Radioprotective effect of amifostine in patients with head and neck squamous cell carcinoma

Interventions for preventing oral mucositis for patients with cancer receiving treatment

BACKGROUND

Treatment of cancer is increasingly more effective but is associated with short and long term side effects. Oral side effects remain a major source of illness despite the use of a variety of agents to prevent them. One of these side effects is oral mucositis (mouth ulcers).

OBJECTIVES

To evaluate the effectiveness of prophylactic agents for oral mucositis in patients with cancer receiving treatment, compared with other potentially active interventions, placebo or no treatment.

SEARCH STRATEGY

Electronic searches of Cochrane Oral Health Group and PaPaS Trials Registers (to 1 June 2010), CENTRAL (The Cochrane Library 2010, Issue 2), MEDLINE via OVID (1950 to 1 June 2010), EMBASE via OVID (1980 to 1 June 2010), CINAHL via EBSCO (1980 to 1 June 2010), CANCERLIT via PubMed (1950 to 1 June 2010), OpenSIGLE (1980 to 2005) and LILACS via the Virtual Health Library (1980 to 1 June 2010) were undertaken. Reference lists from relevant articles were searched and the authors of eligible trials were contacted to identify trials and obtain additional information.

SELECTION CRITERIA

Randomised controlled trials of interventions to prevent oral mucositis in patients receiving treatment for cancer.

DATA COLLECTION AND ANALYSIS

Information regarding methods, participants, interventions, outcome measures, results and risk of bias were independently extracted, in duplicate, by two review authors. Authors were contacted for further details where these were unclear. The Cochrane Collaboration statistical guidelines were followed and risk ratios calculated using random-effects models.

MAIN RESULTS

A total of 131 studies with 10,514 randomised participants are now included. Nine interventions, where there was more than one trial in the meta-analysis, showed some statistically significant evidence of a benefit (albeit sometimes weak) for either preventing or reducing the severity of mucositis, compared to either a placebo or no treatment. These nine interventions were: allopurinol, aloe vera, amifostine, cryotherapy, glutamine (intravenous), honey, keratinocyte growth factor, laser, and polymixin/tobramycin/amphotericin (PTA) antibiotic pastille/paste.

AUTHORS' CONCLUSIONS

Nine interventions were found to have some benefit with regard to preventing or reducing the severity of mucositis associated with cancer treatment. The strength of the evidence was variable and implications for practice include consideration that benefits may be specific for certain cancer types and treatment. There is a need for further well designed, and conducted trials with sufficient numbers of participants to perform subgroup analyses by type of disease and chemotherapeutic agent.

Differential radiation protection of salivary glands versus tumor by Tempol with accompanying tissue assessment of Tempol by magnetic resonance imaging

PURPOSE

The nitroxide free radical, Tempol, was evaluated for potential differential radiation protection of salivary glands and tumor using fractionated radiation. Mechanistic information was explored by monitoring the presence and bioreduction of Tempol in both tissues noninvasively by magnetic resonance imaging (MRI).

EXPERIMENTAL DESIGN

Female C3H mice were immobilized using custom-made Lucite jigs for localized irradiation (five daily fractions) either to the oral cavity or tumor-bearing leg. Tempol (275 mg/kg) was administered (i.p.) 10 min before each radiation fraction. Salivary gland damage was assessed 8 weeks after radiation by measuring pilocarpine-mediated saliva output. Tumor growth was assessed by standard radiation regrowth methods. Dynamic T1-weighted magnetic resonance scans were acquired before and after Tempol injection using a 4.7T animal MRI instrument.

RESULTS

Tempol treatment was found to protect salivary glands significantly against radiation damage (approximately 60% improvement); whereas no tumor protection was observed. Intracellular reduction of Tempol to the nonradioprotective hydroxylamine as assessed by MRI was 2-fold faster in tumor compared with salivary glands or muscle.

CONCLUSIONS

Tempol provided salivary gland radioprotection and did not protect tumor, consistent with the hypothesis that differential radioprotection by Tempol resides in faster reduction to the nonradioprotective hydroxylamine in tumor compared with normal tissues. The unique paramagnetic properties of Tempol afforded noninvasive MRI monitoring of dynamic changes of Tempol levels in tissue to support the finding. These data support further development and consideration of Tempol for human clinical trials as a selective protector against radiation-induced salivary gland damage.

Interventions for preventing oral mucositis for patients with cancer receiving treatment

BACKGROUND

Treatment of cancer is increasingly more effective but is associated with short and long-term side effects. Oral side effects remain a major source of illness despite the use of a variety of agents to prevent them. One of these side effects is oral mucositis (mouth ulcers).

OBJECTIVES

To evaluate the effectiveness of prophylactic agents for oral mucositis in patients with cancer receiving treatment, compared with other potentially active interventions, placebo or no treatment.

SEARCH STRATEGY

The Cochrane Oral Health Group Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE were searched. Reference lists from relevant articles were scanned and the authors of eligible studies were contacted to identify trials and obtain additional information. Date of most recent searches: April 2004.

SELECTION CRITERIA

Trials were selected if they met the following criteria: design - random allocation of participants; participants - anyone with cancer receiving chemotherapy or radiotherapy treatment for cancer; interventions - agents prescribed to prevent oral mucositis; outcomes - prevention of mucositis, pain, amount of analgesia, dysphagia, systemic infection, length of hospitalisation, cost and patient quality of life.

DATA COLLECTION AND ANALYSIS

Information regarding methods, participants, interventions and outcome measures and results were independently extracted, in duplicate, by two review authors. Authors were contacted for details of randomisation and withdrawals and a quality assessment was carried out. The Cochrane Oral Health Group statistical guidelines were followed and risk ratios (RR) calculated using random-effects models.

MAIN RESULTS

Two hundred and two studies were eligible. One hundred and thirty two were excluded for various reasons, usually as there was no useable information on mucositis. Of the 71 useable studies all had data for mucositis comprising 5217 randomised patients. Interventions evaluated were: acyclovir, allopurinol mouthrinse, aloe vera, amifostine, antibiotic pastille or paste, benzydamine, beta carotene, calcium phosphate, camomile, chlorhexidine, clarithromycin, folinic acid, glutamine, GM-CSF, honey, hydrolytic enzymes, ice chips, iseganan, keratinocyte GF, misonidazole, oral care, pentoxifylline, povidone, prednisone, propantheline, prostaglandin, sucralfate, traumeel and zinc sulphate. Of the 29 interventions included in trials, 10 showed some evidence of a benefit (albeit sometimes weak) for either preventing or reducing the severity of mucositis. Interventions where there was more than one trial in the meta-analysis finding a significant difference when compared with a placebo or no treatment were: amifostine which provided minimal benefit in preventing moderate and severe mucositis RR = 0.84 (95% confidence interval (CI) 0.75 to 0.95) and 0.60 (95% CI 0.37 to 0.97), antibiotic paste or pastille demonstrated a moderate benefit in preventing mucositis RR = 0.87 (95% CI 0.79 to 0.97), hydrolytic enzymes reduced moderate and severe mucositis with RRs = 0.52 (95% CI 0.36 to 0.74) and 0.17 (95% CI 0.06 to 0.52), and ice chips prevented mucositis at all levels RR = 0.63 (95% CI 0.44 to 0.91), 0.43 (95% CI 0.23 to 0.81), 0.27 (95% CI 0.11 to 0.68). Other interventions showing some benefit with only one study were: benzydamine, calcium phosphate, honey, oral care protocols, povidone and zinc sulphate. The number needed to treat (NNT) to prevent one patient experiencing moderate or severe mucositis over a baseline incidence of 60% for amifostine is 10 (95% CI 7 to 33), antibiotic paste or pastille 13 (95% CI 8 to 56), hydrolytic enzyme 4 (95% CI 3 to 6) and ice chips 5 (95% CI 3 to 19). When the baseline incidence is 40%/90% the NNTs for amifostine are 16/7, for antibiotic paste or pastille 19/7, for hydrolytic enzyme 5/3 and for ice chips 7/3. The general reporting of RCTs was poor. However, the assessments of the quality of the randomisation improved when the authors provided additional information.

AUTHORS' CONCLUSIONS

Several of the interventions were found to have some benefit at preventing or reducing the severity of mucositis associated with cancer treatment. The strength of the evidence was variable and implications for practice include consideration that benefits may be specific for certain cancer types and treatment. There is a need for well designed and conducted trials with sufficient numbers of participants to perform subgroup analyses by type of disease and chemotherapeutic agent.