Peritoneal washing cytology
agitation, ®, tumor
TUMOR, CAVITY
The peritoneal washing cytology (PWC) will be collected in the operating room. For the procedure, 150 mL of saline solution will be introduced into the abdominal cavity and aspirated after gentle agitation. Three sample tubes (Falcon 15 mL conical tube) with the aspirated material will be collected: one will be destined for conventional cytopathological evaluation (1:1 ratio of 70% alcohol, and processed according to the routine procedure), a second sample will be destined for LBC (added to 10 mL of GynoPrep preservative liquid), and the third will be destined for storage as previously described – which will be centrifuged at 3,000 rpm for 10 min, and the cell pellet will be resuspended with 1 mL of Trizol® (Invitrogen-Life Technologies, Carlsbad, EUA) and stored in a freezer at −80°C. The supernatant will also be stored separately.Briefly, the sample forwarded to conventional cytology will be centrifuged for 10 min at 1,400 rpm. After the process, the supernatant is discarded and the pellet is resuspended in PBS (pH 7.3–7.4). Thus, the sample is placed in three cyto-funnels (100 μL in each of them) and centrifuged in CytoSpin® for 10 min at 1,400 rpm. After the process, the slides with the smear formed will be removed from the centrifuge and placed in absolute alcohol, for later Papanicolaou staining. In total, each cytological sample will result in three slides for microscopic evaluation. The remaining material from the centrifugation not placed in the cyto-funnel will be packed in histological cassettes (cell block), to be processed in an automated system (Zeiss, STP 420D, Thermo Scientific). Histological sections will be stained with hematoxylin and eosin.The samples for LBC will be placed in a vortex for 20 s and then processed using the GynoPrep Processor GP-100 (Stra Medical®), a centrifugation system with filters and vacuum. The equipment will perform all the procedures for homogenization, dispersion, and reduction of artifacts and, using a controlled pneumatic mechanism, transfers the cells to be examined to the surface of the slide. After the process, the slides will be fixed in alcohol and also be submitted to Papanicolaou staining and evaluated by conventional microscopy.The two methodologies will be compared (results and sample quality) to verify which technique presents better performance for the evaluation of the presence of tumor cells in PWC.