Efficacy and Safety of High Dose of Lansoprazole Pretreatment in Patients with Breast Cancer Receiving Neo-Adjuvant Chemotherapy

Background: High dosage of lansoprazole (LPZ) can be used to control acidic microenvironment surrounding the cancerous cells thus improving tumor response.

Aim: The study aimed at investigating the possible antitumor efficacy and safety of high dose of LPZ pretreatment in patients with breast cancer (BC) receiving neo-adjuvant chemotherapy (NAC).

Study Design: Single blinded, randomized placebo-controlled study.

Place and Duration of Study: The study was conducted between June 2021 and November 2022 at Clinical Oncology and Nuclear Medicine Department, Menoufia University Hospital, Egypt.

Methodology: 66 females with stage II and III BC were randomly assigned into two groups; the LPZ group (n=33) which started LPZ capsules 60 mg orally bid 4 days before starting NAC and the control group (n=33) which received placebo capsules and the same NAC regimen as LPZ group. Evaluation of tumor response was done according to the Response Evaluation Criteria in Solid Tumors (RECIST, v1.1). Permeability-glycoprotein (P-gp) and Ki-67 levels were assessed in the two groups before and after treatment. Adverse events were documented and graded using National Cancer Institute-Common Terminology Criteria for Adverse Events (NCI-CTCAE, v5). Trial Registration: ClinicalTrials.gov identifier: NCT04874935.

Results: Lansoprazole group showed more favorable response especially within luminal B/HER2 negative subtype. Lansoprazole group showed non-significant decrease in P-gp (P = 0.19) and Ki-67 (P = 0.44) levels as compared to the control group. Dyspepsia was the only significant adverse effect reported with LPZ group (P = 0.011).

Conclusion: However, LPZ didn't reveal a statistically significant anti-tumor effect as compared to placebo; it produced a clinically important improvement in tumor response which was translated by higher number of patients who achieved complete response. Furthermore, the high dose of LPZ used during this study was tolerable and safe.