MRI ductography of contrast agent distribution and leakage in normal mouse mammary ducts and ducts with in situ cancer

Systemic and Local Strategies for Primary Prevention of Breast Cancer

One in eight women will develop breast cancer in the US. For women with moderate (15-20%) to average (12.5%) risk of breast cancer, there are few options available for risk reduction. For high-risk (>20%) women, such as BRCA mutation carriers, primary prevention strategies are limited to evidence-based surgical removal of breasts and/or ovaries and anti-estrogen treatment. Despite their effectiveness in risk reduction, not many high-risk individuals opt for surgical or hormonal interventions due to severe side effects and potentially life-changing outcomes as key deterrents. Thus, better communication about the benefits of existing strategies and the development of new strategies with minimal side effects are needed to offer women adequate risk-reducing interventions. We extensively review and discuss innovative investigational strategies for primary prevention. Most of these investigational strategies are at the pre-clinical stage, but some are already being evaluated in clinical trials and others are expected to lead to first-in-human clinical trials within 5 years. Likely, these strategies would be initially tested in high-risk individuals but may be applicable to lower-risk women, if shown to decrease risk at a similar rate to existing strategies, but with minimal side effects.

X-Ray Visualization of Intraductal Ethanol-Based Ablative Treatment for Prevention of Breast Cancer in Rat Models

There are still a limited number of primary interventions for prevention of breast cancer. For women at a high risk of developing breast cancer, the most effective intervention is prophylactic mastectomy. This is a drastic surgical procedure in which the mammary epithelial cells that can give rise to breast cancer are completely removed along with the surrounding tissue. The goal of this protocol is to demonstrate the feasibility of a minimally invasive intraductal procedure that could become a new primary intervention for breast cancer prevention. This local procedure would preferentially ablate mammary epithelial cells before they can become malignant. Intraductal methods to deliver solutions directly to these epithelial cells in rodent models of breast cancer have been developed at Michigan State University and elsewhere. The rat mammary gland consists of a single ductal tree that has a simpler and more linear architecture compared to the human breast. However, chemically induced rat models of breast cancer offer valuable tools for proof-of-concept studies of new preventive interventions and scalability from mouse models to humans. Here, a procedure for intraductal delivery of an ethanol-based ablative solution containing tantalum oxide nanoparticles as X-ray contrast agent and ethyl cellulose as gelling agent into the rat mammary ductal tree is described. Delivery of aqueous reagents (e.g., cytotoxic compounds, siRNAs, AdCre) by intraductal injection has been described previously in mouse and rat models. This protocol description emphasizes methodological changes and steps that pertain uniquely to delivering an ablative solution, formulation consideration to minimize local and systemic side effects of the ablative solution, and X-ray imaging for in vivo assessment of ductal tree filling. Fluoroscopy and micro-CT techniques enable to determine the success of ablative solution delivery and the extent of ductal tree filling thanks to compatibility with the tantalum-containing contrast agent.

Dynamic Enhanced Magnetic Resonance Imaging versus Ultrasonic Diffused Optical Tomography in Early Diagnosis of Breast Cancer

Objective

To compare the application value of dynamic enhanced magnetic resonance imaging (MRI) and ultrasonic diffused optical tomography (DOT) in early diagnosis of breast cancer.

Methods

The clinical data of 110 female patients with breast diseases treated in our hospital from June 2018 to June 2021 were selected for the retrospective analysis, and the patients were divided into the benign lesion group (n = 50) and breast cancer group (n = 60) according to the pathologic findings. All patients received dynamic enhanced MRI and ultrasonic DOT examinations for the observation of lesion morphology and analysis of relevant parameters, so as to scientifically evaluate the diagnostic value of dynamic enhanced MRI and ultrasonic DOT for early breast cancer.

Results

The dynamic enhanced MRI examination found that the proportions of irregular shape, increased vascular shadow, obscure boundary, spicule sign, heterogeneous enhancement, etc. of lesion were significantly higher in the breast cancer group than in the benign lesion group (P < 0.05); parameters such as K trans, K ep, and V e were significantly higher in the breast cancer group than in the benign lesion group (P < 0.05); the ultrasonic DOT diagnosis found that the THC value was obviously lower in the benign lesion group than in the breast cancer group (P < 0.05); compared with the pathologic findings, it was believed that combined diagnosis had significantly higher diagnosis accuracy rate, sensitivity, specificity, positive predictive value and negative predictive value than the dynamic enhanced MRI and ultrasonic DOT diagnosis alone (P < 0.05); and after further analyzing the efficacy of the two diagnosis modalities in diagnosing early breast cancer by ROC curves, the result showed combined diagnosis > dynamic enhanced MRI > ultrasonic DOT.

Conclusion

Both dynamic enhanced MRI and ultrasonic DOT present higher diagnostic value to early breast cancer, of which dynamic enhanced MRI obtains results closer to the pathologic findings and has diagnostic efficacy higher than ultrasonic DOT. But the combination of the two can significantly improve the diagnosis accuracy rate for early breast cancer, presenting higher diagnostic value.

Intraductal Delivery and X-ray Visualization of Ethanol-Based Ablative Solution for Prevention and Local Treatment of Breast Cancer in Mouse Models

Breast cancer is the most prevalent cancer and the second-leading cause of cancer-related death for women in the USA. For high-risk women, prophylactic mastectomy is the most effective primary prevention strategy. Prophylactic mastectomy is an aggressive surgical procedure that completely removes the mammary epithelial cells from which breast cancer arises along with the surrounding tissue. We seek to develop a minimally invasive intraductal procedure as an alternative to prophylactic mastectomy to locally ablate the mammary epithelial cells before they can become malignant. We and others have developed an intraductal delivery procedure to reach and treat these epithelial cells in rodent models of breast cancer. While the mouse mammary gland with a single non-anastomosed ductal tree opening at the nipple has a much less complex and tortuous architecture than the human breast, chemically induced and genetically engineered mouse models of breast cancer are valuable to produce proof-of-concept studies of new preventative strategies. Here, we describe a procedure for intraductal delivery of an ethanol-based ablative solution containing micro-CT/X-ray tantalum-based contrast agent within the mouse mammary ductal tree for the therapeutic purpose of primary prevention of breast cancer. Intraductal delivery of aqueous reagents (e.g., cytotoxic compounds, siRNAs, AdCre) has been previously described in mouse models. Thus, we focus our protocol description on methodological modifications and unique experimental considerations for optimizing delivery of ethanol, for minimizing local and systemic side effects of ethanol administration, and for in vivo visualization of ductal tree filling via micro-CT/fluoroscopy imaging. Visualization of the ductal tree immediately after injection of a contrast-containing solution allows for confirmation of complete filling or unsuccessful outcomes such as underfilling or overfilling. This procedure can be applied for delivery and imaging of other ablative compounds aimed at either preventing tumor formation or locally treating early-stage tumors accessible via the ductal tree.