Genetic architectures of proximal and distal colorectal cancer are partly distinct.

OBJECTIVE: An understanding of the etiologic heterogeneity of colorectal cancer (CRC) is critical for improving precision prevention, including individualized screening recommendations and the discovery of novel drug targets and repurposable drug candidates for chemoprevention. Known differences in molecular characteristics and environmental risk factors among tumors arising in different locations of the colorectum suggest partly distinct mechanisms of carcinogenesis. The extent to which the contribution of inherited genetic risk factors for CRC differs by anatomical subsite of the primary tumor has not been examined. DESIGN: To identify new anatomical subsite-specific risk loci, we performed genome-wide association study (GWAS) meta-analyses including data of 48 214 CRC cases and 64 159 controls of European ancestry. We characterised effect heterogeneity at CRC risk loci using multinomial modelling. RESULTS: We identified 13 loci that reached genome-wide significance (p<5×10-8) and that were not reported by previous GWASs for overall CRC risk. Multiple lines of evidence support candidate genes at several of these loci. We detected substantial heterogeneity between anatomical subsites. Just over half (61) of 109 known and new risk variants showed no evidence for heterogeneity. In contrast, 22 variants showed association with distal CRC (including rectal cancer), but no evidence for association or an attenuated association with proximal CRC. For two loci, there was strong evidence for effects confined to proximal colon cancer. CONCLUSION: Genetic architectures of proximal and distal CRC are partly distinct. Studies of risk factors and mechanisms of carcinogenesis, and precision prevention strategies should take into consideration the anatomical subsite of the tumour

The association between anastomotic leakage and health-related quality of life after colorectal cancer surgery

Aim: Colorectal anastomotic leakage (AL) is a serious complication. Studies on the impact of AL on health-related quality of life (HRQoL) are scarce. We aimed to investigate the association between AL and HRQoL in colorectal cancer patients up to 2 years after diagnosis, and to evaluate whether AL is associated with a clinically relevant decrease in HRQoL over time. Methods: Patients diagnosed with Stage I–III colorectal cancer undergoing elective surgical resection with primary anastomosis between 2010 and 2017 were included. HRQoL was evaluated using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire C30, represented by the summary score, and analysed at diagnosis and at 6 months and 2 years post-diagnosis. Multivariable linear regression was performed to assess the association between AL and HRQoL, while multivariable logistic regression was used to investigate the association between AL and a clinically relevant HRQoL decrease (≥10 points) during follow-up compared to the time of diagnosis. Results: In total, 1197 patients were included of whom 63 (5%) developed AL. AL was not associated with HRQoL at 6 months post-diagnosis nor at 2 years post-diagnosis. However, having AL was associated with an increased risk of a clinically relevant decrease in HRQoL at 6 months post-diagnosis (OR 3.65, 95% CI 1.62–8.21) but not at 2 years after diagnosis (OR 1.91, 95% CI 0.62–5.93). Conclusion: Although AL was not associated with HRQoL at 6 months or 2 years post-diagnosis, AL was a determinant of a clinically relevant decrease in HRQoL at 6 months after diagnosis. Future work should identify feasible and effective strategies to prevent declines in QoL in this patient population

Changes in Circulating Levels of 25-hydroxyvitamin D3 in Breast Cancer Patients Receiving Chemotherapy

Cancer treatments, toxicities and their effects on lifestyle, may impact levels of vitamin D. The aim of this study was to determine serum 25-hydroxyvitamin D3 (25(OH)D3) levels before, directly after and 6 months after chemotherapy in breast cancer patients (n = 95), and a comparison group of women (n = 52) not diagnosed with cancer. Changes in 25(OH)D3 levels over time were compared using linear mixed models adjusted for age and season of blood sampling. Before start of chemotherapy, 25(OH)D3 levels were lower in patients (estimated marginal mean 55.8 nmol/L, 95% confidence interval (95%CI) 51.2–60.4) compared to the comparison group (67.2 nmol/L, 95%CI 61.1–73.3, P = 0.003). Directly after chemotherapy, 25(OH)D3 levels were slightly decreased (–5.1 nmol/L, 95%CI –10.7–0.5, P = 0.082), but ended up higher 6 months after chemotherapy (10.9 nmol/L, 95%CI 5.5–16.4, P < 0.001) compared to pre-chemotherapy values. In women without cancer, 25(OH)D3 levels remained stable throughout the study. Use of dietary supplements did not explain recovery of 25(OH)D3 levels after chemotherapy. We reported lower 25(OH)D3 levels in breast cancer patients, which decreased during chemotherapy, but recovered to levels observed in women without cancer within 6 months after chemotherapy. Suboptimal 25(OH)D3 levels in the majority of the participants highlight the relevance of monitoring in this vulnerable population

Changes in Circulating Levels of 25-hydroxyvitamin D3 in Breast Cancer Patients Receiving Chemotherapy

Cancer treatments, toxicities and their effects on lifestyle, may impact levels of vitamin D. The aim of this study was to determine serum 25-hydroxyvitamin D3 (25(OH)D3) levels before, directly after and 6 months after chemotherapy in breast cancer patients (n = 95), and a comparison group of women (n = 52) not diagnosed with cancer. Changes in 25(OH)D3 levels over time were compared using linear mixed models adjusted for age and season of blood sampling. Before start of chemotherapy, 25(OH)D3 levels were lower in patients (estimated marginal mean 55.8 nmol/L, 95% confidence interval (95%CI) 51.2–60.4) compared to the comparison group (67.2 nmol/L, 95%CI 61.1–73.3, P = 0.003). Directly after chemotherapy, 25(OH)D3 levels were slightly decreased (–5.1 nmol/L, 95%CI –10.7–0.5, P = 0.082), but ended up higher 6 months after chemotherapy (10.9 nmol/L, 95%CI 5.5–16.4, P 3 levels remained stable throughout the study. Use of dietary supplements did not explain recovery of 25(OH)D3 levels after chemotherapy. We reported lower 25(OH)D3 levels in breast cancer patients, which decreased during chemotherapy, but recovered to levels observed in women without cancer within 6 months after chemotherapy. Suboptimal 25(OH)D3 levels in the majority of the participants highlight the relevance of monitoring in this vulnerable population.</p