Study description This is an observational study aimed to prospectively evaluate the long term morbidity of aggressive surgical approach to RSTS and the impact over the patients' quality of life. Consecutive patients candidate to surgery for primary RSTS will be offered to be enrolled. We plan to include all the RSTS patients consecutively operated on for primary retroperitoneal sarcoma from first accrual on up to the 24 months after the study start.
At the entrance of the study, an informed written consent will be obtained. Study participants will be asked to complete four self-filled in one-off questionnaires (see "Study parameters" paragraph).
Study parameters Study parameters EORTC QLQ-CR29 and EORTC QLQ C30 questionnaires (baseline, 4 mos, 12 mos) LEFS questionnaire (baseline, 4 mos, 12 mos) BPI questionnaire (baseline, 4 mos, 12 mos) DN4 questionnaire (baseline, 4 mos, 12 mos) Serum creatinin (baseline, 4 mos, 12 mos) Morbidity events (4 mos, 12 mos) Neurologic exam of lower limbs (baseline, 4 mos, 12 mos) Disease status (4 mos, 12 mos)
\* In case of preoperatory complementary treatment, the questionnaires will be administrated just before the beginning of the treatment.
* Quality of Life: the core questionnaire, the EORTC QLQC30,is an extensively validated questionnaire for the assessment of health related quality of life in cancer patients (Aaronson 1991). It contains both functional (physical, role, cognitive, emotional, social), and physical symptom multidimensional scales (fatigue, pain, and nausea and vomiting) as well as two single item "global health status" and "quality of life" scales, plus several single-item symptom measures. The QLQ-CR29 is a condition specific module (colo-rectal disease) developed to be used in conjunction with EORTC QLQC30; it is made up of 29 items for a total of four scales assessing urinary frequency, faecal seepage, stool consistency and body image as well a number single items scales. Both the tools are available and validated in the Italian language.
* Femoral Impairment: the dedicated questionnaire (Lower Extremity Functional Scale - Italian Version, LEFS questionnaire) will investigated daily life activities that require ad adequate function of knee joint stability and quadriceps strength as a surrogate of motor impairment of homolateral femoral nerve.
* Chronic Pain Syndrome: the Italian version of the 'Brief Pain Inventory Short form" (BPI, attached) ( ) will be administered in order to obtain information on pain status at censored time (basal, 4 and 12 months after surgery values).
* Neuropathic Pain: the Italian version of "Douleur Neuropathique en 4 Questions" (DN4, attached) will be administered in order to obtain information on neuropathic pain at censored time (basal, 4 and 12 months after surgery scores).
* Long term morbidity: morbidity events will specifically regard femoral nerve impairment at physical examination, abdominal complications, sexual life and physiological functions. Renal failure in particular will be investigated by renal function blood tests monitoring and glomerular filtration rate (GFR) calculated according to Cockroft-Gault and simplified MDRD (Modification of Diet in Renal Disease) methods. Serum creatinine value will also be registered. Renal failure will be defined according to National Kidney Foundation 2002 criteria (Stage 2 or higher), and classified according to GFR thresholds.
* Disease status will be recorded and in case of local and/or distant relapse the date of events will also be retrieved.
Statistical considerations Statistical analyses
1. Primary end-point The two-sided 95% confidence interval (95%CI) of the paired difference between baseline and 4 (or12) months scores will be calculated for the primary outcome scale variables (items "29" and "30" QLQ-C30).
2. Secondary end-points Descriptive statistics and frequency tabulation were used to summarize patient characteristics and long term morbidity profile. Continuous variables will be described with appropriate summary statistics such as the mean, median, standard deviation, minimum and maximum. Categorical variables will be tabulated with frequencies and percentages. The probabilities of renal failure and femoral neuropathy will be estimated by the corresponding relative frequencies; their corresponding 95% confidence limits will be calculated using the exact method, i.e. taking into account the binomial distribution of proportions. The binary associations between the surgical resection pattern (number and type of organs resected) and the tumor features (size, grading and histological subtype) will be tested by using exact chi-square test. As regards the quantitative parameters measured over time, summary statistics (mean, median, standard deviation, minimum and maximum) or frequencies and percentages - as appropriate for the type of data - will be summarized by each time point; mixed models will be used to analyze the longitudinal measurements, allowing to take into account the within subject correlation and to straightforwardly analyze unbalanced data that may arise in the study.
Interim Analysis We plan to performed an interim cross-sectional analysis at the end of patient enrollment in order to describe the study population at baseline, according to the primary and secondary endpoints.
Sample size
We plan to include all the RSTS patients consecutively operated on for primary retroperitoneal sarcoma from first accrual on for the next 24 months (about 60 patients estimated.
A sample size of 60 patients allows the estimation of a two-sided 95,0% confidence interval for the paired difference between baseline and post treatment scores with a precision (half CI width) of 0.25 times the standard deviation of the difference.
