Appraisal of Systemic Treatment Strategies in Early HER2-Positive Breast Cancer-A Literature Review

BACKGROUND

The overexpression of the human epidermal growth factor receptor 2 (HER2+) accounts for 15-20% of all breast cancer phenotypes. Even after the completion of the standard combination of chemotherapy and trastuzumab, relapse events occur in approximately 15% of cases. The neoadjuvant approach has multiple benefits that include the potential to downgrade staging and convert previously unresectable tumors to operable tumors. In addition, achieving a pathologic complete response (pCR) following preoperative systemic treatment is prognostic of enhanced survival outcomes. Thus, optimal evaluation among the suitable strategies is crucial in deciding which patients should be selected for the neoadjuvant approach.

METHODS

A literature search was conducted in the Embase, Medline, and Cochrane electronic libraries.

CONCLUSION

The evaluation of tumor and LN staging and, hence, stratifying BC recurrence risk are decisive factors in guiding clinicians to optimize treatment decisions between the neoadjuvant versus adjuvant approaches. For each individual case, it is important to consider the most likely postsurgical outcome, since, if the patient does not obtain pCR following neoadjuvant treatment, they are eligible for adjuvant T-DM1 in the case of residual disease. This review of HER2-positive female BC outlines suitable neoadjuvant and adjuvant systemic treatment strategies for guiding clinical decision making around the selection of an appropriate therapy.

Sequencing of systemic therapies in advanced NSCLC with MET exon 14 skipping mutation: A multicenter experience

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Background: The treatment landscape for patients with metastatic non-small cell lung cancer (mNSCLC) with a MET exon 14 skipping mutation ( MET ex14) is rapidly changing, with recent approvals of MET selective tyrosine kinase inhibitors (TKIs) and reports of durable response to immune checkpoint inhibitors (ICI), particularly among those with sarcomatoid histology. Currently there are no published data that inform the sequencing of TKIs and ICI regimens. We sought to characterize treatment patterns and outcomes in this population at 3 Ontario cancer centres. Methods: We reviewed all mNSCLC patients with MET ex14 identified by tissue or plasma NGS in the last 4 years. Patients with EGFR co-mutation or MET amplification alone were excluded. All systemic therapies and outcomes of overall response (ORR), progression free survival (PFS), overall survival (OS), and adverse events (AEs) were captured. Results: We identified 43 patients with MET alterations, of whom 29 had MET ex14: median age 73 years (54-92), 66% female, 79% non-smokers. Tumor histology was adenocarcinoma in 76%, pleomorphic/sarcomatoid in 21% and adenosquamous in 3% of patients. 69% of patients had PD-L1 ≥50%. At presentation, 20% of patients had high disease burden and ECOG ≥2. Among 15 patients who received ICI, ORR with ICI monotherapy was 45% (10/11 had PD-L1 ≥50%) and ORR with ICI plus chemotherapy was 75% (4/4 had PD-L1 0-49%). Responses were seen in 50% of non-smokers (7/12 had PD-L1 ≥50%). The median PFS with ICI was 10.6 months (1.7-NR). MET TKIs were received by 18 patients (16 crizotinib, 1 capmatinib, 1 cabozantinib), with an ORR of 28% (30% amongst those who received crizotinib first line). The median PFS with TKIs was 2.6 months (1.2-8.9). Median OS for the entire cohort was 24.4 months (10.1-48.3). Patients who received initial ICI (n = 13) compared to those who received initial TKI (n = 11) had significantly longer OS (48.3 vs 13.6 months; p = 0.005), not controlled for prognostic factors. All patients who progressed after ICI (9/13) received further treatment while only 50% of patients who progressed after TKI (8/11) received subsequent therapy. 7 patients received TKI therapy after ICI with a median time to TKI of 35 days (24-181). 6 patients (85.7%) experienced an early grade ≥3 AE (4 transaminitis, 2 pneumonitis) resulting in permanent discontinuation of TKI in half of patients. There were no treatment-related deaths. Conclusions: Patients with MET ex14 NSCLC benefit from ICI irrespective of PD-L1 expression and smoking history. ORR and PFS with earlier generation TKIs (crizotinib) were poor. Increased toxicity is seen when a TKI is used after ICI and careful monitoring is necessary. Future studies focusing on the optimal sequencing of TKIs and ICI-containing therapy should be prioritized, as well as broader access to newer generation MET TKIs with greater activity.

Overall survival comparison in patients with and without brain metastases treated with osimertinib for metastatic EGFR mutation positive non-small cell lung cancer (NSCLC)

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Background: With the development of Epidermal Growth factor receptor (EGFR) tyrosine kinase inhibitors such as Osimertinib, the landscape of lung cancer treatment and outcomes has changed. We aimed to describe the outcomes of patients treated with Osimertinib who have brain metastasis compared to those without brain metastases. Methods: This study involved patients diagnosed with metastatic non-small cell lung cancer (NSCLC) with EGFR mutation, from January 2010 to December 2018, who had treatment with Osimertinib at a dose of 80 mg daily. Retrospective data was collected through the electronic medical records from Sunnybrook Health Sciences Centre. Descriptive statistics were used to summarize the population characteristics. The log rank test was used to compare the survival distributions. Results: A total of 56 patients were included, the mean age at initial diagnosis was 63 years (range 27 – 85 years). Overall, 82.2% of this patient population received Osimertinib in 2nd line setting. A total of 50% (n = 28) had brain metastasis, and14.3% (n = 8) had leptomeningeal metastasis. Of the patients with brain metastasis, 14.3% (n = 4) had brain surgery. All patients with brain metastasis received central nervous system (CNS) radiation. With respect to radiotherapy modalities, 67.9% (n = 19) of patients with brain metastasis received gamma knife radiation, 42.85% (n = 12) were treated with stereotactic radiosurgery (SRS), and whole brain radiation was given to 57.1% (n = 16). Of those with brain metastasis, equal numbers of patients, 46.4% (n = 13), had EGFR mutations with exon 19-deletion and exon 21-L858R, 7.1% (n = 2) had unknown gene location EGFR mutation. The median OS for patients without brain metastasis was 38.6 months (95% confidence interval [CI] 37.5 – 39.8 months], compared to 35.9 months (95% [CI] 28.3 – 43.5 months] for those with brain metastasis ; log Rank (Mantel-Cox) p = 0.874. The median OS for patients diagnosed with leptomeningeal metastasis was 21 months (95% [CI] 2.9 – 39.0 months); log rank (mantel-cox). When brain metastasis was examined by EGFR mutation sub-groups, the median OS for patients with EGFR-exon 19-deletion was 26.4 months (95% CI [14.3 – 38.4 months], compared to 36.8 months, 95% CI [34.3 – 39.2 months] for those with EGFR-Exon 21-L858R; log Rank (Mantel-Cox) p = 0.49. Conclusions: Although there is an equivalent prevalence of brain metastasis between the two NSCLC EGFR mutation populations, in unadjusted analyses, no difference in OS was seen between patients with brain metastases compared to those without brain metastases. However, in the small number of patients with leptomeningeal disease, survival was shorter and a larger population should be studied to further explore this finding.