Definition of gross tumor volume with FDG-18F PET-CT in patients with head and neck cancer: comparison of different delineation methods

Objective: Besides the high sensitivity and specificity of positron emission tomography (PET) for head and neck tumors, there is still a lack of consensus about how to use this method inradiotherapy planning. The aim of this study is to compare different gross tumor volume (GTV) obtained with PET images in comparison to the size of the target volume generated with CT scanalone, for treated and untreated head and neck lesions. Methods: Sixty lesions in fifty patients with head and neck squamous cell carcinoma were included in the study. Delineation of the GTV was achieved using computed tomography (CT) images alone (GTV-CT) and PET-CT images with the visual assessment method (GTVPET-CT) and standard uptake value (SUV) thresholds of 40, 50, 60 and 75 percent (GTV40%, GTV50%, GTV60%, GTV75%, respectively). Correlations were measured by the Spearman test and the Friedman test was used to verify differences between GTVs. Results: For all lesions (treated and untreated), only the GTVPET-CT showed a strong correlation with GTV-CT. For only the untreated lesions, GTVPET-CT and GTV75% showed a strong correlation with GTV-CT. The GTV50%, GTV60% and GTV75% showed statistically significant difference in relation to GTV-CT, while GTVPET-CT and GTV40% were similar to GTV-CT. Conclusion: The use of PET-CT changes the volume of the final target in head and neck tumors,depending on the methodology used to calculate the GTV. The results presented here showed that the GTV40% and the GTVPET-CT are those who are closer to the target volumes delineated by conventional CT

Surgical-site infection risk in oncologic digestive surgery

Surgical-site infection (SSI) is the most prevalent type of hospital infection in surgical patients and is associated with an increase in hospital stay, costs and morbidity/lethality. The knowledge of the main risk factors for this type of infection is important for the establishment of prevention measures regarding modifiable risks factors. The objective of the preset study was to assess the occurrence of SSI and study the risk factors in oncologic surgeries of the digestive system at Hospital de Câncer in Barretos, São Paulo, Brazil. Individuals undergoing oncologic surgeries of the digestive system in the period of 08/01/2007 to 08/10/2008 were prospectively followed for 30 days after surgery. Possible risk factors related to the patient and to the surgical procedure were also studied. A total of 210 surgeries were analyzed, with a global SSI incidence of 23.8 percent. The following variables were independently associated with SSI: time and type of surgery, radiotherapy before surgery and surgeon's years of experience. The risk factors found in this study have been described by other authors and are not amenable to intervention for SSI prevention. Further studies are recommended with the objective of investigating interventions that could reduce the risk for SSI in this type of surgery.