Rutten et al. BMC Cancer 2012, 12:31 http://www.biomedcentral.com/1471-2407/12/31 conventional staging are recorded in a case record form (CRF). After randomization, but before surgery, patients are asked to fill out a questionnaire consisting of items regarding quality of life (EORTC QoL-C30 and QoL- OV28, EQ-5D) and a questionnaire on additional home- care (SF-HLQ). The same questionnaires are also asked to be completed three months after start of treatment and six weeks upon ending treatment. At local centres, data collection is the responsibility of the local partici- pating gynaecologist and research nurse. The data col- lected in this study are coded and processed with adequate precautions to ensure patients confidentiality. Interventions Debulking surgery should take place within 6 weeks after randomization. When patients receive a laparo- scopy this should be done within 3 weeks after randomi- zation. After the laparoscopy the decision is made for PDS or NACT with IDS after three courses of che- motherapy. The diagnostic laparoscopy will, when possi- ble, be performed by the referring gynaecologist in attendance of the gynaecological oncologist. In case the laparoscopy can not be attended by the gynaecological oncologist and the laparoscopy can not be performed in the centre hospital, the laparoscopic procedure will be recorded completely. An open laparoscopy has to be performed examining systematically the ovaries, fallo- pian tubes, uterus, pelvic peritoneum, omentum, serosa and mesentery of the large and small bowel, spleen, liver surface, paracolic gutters and diaphragm. Tumour localizations will be documented in size and position to adjacent structures. To confirm diagnosis of ovarian cancer biopsies of tumor localizations will be taken. Judgment for incomplete cytoreduction will be made by the gynaecological oncologist on the following parameters: - Extensive agglutinated intra-abdominal metastatic disease - Extensive serosal invasion of the intestines making multiple bowel resections or more than 1,5 m of bowel resection necessary in order to reach complete cytore- ductive surgery. - Extensive peritoneal carcinomatosis at the diaphrag- matic level After laparoscopy patients will be submitted to either PDS within three weeks, followed by six courses of che- motherapy consisting of Paclitaxel and Carboplatin or to NACT followed by IDS and subsequent adjuvant che- motherapy. Both primary and interval debulking sur- geries will be performed in the center hospital or in the referral hospital in collaboration with a gynaecological oncologist according to standard procedures for advanced ovarian cancer. The surgeon will describe the localization and diameter of all tumor depositions before Page 4 of 6 surgery and of residual tumour in the surgical report upon ending surgery. This will be done for 11 abdom- inal regions. The amount of metastases will be classified as 0, 1, 2-10, 11-50 and > 50 tumour deposits. The size of the largest metastasis will be categorized into 0 mm, ≤ 10 mm, 11-20 mm, 21-50 mm, 51-100 mm and ≥ 100 mm in diameter. Furthermore the surgical procedures, total length of the operation and blood loss will be recorded. Follow-up As the primary outcome measure is the rate of subopti- mal debulking surgery, this will be assessed at the end of the surgical intervention. Data for secondary out- comes will be assessed peri-operatively, during treat- ment and at routine follow-up. All data will be registered on a case record form (CRF) by the treating physician and checked by the research nurse (status review). For the economic evaluation use of health care resources is assessed as part of the clinical data collec- tion (CRF) and additional patient questionnaires. The doctor registers resource utilization on a CRF related to the use of operation time, duration of hospital ward and ICU stay, additional diagnostic or therapeutic interven- tions. The questionnaire addresses health related resource use during follow-up, including visits to general practitioners and other primary care providers, outpati- ent visits and readmission, home care and informal care. Adverse events will be followed until they have abated, or until a stable situation has been reached. Data regarding quality of life (QoL-C30, QoL-OV28, EQ-5D,) are assessed with help of self reported questionnaires before start of treatment, at 3 months and at the end of treatment. Outcome measures Our primary outcome measure is the proportion of debulking laparotomies with a largest residual tumour of more than one centimetre in diameter (futile laparotomy). Our secondary outcome measures will be progression- free and overall survival, the number of debulking sur- gery leaving no residual tumour, debulking surgery in which the largest residual tumour is less than 1 cm in diameter, costs and quality of life. Statistical analysis Sample size Considering the present rate of debulking surgeries for ovarian cancer leaving more than one centimetre of resi- dual tumour in the Netherlands after conventional sta- ging is to be at most 40%, we estimate that after laparoscopy this should be less than 20%. With a two- sided significance level of 0.05 90 patients per arm have