The influence of adjuvant chemotherapy dose intensity on overall survival in resected colon cancer: a multicentered retrospective analysis.

BACKGROUND: Colorectal cancer remains the second leading cause of cancer death in North America. Fluorouracil and oxaliplatin based adjuvant chemotherapy for resected colon cancer (CC) reduces cancer recurrence, but also causes significant toxicity requiring dose reductions. The effect of dose intensity on survival outcomes is not fully understood and strengthening the evidence supports informed decision making between patients and oncologists. METHODS: Patients treated with adjuvant chemotherapy, between 2006 and 2011, for resected colon cancer at four Canadian academic cancer centers were retrospectively analyzed. All patients must have received oxaliplatin with either capecitabine (CAPOX) or 5-FU (FOLFOX). Dose intensity (DI) was calculated as total delivered dose of an individual chemotherapy agent divided by the cumulative intended dose of that agent. The influence of DI on overall survival was examined. RESULTS: Five hundred thirty-one patients with high-risk stage II or stage III resected CC were eligible and included in the analysis. FOLFOX was the most common regimen (69.6%) with 29.7% of patients receiving CAPOX and 0.7% receiving both therapies. Median follow-up was 36.7 months. The median DI for 5-FU and capecitabine was 100% and 100% with 13.6% and 9.8% of patients receiving ≤ 80% DI, respectively. The median DI of oxaliplatin was 70% with 56.8% of patients receiving ≤ 80% DI. A DI of > 80% for each chemotherapy component was associated with a significant improvement in overall survival compared to those with a DI of ≤ 80% (5-FU HR = 0.23, 95% CI = 0.08-0.65, p = 0.006; capecitabine HR = 0.56, 95% CI = 0.33-0.94, p = 0.026; oxaliplatin HR = 0.52, 95% CI = 0.33-0.82, p = 0.005). Patients with T2 and/or N2 disease with an oxaliplatin DI > 80% had a trend towards improved survival (HR = 0.62, 95% CI = 0.38-1.02, p = 0.06). CONCLUSIONS: In resected CC an adjuvant chemotherapy DI of > 80%, of each chemotherapy agent, is associated with improved overall survival.

Effects of gender on capecitabine toxicity in colorectal cancer.

BACKGROUND: Capecitabine is a highly water soluble prodrug of 5-fluorouracil that is dosed by patient body surface area. Body surface area dosing makes no allowances for differences in body composition. There is mounting evidence that lean body mass is a better predictor of toxicity than body surface area for drugs which distribute into the lean compartment. Because women, on average, have lower lean body mass than men, we expect that women would experience a higher incidence of toxicity than men when body surface area dosing is used. OBJECTIVE: To determine whether female colorectal cancer patients experienced a higher incidence of dose-limiting toxicity than men when treated with adjuvant capecitabine. METHODS: We conducted a retrospective chart review of colorectal cancer patients treated with adjuvant capecitabine at our institute between 2008 and 2012. Patients receiving capecitabine were identified from the pharmacy dispensing database and then screened for inclusion. Dosing and toxicity information were gathered and dose-limiting toxicity incidence (defined as a composite endpoint of dose delay, dose reduction, or discontinuation of therapy) was compared between males and females using the chi-square test. Binary logistic regression analysis was then performed to account for differences between male and female populations. RESULTS: A total of 299 patients (163 males, 136 females) met inclusion criteria. Females had a significantly higher dose-limiting toxicity incidence than males (67.7 vs. 52.2%, p = 0.007). Relationships between gender and dose-limiting toxicity incidence remained significant after logistic regression analysis (OR: 2.04; 95% CI: 1.23-3.36). CONCLUSION: Female colorectal cancer patients experience a higher dose-limiting toxicity incidence than male patients when given adjuvant capecitabine dosed according to body surface area.

Renal dysfunction in a renal transplant patient treated concurrently with cyclosporine and imatinib.

Imatinib mesylate has proven activity in treating locally advanced or metastatic gastrointestinal stromal tumors (GIST). Drug interactions are particularly concerning as imatinib is extensively metabolized by the cytochrome P450 enzyme system. We describe the clinical course of a 72 year-old male with a cadaveric renal transplant requiring cyclosporine that presented with a metastatic GIST and was started on imatinib at the standard dose of 400 mg daily. Imatinib initiation resulted in a decline in renal function with the serum creatinine increasing from 123 µmol/L to 196 µmol/L and an elevation in whole blood cyclosporine concentrations from 79 µg/L to 139 µg/L. No other imatinib toxicities were reported. With discontinuation of imatinib, the serum creatinine returned to baseline as did the whole blood cyclosporine levels. Ultimately, decreasing both the cyclosporine and imatinib dosing was associated with stabilized renal function (serum creatinine 150-186 µmol/L) and cyclosporine concentrations (53-97 µg/L). A prolonged partial response to therapy for 19 months was maintained despite low imatinib trough concentrations measured on two separate occasions (127.1 ng/ml and 139 ng/ml). In our patient, imatinib initiation resulted in renal toxicity most likely due to its interaction with cyclosporine resulting in elevation of the whole blood cyclosporine concentration.

Looking to the future: biomarkers in the management of pancreatic adenocarcinoma.

The incidence and mortality of pancreas cancer converge. There has been little advancement in the treatment of pancreas cancer since the acceptance of gemcitabine as the standard therapy. Unfortunately, the efficacy of gemcitabine is dismal. While there is much discussion for the development of biomarkers to help direct therapy in this area, there is little action to move them into clinical practice. Herein, we review potential pancreatic cancer biomarkers and discuss the limitations in their implementation.

Ramucirumab (IMC-1121B): a novel attack on angiogenesis.

Angiogenesis is a critical hallmark of malignancy, and attempts to inhibit this process have characterized the age of biologic anticancer therapies for solid tumors. VEGF receptor-2 is the premier receptor responsible for many of the cancer-driven VEGF-induced spectrum of biologic changes, including modification of blood vessel structure and function, proliferation and migration. Unlike all clinically approved angiogenesis inhibitors, the fully human monoclonal antibody ramucirumab (IMC-1121B) specifically and potently inhibits VEGF receptor-2. Phase I clinical trials have shown safety across a wide range of ramucirumab doses with impressive, albeit early, evidence of both stable disease and partial responses in a variety of tumor types. In this article, we review the current data on ramucirumab and make comparisons with commercially available antiangiogenic agents.

Body composition as an independent determinant of 5-fluorouracil-based chemotherapy toxicity.

PURPOSE: Evidence suggests that lean body mass (LBM) may be useful to normalize doses of chemotherapy. Data from a prospective study were used to determine if the highest doses of 5-fluorouracil (5-FU) per kilogram LBM would be associated with dose-limiting toxicity in stage II/III colon cancer patients treated with 5-FU and leucovorin. EXPERIMENTAL DESIGN: Toxicity after cycle 1 was graded according to National Cancer Institute Common Toxicity Criteria, version 2.0. Muscle tissue was measured by computerized tomography. An extrapolation to the LBM compartment of the whole body was employed. RESULTS: Mean values of 5-FU/LBM of the entire population were different in terms of presence or absence of toxicity (P = 0.036). A cut point of 20 mg 5-FU/kg LBM seemed to be a threshold for developing toxicity (P = 0.005). This observation was pertinent to women (odds ratio, 16.73; P = 0.021). Women in this study had a relatively low proportion of LBM relative to their body surface area. CONCLUSION: Our study shows that low LBM is a significant predictor of toxicity in female patients administered 5-FU using the convention of dosing per unit of body surface area. We conclude that variation in toxicity between females and males may be partially explained by this feature of body composition.

Survival Impact of CAPOX Versus FOLFOX in the Adjuvant Treatment of Stage III Colon Cancer.

BACKGROUND: Capecitabine and oxaliplatin (CAPOX) and folinic acid, fluorouracil, and oxaliplatin (FOLFOX) are both used in the adjuvant treatment of colon cancer, and while their efficacy is assumed to be similar, they have not been directly compared. We reviewed the toxicity profiles, relative dose intensity (RDI), and survival associated with these regimens across a multi-institutional cohort. PATIENTS AND METHODS: We identified 394 consecutively treated patients with stage III colon cancer who received an oxaliplatin-containing regimen. RDI was defined as the total dose received divided by the intended total dose if all cycles were received. RESULTS: FOLFOX was associated with increased mucositis (6.2% vs. 0.7%, P = .0069) and neutropenia (25.9% vs. 8.6%, P < .0001), while CAPOX was associated with increased dose-limiting toxicities (DLTs) (90.7% vs. 80.2%, P = .0055), diarrhea (31.8% vs. 9.0%, P < .0001), and hand-foot syndrome (19.9% vs. 2.1%, P < .0001). Higher median RDI of fluoropyrimidine (93.7% vs. 80.0%, P < .0001) and oxaliplatin (87.2% vs. 76.3%, P < .0001) was noted for patients receiving FOLFOX. Reducing the duration from 6 to 3 months would have prevented 28.7% of FOLFOX and 20.5% of CAPOX patients from ever experiencing a DLT (P = .0008). Overall survival did not differ by regimen (hazard ratio = 0.73; 95% confidence interval 0.45-1.22; P = .24). However, CAPOX was associated with improved disease-free survival (3-year disease-free survival 83.8% vs. 73.4%, P = .022), which remained significant in high-risk (T4 or N2) (P = .039) but not low-risk patients (P = .19). CONCLUSION: CAPOX may be associated with improved disease-free survival despite greater toxicities and lower RDI. Reducing adjuvant chemotherapy duration to 3 months would prevent 26% of patients from ever experiencing a DLT.

Concomitant Administration of Proton Pump Inhibitors and Capecitabine is Associated With Increased Recurrence Risk in Early Stage Colorectal Cancer Patients.

BACKGROUND: Capecitabine is used to treat colorectal (CRC) cancer. TRIO-013, a study examining capecitabine/oxaliplatin ± lapatinib in metastatic gastro-esophageal cancer did not show increases in overall survival (OS) with lapatinib. An analysis showed concurrent proton pump inhibitor (PPI) usage negatively impacted recurrence-free survival (RFS). We retrospectively studied PPI effects on capecitabine efficacy in early stage CRC and how capecitabine adjustments impacted RFS. METHODS: Early stage CRC patients taking monotherapy capecitabine treated from 2008 to 2012 were reviewed for demographics, medications, toxicities, and patient outcomes. RESULTS: Of 298 identified patients, 25.8% (n = 77) received concurrent PPIs. Five-year RFS was 74% versus 83% (hazard ratio [HR], 1.89; 95% confidence interval [CI], 1.07-3.35; P = .03) in PPI versus non-PPI patients respectively. OS was 81% versus 78%, respectively (HR, 1.13; 95% CI, 0.60-2.14; P = .7). After accounting for gender, stage, age, and performance status, PPI patients tended toward decreased RFS (HR, 1.65; 95% CI, 0.93-2.94; P = .09). Capecitabine dose modifications affected outcomes. Five-year RFS was 84% in the control group, 100% in the treatment-delay group (P = .99), 67% in the dose reduction group (HR, 2.46; 95% CI, 1.23-4.93; P = .01), and 64% in the discontinuation group (HR, 2.27; 95% CI, 0.93-5.53; P = .07). Five-year OS was significantly less in the discontinuation group than control group (59% vs. 82%; HR, 3.27; 95% CI, 1.44-7.45; P = .005). CONCLUSIONS: PPIs appear to impact RFS; this may be due to PPIs preventing capecitabine tablet dissolution and absorption. Patients with dose reductions or who stopped treatment had worse outcomes than patients who continued with treatment at starting doses.

Systematic review of management of colorectal cancer in elderly patients.

This study is designed to clarify the benefits and risks of chemotherapy and radiation therapy in elderly patients with colorectal cancer through a systematic review of the literature. Searches of the Medline, Embase, and Cochrane Library databases; PDQ Cancer Information Summaries, American Society of Clinical Oncology Guidelines, Cancer Care Ontario Practice Guideline Initiative, Interprovincial Drug Strategies and Guidelines Group, and OncoLink Web sites; and manual searches of meeting proceedings and bibliographies were performed. Additional studies known to the authors were also identified. Randomized controlled trials, reviews, and guidelines evaluating the impact of age on overall survival and/or toxicity with adjuvant and palliative therapies for colorectal adenocarcinoma were selected. A preset study selection form was applied to all identified studies. All selected studies underwent a preset study appraisal. Analyses of the effect of age on overall survival benefits and/or toxicity of therapy were extracted. A qualitative synthesis and narrative review was undertaken. There is good evidence to support that patients = 80 years of age have similar overall survival benefits with adjuvant 5-fluorouracil (5-FU)-based chemotherapy for colon cancer and with palliative first-line monotherapy for metastatic colorectal cancer, as do younger patients. Data are limited with regard to toxicity of therapy in older patients in these settings. An increase in toxicity with bolus 5-FU chemotherapy regimens is evident. There is a paucity of data regarding adjuvant treatment of older patients with rectal cancer. More elderly patients need to be enrolled in clinical trials in order to fully evaluate the outcomes of colorectal cancer therapy in this population. Further studies are warranted.

CAPOX associated with toxicities of higher grade but improved disease-free survival when compared with FOLFOX in the adjuvant treatment of stage III colon cancer.

INTRODUCTION/BACKGROUND: Adjuvant treatment of colon cancer relies on fluoropyrimidine-containing regimens as the intravenous formulation, 5-FU, or its oral prodrug, CA, combined with oxaliplatin (FOLFOX and CAPOX). There is currently no clinical trial comparing the 2 regimens; however, both are considered standard of care treatment options. MATERIALS AND METHODS: We performed a retrospective chart review comparing average relative dose intensity (ARDI), percentage of intended total dose (PITD), overall survival (OS), DFS, and toxicity profiles of these regimens. The patients (n = 176) received either modified FOLFOX6 (n = 93) or CAPOX (n = 83). RESULTS: Oxaliplatin ARDI (80.72% vs. 87.11%; P = .0033) and PITD (70.09% vs. 88.11%; P = .0013) was significantly lower in those treated with CAPOX compared with FOLFOX. CA ARDI (87.10% vs. 93.60%; P < .0001) and PITD (77.19% vs. 88.11%; P = .0006) was significantly lower than 5-FU dosing. Patients treated with CAPOX had more ≥ Grade 2 toxicities and trended toward more dose-limiting toxicities. Survival analysis demonstrated a trend toward improved OS with CAPOX (hazard ratio [HR], 0.4741; 95% confidence interval [CI], 0.1660-1.354; P = .1663) and improved DFS with CAPOX (HR, 0.4949; 95% CI, 0.2512-0.9749; P = .0420). Multivariate analysis demonstrated similar results with CAPOX being associated with a trend toward improved OS (HR, 0.396; 95% CI, 0.110-1.429; P = .1571) and DFS (HR, 0.458; 95% CI, 0.210-1.001; P = .0504). CONCLUSION: Patients receiving CAPOX had significantly lower ARDI and PITD compared with FOLFOX, but showed trends toward improved outcomes when treated with CAPOX in the adjuvant setting when compared with FOLFOX.

Retrospective comparison of CAPOX and FOLFOX dose intensity, toxicity, and clinical outcomes in the treatment of metastatic colon cancer.

PURPOSE: The treatment of metastatic colon cancer (mCC) utilizes either combination therapies or sequential monotherapy followed by combination therapy in subsequent lines of treatment. Patients often receive therapy consisting of oxaliplatin with intravenous 5-fluoruacil (5-FU) (FOLFOX) or oral capecitabine (CAPOX). A retrospective analysis was performed comparing median dose intensity (MDI), overall survival (OS), progression-free survival (PFS), and toxicity profiles of these two regimens in mCC. METHODS: One hundred twenty-two mCC patients (pts) received either FOLFOX6 (n = 46) or CAPOX (n = 76). Age, gender, and Eastern Cooperative Oncology Group (ECOG) performance status at diagnosis were balanced between groups. MDI was compared by calculating a percent of target dose achieved in the average cycle for each patient and taking the median of this value. RESULTS: Oxaliplatin MDI trended towards being lower in those treated with CAPOX compared to FOLFOX (87.5 vs 93 %, p = 0.0874), and capecitabine (CA) MDI was significantly lower than 5-FU (82.0 vs 100 %, p < 0.0001). There was a trend to more dose-limiting toxicities (DLTs) in pts treated with CAPOX (68.42 vs 54.35 %, p = 0.1268), and grade ≥ 2 toxicities were more frequent in CAPOX-treated pts (38.16 vs 15.22 % of patients, p = 0.0079). Survival analysis demonstrated trends towards improved median OS (9.86 vs 7.46 months, p = 0.1183) and median PFS (4.34 vs 3.33 months, p = 0.1674) with CAPOX. In multivariate analysis, CAPOX was associated with improved OS (p = 0.0156, hazard ratio (HR) 0.559) and disease-free survival (DFS) (p = 0.0094, HR 0.549). CONCLUSIONS: Patients treated with CAPOX received lower doses of oxaliplatin and fluoropyrimidine compared to FOLFOX and had toxicities of higher grade but did not have worsened clinical outcomes.

Efficacy and safety of single agent or combination adjuvant chemotherapy in elderly patients with colon cancer: a Canadian cancer institute experience.

BACKGROUND: The pattern of adjuvant chemotherapy (AC) use, toxicity profile, and survival benefit in elderly patients with colon cancer (CC) is unclear. We sought to (1) determine whether patients ≥ 65 years with stage III CC were offered single-agent or combination AC, (2) evaluate the reason for selecting single-agent versus combination AC, (3) evaluate the toxicity profile of single-agent and combination AC in the elderly, and (4) determine whether a survival benefit exists for elderly patients receiving combination AC. PATIENTS AND METHODS: A retrospective analysis of records of patients ≥ 65 years diagnosed with stage III CC from 2004 to 2010 was performed to identify baseline characteristics, AC protocols, toxicity, dose intensity, and survival. RESULTS: Two hundred sixty-eight patients ≥ 65 years were diagnosed and treated with AC from 2004 to 2010. Of these patients, 178 were treated with single-agent AC and 90 were treated with combination AC. The most common reasons for choosing single-agent AC were patient preference, comorbidities, and lack of drug coverage. For each year over 65 years, the odds of receiving combination over single-agent AC decreased by 22%. There were more dose delays, dose reductions, and early chemotherapy discontinuation in the combination AC group because of hematologic toxicity. The 5-year overall survival (OS) was 73% in patients who received single-agent AC compared with 84% in those who received combination AC. There was no difference in cancer-related deaths between the groups. CONCLUSION: In elderly patients treated with AC for stage III CC, single-agent AC is used more frequently than combination AC, based on age, comorbidities, and patient choice. Toxicity with combination AC in elderly patients is high. No survival benefit was seen with combination AC over single-agent AC.