Proton Pump Inhibitors and Cyclin-Dependent Kinase 4/6 Inhibitors in Patients With Breast Cancer.

BACKGROUND: Proton pump inhibitors (PPIs) reduce the bioavailability of several anticancer drugs. The impact of PPIs co-administered with cyclin-dependent kinase 4 and 6 inhibitors is controversial. We aimed to clarify whether the concomitant use of PPIs impacts palbociclib and abemaciclib effectiveness in breast cancer treatment. PATIENTS AND METHODS: This multicenter, retrospective, observational study, conducted across 4 medical institutions in Japan, consecutively included patients with endocrine-resistant metastatic breast cancer, receiving palbociclib or abemaciclib between December 2017 and August 2022. Propensity score-matched analyses were performed. Treatment efficacy and safety with and without PPIs were compared. Progression-free survival and overall survival were estimated using the Kaplan-Meier method and compared using a log-rank test. A Cox proportional hazards model was used to estimate the hazard ratio. RESULTS: The study included 240 patients. After 1:1 matching, 112 patients were treated with and without PPIs. The median progression-free survival period was 1.2 years in the PPI group and 1.3 years in the non-PPI group (hazard ratio, 1.19; 95% CI, 0.70-2.02). The median overall survival period was 3.6 years in the PPI group, whereas it was not reached in the non-PPI group (hazard ratio, 1.23; 95% CI, 0.61-2.47). Consistent results were obtained for subgroups receiving palbociclib (n = 177) and abemaciclib (n = 63) without propensity score matching. Adverse event incidence and severity were similar in both groups. CONCLUSION: The effectiveness of cyclin-dependent kinase 4/6 inhibitors is unlikely to be affected by concomitant PPI use. Future prospective pharmacokinetic studies are warranted.

Clinical and biomarker factors affecting survival in patients with platinum-sensitive relapsed ovarian cancer receiving olaparib monotherapy: a multicenter retrospective study.

The standard treatment for platinum-sensitive relapsed ovarian cancer (PSROC) is platinum-based chemotherapy followed by olaparib monotherapy. A retrospective study was conducted to identify factors affecting the survival of patients with PSROC undergoing olaparib monotherapy in real-world clinical settings. The study enrolled 122 patients who received olaparib monotherapy between April 2018 and December 2020 at three national centers in Japan. The study used the Kaplan-Meier method and univariable and multivariable Cox proportional hazards models to evaluate the associations between factors and progression-free survival (PFS). Patients with BRCA1/2 mutations had a significantly longer median PFS than those without these mutations. Both the BRCA1/2 mutation-positive and mutation-negative groups exhibited a prolonged PFS when the platinum-free interval (PFI) was ≥ 12 months. Cancer antigen 125 (CA-125) level within reference values was significantly linked to prolonged PFS, while a high platelet-to-lymphocyte ratio (≥ 210) was significantly associated with poor PFS in the BRCA1/2 mutation-negative group. The study suggests that a PFI of ≥ 12 months may predict survival after olaparib monotherapy in patients with PSROC, regardless of their BRCA1/2 mutation status. Additionally, a CA-125 level within reference values may be associated with extended survival in patients without BRCA1/2 mutations. A larger prospective study should confirm these findings.

The impact of the COVID-19 pandemic on perioperative chemotherapy for breast cancer.

BACKGROUND: Since it was first reported in December 2019, coronavirus disease 2019 (COVID-19) spread rapidly across the globe resulting in a pandemic. As of August 2022, seven outbreak peaks have been confirmed in Tokyo, and the numbers of new cases in the fifth and later outbreak periods have been far greater than in the preceding periods. This retrospective study examined the impact of the COVID-19 pandemic on perioperative chemotherapy for breast cancer. METHODS: Patients with breast cancer who received perioperative chemotherapy at the National Cancer Center Hospital East were divided into 2 groups: 120 and 384 patients who started chemotherapy before and during the pandemic, respectively. The incidence of critical events that had potential detrimental effects on the prognosis, such as start of adjuvant chemotherapy ≥91 days after surgery and relative dose intensity of chemotherapy <85% were compared between groups. RESULTS: No significant difference in the incidence of critical events was found. When stratified by outbreak period, the incidence of critical events was positively correlated with the increasing number of new cases of COVID-19 (r = 0.83, p = 0.04). Moreover, 25/173 patients (14%) who started perioperative chemotherapy during the fifth and sixth outbreak periods developed COVID-19 infection, 80% of whom (20/25) had a delay or interruption to their surgery or other perioperative treatments. CONCLUSIONS: Although the impact of the COVID-19 pandemic on perioperative chemotherapy on whole groups of patients was not evident when comparing periods before and after the pandemic, the impact is becoming prominent in parallel with increasing numbers of new COVID-19 cases.

Clinical features of CDK4/6 inhibitor-related interstitial lung disease in patients with breast cancer: a case series study.

BACKGROUND: Cyclin-dependent kinase 4/6 (CDK4/6) inhibitors are the standard treatment for advanced hormone receptor-positive breast cancer. Although interstitial lung disease is a rare (1-3.3%) but serious adverse event associated with CDK4/6 inhibitors, the incidence of interstitial lung disease in Japanese patients in the real world and the risk factors of interstitial lung disease are not clear. METHODS: We retrospectively investigated the incidence of interstitial lung disease in 224 patients with advanced breast cancer who received CDK4/6 inhibitors at our hospital between 31 January 2017 and 31 January 2021. The correlation of age (>50 vs ≤50 years), presence or absence of previous history of interstitial lung disease, lung metastasis, smoking history and chest radiation with the development of interstitial lung disease was evaluated. RESULTS: In total, 177 cases received palbociclib, 39 cases received abemaciclib and 8 cases received both palbociclib and abemaciclib, constituting a palbociclib group (n = 185) and an abemaciclib group (n = 47). At a median observation period of 607 days, 8.0% (18/224) cases (13 definite and 5 probable cases) had interstitial lung disease; 6.5% (12/185) of palbociclib-treated and 13% (6/47) of abemaciclib-treated cases. The median time to interstitial lung disease onset was 178 (range, 14-750) days. There was no significant correlation between the background factors studied and the development of interstitial lung disease. CONCLUSION: The frequency of CDK4/6 inhibitor-induced interstitial lung disease was higher than that reported in clinical trials. We did not identify any risk factors for the development of interstitial lung disease in this study, and thus, larger studies that include patient predisposition are required.

Patient-associated risk factors for severe anemia in patients with advanced ovarian or breast cancer receiving olaparib monotherapy: A multicenter retrospective study.

Background: Olaparib-induced anemia is a frequently occurring complication in patients with advanced ovarian cancer, fallopian tube cancer, or primary peritoneal cancer and is associated with a marked deterioration in patients' health-related quality of life. This study aimed to clarify patient-specific risk factors for severe anemia in patients with advanced ovarian or breast cancer receiving olaparib monotherapy in a real-world setting. Methods: This multicenter, retrospective, observational study enrolled consecutively presenting patients with advanced ovarian or breast cancer who received olaparib monotherapy as maintenance or palliative treatment between April 2018 and December 2020 at three participating medical institutions in Japan. The primary endpoint was patient-associated risk factors underlying the onset of grade ≥3 anemia from olaparib treatment initiation to 90 days after treatment. Receiver operating characteristic curves were constructed and univariable and multivariable logistic regression analyses were performed to evaluate the association between patient-associated risk factors and grade ≥3 anemia. Results: Of 113 patients evaluated in this study, 32.7% (n = 37) had grade ≥3 anemia. Multivariable logistic regression analysis revealed that low baseline red blood cell (RBC) count (<3.3 × 106 cells/µL), low baseline hematocrit level (<35%), low baseline hemoglobin level (<11.6 g/dL), and breast cancer susceptibility (BRCA1/2) mutation were significantly associated with the onset of grade ≥3 anemia (adjusted odds ratio [OR], 3.39; 95% confidence interval [CI], 1.28-9.62; P = 0.017, adjusted OR, 3.63; 95% CI, 1.28-11.64; P = 0.021, adjusted OR, 3.89; 95% CI, 1.39-12.21; P = 0.014, and adjusted OR, 4.09; 95% CI, 1.55-11.67; P = 0.006, respectively). Conclusions: Our findings suggest that low baseline RBC count, low baseline hematocrit level, and low baseline hemoglobin level might be the patient-associated risk factors for severe anemia induced by olaparib monotherapy. Additionally, BRCA1/2 mutation was suggested to be a patient-related risk factor for anemia regardless of severity. Therefore, applying these patient-associated risk factors would help classify and screen patients at risk of severe anemia.

Impact of Older Age and Medico-social Factors on the Decision to Offer Adjuvant Chemotherapy to Patients With Breast Cancer.

BACKGROUND/AIM: Although clinicians are expected to set a higher threshold for administering adjuvant chemotherapy to older than younger patients with breast cancer, the extent to which older patients are less likely to be offered adjuvant chemotherapy and the medico-social factors that influence decision-making are unclear. PATIENTS AND METHODS: We retrospectively evaluated the correlations of clinicopathological factors, including age (≥75 years vs. <75 years), for all candidates for adjuvant chemotherapy, and of additional medico-social factors, including the number of family members living together, for older patients, with the rate of referral from breast surgeons to medical oncologists. RESULTS: Among 872 candidates for adjuvant chemotherapy, age ≥75 years was significantly correlated with a lower referral rate (24 % vs. 44%, p<0.001). In the analysis by age group, we did not identify specific medicosocial factors that were differentially emphasized, but older patients who lived with ≥2 other family members tended not to be referred to a medical oncologist compared to those who lived alone or with one family member (1/23 vs. 15/47). Although 5 of 22 older patients (23%) who were referred to a medical oncologist actually received adjuvant chemotherapy (vs. 60% of younger patients), all needed treatment modifications. CONCLUSION: Breast surgeons regard age ≥75 years as a key factor for avoiding adjuvant chemotherapy but they also consider similar medico-social factors irrespective of the patient's age regarding the decision to refer patients to medical oncologists.

Comparison of Treatment Completion Rate Between Conventional and Dose-dense Doxorubicin and Cyclophosphamide (AC) Followed by a Taxane in Patients With Breast Cancer: A Propensity Score-matched Analysis.

BACKGROUND/AIM: To maximize the effect of perioperative chemotherapy in breast cancer, it is critical to keep the relative dose intensity (RDI) high. While bi-weekly doxorubicin and cyclophosphamide, dose-dense AC (ddAC), instead of tri-weekly conventional AC (cAC) followed by a taxane has been adopted as standard perioperative chemotherapy, postponement or discontinuation are sometimes experienced during ddAC or subsequent taxane phase. This study aimed at evaluating whether ddAC, compared to cAC, was associated with reduced RDI. PATIENTS AND METHODS: We compared ddAC and cAC, both followed by a taxane, for perioperative breast cancer regarding the proportion of completion of planned treatment (%completion), defined as an RDI ≥85% for both AC and taxane phases. RESULTS: There was no remarkable difference between the groups in patient characteristics after propensity score matching (n=46 in ddAC, and n=86 in cAC). The %completion was similar between the groups (67.4% vs. 65.1%). Most other endpoints related to RDI were similar between groups. The incidence of pneumonia was higher in the ddAC group (13% vs. 3%) including one Pneumocystis jiroveci pneumonia. CONCLUSION: ddAC followed by a taxane can be considered with sufficient supportive measures and precautions for pneumonia.

The efficacy and safety of paclitaxel plus bevacizumab therapy in breast cancer patients with visceral crisis.

BACKGROUND: Visceral crisis in metastatic breast cancer (MBC) is defined as severe organ dysfunction requiring rapidly efficacious therapy. Although weekly paclitaxel plus bevacizumab (wPTX + BV) achieves a high response rate in human epidermal growth factor receptor 2 (HER2)-negative MBC, the efficacy and safety of wPTX + BV for visceral crisis is unclear. METHODS: We retrospectively investigated patients with MBC with visceral crisis who received wPTX + BV. Visceral crisis was defined as follows: liver dysfunction (aspartate or alanine aminotransferase >200 U/L or total bilirubin >1.5 mg/dl), respiratory dysfunction (carcinomatous lymphangiomatosis, SpO2 <93% in ambient air or required thoracentesis), superior vena cava (SVC) syndrome, or bone marrow carcinomatosis. The primary outcome was the proportion of patients on-treatment with wPTX + BV after 12 weeks. We also investigated time to treatment failure (TTF), overall survival (OS), objective response rate (ORR), and adverse events. RESULTS: A total of 44 patients with respiratory dysfunction (n = 29), liver dysfunction (n = 10), bone marrow carcinomatosis (n = 7), and SVC syndrome (n = 2) were eligible for this investigation. The proportion of patients on-treatment with wPTX + BV after 12 weeks was 63% (30/44), and the other patients discontinued wPTX + BV because of adverse events (n = 5) and disease progression (n = 9). Median TTF and OS, and the ORR were 131 days and 323 days, and 41%, respectively. No treatment-related death occurred. CONCLUSION: wPTX + BV achieved favorable efficacy and safety for treating patients with visceral crisis and may therefore be considered an option for the treatment of this acutely severe clinical condition.

Infection mechanism of biofilm-forming Staphylococcus aureus on indwelling foreign materials in mice.

Indwelling foreign-body infections are a critical medical problem, especially in immunocompromised patients. To examine the pathogenicity of biofilm-forming bacteria settling on foreign materials, mice implanted with plastic discs were infected with Staphylococcus aureus. After opening a wide subcutaneous pocket on the dorsal side of mice with or without temporal leukocytopenia, a plastic sheet was placed in the left subcutaneous space; subsequently, bacteria in a planktonic state were dispersed over the subcutaneous space. Bacterial numbers were examined 7 days after inoculation. In subcutaneous tissue on the right, S. aureus was found only in leukocytopenic mice. Meanwhile, bacteria were detected on the plastic and neighbouring tissue in both leukocytopenic and normal mice; however, colony-forming analysis indicated that leukocytopenic mice possessed significantly more bacteria. Tissue reaction against bacteria was pathologically examined. Invading S. aureus induced severe inflammation. In transient leukocytopenic mice, bacterial microcolonies formed on the plastic as well as in the developed necrotic tissue - both of which were shielded from inflammatory cell infiltration - result in bacteraemia. These results indicate that biofilm-forming S. aureus settling on indwelling foreign material are tolerant against host immunity and assault neighbouring tissue, which may lead to chronic wound infection.