Polygenic risk scores and risk-stratified breast cancer screening: Familiarity and perspectives of health care professionals

PURPOSE

Health care professionals are expected to take on an active role in the implementation of risk-based cancer prevention strategies. This study aimed to explore health care professionals' (1) self-reported familiarity with the concept of polygenic risk score (PRS), (2) perceived level of knowledge regarding risk-stratified breast cancer (BC) screening, and (3) preferences for continuing professional development.

METHODS

A cross-sectional survey was conducted using a bilingual-English/French-online questionnaire disseminated by health care professional associations across Canada between November 2020 and May 2021.

RESULTS

A total of 593 professionals completed more than 2 items and 453 responded to all questions. A total of 432 (94%) participants were female, 103 (22%) were physicians, and 323 (70%) were nurses. Participants reported to be unfamiliar with (20%), very unfamiliar (32%) with, or did not know (41%) the concept of PRS. Most participants reported not having enough knowledge about risk-stratified BC screening (61%) and that they would require more training (77%). Online courses and webinar conferences were the preferred continuing professional development modalities.

CONCLUSION

The study indicates that health care professionals are currently not familiar with the concept of PRS or a risk-stratified approach for BC screening. Online information and training seem to be an essential knowledge transfer modality.

Risk-Stratified Approach to Breast Cancer Screening in Canada: Women's Knowledge of the Legislative Context and Concerns about Discrimination from Genetic and Other Predictive Health Data

The success of risk-stratified approaches in improving population-based breast cancer screening programs depends in no small part on women’s buy-in. Fear of genetic discrimination (GD) could be a potential barrier to genetic testing uptake as part of risk assessment. Thus, the objective of this study was twofold. First, to evaluate Canadian women’s knowledge of the legislative context governing GD. Second, to assess their concerns about the possible use of breast cancer risk levels by insurance companies or employers. We use a cross-sectional survey of 4293 (age: 30–69) women, conducted in four Canadian provinces (Alberta, British Colombia, Ontario and Québec). Canadian women’s knowledge of the regulatory framework for GD is relatively limited, with some gaps and misconceptions noted. About a third (34.7%) of the participants had a lot of concerns about the use of their health information by employers or insurers; another third had some concerns (31.9%), while 20% had no concerns. There is a need to further educate and inform the Canadian public about GD and the legal protections that exist to prevent it. Enhanced knowledge could facilitate the implementation and uptake of risk prediction informed by genetic factors, such as the risk-stratified approach to breast cancer screening that includes risk levels.

Women's Views on Multifactorial Breast Cancer Risk Assessment and Risk-Stratified Screening: A Population-Based Survey from Four Provinces in Canada

Risk-stratified screening for breast cancer (BC) is increasingly considered as a promising approach. However, its implementation is challenging and needs to be acceptable to women. We examined Canadian women’s attitudes towards, comfort level about, and willingness to take part in BC risk-stratified screening. We conducted an online survey in women aged 30 to 69 years in four Canadian provinces. In total, 4293 women completed the questionnaire (response rate of 63%). The majority of women (63.5% to 72.8%) expressed favorable attitudes towards BC risk-stratified screening. Most women reported that they would be comfortable providing personal and genetic information for BC risk assessment (61.5% to 67.4%) and showed a willingness to have their BC risk assessed if offered (74.8%). Most women (85.9%) would also accept an increase in screening frequency if they were at higher risk, but fewer (49.3%) would accept a reduction in screening frequency if they were at lower risk. There were few differences by province; however, outcomes varied by age, education level, marital status, income, perceived risk, history of BC, prior mammography, and history of genetic test for BC (all p ≤ 0.01). Risk-based BC screening using multifactorial risk assessment appears to be acceptable to most women. This suggests that the implementation of this approach is likely to be well-supported by Canadian women.

Predictors of mammographic density among women with a strong family history of breast cancer

BACKGROUND

Mammographic density is one of the strongest risk factors for breast cancer. In the general population, mammographic density can be modified by various exposures; whether this is true for women a strong family history is not known. Thus, we evaluated the association between reproductive, hormonal, and lifestyle risk factors and mammographic density among women with a strong family history of breast cancer but no BRCA1 or BRCA2 mutation.

METHODS

We included 97 premenopausal and 59 postmenopausal women (age range: 27-68 years). Risk factor data was extracted from the research questionnaire closest in time to the mammogram performed nearest to enrollment. The Cumulus software was used to measure percent density, dense area, and non-dense area for each mammogram. Multivariate generalized linear models were used to evaluate the relationships between breast cancer risk factors and measures of mammographic density, adjusting for relevant covariates.

RESULTS

Among premenopausal women, those who had two live births had a mean percent density of 28.8% vs. 41.6% among women who had one live birth (P=0.04). Women with a high body weight had a lower mean percent density compared to women with a low body weight among premenopausal (17.6% vs. 33.2%; P=0.0006) and postmenopausal women (8.7% vs. 14.7%; P=0.04). Among premenopausal women, those who smoked for 14 years or longer had a lower mean dense area compared to women who smoked for a shorter duration (25.3cm² vs. 53.1cm²; P=0.002). Among postmenopausal women, former smokers had a higher mean percent density (19.5% vs. 10.8%; P=0.003) and dense area (26.9% vs. 16.4%; P=0.01) compared to never smokers. After applying the Bonferroni correction, the association between body weight and percent density among premenopausal women remained statistically significant.

CONCLUSIONS

In this cohort of women with a strong family history of breast cancer, body weight was associated with mammographic density. These findings suggest that mammographic density may explain the underlying relationship between some of these risk factors and breast cancer risk, and lend support for the inclusion of mammographic density into risk prediction models.

Serum osteoprotegerin levels and mammographic density among high-risk women

PURPOSE

Mammographic density is a risk factor for breast cancer but the mechanism behind this association is unclear. The receptor activator of nuclear factor κB (RANK)/RANK ligand (RANKL) pathway has been implicated in the development of breast cancer. Given the role of RANK signaling in mammary epithelial cell proliferation, we hypothesized this pathway may also be associated with mammographic density. Osteoprotegerin (OPG), a decoy receptor for RANKL, is known to inhibit RANK signaling. Thus, it is of interest to evaluate whether OPG levels modify breast cancer risk through mammographic density.

METHODS

We quantified serum OPG levels in 57 premenopausal and 43 postmenopausal women using an enzyme-linked immunosorbent assay (ELISA). Cumulus was used to measure percent density, dense area, and non-dense area for each mammographic image. Subjects were classified into high versus low OPG levels based on the median serum OPG level in the entire cohort (115.1 pg/mL). Multivariate models were used to assess the relationship between serum OPG levels and the measures of mammographic density.

RESULTS

Serum OPG levels were not associated with mammographic density among premenopausal women (P ≥ 0.42). Among postmenopausal women, those with low serum OPG levels had higher mean percent mammographic density (20.9% vs. 13.7%; P = 0.04) and mean dense area (23.4 cm² vs. 15.2 cm²; P = 0.02) compared to those with high serum OPG levels after covariate adjustment.

CONCLUSIONS

These findings suggest that low OPG levels may be associated with high mammographic density, particularly in postmenopausal women. Targeting RANK signaling may represent a plausible, non-surgical prevention option for high-risk women with high mammographic density, especially those with low circulating OPG levels.

Efficacy of antiviral agents in feline herpetic keratitis: Results of anin vitrostudy

PURPOSE

To determine, by a plaque reduction assay, the in vitro efficacy of novel antiviral agents in the treatment of feline herpes virus 1 (FHV-1) keratitis in the domestic cat (Felis felis).

MATERIALS AND METHODS

A standard plaque reduction assay was performed using a laboratory strain of FHV-1 and embryo-derived feline kidney cells to determine the in vitro efficacy of the antiviral drugs penciclovir (PCV), bromovinyldeoxyuridine (BVdU), and (S)-9-(3-hydroxy-2-phosphonylmethoxypropyl) adenine (HPMPA) and to compare these with the drugs acyclovir (ACV) and trifluorothymidine (TFT). Efficacy was assessed by determining the dose of drug at which 50% plaque reduction was noted (ED(50)).

RESULTS

HPMPA was found to have greatest antiviral activity (ED(50) 0.07 microg/ml). ACV was least active (ED(50) 24 microg/ml), while TFT was active with an ED(50) of 5.7 microg/ml. PCV and BVdU had intermediate activity (ED(50) 1.6 and 1.7 microg/ml, respectively).

CONCLUSIONS

This study suggests that the efficacy of HPMPA, BVdU, and penciclovir in cats with herpesviral keratitis should be determined in vivo as their efficacy in vitro was substantially greater than that of acyclovir, already shown to have demonstrable but limited clinical antiviral activity.

Abstract B66: Optical spectroscopy of the breast: Association between breast cancer risk factors and breast tissue composition

B66

Understanding breast tissue development to identify when it is at high risk for tumorigenesis, particularly in younger women, can lead to increased prevention efforts. Current technologies to evaluate breast tissue are not an optimal option for young women due to high costs, invasiveness and risk of ionizing radiation. We are using a novel technique called optical spectroscopy (OS) to examine breast tissue. OS uses light at the red and near-infrared wavelengths shined through the breast and the light scattering and absorption spectra obtained provide information on the breast content of water, lipid, oxyhemoglobin and deoxyhemoglobin. OS measures have been shown to be related to quantitative mammographic measures (i.e. percent density) and association between mammographic density and breast cancer risk factors has been established previously.

The objective of this study was to explore the relationship of OS with breast cancer risk factors (anthropometric measures, reproductive factors, hormonal factors, physical activity and family history).

Women were recruited in three groups: nulliparous women aged 18-21 (group 1), nulliparous women aged 31-40 (group 2), and parous women aged 31-40 who had given birth prior to age 30 (group 3). All women completed a brief questionnaire on their breast cancer risk factors and underwent OS examination. Measurements were made at four standard positions on each breast for each woman (8 total). Principal components analysis (PCA) was used to derive the four main components from the spectral data and four scores were derived indicating the contribution of each of the four principal components to each individual’s spectra. The scores were averaged over all four positions on both breasts for each woman resulting in four scores, t1-t4, for each woman.

We present results from an initial group of 259 women, 137 in group 1, 94 in group 2, and 28 in group 3. Linear regression models were used to look for associations between breast cancer risk factors and the t scores for all groups combined, in groups 2 and 3 combined and in group 1 alone. Multivariate linear regression models were created to adjust for BMI, ethnicity and group and parity differences where applicable.

Preliminary results demonstrated that when considering all three groups together, t1 and t2 measures were associated with body mass index (p<0.0001); t2 (p=0.001),t3 (0.0005) and t4 (0.002) showed an association with ethnicity. In addition t3 was associated with physical activity in childhood (β=0.17(SE 0.09), p=0.05). T4 was inversely associated with age at menarche (β=-0.02 (SE 0.01), p=0.02), and positively associated with a first degree family history of breast cancer (β=0.09(SE 0.05), p=0.07) and age (β=0.01(SE 0.01), p=0.05). In group 1, t1 showed an inverse relationship with the luteal phase of the menstrual cycle (β=5.1(SE 2.3), p=0.03). In a combined analysis of groups 2 and 3, t2 was inversely associated with the luteal phase of the menstrual cycle (β=-0.34 (SE 0.14), p=0.02) and duration of hormonal contraceptive use (p=0.05).

The association between breast cancer risk factors and OS measures from our analysis indicates that the different components of the breast tissue could be a potential indicator of high risk breast tissue. OS may be a useful non-invasive technique to determine breast tissue characteristics associated with breast cancer risk in young women.

Citation Information: Cancer Prev Res 2008;1(7 Suppl):B66.

In vivo study of the inflammatory modulating effects of low-level laser therapy on iNOS expression using bioluminescence imaging

This study was designed to demonstrate that bioluminescence imaging (BLI) can be used as a new tool to evaluate the effects of low-level laser therapy (LLLT) during in vivo inflammatory process. Here, the efficacy of LLLT in modulating inducible nitric oxide synthase (iNOS) expression using different therapeutic wavelengths was determined using transgenic animals with the luciferase gene under control of the iNOS gene expression. Thirty transgenic mice, FVB/N-Tg(iNOS-luc)Xen, were allocated randomly to one of four experimental groups treated with different wavelengths (lambda = 635, 785, 808 and 905 nm) or a control group (nontreated). Inflammation was induced by intra-articular injection of zymosan A in both knee joints. Laser treatment (25 mW cm(-2), 200 s, 5 J cm(-2)) was applied to the knees 15 min after inflammation induction. Measurements of iNOS expression were performed at various times (0, 3, 5, 7, 9 and 24 h) by measuring the bioluminescence signal using a highly sensitive charge-coupled device (CCD) camera. The results showed a significant increase in BLI signal after irradiation with 635 nm laser when compared to the nonirradiated animals and the other LLLT-treated groups, indicating wavelength dependence of LLLT effects on iNOS expression during the inflammatory process, and thus demonstrating an action spectrum of iNOS gene expression following LLLT in vivo that can be detected by BLI. Histological analysis was also performed and demonstrated the presence of fewer inflammatory cells in the synovial joints of mice irradiated with 635 nm compared with nonirradiated knee joints.

Long-term, but not short-term, treatment with somatotropin during pregnancy in underfed pigs increases the body size of progeny at birth1

Treatment of pigs with porcine ST (pST) in early to mid-pregnancy increases body weight and length of their fetuses by mid-pregnancy, but this increased weight may not persist to birth. We investigated the effects of short- (25 d) and long-term (75 d) treatment with pST, and interactions between long-term pST treatment and crude protein content of diet, in restricted-fed gilts. In both experiments, Large White x Landrace gilts were bred at first estrus to Large White x Duroc boars and allowed to farrow naturally. In the first experiment, gilts were fed 1.8 kg/d of a diet containing 13.5 MJ DE/kg of DM and 15.05% CP (as-fed basis) throughout pregnancy, and were injected daily with 0, 2, or 4 mg pST from d 25 to 50 of pregnancy. Maternal treatment with pST from d 25 to 50 of pregnancy did not affect the number of piglets born per litter or progeny size at birth. In the second experiment, gilts were injected daily with 0 or 2 mg of pST and fed 2.2 kg/d of a diet containing 14.5 MJ DE/kg and either (as-fed basis) 16.6% (0.81% lysine) or 22.2% CP (1.16% lysine) from d 25 to 100 of pregnancy. All gilts were then fed 3.0 kg/d of the lower protein diet from d 100 of pregnancy to farrowing. Treatment with 2 mg pST/d from d 25 to 100 of pregnancy increased live weight of all gilts during the treatment period (P = 0.016), but the change in maternal live weight from d 25 to 100 of pregnancy was only increased (P = 0.001) by pST in gilts fed the higher protein diet. Live weight of gilts 1 d after farrowing was increased by pST treatment (P = 0.007), but was not altered by protein content of diet during pregnancy. In gilts fed the lower protein diet, but not in those fed the higher protein diet, pST treatment decreased maternal backfat depth during treatment (P < 0.020) and 1 d after farrowing (P = 0.002). Treatment with pST during pregnancy did not affect the number of piglets born per litter but independently increased body weight by 11.6% (P < 0.001) and length by 3.4% (P = 0.005) of progeny at birth and decreased (P < 0.01) the negative effect of litter size on body weight at birth. We conclude that in feed-restricted gilts, fetal weight gains in response to 25 d of pST treatment before mid-pregnancy are not maintained to term but that treatment with pST during most of pregnancy increases progeny size at birth and reduces maternal constraint of fetal growth.

A prospective comparison of the costs of reusable and limited-reuse laparoscopic instruments

OBJECTIVE

To compare the cost and performance of 2 types of laparoscopic instrumentation: reusable laparoscopic hook cautery instruments and curved scissors, or limited-reuse laparoscopic hook cautery instruments and curved scissors.

DESIGN

A randomized trial.

SETTING

The operating room of a tertiary care hospital.

METHOD

All general surgeons performing laparoscopic procedures at the hospital were randomized to be supplied with either reusable or limited-reuse hook cautery and curved scissors. Instrument use was recorded, together with principal outcome measures.

OUTCOME MEASURES

Life expectancy of the instruments, the number of cases for which they were used, the number, nature and cost of repairs, their purchase cost and surgeon satisfaction.

RESULTS

Reusable hook cautery instruments were less expensive than their limited-reuse counterparts. Excellent surgeon satisfaction was reported with the use of this type of instrument. The limited-reuse curved scissors arm of the study was terminated early because of a breach in study protocol.

CONCLUSIONS

Reusable hook cautery instruments were better than their limited-reuse counterparts. Rigorous attempts to compare the cost of laparoscopic instruments may be limited by their rapid evolution in design and the availability of many types of instruments on the market.