Value of estrogenic recruitment before chemotherapy: first randomized trial in primary breast cancer

The effects of proliferation status and cell cycle phase on the responses of single cells to chemotherapy

DNA-damaging chemotherapeutics are widely used in cancer treatments, but for solid tumors they often leave a residual tumor-cell population. Here we investigated how cellular states might affect the response of individual cells in a clonal population to cisplatin, a DNA-damaging chemotherapeutic agent. Using a live-cell reporter of cell cycle phase and long-term imaging, we monitored single-cell proliferation before, at the time of, and after treatment. We found that in response to cisplatin, cells either arrested or died, and the ratio of these outcomes depended on the dose. While we found that the cell cycle phase at the time of cisplatin addition was not predictive of outcome, the proliferative history of the cell was: highly proliferative cells were more likely to arrest than to die, whereas slowly proliferating cells showed a higher probability of death. Information theory analysis revealed that the dose of cisplatin had the greatest influence on the cells’ decisions to arrest or die, and that the proliferation status interacted with the cisplatin dose to further guide this decision. These results show an unexpected effect of proliferation status in regulating responses to cisplatin and suggest that slowly proliferating cells within tumors may be acutely vulnerable to chemotherapy.

Tidal chemotherapy in premenopausal patients with hormone receptor positive breast cancer

Neoadjuvant chemotherapy remains an inseparable part of systemic therapy for hormone receptor positive (HR+) advanced breast cancer. However, efficacy of neoadjuvant chemotherapy in this subtype of patients is inferior to its hormone receptor negative counterpart. Several preclinical and clinical studies have suggested that it was growth rate rather than hormone receptor status that determined sensitivity to chemotherapy. In addition, estrogen was proved to recruit more HR+ breast cancer cells into actively dividing phase according to various studies. For premenopausal females, sexual hormone like estradiol fluctuates with menstrual cycle. When menstruation occurs, women have the lowest level of estradiol, which is resemble to pharmaceutical effect of endocrine therapy. If chemotherapy is given to females during menstruation, it's almost equal to concurrent use of chemotherapy and endocrine therapy, which is not recommended by guideline. Accordingly, chemotherapy would attain best efficacy applied at the peak of estradiol, because more tumor cells being in actively dividing phase recruited by comparatively high level of estradiol would help cytotoxic agents function better given that majority of chemotherapeutic drugs are cellular phase dependent. We name this rhythmic mode of chemotherapy for premenopausal HR+breast cancer females, giving chemotherapy to patients when estradiol rises and avoiding prescription at menstruation, tidal chemotherapy. It's postulated that tidal chemotherapy would improve efficacy of neoadjuvant chemotherapy for premenopausal HR+breast cancer females, achieve more pathologic complete response and in the long run improve prognosis.

Current limits of knowledge in adjuvant and neoadjuvant endocrine therapy of breast cancer: the need for more clinical research

Adjuvant endocrine therapy following surgical resection of early, endocrine sensitive breast cancer has proven benefits in reducing risk of recurrence and death, as demonstrated in many mature well controlled clinical trials. The introduction of new endocrine therapies as potential alternatives to tamoxifen or ovarian ablation and the incorporation of neoadjuvant endocrine therapy into the overall management strategy continue to provide exciting challenges for clinical research. In this article the focus is on as yet unanswered questions pertinent to adjuvant or neoadjuvant endocrine therapy for breast cancer. In the process, we broadly outline the current limits of knowledge as we understand it. Many relevant and current clinical trials are ongoing and a list of these with contact details or references are provided. Definitive data is urgently needed in many areas and, when available, will provide important evidence on which the management of breast cancer patients in future can be based. Participation in relevant clinical trials is vital for future progress.