Note: The information on this website is not a substitute for
diagnosis and treatment by a qualified, licensed professional.
Accuracy of fecal occult blood screening for colorectal neoplasia. A prospective study using Hemoccult and HemoQuant tests.
Ahlquist DA, et al.
JAMA 1993 Mar 10;269(10):1262-7.The results of this study, conducted on over 13,000 individuals, show that two of the most frequently used tests for the detection of colorectal cancer, the Hemoocult and Hemoquant test, designed to detect the presence of occult blood in the stools, miss approximately 70% of cancers that are later diagnosed by other methods, and 90% of polyps (pre-cancerous conditions) 1 cm or more in size.
Fecal occult blood testing: clinical value and limitations.
Simon JB.
Gastroenterologist 1998 Mar;6(1):66-78.This article emphasizes that only 5% to 10% of patients who test positive at the fecal occult blood screening with the Hemoccult test have cancer. The low specificity of the test is an important problem, since patients who receive a false positive result will undergo unnecessary diagnostic work-up to ascertain the presence of the cancer.
An evaluation of the carcinoembryonic antigen (CEA) test for monitoring patients with resected colon cancer.
Moertel CG, Fleming TR, Macdonald JS, Haller DG, Laurie JA, Tangen C.
JAMA 1993 Aug 25;270(8):943-7.The results of this study show that monitoring the levels of carcinoembryonic antigen (CEA) to detect the occurrence of a relapse in patients with a history of colon cancer has little, if any value, in improving their survival. In the study, 87% of 1216 patients who received surgery for colon cancer had CEA levels monitored. Survival rates more than a year after surgery were 2.3% in CEA-monitored patients, and 2% in non-monitored patients. The authors question the value of performing a test that is associated with substantial costs, that causes considerable psychological stress to the patients, and whose value in improving survival is, at best, minimal.
Honesty about new screening programmes is best policy.
Raffle, A E.
BMJ 2000;320:872 ( 25 March ).This article highlights the benefits and risks associated with screening programs for bowel cancer, and reports on a debate on to whether fully inform screening participants of the complications associated with the practice. The results of two large trials, the Nottingham and the Danish trial, revealed that a screening round of 100,000 individuals resulted in the early detection of bowel cancer in 35 of them, who, as a consequence, had their life expectancy prolonged. However, another 70 individuals had their cancer either missed by the screening, or where injured as a result of it (due to the occurrence of major bleeding or bowel perforation, both requiring surgery). A large group of cancers that are detected at screening are benign, and most of them would have never transformed in malignant cancers. If patients don't know that the majority of benign cancers will never cause them a problem, they will believe that screening saved their life, and the confidence in the screening program will be increased. This however, could translate in the flourishing of an industry not necessarily directed at patient's best interests. Recently, in view of the starting of a bowel cancer screening trial, a debate has sparked as to whether fully inform individuals on the risks associated with screening. If patients are fully informed, they might be less willing to participate to the trial. It is the author's opinion that honesty remains the best policy.
A case-control study of screening sigmoidoscopy and mortality from colorectal cancer.
Selby JV; Friedman GD; Quesenberry CP Jr; Weiss NS.
N Engl J Med, 326(10):653-7 1992 Mar 5.The results of this study show that colorectal cancer screening with sigmoidoscopy is associated with a reduction in mortality from colon cancer, and that screening performed once every 10 years is as effective as screening performed more frequently.
Screening of average-risk individuals for colorectal cancer and postoperative evaluation of patients with colorectal cancer.
Nelson RL.
Surg Clin North Am 1996 Feb;76(1):35-45.This article emphasizes that screening patients with a history of colorectal cancer for recurrence of disease does not reduce morbidity and mortality from the disease, and is therefore unjustified.
COLORECTAL CANCER
Randomized Trial of Postoperative Adjuvant Chemotherapy With or Without Radiotherapy for Carcinoma of the Rectum: National Surgical Adjuvant Breast and Bowel Project Protocol R-02.
Wolmark N, et al.
J Natl Cancer Inst 2000 Mar 1;92(5):388-396.The results of this study show that radiation therapy given after surgery to patients with rectal cancer does not halt disease progression nor improve overall survival. The trial was conducted on 694 patients with stage II and stage III rectal cancer (Dukes' B or Dukes' C rectal cancer), enrolled between 1987 and 1992, and followed up for an average of 8 years. Patients were randomized to receive, after surgery, either chemotherapy alone, or chemotherapy and radiation therapy. No differences in disease-free or overall survival were seen between the two groups. Post-operative radiation therapy has been routinely given to patients with stage II and stage III rectal cancer, without any data from clinical trials demonstrating that it improve survival. This study, specifically designed to evaluate its efficacy, showed no evidence of improved tumor progression and overall survival in patients treated with radiation therapy. Current guidelines for treatment of rectal cancer should be re-examined in light of these results.
Long-term survival following levamisole or placebo adjuvant treatment of colorectal cancer: a Western Cancer Study Group Trial.
Chlebowski RT; Nystrom S; Reynolds R; Weiner JM; Bateman JR.
Oncology, 45(3):141-3 1988.The results of this study show that treatment with levamisole offers no survival advantage compared to placebo, in patients with early stage colorectal cancer.
Prospective randomized trial of 5-fluorouracil versus 5-fluorouracil plus levamisole in the treatment of metastatic colorectal cancer: a Hoosier Oncology Group trial.
Bandealy MT; Gonin R; Loehrer PJ; Monaco F; Einhorn LH.
Clin Cancer Res, 4(4):935-9 1998 Apr.The results of this study show that the addition of levamisole to chemotherapy with 5-fluorouracil (5-FU) in patients with advanced stage colorectal cancer is not associated with better tumor remission rates, nor with survival advantage, compared to treatment with 5-FU only. Average survival of patients receiving 5-FU was 48 weeks, while that of patients receiving 5-FU plus levamisole was 42 weeks.
Adjuvant portal-vein infusion of fluorouracil and heparin in colorectal cancer: a randomised trial.
European Organisation for Research and Treatment of Cancer Gastrointestinal Tract Cancer Cooperative Group, the Gruppo Interdisciplinare Valutazione Interventi in Oncologia, and the Japanese Foundation for Cancer Research.
Rougier P; et al.
Lancet, 351(9117):1677-81 1998 Jun 6.The results of this study show that 5-year survival rates in patients with colorectal cancer that receive local adjuvant chemotherapy with fluorouracil after surgery are no better than those of patients receiving surgery alone.
Cooperative study of surgical adjuvant chemotherapy of colorectal cancer (first report):
Investigation of background factors and adverse effects. Cooperative Study Group of Surgical Adjuvant Chemotherapy of Colorectal Cancer in Japan. Japanese.
Kunii Y, et al.
Gan To Kagaku Ryoho, 14(2):421-33 1987 Feb.The results of this study, conducted on 3,421 patients with localized colorectal cancer, show that 1 year relapse-free and overall survival rates were no different in patients treated, after surgery, with one of 4 types of single- or multiple-agent chemotherapy regimens, compared to patients treated with surgery alone.
Cooperative study of surgical adjuvant chemotherapy of colorectal carcinoma (second study):
A preliminary report. Cooperative Study Group of Surgical Adjuvant Chemotherapy of Colorectal Cancer in Japan. Japanese.
Kodaira S; et al.
Gan To Kagaku Ryoho, 16(10):3399-408 1989 Oct.The results of this study show that the addition of adjuvant chemotherapy to surgical treatment is not associated with prolonged 3-year survival rates in patients with localized colorectal cancer, compared to surgery alone.
Assessing the impact of chemotherapy on tumor-related symptoms in advanced colorectal cancer.
Michael M; Moore MJ.
Oncology (Huntingt), 12(8 Suppl 6):121-8 1998 Aug.This article emphasizes that all patients with diffuse colorectal cancer treated with fluorouracil eventually experience disease progression and worsening of symptoms and quality of life.
