Yara Abdou

The development of immunotherapy agents has revolutionized the field of oncology. The only FDA-approved immunotherapeutic approach in breast cancer consists of immune checkpoint inhibitors, yet several novel immune-modulatory strategies are being actively studied and appear promising. Innovative immunotherapeutic strategies are urgently needed in triple negative breast cancer (TNBC), a subtype of breast cancer known for its poor prognosis and its resistance to conventional treatments. TNBC is more primed to respond to immunotherapy given the presence of more tumor infiltrating lymphocytes, higher PD-L1 expression, and higher tumor mutation burden relative to the other breast cancer subtypes, and therefore, immuno-oncology represents a key area of promise for TNBC research. The aim of this review is to highlight current data and ongoing efforts to establish the safety and efficacy of immunotherapeutic approaches beyond checkpoint inhibitors in TNBC.

PURPOSE Cyclin-dependent kinase (CDK) 4/6 inhibitors (CDK4/6is) are an important component of treatment for hormone receptor–positive/human epidermal growth factor receptor 2–negative (HER2–) metastatic breast cancer (MBC), but it is not known if patients might derive benefit from continuation of CDK4/6i with endocrine therapy beyond initial tumor progression or if the addition of checkpoint inhibitor therapy has value in this setting. METHODS The randomized multicenter phase II PACE trial enrolled patients with hormone receptor–positive/HER2– MBC whose disease had progressed on previous CDK4/6i and aromatase inhibitor (AI) therapy. Patients were randomly assigned 1:2:1 to receive fulvestrant (F), fulvestrant plus palbociclib (F + P), or fulvestrant plus palbociclib and avelumab (F + P + A). The primary end point was investigator-assessed progression-free survival (PFS) in patients treated with F versus F + P. RESULTS Overall, 220 patients were randomly assigned between September 2017 and February 2022. The median age was 57 years (range, 25-83 years). Most patients were postmenopausal (80.9%), and 40% were originally diagnosed with de novo MBC. Palbociclib was the most common previous CDK4/6i (90.9%). The median PFS was 4.8 months on F and 4.6 months on F + P (hazard ratio [HR], 1.11 [90% CI, 0.79 to 1.55]; P = .62). The median PFS on F + P + A was 8.1 months (HR v F, 0.75 [90% CI, 0.50 to 1.12]; P = .23). The difference in PFS with F + P and F + P + A versus F was greater among patients with baseline ESR1 and PIK3CA alterations. CONCLUSION The addition of palbociclib to fulvestrant did not improve PFS versus fulvestrant alone among patients with hormone receptor–positive/HER2– MBC whose disease had progressed on a previous CDK4/6i plus AI. The increased PFS seen with the addition of avelumab warrants further investigation in this patient population.

BACKGROUND: Primary and secondary breast angiosarcoma is a rare and aggressive malignancy with limited published literature. Optimal management is mostly based on expert opinion. Our study aims to describe a single institution experience with breast angiosarcoma and evaluate other publications on this topic to further clarify prognostic outcomes and treatment modalities in this disease. METHODS: Twenty two cases of breast angiosarcoma from Roswell Park Comprehensive Cancer Center were retrospectively analyzed. Additionally, a systemic review and meta-analysis was conducted to study the association between survival outcomes, overall survival (OS), and recurrence-free survival (RFS) in both primary (PAS) and secondary breast angiosarcoma (SAS). RESULTS: 9 PAS patients (41%) and 13 SAS patients (59%) were retrospectively analyzed. No significant differences were noted in tumor characteristics and survival outcomes between PAS and SAS. Treatment modality had no significant effects on survival outcomes although adjuvant chemotherapy demonstrated a trend towards improved RFS in high grade tumors. 380 PAS and 595 SAS patients were included in the outcome meta-analysis. Survival outcomes were significantly worse with high grade tumors and tumor size of > 5 cm. Adjuvant radiation therapy demonstrated significantly better RFS, while adjuvant chemotherapy had no effect on survival outcomes. CONCLUSION: Tumor size and grade seem to be reliable predictors of survival in both PAS and SAS. Mastectomy does not seem to be adding any additional benefit to BCS. Adjuvant radiation therapy showed statistically significant RFS benefit, while adjuvant chemotherapy can be beneficial in high grade tumors.