Mayer, Robert J.

Abstract Background: Hyperinsulinemia is considered to be important in the development of colon cancer, but few studies have investigated the associations of hyperinsulinemia with colon cancer survival via dietary scores. Methods: Empirical dietary index for hyperinsulinemia (EDIH) was derived to assess the insulinemic potential of daily diets reflecting the long-term insulin exposure, with higher (more positive) scores indicating higher insulinemic diets. We prospectively estimated the HRs and 95% confidence intervals (CI) to investigate the association of EDIH with disease-free, recurrence-free, and overall survival among patients with stage III colon cancer (1999–2009) enrolled in a randomized adjuvant chemotherapy trial (CALGB 89803). Results: Of 1,024 patients (median follow-up: 7.3 years), 311 died, 350 had recurrences, and 394 had events for disease-free survival. Compared with patients in the lowest quintile of EDIH, the corresponding HRs of patients in the highest quintile for disease-free survival events, cancer recurrence, and overall mortality were 0.80 (95% CI, 0.56–1.15), 0.76 (95% CI, 0.51–1.11), and 0.77 (95% CI, 0.52–1.14). Conclusions: Higher EDIH was not associated with the risk of colon cancer recurrence or mortality in this population of patients with stage III colon cancer. Impact: EDIH, as a measure of dietary insulinemic potential, may be associated with colon cancer risk but not survival in patients with late-stage colon cancer.

4086 Background: The randomized phase III CALGB/SWOG 80405 trial found no difference in overall survival (OS) in first-line mCRC pts treated with either bevacizumab (Bev) or cetuximab (Cet) combined with the same chemotherapy. We investigated the potential prognostic and predictive value of HER2 amplification and HER2 gene expression using NGS and Nanostring data. Methods: Primary tumor DNA from 559 patients (pts) was profiled for HER2 amplification by NGS (Foundation One). Tumor tissue from 925 pts was tested for Nanostring gene expression using an 800 gene panel. OS and progression free survival (PFS) were the endpoints as time-to-event variables. Cox proportional hazard models with gene expression fitted with linear spline (one internal knot at median) were used, adjusting for pts baseline characteristics, treatment assignment, and molecular features (microsatellite instability, BRAF, all RAS). Results: Of 505 tumors with both NGS and Nanostring data, 16 harbored HER2 amplification (copy number variation > 6), limited to microsatellite stable tumors and significantly associated with HER2 expression ( P < 0.001) and wild-type RAS ( P = 0.036). HER2 amplification was neither prognostic nor predictive for OS or PFS. Conversely, HER2 expression higher than median was associated with longer PFS ( P = 0.018) but not OS ( P = 0.13). Among pts with HER2 not amplified, higher HER2 expression was associated with better OS (hazard ratio [HR], 0.83; 95%CI, 0.72-0.97; P = 0.016) and PFS (HR, 0.85; 95%CI, 0.74-0.98; P = 0.027) when the expression was less than median. Additionally, in pts with no HER2 amplification and HER2 expression lower than median, treatment with Cet was associated with worse PFS compared to Bev (HR, 1.46; 95%CI, 1.12-1.90; P = 0.005). This effect was not observed with expression higher than median regardless of HER2 amplification status. Conclusions: To our knowledge, this is the largest analysis of HER2 amplification and gene expression in mCRC pts treated with standard therapy. Our results provide novel insight on the predictive and prognostic value of HER2 gene expression in pts treated with Cet- and Bev-based regimens. Upon validation, these findings could inform pts selection and the design of more effective treatment options for pts with low HER2 expression. Clinical trial information: NCT00265850.

11011 Background: Beyond KRAS status, there are no validated markers for anti-EGFR therapy in mCRC. While expression of genes within the EGF signaling axis has been reported to correlate with benefit, most reports used data from non-randomized trials which cannot distinguish between general prognostic markers and markers that predict for benefit from C. CALGB 80203 was a 238-patient (pt), 4-arm, randomized phase II study of FOLFOX or FOLFIRI +/- C in mCRC pts. Formalin-fixed, paraffin-embedded (FFPE) tumor samples from CALGB 80203 were analyzed for gene expression of HER family ligands, receptors and regulators. Methods: FFPE tumor samples from consenting pts were analyzed for AREG, BTC, CD73, DUSP4, EGF, EGFR, EPGN, EREG, HB-EGF, HER2, HER3, HER4, PHLDA1 and TGFa by RT-qPCR. Interaction between baseline gene expression levels and treatment (C) with respect to progression-free survival (PFS) and overall survival (OS) was modeled using a multiplicative Cox proportional hazards model. Results: Baseline tumor tissue was available from 103 pts; 55% of tumors were KRAS wild type (WT). Two prognostic markers were identified; higher tumor mRNA levels of HER2 (HR=0.64, p=0.002) and EREG (HR=0.89, p=0.016) were associated with longer PFS across all pts. Potential predictive markers of benefit for C were identified. In KRAS WT tumors, lower HER3 expression was associated with longer OS from C treatment while higher HER3 expression was associated with shorter OS from C treatment (chemo + C: HR=1.15; chemo only: HR=0.48, interaction p=0.029). No association was observed for HER3 and outcome in KRAS mutant (MT) tumors. Interestingly, higher CD73 expression was associated with longer PFS in C-treated pts in both KRASWT (chemo + C: HR=0.91; chemo only: HR=1.57, interaction p=0.026) and MT tumors (chemo + C: HR=0.80; chemo only: HR=1.29, p=0.025). Conclusions: In one of the first reports using data from a randomized study, gene expression of HER3 and CD73 were identified as potential predictive markers for C. These data implicate not only HER axis signaling but also immune modulation as potential mechanisms of C action and sensitivity, and warrant confirmation in other large randomized trials.

e14711 Background: Postoperative adjuvant chemotherapy has been historically limited to single agent 5FU in stage II/III rectal cancer pts. This phase III trial evaluated differences between pts treated with adjuvant FOLFOX versus FOLFIRI versus FU alone in stage II/III rectal cancer. Methods: Eligibility: resectable (T3-4 N0,Tany N1-3) adenocarcinoma rectum ≤12cm from anal verge. Pts had the option to receive FU with pre or postoperative XRT (50.4Gy). Preoperative FU/XRT pts were randomized to adjuvant FOLFIRI (arm A), FOLFOX (arm B), FU/LV(arm C). Postoperative FU/XRT pts were randomized to adjuvant FOLFIRI (arm D), FOLFOX (arm E), FU/LV (arm F). Pts received 8 cycles. Overall survival (OS) was the primary endpoint. Secondary endpoints included toxicity, sphincter preservation and patterns of failure. Results: 225pts out of planned 3150 were enrolled (10/03 to 10/05). Data Monitoring Committee closed E3201 when the GI Intergroup developed an alternative trial with bevacizumab (E5204). 179 pts were randomized; (A:28, B:25, C:30, D:31, E:33, F:32). There was increased grade 3/4 toxicity, mainly diarrhea,in postoperative FU/XRT arms (D:39%), (E:28%), (F:48%). Twenty-two (12%) pts did not receive adjuvant therapy. At a median follow up of 7.4yrs, the five-year recurrence free rate was 69%. Median OS was 8.3 yrs. There was no statistical difference in OS between all randomized groups. Five-year OS in arms (A:B:C:D:E:F) were (73%, 83%, 83%, 73%, 78%, 73%) respectively. Conclusions: FOLFOX can be safely administered to rectal cancer pts following chemo radiation. Given limitations of early trial closure and small sample size, there was no difference in OS between pts who received FU alone, oxaliplatin based or irinotecan based adjuvant therapy. Clinical trial information: NCT00068692.

4009 Background: An ∼65% 5-year disease-free-survival (DFS) rate from 5-FU/mitomycin/radiation for anal carcinoma needs improvement. Methods: A phase III randomized trial compared 5-FU (1,000mg/m2 days 1–4 and 29–32) plus mitomycin (10mg/m2 days 1 and 29) and radiation (45 to 59 Gy) (Arm A) to 5-FU (1,000mg/m2 days 1–4, 29–32, 57–60 and 85–88) plus cisplatin (75mg/m2 on days 1, 29, 57 and 85) and radiation (45 to 59 Gy; start day=57) (Arm B) in anal carcinoma patients. Stratification included gender, clinical N status and tumor diameter. Primary endpoint was DFS. Statistical power was 80% with two-sided test to detect 10% DFS increase for Arm B. Results: Of 682 patients accrued, 598 were analyzable. Most unanalyzed patients’ data are early. Patient characteristics were balanced. Median age was 55 years, women predominated (69%), 27.5% had >5 cm tumor diameter and 26% had clinically N+ cancer. Preliminary 5-year estimated DFS was 56% for Arm A and 48% for Arm B (p=0.28) and 5-year estimated overall survival was 69% for both arms (p=0.24). Men(p=0.04), clinically N+ cancer (p<0.0001) and tumor diameter >5 cm (p=0.005) independently prognosticated DFS in a multivariate analysis. 5-year colostomy rate was 10% for Arm A and 20% for arm B(p=0.12). Grade 3/4 toxicity rates: non-hematologic=76% for Arm A and 75% for Arm B but hematologic=67% for Arm A and 47% for Arm B(p=0.0004). Conclusions: In Intergroup-98–11, induction 5-FU/cisplatin followed by 5-FU/cisplatin/radiation failed to improve DFS compared to the standard treatment, 5-FU/mitomycin/radiation. Supported by RTOG U10 CA21661, CCOP U10 CA37422, Stat U10 CA32115. No significant financial relationships to disclose.

3526 Background: In the US pts with stage II/III rectal cancer routinely receive pre or postoperative RT/FU. To date, in addition to chemoradiation, standard adjuvant chemotherapy has been limited to single agent FU. Improved survival with irinotecan and oxaliplatin in pts with metastatic colorectal cancer led to exploration of combination chemotherapy in the adjuvant setting in pts with rectal cancer. Methods: Pts on E3201 (T3–4 Nany M0, T1- 2 N + M0) had the option to receive FU with either pre- or postoperative RT (50.4 Gy). Pts were randomized to postoperative chemotherapy: FU (500mg/m2) + LV (500mg/m2) weekly x 6/8 wks x 3 cycles or irinotecan (FOLFIRI) (180mg/m2) vs oxaliplatin (FOLFOX) (85mg/m2) both administered with LV (400 mg/m2) FU (400mg/m2 bolus) + continuous FU (2.4 gm/m2/46 hours) q 2 wks x 8 cycles. Results: 225 pts of 3150 planned were recruited. 178 pts were randomized and 126 pts submitted treatment completion forms (accrual period 10/03–4/05). The Data Monitoring Committee closed E3201 when the GI Intergroup developed an alternative trial with bevacizumab (E5204). Toxicity information is reported for 93% of pts (165/178) ( Table ). There were no significant differences in toxicity between those pts treated with pre- vs postoperative RT/FU, although, for the subset of pts who received adjuvant FOLFIRI after postoperative RT/FU, there was a trend towards more diarrhea. Conclusion: FOLFOX as rectal adjuvant therapy is a common platform for new clinical trials, although there have been limited toxicity data reported. E3201 provides important comparative toxicity information demonstrating that FOLFOX can be safely administered to rectal cancer pts following chemoradiation. [Table: see text] [Table: see text]

4006 Background: Lymph node (LN) metastasis is associated with decreased survival in rectal cancer. It has been suggested that at least 14 LN be evaluated for adequate staging. However, a large percentage of patients have fewer than the recommended number of LN examined. We hypothesized that LN ratio would be predictive of overall survival in rectal cancer. Methods: Data was analyzed from Intergroup 0114, a mature trial of postoperative adjuvant chemotherapy and radiation in T3/4 and/or LN positive rectal cancer. Survival was the same for all arms allowing the entire group to be considered as one. The primary endpoint evaluated was overall survival. A proportional hazards model was used to determine the relative prognostic impact of LN ratio compared to number of LN examined, number of positive LN, number of negative LN and AJCC nodal stage. LN ratio was defined as the number of positive LN divided by the total number of LN examined. Four groups were analyzed based on proportion of positive LN: =0.25, >0.25–0.50, >0.50–0.75 and >0.75. Results: 1,648 patients were evaluable. There were 251 T1/2, 1,251 T3 and 146 T4 tumors. 513 patients were N0, 743 N1 and 392 N2. Median number of LN was 9. LN ratio was predictive of 5-year overall survival with rates of 0.71, 0.56, 0.50 and 0.43 respectively when analyzed by quartile (p<0.0001). LN ratio remained significant when overall survival was analyzed by number of LN examined and grouped into <10, <15 and >15 nodes evaluated (p<0.0001 for all). LN ratio also predicted overall survival in N1 (p=0.04) and N2 (p=0.0002) disease. When comparing LN ratio (χ2=79.5, p<0.0001) to number of LN examined (χ2=4.7, p=0.03), number of positive LN (χ2=38, p<0.0001), number of negative LN (χ2=32, p<0.0001) and AJCC nodal stage (χ2=55.5, p<0.0001), LN ratio appears to be the strongest predictor of overall survival. Conclusion: LN ratio predicts overall survival in patients with resected rectal cancer. Importantly, this is true in patients who have had a small number of LN evaluated, in addition to those with a large number of LN examined. LN ratio also appears to be a stronger predictor of overall survival than other described LN prognostic factors. LN ratio may be a useful variable to stratify outcome in patients with node-positive rectal cancer. No significant financial relationships to disclose.

Abstract Background Diabetes is a prognostic factor for some malignancies, but its association with outcome in patients with advanced or metastatic colorectal cancer (CRC) is less clear. Methods This cohort study was nested within a randomized trial of first-line chemotherapy and bevacizumab and/or cetuximab for advanced or metastatic CRC. Patients were enrolled at 508 community and academic centers throughout the National Clinical Trials Network. The primary exposure was physician-documented diabetes at the time of enrollment. The primary endpoint was overall survival (OS); secondary endpoints were progression-free survival (PFS) and adverse events. Tests of statistical significance were two-sided. Results Among 2326 patients, 378 (16.3%) had diabetes. The median follow-up time was 6.0 years. We observed 1973 OS events and 2173 PFS events. The median time to an OS event was 22.7 months among those with diabetes and 27.1 months among those without diabetes (HR = 1.27, 95% CI = 1.13 to 1.44; P &lt; .001). The median time to a PFS event was 9.7 months among those with diabetes and 10.8 months among those without diabetes (HR = 1.16, 95% CI = 1.03 to 1.30; P = .02). Patients with diabetes were more likely to experience no less than grade 3 hypertension (8.1% vs 4.4%; P = .054) but were not more likely to experience other adverse events, including neuropathy. Conclusions Diabetes is associated with an increased risk of mortality and tumor progression in patients with advanced or metastatic CRC. Patients with diabetes tolerate first-line treatment with chemotherapy and monoclonal antibodies similarly to patients without diabetes.

Abstract Purpose: Previous studies have suggested that higher circulating 25-hydroxyvitamin D [25(OH)D] levels are associated with decreased colorectal cancer risk and improved survival. However, the influence of vitamin D status on disease progression and patient survival remains largely unknown for patients with advanced or metastatic colorectal cancer. Experimental Design: We prospectively collected blood samples in 1,041 patients with previously untreated advanced or metastatic colorectal cancer participating in a randomized phase III clinical trial of first-line chemotherapy plus biologic therapy. We examined the association of baseline plasma 25(OH)D levels with overall survival (OS) and progression-free survival (PFS). Cox proportional hazards models were used to calculate hazard ratios (HRs) and confidence intervals (CIs), adjusted for prognostic factors and confounders. Results: At study entry, 63% of patients were vitamin D deficient (&lt;20 ng/mL) and 31% were vitamin D insufficient (20–&lt;30 ng/mL). Higher 25(OH)D levels were associated with an improvement in OS and PFS (Ptrend = 0.0009 and 0.03, respectively). Compared with patients in the bottom quintile of 25(OH)D (≤10.8 ng/mL), those in the top quintile (≥24.1 ng/mL) had a multivariable-adjusted HR of 0.66 (95% CI, 0.53–0.83) for OS and 0.81 (95% CI, 0.66–1.00) for PFS. The improved survival associated with higher 25(OH)D levels was consistent across patient subgroups of prognostic patient and tumor characteristics. Conclusions: In this large cohort of patients with advanced or metastatic colorectal cancer, higher plasma 25(OH)D levels were associated with improved OS and PFS. Clinical trials assessing the benefit of vitamin D supplementation in patients with colorectal cancer are warranted.

PURPOSERegular physical activity is associated with reduced risk of recurrence and mortality in patients with nonmetastatic colorectal cancer. Its influence on patients with advanced/metastatic colorectal cancer (mCRC) has been largely unexplored.PATIENTS AND METHODSWe conducted a prospective cohort study nested in Cancer and Leukemia Group B (Alliance)/SWOG 80405 (ClinicalTrials.gov identifier: NCT00265850 ), a National Cancer Institute–sponsored phase III trial of systemic therapy for mCRC. Within 1 month after therapy initiation, patients were invited to complete a validated questionnaire that reported average physical activity over the previous 2 months. On the basis of responses, we calculated metabolic equivalent task (MET) hours per week to quantify physical activity. The primary end point of the clinical trial and this companion study was overall survival (OS). Secondary end points included progression-free survival (PFS) and first grade 3 or greater treatment-related adverse events. To minimize confounding by poor and declining health, we excluded patients who experienced progression or died within 60 days of activity assessment and used Cox proportional hazards regression analysis to adjust for known prognostic factors, comorbidities, and weight loss.RESULTSThe final cohort included 1,218 patients. Compared with patients engaged in less than 3 MET hours per week of physical activity, patients engaged in 18 or more MET hours per week experienced an adjusted hazard ratio for OS of 0.85 (95% CI, 0.71 to 1.02; PTrend= .06) and for PFS of 0.83 (95% CI, 0.70 to 0.99; PTrend= .01). Compared with patients engaging in less than 9 MET hours per week, patients engaging in 9 or more MET hours per week experienced an adjusted hazard ratio for grade 3 or greater treatment-related adverse events of 0.73 (95% CI, 0.62 to 0.86; PTrend< .001).CONCLUSIONAmong patients with mCRC in Cancer and Leukemia Group B (Alliance)/SWOG 80405, association of physical activity with OS was not statistically significant. Greater physical activity was associated with longer PFS and lower adjusted risk for first grade 3 or greater treatment-related adverse events.