Sporadic deficient mismatch repair in colorectal cancer increases the risk for non-colorectal malignancy: A European multicenter cohort study.

BACKGROUND AND OBJECTIVES: Disparities between tumors arising via different sporadic carcinogenetic pathways have not been studied systematically. This retrospective multicenter cohort study evaluated the differences in the risk for non-colorectal malignancy between sporadic colorectal cancer (CRC) patients from different DNA mismatch repair status. METHODS: A retrospective European multicenter cohort study including in total of 1706 CRC patients treated between 1996 and 2019 in three different countries. The proficiency (pMMR) or deficiency (dMMR) of mismatch repair was determined by immunohistochemistry. Cases were analyzed for tumor BRAFV600E mutation, and BRAF mutated tumors were further analyzed for hypermethylation status in the promoter region of MLH1 to distinguish between sporadic and hereditary cases. Swedish and Finish patients were matched with their respective National Cancer Registries. For the Czech cohort, thorough scrutiny of medical files was performed to identify any non-colorectal malignancy within 20 years before or after the diagnosis of CRC. Poisson regression analysis was performed to identify the incidence rates of non-colorectal malignancies. For validation purposes, standardized incidence ratios were calculated for the Swedish cases adjusted for age, year, and sex. RESULTS: Of the 1706 CRC patients included in the analysis, 819 were female [48%], median age at surgery was 67 years [interquartile range: 60-75], and sporadic dMMR was found in 188 patients (11%). Patients with sporadic dMMR CRC had a higher incidence rate ratio (IRR) for non-colorectal malignancy before and after diagnosis compared to patients with a pMMR tumor, in both uni- (IRR = 2.49, 95% confidence interval [CI] = 1.89-3.31, p = 0.003) and multivariable analysis (IRR = 2.24, 95% CI = 1.67-3.01, p = 0.004). This association applied whether or not the non-colorectal tumor developed before or after the diagnosis of CRC in both uni- (IRR = 1.91, 95% CI = 1.28-2.98, p = 0.004), (IRR = 2.45, 95% CI = 1.72-3.49, p = 0.004) and multivariable analysis (IRR = 1.67,95% CI = 1.05-2.65, p = 0.029), (IRR = 2.35, 95% CI = 1.63-3.42, p = 0.005), respectively. CONCLUSION: In this retrospective European multicenter cohort study, patients with sporadic dMMR CRC had a higher risk for non-colorectal malignancy than those with pMMR CRC. These findings indicate the need for further studies to establish the need for and design of surveillance strategies for patients with dMMR CRC.

Fluid therapy is associated with lower care quality and higher symptom burden during last days of life of patients with cancer - a population-based register study.

BACKGROUND: Parenteral fluid (PF) therapy of patients in end-of-life (EOL) is controversial. The purpose of this study was to assess associations between PF, quality of the EOL care process and symptom burden in dying cancer patients, using a population-based approach. METHODS: This was a nationwide retrospective register study of all adult cancer deaths with documented information on PF in the last 24 h of life as reported to the Swedish Register of Palliative Care during a three-year period (n = 41,709). Prevalence and relief of symptoms during the last week of life as well as EOL care process quality indicators were assessed in relation to PF in those patients who had a documented decision to focus on EOL care (immediately dying, n = 23,112). Odds ratios were calculated, adjusting for place of death (hospital vs. non-hospital). RESULTS: PF was administered to 30.9% of immediately dying patients in hospitals compared to 6.5% outside of hospitals. PF was associated with a higher likelihood for breathlessness and nausea. In patients screened for EOL symptoms with a validated instrument, PF was inversely associated with the likelihood of complete relief of breathlessness, respiratory secretions, anxiety, nausea and pain. Several palliative care quality indicators were inversely associated with PF, including EOL conversations and prescriptions of injectable drugs as needed. These associations were more pronounced in hospitals. CONCLUSIONS: Parenteral fluid therapy in the last 24 h of life was associated with inferior quality of the EOL care process and with increased symptom burden in imminently dying cancer patients.