METHODS: Data of 3,100 Malaysian women with nonmetastatic breast cancer diagnosed between 2010 and 2017 were analyzed. Adherence to the Malaysian Clinical Practice Guidelines for Management of Breast Cancer second Edition was measured. Outcomes comprised overall survival and event-free survival.
RESULTS: Guideline adherence for chemotherapy, radiotherapy, hormonal therapy, and targeted therapy were 61.7%, 79.2%, 85.1%, and 26.2%, respectively. Older age was generally associated with lower adherence to guidelines. Compared with patients who were treated according to treatment guidelines, overall survival and event-free survival were substantially lower in patients who were not treated accordingly; hazard ratios for all-cause mortality were 1.69 (95% CI, 1.29 to 2.22), 2.59 (95% CI, 1.76 to 3.81), 3.08 (95% CI, 1.94 to 4.88), and 4.48 (95% CI, 1.98 to 10.13) for chemotherapy, radiotherapy, hormone therapy, and targeted therapy, respectively. Study inferences remain unchanged following sensitivity analyses.
CONCLUSION: Our study findings appear to suggest that adherence to treatment guidelines that have been adapted for resource-limited settings may still provide effective guidance in improving breast cancer outcomes.
METHODS: We analysed the relationship between pre-diagnostic prolactin levels and the risk of in situ breast cancer overall, and by menopausal status and use of postmenopausal hormone therapy (HT) at blood donation. Conditional logistic regression was used to assess this association in a case-control study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort, including 307 in situ breast cancer cases and their matched control subjects.
RESULTS: We found a significant positive association between higher circulating prolactin levels and risk of in situ breast cancer among all women [pre-and postmenopausal combined, ORlog2=1.35 (95% CI 1.04-1.76), Ptrend=0.03]. No statistically significant heterogeneity was found between prolactin levels and in situ cancer risk by menopausal status (Phet=0.98) or baseline HT use (Phet=0.20), although the observed association was more pronounced among postmenopausal women using HT compared to non-users (Ptrend=0.06 vs Ptrend=0.35). In subgroup analyses, the observed positive association was strongest in women diagnosed with in situ breast tumors<4 years compared to ≥4 years after blood donation (Ptrend=0.01 vs Ptrend=0.63; Phet=0.04) and among nulliparous women compared to parous women (Ptrend=0.03 vs Ptrend=0.15; Phet=0.07).
CONCLUSIONS: Our data extends prior research linking prolactin and invasive breast cancer to the outcome of in situ breast tumours and shows that higher circulating prolactin is associated with increased risk of in situ breast cancer.