Impact of antioxidant supplementation on chemotherapeutic toxicity: a systematic review of the evidence from randomized controlled trials.

Much debate has focused on whether antioxidants interfere with the efficacy of cancer chemotherapy. The objective of this study is to systematically review the randomized, controlled clinical trial evidence evaluating the effects of concurrent use of antioxidants with chemotherapy on toxic side effects. We performed a search of literature from 1966-October 2007 using MEDLINE, Cochrane, CinAhl, AMED, AltHealthWatch and EMBASE databases. Randomized, controlled clinical trials reporting antioxidant-based mitigation of chemotherapy toxicity were included in the final tally. Searches were performed following a standardized protocol for systematic reviews. Only 33 of 965 articles considered, including 2,446 subjects, met the inclusion criteria. Antioxidants evaluated were: glutathione (11), melatonin (7), vitamin A (1), an antioxidant mixture (2), N-acetylcysteine (2), vitamin E (5), selenium (2), L-carnitine (1), Co-Q10 (1) and ellagic acid (1). The majority (24) of the 33 studies included reported evidence of decreased toxicities from the concurrent use of antioxidants with chemotherapy. Nine studies reported no difference in toxicities between the 2 groups. Only 1 study (vitamin A) reported a significant increase in toxicity in the antioxidant group. Five studies reported the antioxidant group completed more full doses of chemotherapy or had less-dose reduction than control groups. Statistical power and poor study quality were concerns with some studies. This review provides the first systematically reviewed evidence that antioxidant supplementation during chemotherapy holds potential for reducing dose-limiting toxicities. However, well-designed studies evaluating larger populations of patients given specific antioxidants defined by dose and schedule relative to chemotherapy are warranted.

Impact of antioxidant supplementation on chemotherapeutic efficacy: a systematic review of the evidence from randomized controlled trials.

PURPOSE: Much debate has arisen about whether antioxidant supplementation alters the efficacy of cancer chemotherapy. Some have argued that antioxidants scavenge the reactive oxygen species integral to the activity of certain chemotherapy drugs, thereby diminishing treatment efficacy. Others suggest antioxidants may mitigate toxicity and thus allow for uninterrupted treatment schedules and a reduced need for lowering chemotherapy doses. The objective of this study is to systematically review the literature in order to compile results from randomized trials that evaluate concurrent use of antioxidants with chemotherapy. DESIGN: MEDLINE, Cochrane, CinAhl, AMED, AltHealthWatch and EMBASE databases were searched. Only randomized, controlled clinical trials that reported survival and/or tumor response were included in the final tally. The literature searches were performed in duplicate following a standardized protocol. No meta-analysis was performed due to heterogeneity of tumor types and treatment protocols used in trials that met the inclusion criteria. RESULTS: Of 845 articles considered, 19 trials met the inclusion criteria. Antioxidants evaluated were: glutathione (7), melatonin (4), vitamin A (2), an antioxidant mixture (2), vitamin C (1), N-acetylcysteine (1), vitamin E (1) and ellagic acid (1). Subjects of most studies had advanced or relapsed disease. CONCLUSION: None of the trials reported evidence of significant decreases in efficacy from antioxidant supplementation during chemotherapy. Many of the studies indicated that antioxidant supplementation resulted in either increased survival times, increased tumor responses, or both, as well as fewer toxicities than controls; however, lack of adequate statistical power was a consistent limitation. Large, well-designed studies of antioxidant supplementation concurrent with chemotherapy are warranted.

Making circadian cancer therapy practical.

Practical circadian therapy for the cancer patient involves 3 spheres of intervention-improving lifestyle, optimizing internal biochemical milieu, and adjusting treatment times. The potential value of improving overall circadian functioning is shown in the work of Mormont et al in which pronounced rest-activity rhythms were associated with better survival in colorectal cancer patients receiving chronomodulated chemotherapy. Lifestyle interventions that may improve circadian functioning involve diet, physical activity, and mind-body therapies. A diet that is anti-inflammatory and has appropriate carbohydrate intake, as well as regular meal timing, encourages normal circadian cycles. Adequate daytime physical activity encourages restful sleep, and morning light exposure during exercise may entrain melatonin rhythms. Meditation and other mind-body therapies can reduce anxiety and depression that may disrupt sleep. Aspects of the biochemical milieu that specifically disrupt circadian functioning are inflammation and stress hormones. Inflammation and cytokine disruption can be addressed with diet, herbs, and other natural substances. Chronomodulation of chemotherapy in a US clinical setting will be discussed. A series of 12 cases will be presented of patients who experienced grade 3 to 4 toxicities with various chemotherapy regimens for colorectal cancer. When rechallenged with the same regimens administered chronotherapeutically, none of the patients experienced grade 3 to 4 toxicity. Integrating all the above treatment modalities has the potential to improve both the quality of life and disease outcomes in cancer patients.

Phase I study of induction chemotherapy and concomitant chemoradiotherapy with irinotecan, carboplatin, and paclitaxel for stage III non-small cell lung cancer.

BACKGROUND: The aim of this study was to determine the maximum tolerated dose (MTD), dose limiting toxicities (DLTs), and determine the phase II dose for the combination of irinotecan-carboplatin-paclitaxel given as induction chemotherapy and with concomitant chest radiotherapy for patients with Stage III non-small cell lung cancer. METHODS: Patients with Cancer and Leukemia Group B performance status of 0 to 2, stage IIIA and IIIB NSCLC patients with resectable or unresectable disease were treated with induction chemotherapy (irinotecan 100 mg/m2, carboplatin AUC 5, and paclitaxel 175 mg/m2 days 1 and 22) followed by concomitant chemotherapy (irinotecan, carboplatin, and paclitaxel) and chest radiotherapy (66 Gy for unresectable and 50 Gy for resectable disease) beginning on week 7. The primary objective was to escalate the dose of irinotecan during chemoradiation in sequential cohorts to determine the DLT and MTD of the regimen. RESULTS: Thirty-eight patients were enrolled (median age 63 years, 57% male, 41% performance status 0, 30% resectable). Induction chemotherapy was tolerable and active (response rate 26%; stable disease 60%). Eight patients did not receive concurrent chemoradiotherapy because of progressive disease (5), death (1), hypersensitivity reaction to paclitaxel (1), and withdrawal of consent (1). Twenty-nine patients received concurrent chemoradiotherapy. The concomitant administration of chest radiotherapy with weekly irinotecan, carboplatin, and paclitaxel was not feasible at the first, second, and third dose levels. DLT was failure to achieve recovery to

Phase II trials of dolastatin-10 in advanced pancreaticobiliary cancers.

BACKGROUND: Pancreaticobiliary malignancies respond poorly to conventional chemotherapy, and novel agents are needed. Dolatstatin-10 is a potent antimitotic pentapeptide isolated from the marine mollusk Dolabella auricularia that inhibits microtubule assembly. We conducted 2 parallel phase II trials of dolastatin-10 in patients with advanced hepatobiliary cancers and pancreatic adenocarcinoma. PATIENTS AND METHODS: Eligible patients had histologically-confirmed metastatic pancreatic adenocarcinoma or metastatic, locally advanced or recurrent cancer of the liver, bile duct or gallbladder, and had received no prior chemotherapy for advanced disease. Dolastatin-10 400 microg/m(2) was administered intravenously by bolus every 21 days. Restaging CT scans were obtained every 2 cycles. RESULTS: Twenty-eight patients (16 hepatobiliary, including 7 hepatomas, 6 cholangiocarcinomas, 2 gallbladder carcinomas, and 12 pancreatic carcinomas) enrolled; 27 were evaluable for response. There were no objective responses. Grade 3/4 neutropenia occurred in 59% of patients and neutropenic fever in 18%. Median and 1-year survival were 5.0 months and 17% for the pancreatic cancer patients, and 3.0 months and 29% for the hepatobiliary patients. Median time to progression was 1.3 months for the pancreatic cancer patients and 1.6 months for the hepatobiliary patients. CONCLUSIONS: Dolastatin-10 is inactive against hepatobiliary and pancreatic carcinomas.