Gastrointestinal Cancer

NEW YORK-A diagnosis of advanced colon cancer may lead some physicians to abandon treatment with curative intent, but John Macdonald, MD, insists that they should be more optimistic and aggressive.

PHOENIX-Conservative, sphincter-sparing surgery followed by chemotherapy plus radiotherapy appears effective in selected patients with early-stage rectal cancer, Anthony Russell, MD, said at the American Society for Therapeutic Radiology and Oncology meeting.

Hormone replacement therapy may reduce the risk of colorectal cancer in women, according to new results of a meta-analysis presented at the North American Menopause Society meeting.

Scientists at Jefferson Medical College believe they’ve uncovered a molecular mechanism by which aspirin interferes with colorectal cancer development in individuals who carry particular gene mutations that make them very likely to get the

Colorectal cancer is one of the most commonly occurring cancers in the United States. In an effort to prevent the occurrence of colorectal cancer, agents identified as reducing risk of the disease are being targeted as potential chemoprevention tools. However, complex associations exist among diet, lifestyle factors, and genetic susceptibility and the eventual development of colon cancer, sometimes making the transition from associations identified in epidemiologic studies to the clinical use of chemoprevention agents difficult. Environmental factors that may serve as chemoprevention agents are addressed in the article by Garay and Engstrom. Does our current knowledge allow us to embrace these agents as tools for chemoprevention?

Remarkable progress has been made in recent years in our understanding of colorectal cancer etiology. The various hypotheses of causality continue to be tested in human observational and intervention studies, as well as experimental models. Drs. Garay and Engstrom provide a comprehensive review of the dietary and chemopreventive factors for colorectal cancer. While their conclusions are noteworthy, those related to dietary factors are debatable.

Colorectal cancer is a major cause of death in the United States, where it accounts for approximately 57,000 deaths per year. Thus, the prevention of this disease would have a significant impact on public health. Chemoprevention is defined as the use of natural or pharmacologic agents to disrupt the process of carcinogenesis. Substances explored as chemopreventive agents in colorectal cancer include: (1) the nonsteroidal anti-inflamma-tory drugs (NSAIDS), which may inhibit the evolution and formation of adenomas by their inhibition of cyclooxygenase and decrease of prostaglandin synthesis; (2) antioxidants, such as vitamin E or C, which may modulate carcinogenic substances; and (3) folate and calcium, which may interfere with tumor cell growth and replication. Dietary intervention can be accomplished by decreasing fat intake and increasing fiber consumption, both of which have been linked to a lower incidence of colon cancer in multiple epidemiologic studies. This field is continuing to evolve. Hopefully, ongoing research efforts will offer a better understanding of the role of these and other substances in chemoprevention. This article summarizes the available data regarding dietary and pharmacologic approaches to colorectal cancer chemoprevention. [ONCOLOGY 1(13):89-98, 1999]

TORONTO-Several studies presented at the Society of Nuclear Medicine’s 45th annual conference support the use of positron emission tomography (PET) with fluorine-18-fluorodeoxyglucose (FDG) to evaluate patients with recurrent colorectal cancer.

DALLAS--A team of developmental biologists examining how tumor growth factor (TGF)-beta sends messages into cells has come up with the first animal model for colon cancer that closely mimics the human disease.

TORONTO--New research suggests that tumor marker levels for colorectal cancer do not consistently indicate the presence of malignant tissue. A German study revealed that 10 of 34 patients with colorectal cancer had normal carcinoembryonic antigen (CEA) levels and 16 had normal CA19-9 levels. In addition, a California study found that patients with elevated CEA levels did not necessarily have disease recurrence.

Data presented at the American Society of Clinical Oncology meeting by Professor Eric Van Cutsem, MD, PhD, University Hospital Gasthuisberg, Leuven, Belgium, demonstrate, for the first time, that people with metastatic colorectal cancer who

LOS ANGELES--Raltitrexed (Tomudex), a folate-based specific inhibitor of thymidylate synthase, has been shown in phase III trials to produce response rates similar to those of the Mayo regimen of 5-fluorouracil (5-FU) and leucovorin in patients with advanced colorectal cancer.

LOS ANGELES--Adding oxaliplatin (Eloxatine) to a bimonthly regimen of leucovorin and 5-fluorouracil (5-FU) in colorectal cancer patients "substantially enhanced the regimen’s activity with little increase in toxicity," Aimery de Gramont, MD, Hospital Saint-Antoine, Paris, reported at ASCO. "The study confirms the good activity and excellent tolerability of the bimonthly leucovorin/5-FU schedule," he said.

In patients with Dukes’ C colorectal cancer, therapy with a novel murine monoclonal antibody, Mab 17-1A (edrecolomab [Panorex]), manufactured by Centocor, reduced death by 32% and recurrence of disease by more than 23%, according to a

Accurate staging plays a primary role in determining the appropriate treatment of gastrointestinal malignancies. Recently, laparoscopy has emerged as a staging modality that is more sensitive and specific in staging most

BETHESDA, Md--"Exercise appears to be one good way, among others, to lower the risk of colorectal cancer," Maria Elena Martinez, PhD, said at the American Society of Preventive Oncology meeting. "And you don’t have to be a marathon runner to get this benefit."

Accurate staging plays a primary role in determining the appropriate treatment of gastrointestinal malignancies. Recently, laparoscopy has emerged as a staging modality that is more sensitive and specific in staging most

Both fluorouracil (5-FU) and irinotecan (CPT-11 [Camptosar]) have shown activity in metastatic colorectal cancer and are approved for its treatment in the United States. Preclinical experiments in cell cultures and human tumor

In this excellent article, Dr. Minsky examines the current state of knowledge about adjuvant therapy for resectable rectal cancer, as well as ongoing research in this area. Reasonable recommendations for the management of patients with rectal cancer are made based on data obtained from clinical trials.

Dr. Minsky provides an excellent overview of the current status of adjuvant therapy for patients with rectal cancer. The article includes not only the results of completed randomized and phase II trials but also some of the early toxicity data from ongoing and maturing neoadjuvant trials. Although it would appear that Dr. Minsky’s personal bias favors neoadjuvant combined-modality therapy, he clearly defines gaps in our existing knowledge that will need to be filled in by randomized trials.

Irinotecan (CPT-11 [Camptosar]) is currently approved for use as a second-line agent in the treatment of metastatic colorectal cancer. Phase II studies have also shown substantial single-agent activity of irinotecan in the

In all patients with advanced colorectal cancer, disease eventually progresses following fluorouracil (5-FU) therapy, with a worsening of disease-related symptoms and quality of life (QOL). Irinotecan (CPT-11[Camptosar])

During the past decade, advances have been made in the adjuvant treatment of resectable rectal cancer. Postoperative combined-modality therapy significantly improves local control and survival. Recent Intergroup

LOS ANGELES--A second-generation topo-isomerase I inhibitor, RFS 2000, has led to significantly improved survival in patients with advanced pancreatic carcinoma, according to interim results of an ongoing phase II study presented at an ASCO poster session.

PHILADELPHIA--"Six months of 5-fluorouracil (5-FU) and leucovorin should be the new standard adjuvant therapy for patients with node-positive, high-risk colon cancer," Daniel Haller, MD, said at the annual ASCO meeting.

In order for the immune system to protect against cancer, it must recognize tumors as "non-self." Markers present on the surface of tumors, known as antigens, allow the immune system to recognize tumors as non-self. However, in order for the

LOS ANGELES--Irinotecan (Camptosar), also known as CPT-11, should be standard therapy for patients whose metastatic colorectal cancer has become resistant to fluorouracil (5-FU), David Cunningham, MD, said at the plenary session of the American Society of Clinical Oncology (ASCO) annual meeting. Dr. Cunningham is head of the Gastrointestinal Cancer Unit, Royal Marsden Hospital, London, UK.

NEW ORLEANS--In a mouse model of colon cancer, the anti-inflammatory drug celecoxib prevented formation of tumors and caused regression of existing tumors, according to research presented at the 89th annual meeting of the American Association for Cancer Research (AACR).

NEW ORLEANS--Five recent discoveries could have a big effect on colorectal cancer prevention, early detection, and treatment, Margaret Tempero, MD, deputy director of the UNMC/Eppley Cancer Center, Omaha, Nebraska, said at a public forum held at the 89th annual meeting of the American Association for Cancer Research.

Drs. Weber and Petrelli review much of the literature regarding patient outcomes after local excision alone, as well as local excision plus chemoradiotherapy, in patients with various stages of low rectal adenocarcinoma. The authors apparently were unaware that the Radiation Therapy Oncology Group (RTOG) experience with local excision plus chemoradiation, which antedated the Cancer and Leukemia Group B (CALGB) study, will soon be in print to provide further multi-institutional support for these methods along with much greater follow-up. They also omitted our long-term data (median follow-up of survivors is 67 months) showing the very low locoregional recurrence rates in patients with T2 cancers treated by local excision and chemoradiotherapy.[1]