He et al. BMC Cancer 2010, 10:681 http://www.biomedcentral.com/1471-2407/10/681 exponent, i.e. 0 or 1 according to the Eastern Coopera- tive Oncology Group (ECOG) performance status; ade- quate renal, hepatic, cardiac and hematologic function. One week before enrolment in the study, the hematolo- gic test should meet the following criteria: WBC ≥ 4.0 × 109/L, ANC ≥ 2.0 × 109/L, HB ≥ 10 g/dL, PLT ≥ 100 × 109/L, TBI, ALT, AST, ALP and Cr counts less than 1.5 times the maximal peak, and TBI, ALT, AST, ALP less than 5 times the peak if liver metastasis occurs. Patients were not enrolled in the study if they had only immeasurable lesions, such as malignant pleural effusion, ill-defined pulmonary densities and osseous metastasis, or if their only measurable lesion had received radiotherapy during the research; or they had brain metastases or meningeal metastases. The study was totally in compliance with the Declara- tion of Helsinki, and was formally approved by the med- ical ethics committee of the First Hospital of China Medical University (No.200715). Each patient gave a written informed consent before any study-related pro- cedures were performed. Treatments All patients with advanced NSCLC were assigned to a combination of platinum-based chemotherapy, i.e. NP (vinorelbine, 25 mg/m2 on days 1 and 8; cisplatin, 75-80 mg/m2 on day 1), GP (gemcitabine, 1000 mg/m2 on days 1 and 8; cisplatin, 75-80 mg/m2 on day 1), PP (paclitaxel, 135-175 mg/m2 on day 1; cisplatin, 75-80 mg/m2 on day 1) or TP (docetaxel, 75 mg/m2 on day 1; cisplatin, 75-80 mg/m2 on day 1) treatment schemes according to their own conditions and wishes. Each patient received 4-6 courses of chemotherapy, and each course lasted 3 weeks. An assessment was made after every 2 courses of chemotherapy. Patients with PD were excluded from this group and received a different treatment regimen. Dosage Adjustment Scheme Adverse events were graded according to the National Cancer Institute Common Toxicity Criteria (NCI-CTC) toxicity scale. If hematologic toxicity III or greater occurred, the dosage for the next cycle was decreased to 75-85% of the original dosage or the next course of treat- ment was postponed by 1 or 2 weeks. If hematologic toxicity III or greater remained, or a fever from combined severe infection and granulocytopenia IV occurred, the planned treatment was terminated. If non-hematologic toxicity (except trichomadesis) III or greater occurs, the dosage for the next course was adjusted to 75-85% of the original dosage. If cardiotoxicity II - IV occurred, treat- ment was discontinued. Throughout chemotherapy, adju- vant medicine such as antanacathartic, colony- stimulating factor and diphosphonate were given to reduce adverse events when necessary. Page 3 of 11 Image Data Collection and Study Each patient had a base-line check within one month before their first-line chemotherapeutic treatment started. To ensure the credibility of the study, images of measurable lesions were obtained by the qualified radiol- ogists through CT or Spiro-CT scans. Subsequent images were obtained by the same radiologist after the first 2 courses of chemotherapy for each patient. To minimize variation between operators, all measurements of the images were done at the same anatomic level and orien- tation by an independent qualified radiologist. In contrast with the base-line images, any change in the size of target lesions was calculated according to RECIST ver.1.1. Patients with an increase of 20% or more in lesion size or those with new lesions were regarded as having PD and were excluded from the study. Patients with a change of lesion size ranging from an increase of <20% to a decrease of <30% and with no new lesion were stratified as having SD. Patients with a 30% or greater decrease in the target lesion were regarded as achieving PR. Patients with disappearance of the lesion were stratified as achiev- ing CR. For those with SD, the percentage of change in tumour size has been recorded for further study. Follow-up Visit A follow-up visit was given to each patient who achieved CR, PR and SD. The assessment process was repeated every 2 courses until the end of the che- motherapy, or the aggravation of the disease, and after that, every 2 months until the progression of the disease or death occurred. This kind of service could be pro- vided to meet a patient’s need at any time. The percen- tage of change in size of target tumours and the PFS were the main contents for a follow-up visit. Statistical Analysis SPSS13.0 software was used for all statistical analysis. The correlation between the change in size of target lesions before and after the first two courses of che- motherapy and their PFS and OS were calculated. According to the RECIST ver.1.1, the sum of the longest dimension of all the target lesions was calculated for each patient to provide the baseline before treatment. The same measurements and calculation were done after the first two courses of chemotherapy to obtain the initial assessment sum. The change ratio of target lesions was calculated as: (Assessment sum − Baseline sum) / Baseline sum The primary endpoint was PFS, which is calculated from the date of first treatment to disease progression (local or metastatic) or death; and the secondary end- point was OS, which is calculated from the date of first