Late effects of adjuvant chemotherapy adumbrate dormancy complexity in breast cancer.

BACKGROUND: Dormant avascular micrometastases and single, or small groups of, non-proliferating cells are currently assumed to explain the multipeak dynamics of distant metastases (DM) following primary breast cancer surgical removal. METHODS: The hazard rate pattern for DM was analysed in 1518 premenopausal node-positive patients, enrolled in a series of randomized clinical trials on early breast cancer, which were carried out in Italy and Belgium. Patients underwent surgery alone (n = 397) or surgery plus adjuvant chemotherapy (n = 1121) and the minimal follow up was 15 years. RESULTS: The DM hazard rate for patients undergoing surgery alone displayed two early sharp peaks at 9 and 33 months, a wide intermediate one spanning from about 50 to 90 months and a late peak at 115-120 months. Adjuvant chemotherapy was associated with a prominent reduction of the two early peaks leaving a residual one at about 18 months and a reduction of the intermediate peak leaving two small peaks at about 50 and 80 months. The late peak remained unchanged. CONCLUSIONS: Present results reveal the ability of adjuvant chemotherapy to reduce not only the rate of early relapses, but also the rate of intermediate relapses at about the sixth year of follow up. Adjuvant chemotherapy is not impacting on the development of metastases underlying the late peak detected at the tenth year. These findings suggest the existence of a previously unknown dormancy state that, at the primary tumour surgical removal, results in evolving chemo-sensitive metastatic processes, and, moreover, of a later chemo-refractory dormancy state.

Detection of Micrometastases Using SPECT/Fluorescence Dual-Modality Imaging in a CEA-Expressing Tumor Model.

Intraoperative dual-modality imaging can help the surgeon distinguish tumor from normal tissue. This technique may prove particularly valuable if small tumors need to be removed that are difficult to detect with the naked eye. The humanized anticarcinoembryonic antigen (anti-CEA) monoclonal antibody, labetuzumab, can be used as a tumor-targeting agent in colorectal cancer, since CEA is overexpressed in approximately 95% of colorectal cancer. Dual-labeled labetuzumab, labeled with both a near-infrared fluorescent dye (IRDye800CW) and a radioactive label (111In), can be used as a tracer for dual-modality imaging. This study aimed to assess whether dual-modality imaging using 111In-diethylenetriaminepentaacetic acid (DTPA)-labetuzumab-IRDye800CW can detect pulmonary micrometastases in a mouse model. Methods: Pulmonary GW-39 human colonic carcinoma microcolonies were induced in athymic BALB/c mice by intravenous injection of 100 µL of a GW-39 cell suspension. After 1, 2, 3, and 4 wk of tumor growth, dual-modality imaging was performed 3 d after intravenous injection of 111In-DTPA-labetuzumab-IRDye800CW (10 µg, 25 MBq). Small-animal SPECT images and optical images were acquired, and image-guided surgery was performed. Finally, the biodistribution of the dual-labeled tracer was determined. Formalin-fixed sections of the lungs were analyzed using fluorescence imaging, autoradiography, and immunohistochemistry. Results: Submillimeter pulmonary tumor colonies could be visualized with both small-animal SPECT and fluorescence imaging from the first week of tumor growth, before they became visible to the naked eye. Furthermore, dual-modality imaging could be used to guide resection of tumors. Mean uptake (percentage injected dose per gram) of the dual-labeled tracer in tumors was 17.2 ± 5.4 and 16.5 ± 4.4 at weeks 3 and 4, respectively. Immunohistochemical analysis of the tumorous lungs showed that the distribution of the radioactive and fluorescent signal colocalized with CEA-expressing tumors. Conclusion: Dual-modality imaging after injection of 111In-labetuzumab-IRDye800CW can be used to detect submillimeter CEA-expressing pulmonary tumors before they become visible to the naked eye, supporting the added value of this technique in the resection of small tumors.

Computational Modeling of Micrometastatic Breast Cancer Radiation Dose Response.

PURPOSE: Prophylactic cranial irradiation (PCI) involves giving radiation to the entire brain with the goals of reducing the incidence of brain metastasis and improving overall survival. Experimentally, we have demonstrated that PCI prevents brain metastases in a breast cancer mouse model. We developed a computational model to expand on and aid in the interpretation of our experimental results. METHODS AND MATERIALS: MATLAB was used to develop a computational model of brain metastasis and PCI in mice. Model input parameters were optimized such that the model output would match the experimental number of metastases per mouse from the unirradiated group. An independent in vivo-limiting dilution experiment was performed to validate the model. The effect of whole brain irradiation at different measurement points after tumor cells were injected was evaluated in terms of the incidence, number of metastases, and tumor burden and was then compared with the corresponding experimental data. RESULTS: In the optimized model, the correlation between the number of metastases per mouse and the experimental fits was >95. Our attempt to validate the model with a limiting dilution assay produced 99.9% correlation with respect to the incidence of metastases. The model accurately predicted the effect of whole-brain irradiation given 3 weeks after cell injection but substantially underestimated its effect when delivered 5 days after cell injection. The model further demonstrated that delaying whole-brain irradiation until the development of gross disease introduces a dose threshold that must be reached before a reduction in incidence can be realized. CONCLUSIONS: Our computational model of mouse brain metastasis and PCI correlated strongly with our experiments with unirradiated mice. The results further suggest that early treatment of subclinical disease is more effective than irradiating established disease.

Dormant breast cancer micrometastases reside in specific bone marrow niches that regulate their transit to and from bone.

Breast cancer metastatic relapse can occur years after therapy, indicating that disseminated breast cancer cells (BCCs) have a prolonged dormant phase before becoming proliferative. A major site of disease dissemination and relapse is bone, although the critical signals that allow circulating BCCs to identify bone microvasculature, enter tissue, and tether to the microenvironment are poorly understood. Using real-time in vivo microscopy of bone marrow (BM) in a breast cancer xenograft model, we show that dormant and proliferating BCCs occupy distinct areas, with dormant BCCs predominantly found in E-selectin- and stromal cell-derived factor 1 (SDF-1)-rich perisinusoidal vascular regions. We use highly specific inhibitors of E-selectin and C-X-C chemokine receptor type 4 (CXCR4) (SDF-1 receptor) to demonstrate that E-selectin and SDF-1 orchestrate opposing roles in BCC trafficking. Whereas E-selectin interactions are critical for allowing BCC entry into the BM, the SDF-1/CXCR4 interaction anchors BCCs to the microenvironment, and its inhibition induces mobilization of dormant micrometastases into circulation. Homing studies with primary BCCs also demonstrate that E-selectin regulates their entry into bone through the sinusoidal niche, and immunohistochemical staining of patient BMs shows dormant micrometastatic disease adjacent to SDF-1(+) vasculature. These findings shed light on how BCCs traffic within the host, and suggest that simultaneous blockade of CXCR4 and E-selectin in patients could molecularly excise dormant micrometastases from the protective BM environment, preventing their emergence as relapsed disease.

Proposed new lymphology combined with lymphatic physiology, innate immunology, and oncology.

As one of the lymphatic functions, it is well known that the transport and drainage of hydrophilic substances including plasma protein through the lymphatic system play pivotal roles in maintaining the homeostasis of the internal environment between the cells in tissues in collaboration with the exchange of the substances through the blood capillaries and venules. The physiological functions of the lymphatic system have been studied by many investigations of microcirculation, i.e., Yoffey and Courtice, Ruszunyak et al., Földie and Casley-Smigh et al., Roddie, Schmid-Schönbein et al., and Ohhashi et al. On the other hand, it is also well known that the initial clinical signs of primary diseases such as inflammation, tumors, and circulatory disorders including infarction and thrombosis appear as functional abnormalities of the internal environment in tissues. These abnormalities of the functions are strongly related to immunological defense reactions around the internal environment and abnormal actions of the transport and drainage of the lymphatic system. Taking into consideration the current inspired findings in lymphatic physiology, innate immunology, and oncology, we have proposed a new lymphology combined with new knowledge of the three above-mentioned academic fields from a defense mechanism points of view. In this review, we would like to demonstrate comprehensively our latest studies related to the possibility of establishing a new lymphology, hoping the readers will evaluate this possibility.

[Colorectal liver metastases: history, sciences and clinical practices]. / Métastases hépatiques d'origine colorectale: histoire, sciences et pratiques.

Colorectal liver metastasis is one of the best-known clinical models of multidisciplinary approach. Chemotherapy, targeted therapies, surgery and interventional radiology permitted to obtain up to 40 months of survival in palliative intent for liver metastases only and between 40 to 50% of overall survival in curative intent. Genetic, epigenetic, cellular and tissular processes are more and more well described but attempts to link biological knowledge to clinical practice are still faint. The cut-off between curative and palliative intents is progressively pushed away but consequently, its signification is less clear. Maybe an additional intermediary new concept should be added, the metastatic disease chronicisation? Evaluating the patient benefice is difficult and should stand on progression free survival as surrogate marker.

[Micrometastasis: biological entity and clinical impact?]. / Les micrométastases : entité biologique et réalité clinique ?

Micrometastases or sub-micrometastases can be detected by standard histopathological method sometimes associated with immunohistochemistry in lymph nodes, bone marrow and blood. The consequence of these small size involvement may be prognostic and therapeutic. Two factors are necessary to assess this kind of involvement: the rate of involvement of non-sentinel lymph node after axillary lymph node dissection and significative difference of survivals. The rate of involvement of non-sentinel lymph node in case of micrometastases or sub-micrometastases is different from the rate of involvement in case of no lymph node metastases (7 to 8%) or in case of macrometases (30 to 50%). Micrometastase is an important factor to determine the rate of involvement of non-sentinel lymph node, the overall or disease free survival and to assess the need of radiotherapy and chemotherapy. In conclusion, micrometastases and sub-micrometastases have a clinical impact even if complementary axillary lymph node dissection is still discussed.

Quantitative molecular analysis of sentinel lymph node may be predictive of axillary node status in breast cancer classified by molecular subtypes.

To determine the performance of intraoperative one-step nucleic acid amplification (OSNA) assay in detecting sentinel lymph node metastases compared to postoperative histology taking into account breast cancer molecular classification and to evaluate whether the level of cytokeratin 19 mRNA copy number may be useful in predicting the likelihood of a positive axillary lymph node dissection. OSNA assay was performed in a prospective series of 903 consecutive sentinel lymph nodes from 709 breast cancer patients using 2 alternate slices of each sentinel lymph node. The remaining 2 slices were investigated by histology. Cytokeratin 19 mRNA copy number, which distinguishes negative cases (<250 copies), micrometastases (+, ≥250≤5000 copies) and macrometastases (++, >5000 copies), was compared to axillary lymph node dissection status and to the biological tumor profile. Concordance between OSNA and histopathology was 95%, specificity 95% and sensitivity 93%. Multiple Corresponce Analysis and logistic regression evidenced that positive axillary lymph node dissection was significantly associated with a higher cytokeratin 19 mRNA copy number (>5000; p<0.0001), HER2 subtype (p = 0.007) and lymphovascular invasion (p<0.0001). Conversely, breast cancer patients with cytokeratin 19 mRNA copy number <2000 mostly presented a luminal subtype and a negative axillary lymph node dissection. We confirmed that OSNA assay can provide standardized and reproducible results and that it represents a fast and quantitative tool for intraoperative evaluation of sentinel lymph node. Omission of axillary lymph node dissection could be proposed in patients presenting a sentinel lymph node with a cytokeratin 19 mRNA copy number <2000 and a Luminal tumor phenotype.