A Therapeutic Challenge: Chemo-refractory Non-metastatic Inflammatory Breast Cancers

Clinical outcomes of curative-intent multimodal management of chemorefractory nonmetastatic inflammatory breast cancer

INTRODUCTION

Chemorefractory nonmetastatic inflammatory breast cancer (IBC) which progresses under neoadjuvant chemotherapy poses specific therapeutic challenges: either pursuing a curative-intent treatment with a salvage combination of radiotherapy and surgery or switching to second-line systemic treatments despite the absence of metastasis. Due to the rarity of this situation, no specific management guidelines exist and the outcomes of these patients remain uncertain. In this retrospective observational study, we aimed to report the clinical outcomes of patients treated in a curative intent for chemorefractory nonmetastatic IBC, with a multimodal salvage treatment combining radiotherapy and surgery.

MATERIALS AND METHODS

This single-center retrospective observational study included all chemorefractory nonmetastatic IBC treated at the Institut Curie (Paris, France). Overall survival (OS), disease-free survival (DFS), and locoregional relapse-free survival (LRRFS) were calculated from the time of diagnosis and from the time of neoadjuvant chemotherapy interruption.

RESULTS

Between January 2010 and January 2018, 7 patients presented with chemorefractory nonmetastatic IBC with a progressive disease during neoadjuvant chemotherapy. Overall, chemorefractory IBC patients were young (median age of 50 years), had a good performance status, and usually presented with node-positive tumors characterized by a combination of adverse histological factors such as triple-negative breast cancer (TNBC), grade III, and high proliferation index. From the date of pathological diagnosis, 1‑year OS, DFS, and LRRFS were 64.3%, 53.6%, and 71.4%, respectively. From the date of neoadjuvant chemotherapy interruption, 1‑year OS, DFS, and LRRFS were 47.6%, 19.0%, and 45.7%, respectively, and median OS, DFS, and LRRFS were 8.3, 5.0, and 5.0 months, respectively.

CONCLUSION

The prognosis of chemorefractory nonmetastatic IBC treated with a multimodal approach combining surgery and radiotherapy is particularly reserved, despite the curative intent of the salvage treatment and the lack of distant metastasis at the time of treatment. Optimal treatment modalities are still to be defined in this rare but critical presentation of IBC.

Concurrent Olaparib and Radiotherapy in Patients With Triple-Negative Breast Cancer: The Phase 1 Olaparib and Radiation Therapy for Triple-Negative Breast Cancer Trial

Importance

Triple-negative breast cancer (TNBC) cells are sensitive to poly(adenosine diphosphate ribose) polymerase (PARP) inhibitors used as radiosensitizers. Whether combining PARP inhibitors with radiotherapy in patients with TNBC would enhance the biological effectiveness of the irradiation and improve locoregional control is unclear.

Objective

To assess the safety and tolerability of PARP inhibition with olaparib used concurrently with radiotherapy in patients with TNBC with residual disease after neoadjuvant chemotherapy.

Design, Setting, and Participants

This phase 1 prospective dose-escalation trial (Olaparib and Radiation Therapy for TNBC [RadioPARP] trial) using a time-to-event continual reassessment method was performed from September 2017 to November 2019, with follow-up until November 2021. Participants had an incomplete pathologic response after neoadjuvant chemotherapy or unresectable TNBC despite previous neoadjuvant chemotherapy, an Eastern Cooperative Oncology Group Performance Status score of 0 or 1, and adequate organ functions.

Interventions

Olaparib was administered orally in the form of tablets and given at increasing doses (50 mg, 100 mg, 150 mg, or 200 mg twice daily). Olaparib therapy was started 1 week before radiotherapy and was continued concomitantly with radiotherapy. After breast-conserving surgery, a total dose of 50.4 Gy was delivered to the whole breast, with a 63-Gy simultaneously integrated boost to the tumor bed for patients younger than 60 years. After radical mastectomy or for unresectable tumors despite neoadjuvant chemotherapy, a total dose of 50.0 Gy was delivered to the chest wall (after mastectomy) or to the whole breast (for unresectable tumors). Regional lymph node stations could be treated with a total dose of 50.0 Gy to 50.4 Gy in cases of node-positive disease.

Main Outcomes and Measures

Main outcomes were the safety and tolerability of PARP inhibition with radiotherapy for early-stage, high-risk TNBC. Secondary outcomes included overall survival (OS) and event-free survival (EFS).

Results

Among the 24 patients included in the trial (100% female; median age, 46 years [range, 25-74 years]), no dose-limiting toxic effects were observed, and olaparib was escalated to 200 mg twice daily without reaching the maximum tolerated dose. No late treatment-related grade 3 or greater toxic effect was observed, and the maximum observed treatment-related toxic effects at the 2-year follow-up were grade 2 breast pain, fibrosis, and deformity in 1 patient (4.2%). Three-year OS and EFS were 83% (95% CI, 70%-100%) and 65% (95% CI, 48%-88%), respectively. Homologous recombination status was not associated with OS or EFS.

Conclusions and Relevance

The findings of this phase 1 dose-escalation trial suggest that PARP inhibition with olaparib concurrently with radiotherapy for early-stage, high-risk TNBC is well tolerated and should continue to be evaluated in further clinical trials.

Trial Registration

ClinicalTrials.gov Identifier: NCT03109080.