Hand-held Gamma Camera in the SNOLL Procedure

Overview

In France, breast cancer affects approximately 53,000 new cases per year. The investigators have to take care more and more women with subclinical lesions (nonpalpable), and it represents around 25% to 35% of the diagnosed breast cancers. The main problem of the surgical management of these lesions is the quality of preoperative identification which determines the quality of surgery and oncological and cosmetic outcomes. For this type of lesion, SNOLL (Sentinel Node and Occult Lesion Localization) procedure could be proposed. This is a radioactive labeling of the tumor site and sentinel lymph node (SLN). The investigators want to evaluate the potential benefits of using a hand held camera called TreCam in this SNOLL procedure. This camera permits to obtain nuclear imaging at the bedside and in the operating theater.

Hypothesis: The use of intraoperative TReCam improves the surgical procedure by providing relevant information during surgery to reduce the rate of further surgery for inappropriate margins. Main Objective: Evaluation of the contribution of TreCam in SNOLL procedure. Main endpoint: The rate of further surgery for inappropriate margins of the lumpectomy (less than 3mm) Second endpoint: Lumpectomy's characteristics, Cosmetics results Number of SLNs detected with TreCam at the different times of the procedure. Operative duration Plan experimental : Multicentric (3 centers) Phase II randomized non comparative study. All patients with non-palpable invasive cancer histologically proven and with ultrasound target will have SNOLL procedure. Patients will be randomized preoperatively into two groups. Group 1: patients with a resection of the lesions according to the procedure SNOLL without the use of TReCam. Group 2: patients with a resection of the lesions according to the procedure SNOLL with the use of TReCam. In group 1: * Day-1: Injection of Tc99m (Nanocis) in contact with the tumor under ultrasound guidance followed by a lymphoscintigraphy (LS): Localization and counting of the radioactive SLNs. Localization of the tumor site. * Day 0: Before incision, exploration with the classic gamma probe (GP) for the localization of the different surgical areas (breast and axillary) is performed. Removal of SLN is achieved thanks to double detection (colorimetric and radioactive). After incision, radioactive SLN are identified by GP. At the end of the SLN procedure, the operator checks the absence of residual activity and controls with preoperative LS. In case of non detection of SLN or metastases identified during extemporaneous examination an axillary node dissection is performed. The GP is also used to guide lumpectomy and verify the absence of significant residual radioactivity after lumpectomy. Extemporaneous examination of lumpectomy specimen (size, limits of resection) is performed. Additional shaving of the cavity margins is appreciated by the surgeon. In group 2 : TReCam is used at different stages of SNOLL procedure: * Day-1: A mapping with TReCam is performed after LS. (without LS results) * Day 0: Before incision, in addition to GP, TReCam is used to define number and localization of SLN and the tumor site. * At the end of the usual SLN procedure, axillary area is also explored by TReCam in order to find residual SLN. * After lumpectomy, absence of significant residual radioactivity is checked by GP and TReCam * Operative duration will be reported. * Difficulties in data acquisition with TReCam. * Collection of all the histological results. * Outcome: Cosmetic results, decision of further surgery for inappropriate margins. Total duration study: 13 months: Inclusion period : 12 months; Follow up : 1 month Statistics 1. Sample size. This is a phase II 2-steps randomized non comparative study. N= 30 patients in each group. This will allow to test the potential interest of TReCAm in group 2 using an optimal II-stage design based on the number of patients without reintervention (success). The tested hypothesis are: H0: p=p0 avec p0 = 80% (poor technique) H1: p=p1\>p0 avec p1 = 95% (good technique) N= 30 patients per group will be considered, method proposed by R.P. A'Hern (Stat Med 2001 :20. 859-866). The required power was set at 80% and the alpha risk was set at 5%. 2. Strategy analysis of data collected Populations studied: The primary analysis will focus on all randomized patients (intention to treat analysis). Given the type of patients and the evaluation time of the primary endpoint, it is unlikely that there is lost sight. However, any patient with no information available on the primary endpoint will be classified as having a reoperation. 3. Justification of statistical tests Descriptive analysis: All quantitative parameters will be summarized descriptively in each group of treatment modality and for each time they are collected. The analysis will include descriptive statistics for each quantitative parameter each time: average, standard deviation, minimum, maximum, median and quartiles, number of missing values. Qualitative parameters are expressed by the frequency distribution and accurate bilateral confidence intervals to 95% associated. (asymptotic estimators will not be used because of the considered effective).