Review question
The review is going to resolve conflicting evidence: whether the molecular-targeted agents improves the survival for patients with NSCLC.

Sources to be searched
PubMed, EMBASE, and Cochrane Center Register of Controlled Trials. Websites for the information of registered randomized controlled trials (RCTs): http://www.who.int/triasearch and http://www.ClinicalTrials.gov . Annual meeting proceedings of American Society of Clinical Oncology (ASCO).

Types of study to be included
To be included in this meta-analysis, trials should have compared molecular-targeted agents with either placebo or observation, or multi-molecular-targeted agents with single agent in maintenance treatment of patients with NSCLC. After initial therapy, options for maintenance therapy including: (1) continuing treatment with at least one of the molecular-targeted agents given in the initial therapy (continuous design); (2) switching to new molecular-targeted agents (switch design).

Participants
Eligible patients had histologically or cytologically confirmed stage IV, stage IIIB (with malignant pleural effusion), or recurrent (after radiotherapy or surgery) NSCLC with bidimensionally measurable disease, were >18 years of age, and had an ECOG PS less than two.

Interventions
Molecular-targeted agents vs either placebo or observation; or multi-molecular-targeted agents vs single agent for maintenance treatment of patients with NSCLC.

Primary outcomes
1. Number of patients dying (primary outcome measure). When the number is not reported by the authors we will contact them for further information.
2. Objective response, according to the World Health Organization (WHO 1981) criteria (See Appendix 1). When the authors have used different definition criteria, we will report them.

Key secondary outcomes
1. overall survival (OS): from the date of randomization to the date of patient death
2. progression-free survival (PFS): from the date of randomization to date of objective disease progression
3. Adverse events (AE): WHO grade 3 or greater toxicity between maintenance arm and non maintenance arm as the percentage of treated patients who experienced such toxicity.
4. Quality of life (QoL)

Strategy for data synthesis
Meta-analysis