Long-term Survival Among Patients With De Novo Human Epidermal Growth Receptor 2-Positive Metastatic Breast Cancer in Manitoba.

OBJECTIVES: Although metastatic breast cancer (MBC) is considered incurable, human epidermal growth receptor 2 (HER2)-directed therapy has improved outcomes significantly, with some patients experiencing durable responses to treatment. The aim of this study was to identify potential predictors of long-term survival (LTS) among patients with de novo HER2-positive MBC who received HER2-directed treatment. METHODS: Eligible patients from 2008 to 2018 were identified using the Manitoba Cancer Registry. LTS was defined as survival ≥5 years from the time of diagnosis. Univariate logistic regression models were performed to assess variables of clinical interest and the odds of LTS. Overall survival (OS) was defined as the time from diagnosis of MBC to death of any cause. OS was estimated using the Kaplan-Meier method with log-rank comparative analyses as a univariate analysis. A Cox proportional hazards model was used for OS estimates in a univariate analysis. RESULTS: A total of 62 patients were diagnosed with de novo HER2-positive MBC and received HER2-directed therapy. Eighteen (29%) achieved LTS. The median OS of the whole cohort was 50.2 months (95% CI: 28.6-not reached). Radiographic response to first-line treatment was associated with LTS; complete and partial responses were both associated with higher odds of LTS (odds ratio: 28.33 [95% CI: 2.47-4006.71, P = 0.0043] and odds ratio: 7.80 [95% CI: 0.7317-1072.00, P = 0.0972], respectively). The best radiographic response was associated with improved OS. CONCLUSIONS: Radiographic response to first-line HER2-directed therapy is a predictor for LTS in patients with de novo HER2-positive MBC. Larger studies are needed to identify patients who can safely discontinue HER2-targeted therapy.

Treatment Patterns, Toxicity, and Outcomes of Older Adults With Advanced Pancreatic Cancer Receiving First-line Palliative Chemotherapy.

OBJECTIVES: Advanced pancreatic cancer (APC) disproportionately impacts older adults. Randomized trials demonstrate improved overall survival (OS) with combination chemotherapy including 5-fluorouracil, irinotecan, leucovorin, and oxaliplatin (FOLFIRINOX) or nab-paclitaxel and gemcitabine compared with gemcitabine alone, but with increased toxicity. Older adults are at increased risk of side effects from chemotherapy. The aim of this study was to assess the efficacy and toxicity of chemotherapy in older adults with APC. METHODS: Patients diagnosed with APC from 2011 to 2016 were identified using the Manitoba Cancer Registry. Patient and treatment characteristics, toxicity, and outcomes of patients 65 years of age and above treated with palliative chemotherapy were compared by treatment regimen. OS was assessed using the Kaplan-Meier method. A Cox regression was used to identify independent predictors of OS. RESULTS: A total of 87 patients aged 65 years and above received palliative chemotherapy: 52 (59.7%) FOLFIRINOX, 21 (24.1%) nab-paclitaxel and gemcitabine, and 14 (16.1%) gemcitabine, with a median age of 69 (65 to 84), 75 (65 to 88), and 73 (67 to 82), Eastern Cooperative Oncology Group (ECOG) performance status difference in hematologic toxicity between regimens (P=0.807). An increase in nonhematologic toxicity was seen with FOLFIRINOX (P<0.001), specifically neuropathy (P=0.008), fatigue (P<0.001), and nausea/vomiting (P=0.008). FOLFIRINOX was associated with improved radiologic response (P=0.05) and OS (P=0.035). PS, baseline carbohydrate antigen 19-9 level, and chemotherapy regimen were independent predictors of survival. CONCLUSIONS: FOLFIRINOX is associated with improved response and OS in older adults with APC. FOLFIRINOX has a manageable safety profile in this population and should be considered in fit older adults with APC.

Capecitabine-mediated heart failure in colorectal cancer: a case series.

BACKGROUND: Capecitabine is a pyrimidine antimetabolite that inhibits thymidylate synthase and is commonly used in the treatment of colorectal cancer. Adverse cardiac side effects are reported in 1-18% of patients receiving Capecitabine. The most commonly proposed mechanism of cardiotoxicity in the setting of Capecitabine use is vasospasm of the coronary arteries. However, cardiotoxicity can also present as an acute coronary syndrome, arrhythmia, hypertension, and/or sudden cardiac death. Profound non-vasospastic cardiotoxicity is rare. CASE SUMMARY: We describe two cases of acute heart failure leading to cardiogenic shock in patients shortly after exposure to Capecitabine. Both patients did not demonstrate the characteristic transient ST elevation seen in patients with coronary artery vasospasms secondary to Capecitabine. Both patients required admission to the Acute Cardiac Care Unit requiring vasopressor and inotropic support. Thorough diagnostic investigations including echocardiography, cardiac magnetic resonance imaging, and cardiac computed tomography did not identify infarction, myocarditis, or any infiltrative process to explain their symptoms. Both patients had complete resolution of cardiac function, with no long-term sequalae. DISCUSSION: In patients receiving Capecitabine, reversible heart failure leading to cardiogenic shock should be considered as a potential cardiotoxic side effect.

The enigmatic oncogene and tumor suppressor-like properties of RAD54B: Insights into genome instability and cancer.

One of the major challenges to the cell is to ensure genome stability, which can be compromised through endogenous errors or exogenous DNA damaging agents, such as ionizing radiation or common chemotherapeutic agents. To maintain genome stability the cell has a multifaceted line of defense, including cell cycle checkpoints and DNA damage repair pathways. RAD54B is involved in many of these pathways and thus exhibits a role in maintaining and repairing genome stability following DNA damage. RAD54B is involved in cell cycle regulation after DNA damage and participates in homologous recombinational repair, which ensures the precise repair of the most deleterious DNA lesions, double-stranded breaks. This review focuses on structural aspects of RAD54B, molecular functions associated with its cellular roles in preventing genome instability, and how aberrant function contributes to oncogenesis. By understanding how aberrant RAD54B expression and/or function can contribute to oncogenesis, novel therapeutic approaches that specifically exploit these aberrant genetics are now being explored for precision medicine targeting. RAD54B represents an ideal candidate for synthetic genetic therapeutic approaches (synthetic dosage lethality or synthetic lethality), which are designed to target the specific genetics associated with cancer formation. These therapeutic approaches represent a precision-based approach, which is ideal as we are now entering the era of precision medicine.

The synthetic lethal killing of RAD54B-deficient colorectal cancer cells by PARP1 inhibition is enhanced with SOD1 inhibition.

Colorectal cancer (CRC) is a leading cause of cancer-related death throughout the world. Despite improved screening efforts, most CRCs are diagnosed at late stages when surgery alone is not curative. Moreover, the low 5-year survival rate (~8-13%) for those living with stage IV CRC highlights the need for better treatment options. Many current chemotherapeutic approaches are non-specific and associated with side effects due to their tendency to target both normal and cancer cells. To address this issue, synthetic lethal (SL) approaches are now being explored in cancer and are defined as the lethal combination of two independently viable mutations/deletions. From a therapeutic perspective, SL interactors of genes mutated in cancer serve as candidate drug targets. The present study focuses on RAD54B, a gene that is aberrantly expressed in many cancer types, including CRC. We show that PARP1 silencing or inhibition (BMN673 or Olaparib) leads to selective killing within RAD54B-deficient cells relative to controls, and is accompanied by increases in γ-H2AX (a surrogate marker of DNA double strand breaks) and cleaved Caspase-3 (an apoptotic indicator). We further show that BMN673 synergizes with LCS-1 (an inhibitor of an established RAD54B SL interactor) to induce enhanced killing in RAD54B-deficient cells. Collectively, these data identify RAD54B and PARP1 as SL interactors, and thus reveal PARP1 as a novel candidate drug target in RAD54B-deficient CRCs. These findings further show that combinatorial chemotherapies involving multiple SL targets may promote synergistic killing within cancer cells, a strategy that may hold potential in many cancer contexts.