Gastrointestinal Cancers

Published: Wednesday, Jun 16, 2010
Gastrointestinal Cancers

ASCO Symposium Presents Latest Research of Gastrointestinal Malignancies

The 5th Annual Gastrointestinal (GI) Cancers Symposium was held in January in Orlando, Florida. The event was cosponsored by the American Society of Clinical Oncology (ASCO), the American Gastroenterological Association (AGA) Institute, the Society of Surgical Oncology (SSO), and the American Society for Therapeutic Radiology and Oncology (ASTRO).

The symposium served as an opportunity for researchers to discuss the newest strategies related to the prevention, screening, and treatment of GI cancers. Educational sessions and abstract presentations focused on each type of GI cancer, including cancers of the esophagus, stomach, hepatobiliary tree, pancreas, small bowel, colon, and rectum. Key presentations are summarized below.






â–º Colon and Rectum

Capecitabine Versus 5-Fluorouracil/Leukovorin in Stage III Colon Cancer: Updated Five-Year Efficacy Data From the X-ACT

Chris Twelves, MD, University of Leeds and St. James Hospital, Leeds, United Kingdom (UK) and Beatson Oncology Centre, Glasgow, UK, presented Five-year follow-up overall survival (OS) data from the X-ACT (Xeloda in Adjuvant Colon Cancer Trial). These data showed that oral capecitabine (Xeloda) is as effective as the current standard treatment—intravenous bolus 5-fluorouracil/leucovorin (5-FU/ LV)—in the adjuvant treatment of Dukes’ C colon cancer.

The international, phase III X-ACT enrolled 1,987 patients, 1,004 of whom were randomized to receive capecitabine and 983 of whom were randomized to receive 5-FU/LV. Study enrollees were treated for a period of 24 weeks between 1998 and 2001 at 164 centers worldwide. The primary objective of the study was to show equivalence in disease-free survival (DFS) between oral capecitabine and intravenous 5-FU/LV. Secondary objectives included relapse-free survival (RFS), OS, and safety.

Results show Five-year OS rates for capecitabine at 71.4%, compared with 68.4% in the 5-FU/LV arm (P = 0.06). Additional data presented at the meeting from a previous analysis showed that capecitabine is also comparable to 5-FU/LV with regard to DFS and RFS.

Capecitabine caused significantly less toxicity than 5-FU/LV, with the exception of hand–foot syndrome (HFS). Survival subanalysis was performed in a sample of 995 patients, 614 with Grade 1–3 HFS and 382 with no HFS. Five-year OS was 73.8% and 66.3% in the groups with and without HFS, respectively.

Dr. Twelves concluded his presentation by stating the X-ACT demonstrated that oral capecitabine is an effective alternative to 5-FU/LV as adjuvant treatment for stage III colon cancer. This update shows that capecitabine is at least equivalent to 5-FU/LV, with a trend toward superiority (P = 0.06) for Five-year OS. The HFS subanalysis findings also suggest that it is important to individualize capecitabine dosing.

Capecitabine is the only FDA-approved oral chemotherapy for both metastatic breast cancer and adjuvant and metastatic colorectal cancer. Although inactive in pill form, capecitabine is enzymatically activated within the body; when it comes into contact with thymidine phosphorylase— a naturally occurring protein—it is transformed into 5-FU. Since many tumors have greater levels of thymidine phosphorylase than normal tissue, more 5-FU is delivered to the tumor than to other tissues.




Updated Analysis of Safety and Efficacy of Oxaliplatin/Bevacizumab With or Without Panitumumab for First-Line Treatment of Metastatic Colorectal Cancer

Joel R. Hecht, MD, University of California School of Medicine, Los Angeles, California presented the results of the randomized, controlled PACCE (Panitumumab Advanced Colorectal Cancer Evaluation) trial, which was performed to evaluate the benefit of adding panitumumab (Vectibix) to either oxaliplatin/bevacizumab-based (e.g., FOLFOX) or irinotecan/bevacizumab-based (e.g., FOLFIRI) chemotherapy as first-line therapy for patients with metastatic colorectal cancer.

Previously, panitumumab treatment, in this study was discontinued. A decision based on a preliminary review of data from a preplanned interim efficacy analysis scheduled after the first 231 events (death or disease progression). This analysis revealed a statistically significant difference in progres- sion-free survival (PFS) in favor of the control arm. An unplanned analysis of overall survival (OS) also demonstrated a statistically significant difference favoring the control arm.

Dr. Hecht presented updated results from the PACCE trial. A total of 823 patients were randomized to receive either oxaliplatin/bevacizumab/ panitumumab (N = 413) or oxaliplatin/bevacizumab (N = 410). At data cutoff, 94% of patients had ended first-line treatment. Median follow-up was 12.2 months. Baseline demographic and disease characteristics were generally well balanced between the two groups. Median PFS in the oxaliplatin/bevacizumab/ panitumumab and oxaliplatin/bevacizumab arms was 9.5 months and 11.0 months, respectively. Median OS in these two groups was 19.3 months and 20.6 months, respectively.


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