Rachel Anne Goodwin

Location of colon cancer (right-sided versus left-sided) as a prognostic factor and a predictor of benefit from cetuximab in NCIC CO.17

BACKGROUND Right- and left-sided colon cancers (RC, LC) differ with respect to biology, pathology and epidemiology. Previous data suggest a mortality difference between RC and LC. We examined if primary tumour side also predicts for outcome in chemotherapy refractory, metastatic colon cancer (MCC). We also compared RC versus LC as a predictor of efficacy of epidermal growth factor receptor (EGFR) inhibition with cetuximab. METHODS Reanalyzing NCIC CO.17 trial (cetuximab versus best supportive care [BSC]), we coded the primary tumour side as RC (caecum to transverse colon) or LC (splenic flexure to rectosigmoid). The association between tumour side and baseline characteristics was assessed. Cox regression models determined factors affecting overall survival (OS) and progression free survival (PFS). RESULTS Patients with RC (150/399) had more poorly differentiated, mutant KRAS, mutated PIK3CA and wild-type BRAF tumours, fewer liver and lung metastases, and shorter interval between diagnosis and study entry. Among BSC patients, tumour side was not prognostic for PFS (hazard ratios (HR) 1.07 [0.79-1.44], p = 0.67) or OS (HR 0.96 [0.70-1.31], p = 0.78). Among wild-type KRAS patients, those with LC had significantly improved PFS when treated with cetuximab compared to BSC (median 5.4 versus 1.8 months, HR 0.28 [0.18-0.45], p < 0.0001), whereas those with RC did not (median 1.9 versus 1.9 months, HR 0.73 [0.42-1.27], p = 0.26), [interaction p = 0.002]. CONCLUSION In refractory MCC, tumour location within the colon is not prognostic, but is strongly predictive of PFS benefit from cetuximab therapy. Additional research is needed to understand the molecular differences between RC and LC and their interaction with EGFR inhibition.

Overview of systemic therapy for colorectal cancer.

Colorectal cancer (CRC) is the third most common cancer and second leading cause of death from cancer in North America. The authors provide an overview of the indications for both chemotherapy and targeted therapy, as well as discuss the efficacy and toxicity of systemic therapy. They highlight the key studies that lead to the initial historical use of fluorouracil (5FU) based chemotherapy in the adjuvant and metastatic setting, the recent adoption of 5FU plus leucovorin (LV) and oxaliplatin (FOLFOX) chemotherapy over 5FU when treating adjuvant patients, and the use of FOLFOX or 5FU plus LV and irinotecan (FOLFIRI) in metastatic patients. They also review the role of chemotherapy in treating rectal cancer and resectable liver metastatic disease. Future areas of research focus for systemic therapy of colorectal cancer are highlighted.

Diagnosis and management of gastrointestinal neuroendocrine tumors: An evidence-based Canadian consensus.

The majority of neuroendocrine tumors originate in the digestive system and incidence is increasing within Canada and globally. Due to rapidly evolving evidence related to diagnosis and clinical management, updated guidance on the diagnosis and treatment of gastrointestinal neuroendocrine tumors (GI-NETs) are of clinical importance. Well-differentiated GI-NETs may exhibit indolent clinical behavior and are often metastatic at diagnosis. Some NET patients will develop secretory disease requiring symptom control to optimize quality of life and clinical outcomes. Optimal management of GI-NETs is in a multidisciplinary environment and is multimodal, requiring collaboration between medical, surgical, imaging and pathology specialties. Clinical application of advances in pathological classification and diagnostic technologies, along with evolving surgical, radiotherapeutic and medical therapies are critical to the advancement of patient care. We performed a systematic literature search to update our last set of published guidelines (2010) and identified new level 1 evidence for novel therapies, including telotristat etiprate (TELESTAR), lanreotide (CLARINET), everolimus (RADIANT-2; RADIANT-4) and peptide receptor radionuclide therapy (PRRT; NETTER-1). Integrating these data with the clinical knowledge of 16 multi-disciplinary experts, we devised consensus recommendations to guide state of the art clinical management of GI-NETs.

Predictors of Pathologic Complete Response After Neoadjuvant Treatment for Rectal Cancer: A Multicenter Study

BACKGROUND Pathologic complete response (pCR) to neoadjuvant chemoradiation (CRT) for rectal cancer is associated with better long-term outcomes, and is used as an early indicator of response to novel agents. To assess the rate and predictors of pCR, we performed a retrospective multicenter study involving 5 Canadian cancer centers. PATIENTS AND METHODS Cancer registries identified consecutive patients with locally advanced rectal adenocarcinoma from the Tom Baker Cancer Centre, Cross Cancer Institute, British Columbia Cancer Agency, Ottawa Hospital Cancer Centre, and the Dr H. Bliss Murphy Cancer Centre who received fluoropyrimidine-based CRT and had curative intent surgery from 2005 to 2012. Patient, tumor, and therapy characteristics were correlated with response. RESULTS Of the 891 patients included, 885 patients had pCR data available. Of the included patients, 161 (18.2%) had a pCR to CRT, and 724 (81.8%) did not. Patients with a pCR had a lower pretreatment carcinoembryonic antigen (CEA) level, and higher hemoglobin level in univariate analysis. In multivariable analysis, statin use at baseline (odds ratio [OR], 1.7; 95% confidence interval [CI], 1.02-2.92; P = .04), lower pretreatment CEA level (OR, 1.03; 95% CI, 1.01-1.06; P = .03), and distance closer to anal verge (OR, 1.07; 95% CI, 1.01-1.15; P = .04) were significant predictors of pCR. The 3-year disease-free survival was 86% in those with a pCR versus 62.5% in those without a pCR (P < .0001) and pCR was associated with improved overall survival (hazard ratio, 0.29; 95% CI, 0.17-0.51; P < .0001). CONCLUSION Lower pretreatment CEA level, proximity to anal verge, and statin use are predictors of pCR in our large retrospective cohort. Clinical trials to investigate statins combined with neoadjuvant CRT might be warranted.

Reasons for Delay in Time to Initiation of Adjuvant Chemotherapy for Colon Cancer

PURPOSE Adjuvant chemotherapy (AC) improves survival among patients with colon cancer (CC). Two meta-analyses have demonstrated a decrease in survival with increasing time to AC (TTAC). Here, we examine the predominant factors leading to delay in TTAC. METHODS Individual medical records of 580 patients with CC who initiated AC August 2005-November 2010 at two large academic cancer centers in Eastern Ontario were reviewed. Information regarding patient, disease, and treatment characteristics, including time intervals between each step in the cancer care pathway from surgery to AC, was captured. Patients were then categorized into three groups for comparison: (I) postoperative complication, (II) oncologist- or patient-initiated delay, (III) no delay. These groups were compared using χ(2) tests and one-way analysis of variance. A multivariable logistic regression model was used to determine factors associated with TTAC > 8 weeks in all patients and in group 1 alone. RESULTS TTAC among the three groups was (I) 10.1 ± 2.7 weeks, (II) 10.5 ± 3.6 weeks, (III) 8.5 ± 2.1 weeks (P < .001). The only significant predictor of TTAC > 8 weeks on multivariable analysis in group I was route of AC via central venous catheter (odds ratio [OR] = 2.4; 95% CI, 1.2 to 4.9). When multivariable analysis was performed on all patients, the presence of postoperative complications (OR = 2.4; 95% CI, 1.6 to 3.8) and oncologist- or patient-initiated delay were the strongest predictors of delay (OR = 3.5; 95% CI, 2.1 to 6.0). The percentages of patients with TTAC > 8 weeks were (I) 76.4% (n = 110), (II) 81.4% (n = 92), (III) 57.9% (n = 187). CONCLUSIONS In patients with no reason for delay, most experienced TTAC > 8 weeks. This likely reflects delays in referral, consultation, and chemotherapy booking. These health-system factors are modifiable, and future quality improvement initiatives should focus on how to reduce them.

Clinical outcomes of elderly patients receiving neoadjuvant chemoradiation for locally advanced rectal cancer

BACKGROUND Studies of clinical outcomes of elderly patients treated with neoadjuvant chemoradiation (nCRT) for locally advanced rectal cancer (LARC) are limited. Our aim was to assess the impact of age on clinical outcomes in a large multi-institutional database. PATIENTS AND METHODS Data for patients diagnosed with LARC who received nCRT and curative-intent surgery between 2005 and 2012 were collected from five major Canadian cancer centers. Age was analyzed as a continuous and dichotomous variable (< 70 versus ≥ 70 years) and correlated with disease-free survival (DFS), cancer-specific survival (CSS) and overall survival (OS). Cox regression models were used to adjust for important prognostic factors. RESULTS Of 1172 patients included, 295 (25%) were ≥ 70 years, and they were less likely to receive adjuvant chemotherapy (ACT; 60% versus 79%, P < 0.0001), oxaliplatin-based ACT (12% versus 31%, P < 0.0001), less likely to complete nCT (76% versus 86%, P < 0.001), and more likely to be anemic at initiation of nCRT (42% versus 30%, P = 0.0004). In multivariate analyses, age ≥ 70 years was associated with similar DFS [hazard ratio (HR) 0.93, 95% confidence interval (CI) 0.68-1.26, P = 0.63], similar CSS (HR 0.81, 95% CI 0.46-1.41, P = 0.45), and similar OS (HR 1.28, 95% CI 0.88-1.86, P = 0.20), compared with the younger age group. As a continuous variable, increasing age was not predictive of DFS (HR 1.00, 95% CI 0.99-1.02, P = 0.49) or CSS (HR 1.002, 95% CI 0.98-1.02, P = 0.88); however, it correlated with an inferior OS (HR 1.02, 95% CI 1.00-1.03, P = 0.04). CONCLUSIONS Elderly patients (≥ 70 years) who receive nCRT followed by surgery appear to have similar outcomes compared with younger patients. Decisions regarding eligibility for nCRT and surgery should not be based on age alone.

Clinical and toxicity predictors of response and progression to temsirolimus in women with recurrent or metastatic endometrial cancer

OBJECTIVE Temsirolimus (TEM) has recently shown activity (NCIC CTG phase II trial) in endometrial cancer (EC). Despite EC having a high rate of PTEN mutation, in this trial activity was independent of PTEN and other molecular markers. We explored whether treatment related toxicity occurring in cycle one was predictive of outcomes. METHODS Patients were those enrolled on two sequential phase II studies of the NCIC CTG that evaluated single agent TEM in women with recurrent or metastatic chemotherapy naïve or treated EC. An exploratory landmark analysis examined the relationship between early treatment related toxicities as well as prior chemotherapy and efficacy outcomes (response, progression, and tumor size shrinkage) in univariate and multivariate analyses. The relationship between molecular markers and outcomes was also reexamined in patients. RESULTS Mucositis, diarrhea, decreased absolute neutrophil count, as well as elevated glucose, or cholesterol were not independent predictors of response or progression. Highest fasting triglyceride predicted for a 3.5% tumor shrinkage from baseline. Women previously treated with chemotherapy were at 7.37 times greater risk of progression and experienced 20.9% increased tumor growth compared to chemotherapy naïve women. Molecular markers were not predictors of response or progression. CONCLUSIONS Except for elevation in fasting triglyceride being associated with minimal tumor shrinkage, no other relationship between efficacy and TEM induced adverse events was found. mTOR inhibition activity in EC seems greatest in chemo-naïve patients. Future studies of mTOR inhibitors in EC should focus on women without prior chemotherapy while continuing to explore molecular mechanisms of benefit.

Management of Epidermal Growth Factor Receptor Inhibitor-Induced Hypomagnesemia: A Systematic Review

BACKGROUND Despite occurring in 30% of patients, there are no evidence-based guidelines on the management of epidermal growth factor receptor inhibitor (EGFRI)-induced hypomagnesemia. Based on expert opinion, severe hypomagnesemia should be treated by intravenous magnesium replacement. A systematic review of published data of intervention on EGFRI-induced hypomagnesemia was performed. METHODS Articles from 1960 to March 2015 were identified from Medline, Embase, Cochrane Central Register of Controlled Trials, and PubMed using a peer-reviewed systematic search strategy. Eligible studies included randomized controlled trials or observational studies that evaluated management of hypomagnesemia in adult patients treated with EGFRIs. Risk factors for severe hypomagnesemia were also assessed. The quality of included studies was rated using Jadad scores. RESULTS A total of 1327 references were identified, and 6 studies, involving 486 patients, met inclusion criteria for analysis. There were no randomized controlled trials, and all included studies were of poor quality. From the studies included in this review, severity of EGFRI-induced hypomagnesemia was associated with length of EGFRI treatment, concomitant platinum chemotherapy, increasing age, and baseline magnesium concentration. In most patients with grade 3 or 4 hypomagnesemia, high-dose intravenous magnesium replacement did not achieve sustainable magnesium repletion beyond 72 hours. Oral magnesium supplementation was not effective or tolerable. Severe hypomagnesemia has been associated with tachycardia and mental alteration. After discontinuation of EGFRI therapy, hypomagnesemia generally resolves within weeks to months. CONCLUSIONS There is an absence of high-quality evidence for the management of EGFRI-induced hypomagnesemia. As hypomagnesemia is often refractory to frequent intravenous or oral replacement, there is a need for prospective trials of new interventions for this common toxicity.

A phase-I study of lapatinib in combination with foretinib, a c-MET, AXL and vascular endothelial growth factor receptor inhibitor, in human epidermal growth factor receptor 2 (HER-2)-positive metastatic breast cancer

BackgroundThe mechanisms of resistance to anti-human epidermal growth factor receptor 2 (HER 2) therapies are unclear but may include the tyrosine-protein kinase Met (c-Met), vascular endothelial growth factor (VEGF) and AXL pathways. Foretinib is an inhibitor of c-Met, VEGF receptor 2 (VEGFR-2), platelet-derived growth factor receptor beta (PDGFRB), AXL, Fms-like tyrosine kinase 3 (FLT3), angiopoiten receptor (TIE-2), RET and RON kinases. This phase Ib study sought to establish the associated toxicities, pharmacokinetics (PK) and recommended phase II doses (RP2D) of foretinib and lapatinib in a cohort of HER-2-positive patients with metastatic breast cancer (MBC).MethodsWomen with HER-2 positive MBC, Performance status (PS 0-2), and no limit on number of prior chemotherapies or lines of anti-HER-2 therapies were enrolled. A 3 + 3 dose escalation design was utilized. Four dose levels were intended with starting doses of foretinib 30 mg and lapatinib 750 mg orally once a day (OD) on a 4-weekly cycle. Assessment of c-MET status from the primary archival tissue was performed.ResultsWe enrolled 19 patients, all evaluable for toxicity assessment and for response evaluation. Median age was 60 years (34–86 years), 95% were PS 0-1, 53% were estrogen receptor-positive and 95% had at least one prior anti-HER-2-based regimen. The fourth dose level was reached (foretinib 45 mg/lapatinib 1250 mg) with dose-limiting toxicities of grade-3 diarrhea and fatigue. There was only one grade-4 non-hematological toxicity across all dose levels. There were no PK interactions between the agents. A median of two cycles was delivered across the dose levels (range 1–20) with associated progression-free survival of 3.2 months (95% CI 1.61–4.34 months). By immunohistochemical assessment with a specified cutoff, none of the 17 samples tested were classified as positive for c-Met.ConclusionsThe RP2D of the combined foretinib and lapatinib is 45 mg and 1000 mg PO OD, respectively. Limited activity was seen with this combination in a predominantly unselected cohort of HER-2-positive patients with MBC.

Real-life treatment of metastatic colorectal cancer with regorafenib: a single-centre review

BACKGROUND Various tyrosine kinase signalling pathways affect the development and progression of colorectal cancer (crc). In clinical trials, regorafenib has been associated with a survival benefit in metastatic crc (mcrc). We assessed the safety and efficacy of regorafenib in real-world patients. METHODS In a retrospective review of patients with mcrc treated with regorafenib at our institution from 2013 to 2015, patient demographics, treatment, and survival data were collected. Progression-free survival (pfs) and overall survival (os) were estimated using the Kaplan-Meier method. RESULTS In total, 48 patients were offered regorafenib, and 35 (73%) started treatment. Of the patients who started regorafenib, 57% were men. Median age in the cohort was 61 years, and all patients had a performance status in the range 0-2. Time from diagnosis of mcrc to regorafenib treatment was more than 18 months in 71% of patients. Starting dose was 160 mg in 54% of the patients, 120 mg in 40%, and 80 mg in 6%. Dose reductions occurred in 34% of the patients, and interruptions, in 29%. Best response was progressive disease (60%) and stable disease (17%); response in the rest of the patients was unknown. The most common adverse events on regorafenib (any grade) were fatigue (57%), hyperbilirubinemia (43%), thrombocytopenia (37%), anorexia (31%), and hypertension (31%). The most common grade 3 or 4 adverse events were fatigue (29%), hypophosphatemia (17%), weight loss (11%), and hyperbilirubinemia (9%). Common reasons for discontinuing regorafenib included progressive disease (51%) and toxicity (26%). In patients treated with regorafenib, pfs was 2.4 months (95% confidence interval: 1.8 to 3.3 months) and os was 5.6 months (95% confidence interval: 3.7 to 8.9 months). No factors were associated with survival in univariate or multivariate analysis. CONCLUSIONS In a real-world setting, regorafenib is associated with survival similar to that reported in the randomized controlled trials, but at the expense of toxicity leading to discontinuation in many patients. Future studies of regorafenib should focus on identifying the patients most likely to benefit and on minimizing toxicity.