Impact of Primary Tumor Localization on the Efficacy of Bevacizumab in Metastatic Colorectal Cancer.

AIM: Right- and left-sided primary tumors of colorectal origin differ substantially in several aspects. Recent retrospective analyses show distinct efficacy of EGFR-epidermal growth factor receptor (EGFR)-directed therapies for left- and right-sided primary tumors. Current treatment guidelines have accommodated these findings such that for right-sided primary tumors, EGFR-directed therapy is no longer recommended. Instead, vascular endothelial growth factor (VEGF)-directed therapies are recommended frequently in first line, even in tumors with wild-type rat sarcoma (RAS) status. However, data supporting this recommendation are scarce. The purpose of this analysis was to investigate the efficacy of bevacizumab added to chemotherapy depending on the primary tumor localization in a retrospective setting. PATIENTS AND METHODS: From the central clinical cancer registry of one of Germany's largest medical centers, data were analyzed for patients with metastatic colorectal cancer (mCRC) treated with either chemotherapy alone (CT) or bevacizumab-containing regimens (BEV/CT). RESULTS: Of 1,080 documented mCRC cases within the period of 2003 through 2016, 242 were treated with chemotherapy alone and 166 with bevacizumab-containing regimes in any line of therapy meeting the criterion above. In patients with left-sided primary tumor localization, a significant survival benefit was found when bevacizumab was added to chemotherapy. Patients with right-sided primaries, instead, did not derive any advantage when bevacizumab was added to chemotherapy. For the whole group of patients, this translated into a trend towards improved survival in bevacizumab-treated patients with mCRC. CONCLUSION: Adding bevacizumab to chemotherapy in mCRC may be beneficial only in patients with left-sided primary tumor, while those with right-sided primary tumors may have no additional benefit from the addition of bevacizumab. This hypothesis-generating analysis should provide a basis for in-depth analysis of this issue in future prospective trials.

The effect of chromoendoscopy on the diagnostic improvement of gastric ulcers by endoscopists with different levels of experience.

BACKGROUND: In recent years chromoendoscopy has become popular as a diagnostic enhancement tool in endoscopy. Using the macroscopic description of gastric ulcers, experienced endoscopists may be able to differentiate malignant and benign lesions. The aim of our study was to determine whether indigo carmine staining improves the ulcer differentiation by experienced and inexperienced endoscopists. METHODS: 50 patients were enrolled, 7 with malignant gastric ulcers and 43 with benign gastric ulcers. Gastroscopy was initially videotaped native, then on a second tape after staining with 0.2% indigo carmine. Later on biopsies were taken for histology. Subsequently the tapes were randomly evaluated by three experienced (>2000 gastroscopies; group A) and by three inexperienced (<100 gastroscopies; group B) investigators blinded from any personal data of the patients. The investigators had to classify the ulcers, using published criteria, native as well as stained. The results were compared within each group and with the histology. RESULTS: The endoscopic native diagnosis showed a sensitivity of 66.3%, a specificity of 86.3%, a positive predictive value of 48.1% and a negative predictive value of 94% for group A, respectively 66%, 62.5%, 22.7% and 92% for group B. After staining, the values of these parameters were reduced insignificantly to a sensitivity of 60.2%, a specificity of 78.5%, a positive predictive value of 36.1% and a negative predictive value of 92.8% for group A. Group B, on account of one investigator who demonstrated excellent skills, showed a significant better sensitivity (79.9%) and a slight improvement of the positive and negative predictive values to 25.7% respectively 94.8%, whereas the specificity very slightly decreased to 61.3%. The diagnostic accuracy before and after staining was 83.6%, respectively 76.5%, in group A and 63.2%, respectively 63.9% in group B. The correlation with the histology, determined by Cohen's kappa coefficient (median value), decreased from 0.46 for the native to 0.30 for the chromoendoscopic diagnosis in group A and remained unchanged (0.17) in group B. CONCLUSION: We concluded that chromoendoscopy does not improve the classification of gastric ulcers with respect to malignant or benign origin. The role of endoscopic experience could only be proved in the native macroscopic diagnosis of the investigators. After staining, with the exception of one investigator, experienced as well as inexperienced endoscopists lost their diagnostic accuracy.