The value of case reports in rare oncological scenarios: mixed method analysis of colorectal metastases from breast cancer

AbstractWith improved survival of cancer patients, we increasingly encounter infrequent metastatic locations. While for the common metastatic locations both prognostic information as well as evidence-based guidelines are available, for rare locations we have to rely on anecdotal case reports, the value of which is currently unknown. Therefore, we performed a systemic literature review and compare the results with a large national real-life cohort focussed on breast cancer patients with colorectal metastases. We performed a systematic literature search for breast cancer patients with colorectal metastases. Autopsy studies were excluded. Data on stage, histological factors, treatment and outcome were extracted. All identified cases were analysed as individual patients. The real-life cohort was extracted from the nationwide Dutch pathology databank. Linkage with the Netherlands Cancer Registry provided clinical characteristics, treatment and outcome data. Survival analyses and univariate regression were performed to identify relevant features for future treatment decisions. We identified 308 patients from 207 studies in the literature, and 454 patients in the real-life cohort. Colorectal metastases were the first metastatic event in 42.5% and 47.0% respectively. Cohorts were comparable for age, gender, location and hormone status, but differed in tumour type, stage and treatment. The time to colorectal metastases was similar in both cohorts (median of 68  months), and was depen...
Source: Clinical and Experimental Metastasis - Category: Cancer & Oncology Source Type: research