Social characteristics and social benefit use among premenopausal breast cancer survivors in Denmark: a population-based cohort study.

PURPOSE: In 2020, one million women aged < 55 years were diagnosed with breast cancer globally. The impact of breast cancer and its treatments on these women's ability to work and need for social benefits may differ by social characteristics. We evaluated social benefit use following breast cancer by education and cohabitation. METHODS: We conducted a nationwide population-based cohort study, including women aged 18-55 years diagnosed with stage I-III breast cancer in Denmark during 2002-2011. Statistics Denmark provided information on cohabitation, education, and social benefit use from 1 year pre-diagnosis to 10 years post-diagnosis. We calculated weekly proportions of self-support, unemployment, disability pension, flexi jobs, and sick leave according to education and cohabitation. RESULTS: Of 5345 women, 81.8% were self-supporting, 4.5% received disability pensions, 1.6% had flexi jobs, 3.6% were on sick leave, and 5.5% were unemployed 1 year pre-diagnosis. Ten years post-diagnosis, the proportions were 69.0%, 13.0%, 10.5%, 3.4%, and 2.0% of 3663 survivors. Disability pensions and flexi jobs increased from 12.1 to 26.4% and 2.8 to 13.5% in women with short education, from 4.1 to 12.8% and 1.8 to 12.2% in women with medium education, and from 0.8 to 6.0% and 0.9 to 6.9% in longer educated. Disability pensions increased more in women living alone (7.8 to 19.9%), than in cohabiting women (3.6 to 11.3%). CONCLUSIONS: Use of social benefits reflecting lost ability to work was highest in less educated women and in women living alone. IMPLICATIONS FOR CANCER SURVIVORS: Awareness of these groups is crucial when tailoring efforts to support work participation in cancer survivors.

Clinical factors associated with patterns of endocrine therapy adherence in premenopausal breast cancer patients.

INTRODUCTION: Patients with hormone receptor positive breast cancer are recommended at least five years of adjuvant endocrine therapy, but adherence to this treatment is often suboptimal. We investigated longitudinal trends in adjuvant endocrine therapy (AET) adherence among premenopausal breast cancer patients and identified clinical characteristics, including baseline comorbidities and non-cancer chronic medication use, associated with AET adherence. METHODS: We included stage I-III premenopausal breast cancer patients diagnosed during 2002-2011 and registered in the Danish Breast Cancer Group clinical database who initiated AET. We used group-based trajectory modeling to describe AET adherence patterns. We also linked patients to Danish population-based registries and fit multinomial logistic models to compute odds ratios (ORs) and 95% confidence intervals (95% CIs) associating clinical characteristics with AET adherence patterns. RESULTS: We identified three adherence patterns among 4,353 women-high adherers (57%), slow decliners (36%), and rapid decliners (6.9%). Women with stage I disease (vs. stage II; OR: 1.9, 95% CI 1.5, 2.5), without chemotherapy (vs. chemotherapy; OR: 4.3, 95% CI 3.0, 6.1), with prevalent comorbid disease (Charlson Comorbidity Index score ≥ 1 vs. 0; OR: 1.6, 95% CI 1.1, 2.3), and with a history of chronic non-cancer medication use (vs. none; OR: 1.3, 95% CI 1.0, 1.8) were more likely to be rapid decliners compared with high adherers. CONCLUSIONS: Women with stage I cancer, no chemotherapy, higher comorbidity burden, and history of chronic non-cancer medication use were less likely to adhere to AET. Taking steps to promote adherence in these groups of women may reduce their risk of recurrence.

New Horizons: Epidemiology of Obesity, Diabetes Mellitus, and Cancer Prognosis.

The global prevalence of obesity and diabetes mellitus has increased in parallel with increasing cancer incidence, due to environmental and lifestyle factors and population aging. Metabolic diseases are associated with increased cancer risk, so a growing number of patients with cancer have coexistent obesity and/or diabetes mellitus. In this narrative review, we highlight recent evidence on the clinical impact of obesity and diabetes mellitus on the prognosis of prostate, breast, and colorectal cancer, and provide an overview of the underlying mechanisms. There is evidence that obesity is associated with increased risk of recurrence, and all-cause and cancer-specific mortality among adults with prostate, breast, and colorectal cancer. Diabetes mellitus is associated with increased all-cause and cancer-specific mortality for these 3 cancers, beyond any impact of obesity. Evidence also suggests increased risk of colorectal cancer recurrence in patients with diabetes mellitus. The underlying mechanisms are multifactorial and likely include hormonal imbalances and chronic inflammation that promote cancer cell growth. Obesity and diabetes mellitus are associated with increased risk of complications and side effects of cancer treatment. Associated comorbidities such as impaired kidney function, cardiovascular disease, and neuropathies may preclude the use of guideline cancer treatment and are competing causes of death. Cancer patients with metabolic diseases require a designated clinical program and a multidisciplinary approach involving oncologists, endocrinologists, surgeons, nutritionists, and physiotherapists, to ensure coordinated and optimized patient care.

The impact of single nucleotide polymorphisms on return-to-work after taxane-based chemotherapy in breast cancer.

PURPOSE: Breast cancer treatment is associated with adverse effects, which may delay return-to-work. Single nucleotide polymorphisms (SNPs) may influence the risk and severity of treatment toxicities, which in turn could delay return-to-work. We examined the association of 26 SNPs with return-to-work in premenopausal women with breast cancer. METHODS: Using Danish registries, we identified premenopausal women diagnosed with non-distant metastatic breast cancer during 2007‒2011, assigned adjuvant combination chemotherapy including cyclophosphamide and docetaxel. We genotyped 26 SNPs in 20 genes (ABCB1, ABCC2, ABCG2, CYP1A1, CYP1B1, CYP3A, CYP3A4, CYP3A5, GSTP1, SLCO1B1, SLCO1B3, ARHGEF10, EPHA4, EPHA5, EPHA6, EPHA8, ERCC1, ERCC2, FGD4 and TRPV1) using TaqMan assays. We computed the cumulative incidence of return-to-work (defined as 4 consecutive weeks of work) up to 10 years after surgery, treating death and retirement as competing events and fitted cause-specific Cox regression models to estimate crude hazard ratios (HRs) and 95% confidence intervals (CIs) of return-to-work. We also examined stable labor market attachment (defined as 12 consecutive weeks of work). RESULTS: We included 1,964 women. No associations were found for 25 SNPs. The cumulative incidence of return-to-work varied by CYP3A5 rs776746 genotype. From 6 months to 10 years after surgery, return-to-work increased from 25 to 94% in wildtypes (n = 1600), from 17 to 94% in heterozygotes (n = 249), and from 7 to 82% in homozygotes (n = 15). The HR showed delayed return-to-work in CYP3A5 rs776746 homozygotes throughout follow-up (0.48, 95% CI 0.26, 0.86), compared with wildtypes. Estimates were similar for stable labor market attachment. CONCLUSION: Overall, the SNPs examined in the study did not influence return-to-work or stable labor market attachment after breast cancer in premenopausal women. Our findings did suggest that the outcomes were delayed in homozygote carriers of CYP3A5 rs776746, though the number of homozygotes was low.

Risk of primary haematologic cancers following incident non-metastatic breast cancer: A Danish population-based cohort study.

BACKGROUND: Breast cancer survivors may have increased risk of subsequent haematologic cancer. We compared their risk of haematologic cancers with the general population during 38 years of follow-up. METHODS: Using population-based Danish medical registries, we assembled a nationwide cohort of women diagnosed with incident non-metastatic breast cancer during 1980-2017, with follow-up through 2018. We compared breast cancer survivors with the general population by computing standardised incidence ratios (SIR) and 95% confidence intervals (CI). RESULTS: Among 101,117 breast cancer survivors, we observed 815 incident haematologic cancers (median follow-up: 7.9 years). We observed excess risk of acute myeloid leukaemia (AML) (SIR: 1.65, 95%CI: 1.33-2.01), particularly in women who received chemotherapy (SIR: 3.33, 95%CI: 2.24-4.75) and premenopausal women (SIR: 3.23, 95%CI: 2.41-4.25). The risk of acute lymphoid leukaemia (ALL) was increased (SIR: 2.25, 95%CI: 1.29-3.66), whereas the risk of chronic lymphoid leukaemia (CLL) was decreased (SIR: 0.66, 95%CI: 0.53-0.82). An additional analysis showed elevated risk of CLL 0-6 months after breast cancer diagnosis (SIR: 3.00 95%CI: 1.75-4.80). CONCLUSION: Compared to the general population, breast cancer survivors had elevated risk of AML, particularly when treated with chemotherapy. The risk of ALL was elevated, whereas the risk of CLL was lower. The higher risk of CLL in the first six months after diagnosis likely reflects surveillance bias-due to intensified diagnostic efforts at breast cancer diagnosis and treatment-prompting earlier detection. This has likely reduced the long-term risk of CLL in breast cancer survivors.

Single-nucleotide polymorphisms and the effectiveness of taxane-based chemotherapy in premenopausal breast cancer: a population-based cohort study in Denmark.

PURPOSE: Taxane-based chemotherapy is the primary treatment for premenopausal breast cancer. Although being inconsistent, research suggests that variant alleles alter pharmacokinetics through reduced function of OATP transporters (limiting hepatic uptake), CYP-450 enzymes (hampering drug metabolism), and ABC transporters (decreasing clearance). Reduced function of DNA repair enzymes may hamper effectiveness through dose-limiting toxicities. We investigated whether single-nucleotide polymorphisms (SNPs) were associated with breast cancer recurrence or mortality in premenopausal women diagnosed with breast cancer. METHODS: We conducted a population-based cohort study of premenopausal women diagnosed with non-distant metastatic breast cancer in Denmark during 2007‒2011, when guidelines recommended adjuvant combination chemotherapy (taxanes, anthracyclines, and cyclophosphamide). Using archived formalin-fixed paraffin-embedded primary tumor tissue, we genotyped 26 SNPs using TaqMan assays. Danish health registries provided data on breast cancer recurrence (through September 25, 2017) and death (through December 31, 2019). We fit Cox regression models to calculate crude hazard ratios (HRs) and 95% confidence intervals (CIs) for recurrence and mortality across genotypes. RESULTS: Among 2,262 women, 249 experienced recurrence (cumulative incidence: 13%) and 259 died (cumulative incidence: 16%) during follow-up (median 7.0 and 10.1 years, respectively). Mortality was increased in variant carriers of GSTP1 rs1138272 (HR: 1.30, 95% CI 0.95-1.78) and CYP3A rs10273424 (HR: 1.33, 95% CI 0.98-1.81). SLCO1B1 rs2306283 (encoding OATP1B1) variant carriers had decreased recurrence (HR: 0.82, 95% CI 0.64-1.07) and mortality (HR: 0.77, 95% CI 0.60-0.98). CONCLUSION: Docetaxel effectiveness was influenced by SNPs in GSTP1, CYP3A, and SLCO1B1 in premenopausal women with non-distant metastatic breast cancer, likely related to altered docetaxel pharmacokinetics. These SNPs may help determine individual benefit from taxane-based chemotherapy.

Digital Image Analysis of Ki-67 Stained Tissue Microarrays and Recurrence in Tamoxifen-Treated Breast Cancer Patients.

PURPOSE: The proliferation marker Ki-67 has been used as a prognostic marker to separate low- and high-risk breast cancer subtypes and guide treatment decisions for adjuvant chemotherapy. The association of Ki-67 with response to tamoxifen therapy is unclear. High-throughput automated scoring of Ki-67 might enable standardization of quantification and definition of clinical cut-off values. We hypothesized that digital image analysis (DIA) of Ki-67 can be used to evaluate proliferation in breast cancer tumors, and that Ki-67 may be associated with tamoxifen resistance in early-stage breast cancer. PATIENTS AND METHODS: Here, we apply DIA technology from Visiopharm using a custom designed algorithm for quantifying the expression of Ki-67, in a case-control study nested in the Danish Breast Cancer Group clinical database, consisting of stages I, II, or III breast cancer patients of 35-69 years of age, diagnosed during 1985-2001, in the Jutland peninsula, Denmark. We assessed DIA-Ki-67 score on tissue microarrays (TMAs) from breast cancer patients in a case-control study including 541 ER-positive and 300 ER-negative recurrent cases and their non-recurrent controls, matched on ER-status, cancer stage, menopausal status, year of diagnosis, and county of residence. We used logistic regression to estimate odds ratios and associated 95% confidence intervals to determine the association of Ki-67 expression with recurrence risk, adjusting for matching factors, chemotherapy, type of surgery, receipt of radiation therapy, age category, and comorbidity. RESULTS: Ki-67 was not associated with increased risk of recurrence in tamoxifen-treated patients (ORadj =0.72, 95% CI 0.54, 0.96) or ER-negative patients (ORadj =0.85, 95% CI 0.54, 1.34). CONCLUSION: Our findings suggest that Ki-67 digital image analysis in TMAs is not associated with increased risk of recurrence among tamoxifen-treated ER-positive breast cancer or ER-negative breast cancer patients. Overall, our findings do not support an increased risk of recurrence associated with Ki-67 expression.

Multi-drug resistance protein 2 (MRP2) expression, adjuvant tamoxifen therapy, and risk of breast cancer recurrence: a Danish population-based nested case-control study.

BACKGROUND: Adjuvant tamoxifen therapy approximately halves the risk of recurrence in estrogen receptor-positive (ER+) breast cancer patients, but many women respond insufficiently to therapy. Expression of multi-drug resistance protein 2 (MRP2) in breast cancer may potentiate tamoxifen resistance. Thus, we investigated the expression of MRP2 in breast cancer as a predictor of tamoxifen therapy effectiveness. MATERIAL AND METHODS: We conducted a case-control study nested in the Danish Breast Cancer Group clinical database. The study included women aged 35-69 years diagnosed with stage l-lll breast cancer during 1985-2001, in Jutland, Denmark. We identified 541 recurrent breast cancers (cases) among women with estrogen receptor positive (ER+) disease treated with tamoxifen for at least 1 year (ER+/TAM+) and 300 cases among women with estrogen receptor-negative (ER-) disease, never treated with tamoxifen (ER-/TAM-). We matched one recurrence-free control to each recurrent case. We retrieved paraffin-embedded primary tumor tissue for all patients, and all available recurrent tumor tissue from pathology archives. MRP2 expression was evaluated using immunohistochemistry. We computed odds ratios (ORs) and 95% confidence intervals (95% CIs) associating MRP2 expression (positive vs. none) with breast cancer recurrence in conditional logistic regression models. We compared MRP2 expression in paired primary- and recurrent tumors. RESULTS: MRP2 expression was more prevalent in the ER+/TAM + group, than in the ER-/TAM - group. No predictive utility of MRP2 for breast cancer recurrence was found in the ER+/TAM + group (ORadj = 0.96, 95% CI 0.70, 1.33). Further, no prognostic utility was found in the ER-/TAM - group (ORadj = 0.81, 95% CI 0.53, 1.23). MRP2 expression was not increased in recurrent versus primary tumors. CONCLUSIONS: MRP2 expression is neither a predictive marker of tamoxifen effectiveness nor a prognostic marker in breast cancer.