Abstract P1-09-04: Association between a breast cancer polygenic risk score and contralateral breast cancer risk

Background

Breast cancer patients are at significant risk of a second contralateral, breast cancer (CBC). Identification of women at high or low CBC risk could improve patient management decisions. Previous research has shown that breast cancer-associated single nucleotide polymorphisms (SNPs) summarized in a polygenic risk score (PRS) predict the risk of a first breast cancer with an odds ratio (OR) per 1 SD of 1.55 (95% confidence interval (95%CI)=1.52-1.58) (77-SNP PRS). The aim of this study was to evaluate the association between a recently developed PRS and CBC risk.

Methods

We identified 19 studies from the Breast Cancer Association Consortium (BCAC) with follow-up information on participating patients and at least 10 patients diagnosed with CBC. This included 38,228 females of European ancestry diagnosed with first invasive breast cancer since 1990. Genotyping was done using the iCOGS array or OncoArray, with genotypes for SNPs not on the arrays estimated by imputation. We used a 313-SNP PRS, optimized for prediction of overall (first) breast cancer in the BCAC dataset. Metachronous CBC risk by PRS was quantified using univariable and multivariable Cox regression analyses stratified by country and adjusted for multiple patient, tumor, and treatment characteristics. We assessed PRS interaction with age, family history, adjuvant systemic therapy, and ER-status.

Results

Median time to develop a CBC (N=1,046) after a first breast cancer was 5.8 years (range 0.3-21.9). Higher PRS was associated with increased CBC risk: hazard ratio (HR) per 1 SD=1.31 (95%CI=1.23-1.39). Patients in the highest and lowest 5% of the PRS had 1.95 fold and 0.67 fold risks of CBC, respectively, compared with patients in the middle quintile. Adjustments for age, year of diagnosis, family history, tumor size, nodal status, ER-status, or treatment (chemotherapy, endocrine therapy, radiotherapy) did not substantially alter these results. We found an interaction with age at first breast cancer diagnosis (Pinteraction=.002); the PRS was associated with an increased CBC risk for patients aged ≥40 years (HR=1.37, 95%CI=1.28-1.47), but not for patients <40 years (HR=1.06, 95%CI=0.93-1.21).

Conclusion

The PRS is predictive for the development of CBC in patients ≥40 years at first breast cancer diagnosis. For this group, the PRS could be incorporated in CBC risk prediction models to help define high and low risk patients, and hence optimize screening and treatment strategies.

Citation Format: Kramer I, Hooning MJ, Breast Cancer Association Consortium (BCAC), Mavaddat N, Canisius S, Keeman R, van den Broek AJ, Steyerberg E, Hauptmann M, Pharoah PD, Easton DF, Hall P, Schmidt MK. Association between a breast cancer polygenic risk score and contralateral breast cancer risk [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-09-04.

A prospective polysomnographic study on the evolution of complex sleep apnoea

Complex sleep apnoea (CompSA) may be observed following continuous positive airway pressure (CPAP) treatment. In a prospective study, 675 obstructive sleep apnoea patients (mean age 55.9 yrs; 13.9% female) participated. Full-night polysomnography was performed at diagnosis, during the first night with stable CPAP and after 3 months of CPAP. 12.2% (82 out of 675 patients) had initial CompSA. 28 of those were lost to follow-up. Only 14 out of the remaining 54 patients continued to satisfy criteria for CompSA at follow-up. 16 out of 382 patients not initially diagnosed with CompSA exhibited novel CompSA after 3 months. 30 (6.9%) out of 436 patients had follow-up CompSA. Individuals with CompSA were 5 yrs older and 40% had coronary artery disease. At diagnosis, they had similar sleep quality but more central and mixed apnoeas. On the first CPAP night and at follow-up, sleep quality was impaired (more wakefulness after sleep onset) for patients with CompSA. Sleepiness was improved with CPAP, and was similar for patients with or without CompSA at diagnosis and follow-up. CompSA is not stable over time and is mainly observed in predisposed patients on nights with impaired sleep quality. It remains unclear to what extent sleep impairment is cause or effect of CompSA.

Comparison of the effects of nebivolol and valsartan on BP reduction and sleep apnoea activity in patients with essential hypertension and OSA

OBJECTIVES

To investigate the effect of nebivolol, a third generation beta-blocker, on blood pressure (BP) reduction and polysomnographic parameters in hypertensive patients with mild-to-moderate obstructive sleep apnoea (OSA).

METHODS

In this double-blind, parallel group study, patients were randomized to nebivolol 5 mg or valsartan 80 mg once daily following a 14-day, placebo run-in period during which any antihypertensive medication were discontinued. BP and heart rate measurements and overnight polysomnography were performed at baseline and after 6 weeks of treatment. Safety and tolerability were assessed.

RESULTS

Thirty-one patients were randomized to nebivolol (n = 16) or valsartan (n = 15). After six weeks both systolic and diastolic BP were effectively reduced by both treatments. Reductions in BP were not statistically significant different between agents, but mean heart rate was significantly decreased with nebivolol (compared with valsartan (p < 0.001). There was no statistically significant difference between both treatments for the change from baseline to treatment end for mean (+/-SD) Apnoea Hypopnoea Index (AHI) (nebivolol: 23.0 +/- 9.2 to 27.9 +/- 21.2 events/h; valsartan: 23.8 +/- 6.6 to 22.5 +/- 18.0 events/h; p = 0.48) or for any other sleep-related parameters. Both agents were well tolerated.

CONCLUSION

Nebivolol has a significant BP reduction effect in patients with OSA that is similar to valsartan and reduces heart rate to a greater extent which may prove beneficial in selected patients.

[Perioperative management of patients suffering from sleep-related breathing disorders]

Sleep-related breathing disorders have been associated with increased perioperative morbidity and mortality. The respective patients are at risk during two independent periods. Besides an early period, characterised by the influence of anaesthetics, patients are at risk also during a late period, which is characterised by nocturnal desaturation and disturbances of the cardiovascular system, caused by interference with the sleep architecture, especially of the REM sleep. To assure a safe perioperative management, a close monitoring (O2 saturation and pCO2) and the option for non-invasive ventilation have to be guaranteed.

SENSATION remote monitoring system for enabling the "anytime, anywhere" monitoring of patients with selected sleep disorders

The SENSATION Integrated Project aims at promoting the health, safety and quality of life of people and protect the environment by reducing relevant accidents and thus the impact on environment through the application of novel micro and nano sensors and related technologies, of low-cost and high-efficiency, for physiological state monitoring. The focus of the work will be the brain activity, including the sleep and wakefulness states and their boundaries, stress, inattention and hypovigilance states, for hypovigilance detection, prediction and management as well as diagnosis, treatment and remote monitoring of sleep disorders. In this paper, a presentation of the application scenarios of the integrated medical system will be made.

Hypercapnic duty cycle is an intermediate physiological phenotype linked to mouse chromosome 5

We hypothesized that upper airway obstruction (UAO) leads to a compensatory increase in the duty cycle [ratio of inspiratory time to respiratory cycle length (Ti/Tt)], which is determined by genetic factors. We examined the compensatory Ti/Tt responses to 1). UAO and hypercapnia among normal individuals and 2). hypercapnia in different inbred strains, C3H/HeJ (C3) and C57BL/6J (B6), and their first- and second-generation (F2) offspring. 3). We then used the compensatory Ti/Tt response in the F2 to determine genetic linkage to the mouse genome. First, normal individuals exhibited a similar increase in the Ti/Tt during periods of hypercapnia (0.11 +/- 0.07) and UAO (0.09 +/- 0.06) compared with unobstructed breathing (P < 0.01). Second, the F2 offspring of C3 and B6 progenitors showed an average Ti/Tt response to 3% CO2 (0.42 +/- 0.005%) that was significantly (P < 0.01) greater than that of the two progenitors. Third, with a peak log of the odds ratio score of 4.4, Ti/Tt responses of F2 offspring are genetically linked to an interval between 58 and 64 centimorgans (cM) on mouse chromosome 5. One gene in the interval, Dagk4 at 57 cM, is polymorphic for C3 and B6 mice. Two other genes, Adrbk2 at 60 cM and Nos1 at 65 cM, have biological plausibility in mechanisms of upper airway patency and chemosensitivity, respectively. In summary, Ti/Tt may serve as an intermediate physiological phenotype for compensatory neuromuscular response mechanisms for maintaining ventilation in the face of UAO and hypoventilation and to help target specific candidate genes that may play a role in the expression of sleep-disordered breathing.