Gastrointestinal Cancers Symposium, Jan. 24-26, 2013Last Updated: January 31, 2013.
The American Society of Clinical Oncology's 10th annual Gastrointestinal Cancers Symposium was held from Jan. 24 to 26 in San Francisco and attracted approximately 3,000 participants from around the world, including gastrointestinal oncology specialists as well as clinical practitioners and other health care professionals. The conference featured presentations focusing on the latest advances in the diagnosis and management of gastrointestinal cancers.
In one study, Kenneth H. Yu, M.D., of the Memorial Sloan-Kettering Cancer Center in New York City, and colleagues developed a tool to help clinical practitioners pick the most effective treatment for patients with advanced pancreatic cancer, modeling drug treatment based on gene expression profiling.
"We evaluated the use of this model in 50 patients with advanced pancreatic cancer and found that the model effectively predicted patients who would respond to treatment. Patients who the model predicted would respond to a particular treatment actually responded longer than those who the model predicted would not respond," Yu said. "We are optimistic that this model will be a useful tool to help physicians choose the most effective chemotherapy for patients with metastatic pancreatic cancer. We also are studying whether this tool can help predict the emergence of treatment resistance, and how to change a treatment approach accordingly. Further work is required to validate this model, and planning for these studies is underway."
In another study, Hugo Ford, M.D., of Addenbrooke's Hospital in Cambridge, U.K., and colleagues evaluated the efficacy and safety of docetaxel in patients with relapsing gastric cancer.
"We randomized patients to either docetaxel up to six cycles or active symptom control. We found that survival was significantly longer in patients who received docetaxel -- 5.2 versus 3.6 months," Ford said. "Importantly, in a disease with such a poor overall prognosis, we also found that quality of life was not negatively impacted by the use of docetaxel, as we did not see any deterioration of global quality of life or function scores in those who received the drug. Patients who received docetaxel also demonstrated improved symptom scores and especially pain control."
The investigators also found that docetaxel was generally well tolerated, with the most common adverse event being bone marrow suppression. However, approximately 30 percent of patients discontinued treatment due to adverse events or disease-related events.
"Overall, this trial confirmed that docetaxel is an appropriate second-line treatment, especially for fitter patients, and we recommend that docetaxel be the baseline against which future treatments be compared," Ford said.
Several authors disclosed financial ties to Sanofi-Aventis, which markets docetaxel.
In a phase III study, Katsuhiko Uesaka, M.D., Ph.D., of the Shizuoka Cancer Center in Japan, and colleagues evaluated whether the oral fluoropyrimidine S-1 was non-inferior to gemcitabine in terms of overall survival as postoperative adjuvant chemotherapy in patients with resected pancreatic cancer. A total number of 385 patients were enrolled between April 2007 and June 2010.
"We randomized patients after resection to either gemcitabine or S-1 for six months. Interim analysis, using the follow-up data up to July 2012 for 378 patients of the full analysis set, revealed that overall survival in those patients who received S-1 was not only non-inferior as compared to gemcitabine but actually superior to the drug," Uesaka said. "The two-year survival rate for S-1 was 70 percent, while the rate for gemcitabine was 53 percent. The mortality hazard ratio for S-1 to gemcitabine was 0.56. In addition, recurrent-free survival was 23.2 months in those who received S-1 as compared to 11.2 months in those who received gemcitabine. Both S-1 and gemcitabine were well tolerated for adjuvant chemotherapy of resected pancreatic cancer."
Several authors disclosed financial ties to Lilly and the Taiho Pharmaceutical Co., the manufacturers of gemcitabine and S-1, respectively.
Josep Tabernero, M.D., of the Vall d'Hebron Institute of Oncology in Barcelona, Spain, and colleagues identified three different molecular subtypes of colorectal cancer using a new diagnostic classification system. Using data from 188 patients with colorectal cancer, the investigators categorized colorectal cancers into subtypes based on tumor gene expression patterns.
The researchers validated the classification system using tumor samples from 543 stage II and III patients and found that 21.5 percent of samples belonged to subtype A, 62 percent to subtype B, and 16.5 percent to subtype C. At 10-year follow-up, the investigators found that patients with subtype C had worse outcomes and no benefit from adjuvant chemotherapy, while patients with subtype A and B had better outcomes and benefit from adjuvant chemotherapy. The investigators also found differences in tissue characteristics between the subtypes as well as differences in gene expression.
"This study clearly shows that there are different subtypes in colorectal cancer with completely different biological and clinical characteristics," Tabernero said in a statement. "We hope that with continued research, we'll be able to develop new molecular tests based on this classification system, not only to identify patients needing more aggressive adjuvant treatment but also help us to predict which patients will respond to specific chemotherapy drugs and targeted agents, regardless of cancer stage."
Several authors disclosed financial relationships with Agendia and AstraZeneca.
In a retrospective study, Seong Joon Park, M.D., of the University of Ulsan College of Medicine in Seoul, South Korea, and colleagues found that surgery after imatinib therapy improved survival for metastatic or recurrent gastrointestinal stromal tumors (GIST).
The investigators evaluated 92 patients who underwent imatinib alone and 42 patients who received imatinib plus surgery. The researchers found that progression-free survival in patients who received the imatinib alone was 42.8 months, while in those who received surgery plus imatinib, progression-free survival was 87.7 months. In addition, overall survival was significantly improved in patients who received surgery plus imatinib.
"Many clinicians think that adding surgery is beneficial to the patient if the patient is responsive to imatinib, but the clinical evidence for this is very scarce," Park said in a statement. "This study suggests that surgery offers a substantial survival benefit for patients with metastatic or recurrent GIST."