to Cryoablation and Adjunctive Gemcitabine-Based Cryo-Chemotherapy Using the A549 Cell Line

Due to the rising annual incidence of lung cancer (LC), new treatment strategies are needed. While various options exist, many, if not all, remain suboptimal. Several studies have shown cryoablation to be a promising approach. Yet, a lack of basic information pertaining to LC response to freezing and requirement for percutaneous access has limited clinical use. In this study, we investigated the A549 lung carcinoma cell line response to freezing. The data show that a single 5 min freeze to -15 °C did not affect cell viability, whereas -20 °C and -25 °C result in a significant reduction in viability 1 day post freeze to <10%. These populations, however, were able to recover in culture. Application of a repeat (double) freeze resulted in complete cell death at -25 °C. Studies investigating the impact of adjunctive gemcitabine (75 nM) pretreatment in combination with freezing were then conducted. Exposure to gemcitabine alone resulted in minimal cell death. The combination of gemcitabine pretreatment and a -20 °C single freeze as well as combination treatment with a -15 °C repeat freeze both resulted in complete cell death. This suggests that gemcitabine pretreatment may be synergistically effective when combined with freezing. Studies into the modes of cell death associated with the increased cell death revealed the increased involvement of necroptosis in combination treatment. In summary, these results suggest that repeat freezing to -20 °C to -25 °C results in a high degree of LC destruction. Further, the data suggest that the combination of gemcitabine pretreatment and freezing resulted in a shift of the minimum lethal temperature for LC from -25 °C to -15 °C. These findings, in combination with previous reports, suggest that cryoablation alone or in combination with chemotherapy may provide an improved path for the treatment of LC.

Targeting Cell Signaling Pathways in Lung Cancer by Bioactive Phytocompounds

Lung cancer is a heterogeneous group of malignancies with high incidence worldwide. It is the most frequently occurring cancer in men and the second most common in women. Due to its frequent diagnosis and variable response to treatment, lung cancer was reported as the top cause of cancer-related deaths worldwide in 2020. Many aberrant signaling cascades are implicated in the pathogenesis of lung cancer, including those involved in apoptosis (B cell lymphoma protein, Bcl-2-associated X protein, first apoptosis signal ligand), growth inhibition (tumor suppressor protein or gene and serine/threonine kinase 11), and growth promotion (epidermal growth factor receptor/proto-oncogenes/phosphatidylinositol-3 kinase). Accordingly, these pathways and their signaling molecules have become promising targets for chemopreventive and chemotherapeutic agents. Recent research provides compelling evidence for the use of plant-based compounds, known collectively as phytochemicals, as anticancer agents. This review discusses major contributing signaling pathways involved in the pathophysiology of lung cancer, as well as currently available treatments and prospective drug candidates. The anticancer potential of naturally occurring bioactive compounds in the context of lung cancer is also discussed, with critical analysis of their mechanistic actions presented by preclinical and clinical studies.

Generation of a Perfusable 3D Lung Cancer Model by Digital Light Processing

Lung cancer still has one of the highest morbidity and mortality rates among all types of cancer. Its incidence continues to increase, especially in developing countries. Although the medical field has witnessed the development of targeted therapies, new treatment options need to be developed urgently. For the discovery of new drugs, human cancer models are required to study drug efficiency in a relevant setting. Here, we report the generation of a non-small cell lung cancer model with a perfusion system. The bioprinted model was produced by digital light processing (DLP). This technique has the advantage of including simulated human blood vessels, and its simple assembly and maintenance allow for easy testing of drug candidates. In a proof-of-concept study, we applied gemcitabine and determined the IC₅₀ values in the 3D models and 2D monolayer cultures and compared the response of the model under static and dynamic cultivation by perfusion. As the drug must penetrate the hydrogel to reach the cells, the IC₅₀ value was three orders of magnitude higher for bioprinted constructs than for 2D cell cultures. Compared to static cultivation, the viability of cells in the bioprinted 3D model was significantly increased by approximately 60% in the perfusion system. Dynamic cultivation also enhanced the cytotoxicity of the tested drug, and the drug-mediated apoptosis was increased with a fourfold higher fraction of cells with a signal for the apoptosis marker caspase-3 and a sixfold higher fraction of cells positive for PARP-1. Altogether, this easily reproducible cancer model can be used for initial testing of the cytotoxicity of new anticancer substances. For subsequent in-depth characterization of candidate drugs, further improvements will be necessary, such as the generation of a multi-cell type lung cancer model and the lining of vascular structures with endothelial cells.

KIF20A is associated with clinical prognosis and synergistic effect of gemcitabine combined with ferroptosis inducer in lung adenocarcinoma

Gemcitabine (GEM), an antimetabolite that terminates DNA synthesis, is commonly used in the treatment of cancers including lung adenocarcinoma (LUAD). However, downregulation of sensitivity limits the therapeutic effect. Ferroptosis as the new form of regulated cell death has been shown to have great potential for cancer treatment with chemoresistance. Here, three genes with both ferroptosis and GEM-response-associated features were screened from RNA sequencing and public data for constructing an independent risk model. LUAD patients with different risk scores had differences in mutational landscape, gene enrichment pathways, and drug sensitivity. By Cell Counting Kit-8 assay, flow cytometry, and colony forming assay, we demonstrate that GEM and ferroptosis inducer (FIN) imidazole Ketone Erastin had a synergistic combined anti-proliferative effect on LUAD cells and knockdown of KIF20A (the core gene of our model) further enhanced cell death in vitro by inducing ferroptosis. In conclusion, we identified a link between ferroptosis and GEM response in LUAD cells and developed a robust signature that can effectively classify LUAD patients into subgroups with different overall survival. For LUAD, the combined treatment modality of GEM and FIN is potentially effective and KIF20A may be a new therapeutic target.

PTBPs: An immunomodulatory-related prognostic biomarker in pan-cancer

Background: The polypyrimidine tract-binding protein (PTBP) nuclear ribonucleoprotein family of proteins, including PTBP1, PTBP2 and PTBP3, regulate the process of cell proliferation, differentiation, apoptosis and carcinogenesis. PTBPs exhibit oncogenic effects in certain tumors. However, the role of PTBPs in pan-cancer remains unclear. Our study examined the clinical significance and mechanism of PTBPs in pan-cancer.

Methods: We compared the expression of PTBPs in paired and unpaired tissue samples from the Cancer Genome Atlas (TCGA) database. Univariate and multivariate Cox regression, Kaplan–Meier curves, and time-dependent receiver operating characteristic (ROC) curves were used to assess the prognostic significance of PTBPs in pan-cancer. The cBioPortal database also identified genomic abnormalities in PTBPs. TISIDB, TCGA, and Cellminer were used to investigate the relationship between PTBP expression and immune subtypes, immune checkpoint (ICP) genes, tumor mutational burden (TMB), microsatellite instability (MSI), tumor-infiltrating immune cells, and chemosensitivity. cBioPortal was used to search for PTBP co-expressing genes in pan-cancer, and GO and KEGG enrichment analyses were performed to search for PTBP-related signaling pathways.

Results:PTBPs were shown to be widely upregulated in human tumor tissues. PTBP1 showed good prognostic value in ACC, KIRP, and LGG; PTBP2 in ACC and KICH; and PTBP3 in ACC, LGG, and PAAD, with AUC >0.7. PTBPs were differentially expressed in tumor immune subtypes and had a strong correlation with tumor-infiltrating lymphocytes (TILs) in the tumor microenvironment (TME). In addition, PTBP expressions were related to ICP, TMB, and MSI, suggesting that these three PTBPs may be potential tumor immunotherapeutic targets and predict the efficacy of immunotherapy. Enrichment analysis of co-expressed genes of PTBPs showed that they may be involved in alternative splicing, cell cycle, cellular senescence, and protein modification.

Conclusion: PTBPs are involved in the malignant progression of tumors. PTBP1, PTBP2 and PTBP3 may be potential biomarkers for prognosis and immunotherapy in pan-cancer and may be novel immunotherapeutic targets.

A redox probe screens MTHFD1 as a determinant of gemcitabine chemoresistance in cholangiocarcinoma

Cholangiocarcinoma (CCA) is a type of solid tumor derived from the bile duct epithelium that features universal gemcitabine resistance. Here, we utilized a gene-encoded ROS biosensor probe (HyPer3 probe) to sort subpopulations with different redox statuses from CCA cells. The isolated HyPer-low subpopulation CCA cells, which exhibited relatively lower cellular ROS levels, exhibited higher chemoresistance to gemcitabine than HyPer-high subpopulation CCA cells in vitro and in vivo. Mechanistically, increased expression of MTHFD1 was found in HyPer-low cells. Knocking down MTHFD1 in HyPer-low cells enhanced cellular ROS and restored sensitivity to gemcitabine. Furthermore, the MTHFD1 inhibitor antifolate compound methotrexate (MTX) increased cellular ROS, and combining gemcitabine with MTX effectively suppressed cholangiocarcinoma cell growth. In summary, the MTHFD1 level mediated the heterogeneous cellular redox status in CCA, which resulted in chemoresistance to gemcitabine. Our data suggest a novel strategy for CCA chemotherapy.

MicroRNA-147 targets BDNF to inhibit cell proliferation, migration and invasion in non-small cell lung cancer

Lung cancer is one of the most common cancers that threaten human life and health. Recently, microRNAs (miRNAs) have been shown to play a unique role in many malignancies. Although the dysregulation of miR-147 has been detected in non-small cell lung cancer (NSCLC), the biological function of miR-147 is still unknown in NSCLC. The expression of miR-147 was observed by real-time quantitative polymerase chain reaction (RT-qPCR). Methyl thiazolyl tetrazolium (MTT) and Transwell assays were used to investigate the function of miR-147 in NSCLC. Target genes of miR-147 were verified using dual luciferase reporter assay. Western blot analysis was used to explore the PI3K/AKT pathway. The expression of miR-147 was decreased in NSCLC tissues, which was associated with poor prognosis in NSCLC patients. Furthermore, overexpression of miR-147 inhibited the viability and metastasis of NSCLC cells. In addition, miR-147 inhibited epithelial-mesenchymal transition (EMT) and inactivated the PI3K/AKT pathway in NSCLC. Furthermore, miR-147 directly targets brain-derived neurotrophic factor (BDNF) and negatively regulates BDNF expression in NSCLC. Upregulation of BDNF attenuated the inhibitory effect of miR-147 in NSCLC. In conclusion, miR-147 inhibits cell proliferation, migration and invasion in NSCLC through suppressing BDNF expression.

Long noncoding RNA HOXA-AS2 promotes non-small cell lung cancer progression by regulating miR-520a-3p

Background: The HOXA cluster antisense RNA 2 (HOXA-AS2) has recently been discovered to be involved in carcinogenesis in multiple cancers. However, the role and underlying mechanism of HOXA-AS2 in non-small cell lung cancer (NSCLC) yet need to be unraveled. Methods: HOXA-AS2 expression in NSCLC tissues and cell lines was detected using quantitative real-time PCR (qRT-PCR). Furthermore, the effects of HOXA-AS2 on NSCLC cell proliferation, apoptosis, migration, and invasion were assessed by MTS, flow cytometry, wound healing and transwell invasion assays, respectively. Starbase2.0 predicted and luciferase reporter and RNA immunoprecipitation (RIP) assays were used to validate the association of HOXA-AS2 and miR-520a-3p in NSCLC cells. Results: Our results revealed that HOXA-AS2 in NSCLC tissues were up-regulated and cell lines, and were associated with poor prognosis and overall survival. Further functional assays demonstrated that HOXA-AS2 knockdown significantly inhibited NSCLC cell proliferation, induced cell apoptosis and suppressed migration and invasion. Starbase2.0 predicted that HOXA-AS2 sponge miR-520a-3p at 3'-UTR, which was confirmed using luciferase reporter and RIP assays. miR-520a-3p expression was inversely correlated with HOXA-AS2 expression in NSCLC tissues. In addition, miR-520a-3p inhibitor attenuated the inhibitory effect of HOXD-AS2-depletion on cell proliferation, migration and invasion of NSCLC cells. Moreover, HOXA-AS2 could regulate HOXD8 and MAP3K2 expression, two known targets of miR-520a-3p in NSCLC. Conclusion: These findings implied that HOXA-AS2 promoted NSCLC progression by regulating miR-520a-3p, suggesting that HOXA-AS2 could serve as a therapeutic target for NSCLC.

The Hsp70 co-chaperone Ydj1/HDJ2 regulates ribonucleotide reductase activity

Hsp70 is a well-conserved molecular chaperone involved in the folding, stabilization, and eventual degradation of many “client” proteins. Hsp70 is regulated by a suite of co-chaperone molecules that assist in Hsp70-client interaction and stimulate the intrinsic ATPase activity of Hsp70. While previous studies have shown the anticancer target ribonucleotide reductase (RNR) is a client of Hsp70, the regulatory co-chaperones involved remain to be determined. To identify co-chaperone(s) involved in RNR activity, 28 yeast co-chaperone knockout mutants were screened for sensitivity to the RNR-perturbing agent Hydroxyurea. Ydj1, an important cytoplasmic Hsp70 co-chaperone was identified to be required for growth on HU. Ydj1 bound the RNR subunit Rnr2 and cells lacking Ydj1 showed a destabilized RNR complex. Suggesting broad conservation from yeast to human, HDJ2 binds R2B and regulates RNR stability in human cells. Perturbation of the Ssa1-Ydj1 interaction through mutation or Hsp70-HDJ2 via the small molecule 116-9e compromised RNR function, suggesting chaperone dependence of this novel role. Mammalian cells lacking HDJ2 were significantly more sensitive to RNR inhibiting drugs such as hydroxyurea, gemcitabine and triapine. Taken together, this work suggests a novel anticancer strategy-inhibition of RNR by targeting Hsp70 co-chaperone function.

Ribonucleotide reductase (RNR) is a key enzyme in the synthesis of DNA and inhibition of RNR leads to cellular sensitivity to radiation. As such, RNR is a well-validated therapeutic target for a variety of diseases including cancer. Anti-RNR drugs are effective but are associated with a range of side effects in patients. Our previous work had identified that the Hsp90 and Hsp70 molecular chaperone proteins regulate RNR. The specificity and activity of Hsp70 and Hsp90 are regulated by “co-chaperone” proteins. We examined RNR activity in cells lacking individual co-chaperones and identified the Ydj1/HDJ2 protein as a novel regulator of RNR in yeast and human cells. Importantly, we demonstrate that inhibiting HDJ2 sensitizes cells to currently used anticancer drugs.

PEGylated squalenoyl-gemcitabine nanoparticles for the treatment of glioblastoma

New treatments for glioblastoma multiforme (GBM) are desperately needed, as GBM prognosis remains poor, mainly due to treatment resistance, poor distribution of therapeutics in the tumor tissue, and fast metabolism of chemotherapeutic drugs in the brain extracellular space. Convection-enhanced delivery (CED) of nanoparticles (NPs) has been shown to improve the delivery of chemotherapeutic drugs to the tumor bed, providing sustained release, and enhancing survival of animals with intracranial tumors. Here we administered gemcitabine, a nucleoside analog used as a first line treatment for a wide variety of extracranial solid tumors, within squalene-based NPs using CED, to overcome the above-mentioned challenges of GBM treatment. Small percentages of poly(ethylene) glycol (PEG) dramatically enhanced the distribution of squalene-gemcitabine nanoparticles (SQ-Gem NPs) in healthy animals and tumor-bearing animals after administration by CED. When tested in an orthotopic model of GBM, SQ-Gem-PEG NPs demonstrated significantly improved therapeutic efficacy compared to free gemcitabine, both as a chemotherapeutic drug and as a radiosensitizer. Furthermore, MR contrast agents were incorporated into the SQ-Gem-PEG NP formulation, providing a way to non-invasively track the NPs during infusion.

Phase 1 adaptive dose-finding study of neoadjuvant gemcitabine combined with radiation therapy for patients with high-risk extremity and trunk soft tissue sarcoma

BACKGROUND

This study was performed to determine the maximum tolerated dose (MTD) of gemcitabine given concurrently with preoperative, fixed-dose external-beam radiation therapy (EBRT) for patients with resectable, high-risk extremity and trunk soft tissue sarcoma (STS).

METHODS

Gemcitabine was administered on days 1, 8, 22, 29, 43, and 50 with EBRT (50 Gy in 25 fractions over 5 weeks). The gemcitabine MTD was determined with a toxicity severity weight method (TSWM) incorporating 6 toxicity types. The TSWM is a Bayesian procedure that choses each cohort's dose to have a posterior mean total toxicity burden closest to a predetermined clinician-defined target. Clinicopathologic and outcome data were also collected.

RESULTS

Thirty-six patients completed the study. According to the TSWM, the gemcitabine MTD was 700 mg/m(2). At this dose level, 4 patients (24%) experienced grade 4 toxicity; no toxicity-related deaths occurred. All tumors were resected with microscopically negative margins. Pathologic responses of >90% tumor necrosis were achieved in 17 patients (47%); 14 (39%) had complete responses. With a median follow-up of 6.2 years, the 5-year locoregional recurrence-free survival, distant metastasis-free survival, and overall survival rates were 85%, 80%, and 86%, respectively.

CONCLUSIONS

The TSWM combines data from qualitatively different toxicities and can be used to determine the MTD for a drug given as part of a multimodality treatment. Neoadjuvant gemcitabine plus radiation therapy is feasible and safe in patients with high-risk extremity and trunk STS. Major pathologic responses can be achieved, and after complete resection, long-term clinical outcomes are encouraging.

Preclinical absorption, distribution, metabolism, and excretion of an oral amide prodrug of gemcitabine designed to deliver prolonged systemic exposure

Gemcitabine is an intravenously administered nucleoside analog chemotherapeutic agent. The ability to deliver this agent as an oral drug would allow greater flexibility of administration and patient convenience; however, attempts have been fraught with high first-pass metabolism and potential intestinal toxicity. Alternatively, an amide prodrug of gemcitabine (LY2334737) was discovered, which is able to avoid the extensive first-pass metabolism that occurs following administration of gemcitabine. Preclinical in vitro and in vivo experiments were conducted to evaluate the hydrolysis and pharmacokinetics of LY2334737 and its downstream metabolites. In mice, rats, and dogs, the prodrug is absorbed largely intact across the intestinal epithelium and delivers LY2334737 to systemic circulation. The hydrolysis of LY2334737 is relatively slow, resulting in sustained release of gemcitabine in vivo. In vitro experiments identified carboxylesterase 2 (CES2) as a major enzyme involved in the hydrolysis of LY2334737, but with relatively low intrinsic clearance. Following hydrolysis of the prodrug, gemcitabine is cleared predominantly via the formation of its inactive metabolite dFdU. Both biliary and renal excretion was responsible for the elimination of LY2334737 and its metabolites in both mice and dogs.

Quantification of gemcitabine incorporation into human DNA by LC/MS/MS as a surrogate measure for target engagement

In this study, we report a method for direct determination of gemcitabine incorporation into human DNA. Gemcitabine (dFdC), a structural analog of the nucleoside deoxycytidine (dC), derives its primary antitumor activity through interruption of DNA synthesis. Unlike other surrogate measures, DNA incorporation provides a mechanistic end point useful for dose optimization. DNA samples (ca. 25 microg) were hydrolyzed using a two-step enzymatic procedure to release dFdC which was subsequently quantified by LC-ESI-MS/MS using stable isotope labeled internal standards and selected reaction monitoring (SRM). dFdC was quantitated and reported relative to deoxyguanosine (dG) since dG is the complementary base for both dFdC and dC. The SRM channel for dG was detuned using collision energy as the attenuating parameter in order to accommodate the difference in relative abundance for these two analytes (>104) and enable simultaneous quantification from the same injection. The assay was shown to be independent of the amount of DNA analyzed. The method was validated for clinical use using a 3 day procedure assessing precision, accuracy, stability, selectivity, and robustness. The validated ranges for dFdC and dG were 5-7500 pg/mL and 0.1-150 microg/mL, respectively. Results are presented which confirm that the ratio of dFdC to dG in DNA isolated from tumor cells incubated with dFdC increases with increased exposure to the drug and that dFdC can also be quantified from DNA extracted from blood.

Dose escalation of gemcitabine concomitant with radiation and cisplatin for nonsmall cell lung cancer: a phase 1-2 study

BACKGROUND

The current study was conducted to evaluate the maximum tolerable dose of weekly gemcitabine administered simultaneously with radiation and cisplatin in patients with locally advanced nonsmall cell lung cancer (NSCLC).

METHODS

Patients with stage IIIA/B NSCLC received concurrently 63 grays radiation and 20 mg/m² cisplatin Day 1 to 3 in Weeks 1 and 5, plus weekly gemcitabine at escalating doses (150-700 mg/m²) on Fridays after radiation to avoid radiosensitization. The authors assessed dose-limiting toxicities according to Common Toxicity Criteria. The primary endpoint was maximum tolerated dose (MTD) of gemcitabine. Tumor resectability, survival, and disease-free survival (DFS) were also determined.

RESULTS

Forty-two patients were accrued, of whom 95% received radiation and 66% cisplatin as above. Weekly doses of gemcitabine were escalated to 700 mg/m². Grade 3 dysphagia and 1 case of fatal, probably treatment-related pulmonary deterioration established the MTD of gemcitabine at 550 mg/m² weekly. Twenty-five patients underwent surgery, and histopathological complete regression was documented in 26% of these patients. Overall, median actuarial survival and DFS were 23.8 and 12.4 months, respectively.

CONCLUSIONS

Gemcitabine at doses up to 550 mg/m² weekly can be given simultaneously with radiation and cisplatin to patients with locally advanced NSCLC. Radical resection thereafter is feasible. The impact of this aggressive therapy should be evaluated further.

High frequency of radiation pneumonitis in patients with locally advanced non-small cell lung cancer treated with concurrent radiotherapy and gemcitabine after induction with gemcitabine and carboplatin

INTRODUCTION

The combination of chemotherapy and thoracic radiation is the standard treatment for locally advanced non-small cell lung cancer (NSCLC). However, most favorable chemotherapy regimen, timing of full-dose chemotherapy, and optimal combination of chemotherapy with radiation remain to be determined. Our primary objective was to evaluate the efficacy and safety of gemcitabine concurrent with radiotherapy after induction chemotherapy with gemcitabine plus carboplatin for locally advanced NSCLC.

PATIENTS AND METHODS

Patients with histologically proven NSCLC stage IIIA and -B received carboplatin (area under the curve of 2.5) and gemcitabine (800 mg/m) on days 1 and 8, every 21 days for two cycles, followed by conventional fractioned thoracic radiotherapy and concomitant weekly gemcitabine 200 mg/m, and finally, consolidation chemotherapy.

RESULTS

Inclusion was discontinued because of high-grade 3 to 5 radiation-pneumonitis events (6 of 19 patients, 31.6%), including one treatment-related death associated with radiation pneumonitis. Median follow-up was 11.9 months. Most common grades 3/4 hematological side effects comprised anemia, neutropenia 3 of 19 patients, each (15.8%), and thrombocytopenia (4 of 19, 21.1%) during induction. Partial response was observed in 10 patients (52.6%) following induction chemotherapy. After concurrent chemo-radiotherapy, overall response was 68.4%. Four patients (21.1%) underwent surgical resection. Median progression-free survival and overall survival were 12 +/- 1 month (95% confidence interval [CI], 9.8-14.1) and 21 +/- 3.5 months (95% CI, 14-27.9 months), respectively.

CONCLUSION

Concurrent radiotherapy with gemcitabine after induction with gemcitabine and carboplatin showed a high-response rate; however, it is associated with excessive pulmonary toxicity. Adjustments in gemcitabine dosage during radiotherapy or changes in radiotherapy planning could reduce toxicity.

Outpatient Chemotherapy plus Radiotherapy in Sarcomas: Improving Cancer Control with Radiosensitizing Agents

Background

Cancer control by radiotherapy (RT) can be improved with concurrent chemotherapy. Outpatient strategies for sarcomas that combine chemotherapy and RT are possible since supportive care and RT techniques have improved.

Methods

The current status of non-anthracycline chemotherapy in combination with radiation for high-risk sarcoma is reviewed.

Results

Ifosfamide with mesna and newer activated ifosfamide agents (ZIO-201 and glufosfamide) have high potential to improve sarcoma cancer control. In Ewing's sarcoma and osteosarcoma, high-dose ifosfamide with mesna (2.8 g/m2/day of each x 5 days; mesna day 6) can be safely given to outpatients using continuous infusion. Reducing ifosfamide nephrotoxicity and central nervous system side effects are discussed. Other outpatient radiosensitization regimens include gemcitabine (600–1000 mg/m2/dose IV over 1 hour weekly x 2–3 doses), temozolomide (75 mg/m2/daily x 3–6 weeks), or temozolomide (100 mg/m2/dose daily x 5) + irinotecan (10 mg/m2/dose daily x 5 x 2 weeks). In osteosarcoma with osteoblastic metastases on bone scan, samarium (1 mCi/kg; day 3 of RT) and gemcitabine (600 mg/m2 IV over 1 hour day 9 of RT) is a radiosensitization strategy. Future drugs for radiosensitization include beta-D-glucose targeted activated ifosfamide (glufosfamide) and sapacitabine, an oral nucleoside with in vitro activity against solid tumors including sarcomas.

Conclusions

The potential to treat major causes of sarcoma treatment failure (local recurrence and distant metastases) with concurrent chemotherapy during radiation should be considered in high-grade sarcomas.

Chimioradiothérapie exclusive des cancers bronchiques non à petites cellules localement évolués

Chemoradiation is one of the major therapeutic options in thoracic oncology: besides surgery, the best treatment for early-stage tumors, and chemotherapy, not only used in metastatic tumors, but also in a neoadjuvant and adjuvant setting, chemoradiation is the standard strategy for unresectable locally advanced non-small cell lung cancer. Its current modalities include three-dimensional conformal techniques, allowing dose escalation and sequential and concurrent combination with new generation cytotoxic agents to occur. Phase III trials are currently evaluating the benefit from induction and consolidation chemotherapy in this setting. New techniques of radiation may also increase the efficacy and the feasibility of radiation. This constant progress makes chemoradiation one of the most promising combined treatments in thoracic oncology.

Complications aiguës et tardives des irradiations thoraciques

Radiotherapy of lung cancer is often complexe because of several organs at risk such as lung, heart, esophagus or spinal cord. An accurate balance needs to be defined between the necessities to reach a local control and to limit the risks of toxicities for each of them. Several parameters were significantly correlated with radiation induced lung toxicities (V13, V20, 30, Mean Dose) and esophagitis (V40 to V60). However no parameters are clearly defined for heart toxicities. The large number of parameters described for lung and esophagus highlights the necessity to perform an overall analysis of the DVHs that could be possible by using Nomal Tissue Complication Probability models.