(Med Lett Drugs Ther 2008; 50:94) In Table 1, "Invasive" should be "less" and "more" rather than "no" and "yes" for CT colonography and colonoscopy, respectively. In the conclusion, CT colonography should be changed to "less invasive" rather than "noninvasive".

(Med Lett Drugs Ther 2008; 50:94) In table 1, "Invasive" should be "less" and "more" rather than "no" and "yes" for CT colonography and colonoscopy, respectively.

Options in screening for colon cancer include fecal occult blood tests, flexible sigmoidoscopy, colonoscopy, computed tomography (CT) colonography and fecal DNA tests. Since the last Medical Letter article on this subject, more data have become available on colonography.

Panitumumab (Vectibix - Amgen), a fully human IgG₂ monoclonal antibody that inhibits the epidermal growth factor receptor (EGFR), has been approved by the FDA for treatment of patients with EGFR-expressing metastatic colorectal cancer that has progressed despite standard chemotherapy. It is the second monoclonal antibody EGFR inhibitor to be approved for metastatic colorectal cancer; cetuximab (Erbitux), a human-murine chimeric IgG₁ monoclonal antibody, was approved in 2004.

A variety of cancer chemotherapy drugs are used, mostly in combination, for treatment of locally advanced and metastatic esophageal, gastric and colorectal cancers. The mechanism of action, indications and adverse effects of some of these drugs are discussed in thei article.

The FDA has approved a new genetic test to identify patients who may be at increased risk of severe toxicity when treated with the cancer chemotherapy drug irinotecan (Camptosar). The Invader UGT1A1 Molecular Assay (Third Wave Technologies) detects the UGT1A1*28 allele, a variation in the uridine diphosphate glucuronosyltranferase 1A1 (UGT1A1) gene. The FDA recently revised the safety labeling for irinotecan, recommending that the dosing of irinotecan be reduced for patients who are homozygous for the UGT1A1*28 allele.

Use of screening tests to identify cancers before they cause symptoms can lead to earlier therapy and may improve outcomes. Screening tests for some common cancers are reviewed.

Currently available techniques for colorectal cancer screening include fecal occult-blood testing, flexible sigmoidoscopy, double contrast barium enema (DCBE) and traditional optical colonoscopy. Optical colonoscopy requires bowel cleansing and sedation, and involves some risk, but is generally accepted as the best available method for detection of lesions and offers the advantage that polyps can be removed when they are identified. A less invasive screening tool, computed tomography (CT) colonography, also known as virtual colonoscopy (VC), offers an additional option.

Cetuximab (Erbitux - ImClone Systems/Bristol-Myers Squibb), an epidermal growth factor receptor (EGFR) inhibitor, and bevacizumab (Avastin - Genentech), the first vascular endothelial growth factor angiogenesis inhibitor, have recently been approved by the FDA for treatment of patients with metastatic colorectal cancer. Cetuximab is approved for treatment of patients with EGFR-expressing tumors, either in combination regimens with irinotecan (Camptosar)when the cancer has progressed on irinotecan-based therapy, or as monotherapy for those who cannot tolerate irinotecan. Bevacizumab is approved for first-line therapy in combination with a fluorouracil-based regimen.

The tables in this article list drugs used for treatment of cancer in the USA and Canada and their major adverse effects. The choice of drugs in Table I is based on the opinions of Medical Letter consultants. Some drugs are listed for indications for which they have not been approved by the US Food and Drug Administration. In some cases, such as elderly patients or those with many co-morbid illnesses, the regimen of choice might not be suitable. For many of the cancers listed, surgery and/or radiation therapy may be the treatment of choice or may also be part of the management. Anticancer drugs and their adverse effects are listed in Table II on page 46. A partial list of brand names appears on page 52.

Oxaliplatin (Eloxatin -Sanofi-Synthelabo) has been approved by the FDA for use in combination with fluorouracil (5-FU; Adrucil, and others) and leucovorin (LV; Wellcovorin) for patients with metastatic colorectal cancer whose disease has recurred or progressed despite treatment with 5-FU/LV plus irinotecan (Camptosar - Medical Letter 1997; 39:8).

Levamisole (Janssen), an old antiparasitic drug widely used for treatment of ascariasis in animals, is now available from the National Cancer Institute (NCI) for investigational use with fluorouracil (5-FU; Adrucil; and others) as an adjuvant for treatment of resectable colon cancer that has metastasized to regional lymph nodes (Dukes stage C).