Clinical benefit of fulvestrant monotherapy in the multimodal treatment of hormone receptor and HER2 positive advanced breast cancer: a case series

Abstract

Fulvestrant is a pure estrogen receptor (ER) antagonist approved for the treatment of metastatic ER positive breast cancer in postmenopausal women with disease progression following antiestrogen therapy. The clinical results of fulvestrant demonstrated encouraging activity in tumors in spite of HER2 positivity, but data about its use after progression on anti-HER2 agents are limited. Partial responses and durations of response of 12, 25, and 38 months in three cases with multiple metastases of ER positive and HER2 positive breast cancer were observed; all patients had been treated with 1–4 regimens of an anti-HER2 agent in combination with chemotherapy or an aromatase inhibitor before the initiation of fulvestrant. Fulvestrant is a valuable option with limited toxicity and durable response in metastatic HER2 and ER positive breast cancer after progression on anti-HER2 agents as well. Therapeutic benefit even in extensive skin metastases and (irradiated) brain metastases may be expected. Further investigations are warranted to establish where it fits into the multimodal management of ER and HER positive breast cancer.

Treatment strategies for breast cancer brain metastases

“…Treatment for patients with HER2 -BM For the treatment of patients with ER + /HER2 -BCBM, some responses have been observed with tamoxifen, 85 aromatase inhibitors 86,87 and fulvestrant 88 , and therefore, in the absence of therapeutic alternatives, these low-toxicity treatments have a place in paucisymptomatic ER + patients.…”

Concomitant fulvestrant with reirradiation for unresectable locoregional recurrent estrogen receptor positive (ER+) breast cancer

“…Fulvestrant has been found to be as effective as the third-generation aromatase inhibitors (AIs) anastrozole and letrozole for advanced, post-menopausal, tamoxifen-resistant breast cancer, and also appears to be effective after treatment with non-steroidal AIs. [ 19 ] Based on the evidence available, for the patient we presented here, concomitant fulvestrant with irradiation was prescribed under our MDT. Throughout radiation treatment, patients were examined weekly by the radiation oncologist for acute toxicities using the Radiation Therapy Oncology Group (RTOG) radiation morbidity scoring criteria.…”

<p>A temperature-sensitive phase-change hydrogel of tamoxifen achieves the long-acting antitumor activation on breast cancer cells</p>

“…Fulvestrant (ICI-182780), another antagonist of estrogen receptors, has also been widely used as first-line or second-line therapy for locally advanced or metastatic breast cancer 58,59. Fulvestrant is also the foremost therapeutic choice for post-menopausal patients with breast cancer 60,61. In the future, we will try to establish various new pharmaceutical formulations of fulvestrant to achieve more effective antitumor treatments for breast cancer.…”