Prognostic Factors in Merkel Cell Carcinoma: A Retrospective Single-Center Study in 90 Patients

Merkel Cell Carcinoma (MCC) is a rare but highly aggressive neuroendocrine neoplasm of the skin. This study aimed at describing characteristics, treatment, and prognosis of a series of consecutive cases of MCC patients, in order to contribute to the investigation of this rare malignancy and provide better patient care. This is a retrospective cohort study including all 90 patients diagnosed and/or treated for MCC between 1991 and 2018 at the Veneto Institute of Oncology in Padua (Italy). Patient and tumor characteristics, treatment, and immunohistochemical data were extracted from a prospectively collected local database. There were 68 primary (76%) and 22 non-primary (15 occult primary, three metastatic, four recurrence) tumors (24%). CK20 expression was associated with reduced overall (HR 2.92, 95% CI 1.04–8.16) and disease-specific (HR 4.62, 95% CI 1.31–16.28) survival. Immunomodulatory regimens for treatment of other comorbidities were associated with reduced disease-specific ((HR 2.15, 95% CI 1.06–4.36) and recurrence-free (HR 3.08, 95% CI 1.44–6.57) survival. Iatrogenic immunomodulation resulted as the main factor associated with impaired prognosis. Lack of CK20 expression was associated with better survival.

Impact of clinical and molecular features on risk of recurrence following curative intent resection of metastases in metastatic colorectal cancer.

785 Background: Resection of metastases with curative intent is an integral component of mCRC management. However, relapse rates are high and identifying patients most likely to benefit from this approach is of considerable importance. Among patients with mCRC, mutations (mt) in RAS and BRAF genes portent a worse prognosis. Our hypothesis, therefore, is that patients harbouring these mutations may have a higher relapse rate after resection of metastases. We also wished to analyse clinical predictors of relapse, including site of metastases. Methods: We interrogated the TRACC database of patients undergoing resection with curative intent who had mutation status available. The frequency of RAS and BRAF mt was established and their association with clinical parameters determined. Relapse free (RFS) and overall survival (OS), from the date of resection, was estimated for the mt and wild type (wt) groups using the Kaplan Meier method. Multivariate analysis is planned to investigate factors associated with RFS, including stage of the primary tumour, synchronous metastases, site and number of metastases, CEA, peri-operative chemotherapy use, site of the primary (left v right) and RAS and BRAF mutation status. Results: 188 patients were identified. 89 were KRAS/BRAF wt, 92 KRAS mt and 7 BRAF mt. 40% had presented with metastatic disease and 27% had a right sided primary. 76%, 22% and 2% underwent resection of liver, lung or both metastases. Microscopic resection margin was involved in 6%. Resection was performed prior to any chemotherapy in 48%. No difference was seen in relapse free or overall survival between the mt and wt groups. Conclusions: We found no difference in relapse free or overall survival by mutation subgroup suggesting this should not influence suitability for curative intent resection, but analyses is planned on a much larger cohort once data is available. A multivariate analysis, adjusting for important prognostic variables, is planned.