Adjuvant tamoxifen reduces breast cancer recurrence risk and mortality; however, initiation and treatment persistence are poor for younger patients. We hypothesized that a unique set of factors, including fertility concerns, would contribute to the poor tamoxifen use among premenopausal patients. From 2007 to 2012, 515 premenopausal patients younger than age 45 years, with stage 0 to III hormone receptor–positive breast cancer, for whom tamoxifen was recommended, were identified. Clinical and pathologic tumor characteristics, treatment regimens, and fertility concerns were recorded. Clinical factors associated with tamoxifen noninitiation and discontinuation were identified using univariate and multivariable analysis. After the recommendation for tamoxifen, patient reasons for tamoxifen noninitiation or discontinuation were also documented. All statistical tests were two-sided. Based on multivariable analysis, fertility concerns were statistically associated with both noninitiation (odds ratio = 5.04, 95% confidence interval (CI) = 2.29 to 11.07) and early discontinuation (hazard ratio = 1.78, 95% CI = 1.09 to 3.38) of tamoxifen. Other independent predictors of noninitiation included a diagnosis of ductal carcinoma in situ, declining radiation, and not receiving chemotherapy (stage I-III). Additionally, smoking and not receiving radiation therapy were statistically significant predictors of early withdrawal from therapy. Primary patient reasons for noninitiation and early discontinuation included concerns about side effects and fertility. This study provided insight into factors associated with tamoxifen use for reproductive-aged breast cancer survivors, with a new focus on fertility. Fertility concerns negatively impacted tamoxifen initiation and continuation among premenopausal patients. Interventions to optimize treatment initiation and persistence for young cancer patients should include access to fertility preservation options.

The pre-metastatic niche — the accumulation of aberrant immune cells and extracellular-matrix proteins in target organs — primes the initially healthy organ microenvironment and renders it amenable for subsequent colonization by metastatic cancer cells. By attracting metastatic cells, mimics of the pre-metastatic niche offer both diagnostic and therapeutic potential. However, deconstructing the complexity of the niche by identifying the interactions between cell populations as well as the mediatory roles of the immune system, soluble factors, extracellular-matrix proteins and stromal cells has proved challenging. Experimental models are needed to recapitulate niche-population biology in situ and to mediate in vivo tumour-cell homing, colonization and proliferation. In this Review, we outline the biology of the pre-metastatic niche and discuss advances in the engineering of niche-mimicking biomaterials that regulate the behaviour of tumour cells at an implant site. Such ‘oncomaterials’ offer strategies for the early detection of metastatic events, the inhibition of the formation of the pre-metastatic niche and the attenuation of metastatic progression.

The onset of distant organ metastasis from primary breast cancer marks the transition to a stage IV diagnosis. Standard imaging modalities often detect distant metastasis when the burden of disease is high, underscoring the need for improved methods of detection to allow for interventions that would impede disease progression. Here, microporous poly(ε-caprolactone) scaffolds were developed that capture early metastatic cells and thus serve as a sentinel for early detection. These scaffolds were used to characterize the dynamic immune response to the implant spanning the acute and chronic foreign body response. The immune cell composition had stabilized at the scaffold after approximately 1 month and changed dramatically within days to weeks after tumor inoculation, with CD11b⁺Gr1^hiLy6C⁻ cells having the greatest increase in abundance. Implanted scaffolds recruited metastatic cancer cells that were inoculated into the mammary fat pad in vivo, which also significantly reduced tumor burden in the liver and brain. Additionally, cancer cells could be detected using a label-free imaging modality termed inverse spectroscopic optical coherence tomography, and we tested the hypothesis that subsequent removal of the primary tumor after early detection would enhance survival. Surgical removal of the primary tumor following cancer cell detection in the scaffold significantly improved disease-specific survival. The enhanced disease-specific survival was associated with a systemic reduction in the CD11b⁺Gr1^hiLy6C⁻ cells as a consequence of the implant, which was further supported by Gr-1 depletion studies. Implementation of the scaffold may provide diagnostic and therapeutic options for cancer patients in both the high-risk and adjuvant treatment settings. Cancer Res; 76(18); 5209–18. ©2016 AACR.

The gonadotoxic effects of chemotherapy and radiation may result in premature ovarian failure in premenopausal oncology patients. Although autotransplantation of ovarian tissue has led to successful live births, reintroduction of latent malignant cells inducing relapse is a significant concern. In this report, we investigated the design of biomaterial grafts for transplantation of isolated ovarian follicles as a means to preserve fertility. Primordial and primary ovarian follicles from young female mice were extracted and encapsulated into biomaterials for subsequent transplantation into adult mice. Among the formulations tested, aggregated follicles encapsulated within fibrin had enhanced survival and integration with the host tissue following transplantation relative to the fibrin-alginate and fibrin-collagen composites. All mice transplanted with fibrin-encapsulated follicles resumed cycling, and live births were achieved only for follicles transplanted within VEGF-loaded fibrin beads. The extent to which these procedures reduce the presence of metastatic breast cancer cells among the isolated follicles was evaluated, with significantly reduced numbers of cancer cells present relative to intact ovaries. This ability to obtain live births by transplanting isolated primordial and primary follicles, while also reducing the risk of re-seeding disease relative to ovarian tissue transplantation, may ultimately provide a means to preserve fertility in premenopausal oncology patients.