Data extraction
The following data were extracted from the research included: authors, year of study, study type, number of patients, age, gender, chemotherapy regimen, phase of treatment and patient outcome. To abstract the papers, two authors evaluated different parts of the articles to ensure the relevance of the subject to the research objectives. Results of data classification were reviewed by one of the authors. In terms of article inclusion, if any disagreement existed between the two reviewers, another member of our research team was contacted to resolve any discrepancies.