Latest treatment options for colorectal cancer highlighted at NCCN Annual Conference

Despite statistics stating that colorectal cancer is the fourth most frequently diagnosed cancer in men and women in the United States, mortality from colon cancer has decreased slightly over the past 30 years, possibly because of earlier diagnoses through screening and better treatment modalities. Recommendations relating to the latest treatment options were recently highlighted by Paul F. Engstrom, MD, of Fox Chase Cancer Center and chair of the NCCN Guidelines Panel for Colon and Rectal Cancer at the NCCN 15^th Annual Conference on March 11, 2010.

“Patients with stage II colon cancer may be candidates for adjuvant chemotherapy based on poor prognostic features, pathologic findings, microsatellite instability, and possibly oncotype analysis”

Dr. Engstrom discussed notable changes to the recently updated NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines^™) for Colon and Rectal Cancer including the appropriate role of adjuvant therapy for colon cancer. He stressed that the NCCN Guidelines Panel does not endorse the use of bevacizumab (Avastin^™, Genentech/Roche) or cetuximab (Erbitux^®, Bristol-Myers Squibb/ImClone Systems) in the adjuvant treatment of patients with high risk colon cancer outside of a clinical trial.

“Patients with stage II colon cancer may be candidates for adjuvant chemotherapy based on poor prognostic features, pathologic findings, microsatellite instability, and possibly oncotype analysis,” said Dr. Engstrom.

Determination of tumor KRAS and BRAF gene status can be used for metastatic colorectal cancer prognosis and therapy evaluation and are referenced in the updated NCCN Guidelines.

Dr. Engstrom noted, “These molecular findings in a tumor continue to be important because they signal whether the use of epidermal growth factor receptor antagonists such as cetuximab and panitumumab (Vectibix^®, Amgen) will be effective in treating a patient.”

BRAF analysis continues to be controversial since its impact in patients with KRAS wild type is not well studied. The updated NCCN Guidelines state that patients with a known V600E BRAF mutation appear unlikely to benefit from anti-EGFR monoclonal antibodies - although the data are somewhat inconsistent.

The updated NCCN Guidelines also provide direction for patients who are being treated with the chemotherapy regimen FOLFOX, comprised of a combination of therapies including fluorouracil (FU), leucovorin (LV), and oxaliplatin (Eloxatin^®, sanofi-aventis).

Dr. Engstrom discussed that for patients with metastatic colorectal cancer who are being treated with FOLFOX and responding, but are experiencing symptomatic neuropathy, that the patient should discontinue oxaliplatin, but continue FU/LV without a significant drug holiday.

The criteria for transanal excision, a procedure for patients with rectal cancer that is designed to help retain bowel function, is carefully described in the NCCN Guidelines, however Dr. Engstrom stressed that it may not be a curative procedure in patients with T1-classified tumors because of the potential high recurrence rate and poor overall survival compared to more radical surgical procedures.

Neo-adjuvant therapy for select patients with rectal cancer, those with T1 or T2, N1 or N2 classified lesions, is strongly recommended as Dr. Engstrom stated, “Total regression of cancer in the post-radiotherapy specimen predicts an excellent disease-free survival.”

Additionally, Dr. Engstrom highlighted that patients who present with unresected primary tumor synchronous stage IV colorectal cancer benefit from combination chemotherapy and may not require palliative resection of the primary or bypass procedures.

Dr. Engstrom concluded stating that the NCCN Guidelines Panel believes that a multidisciplinary approach is necessary for managing colorectal cancer and that they strongly support the concept that treating patients in a clinical trial has priority over standard or accepted therapy.

The NCCN Guidelines are developed and updated through an evidence-based process with explicit review of the scientific evidence integrated with expert judgment by multidisciplinary panels of physicians from NCCN Member Institutions. The most recent versions of all the NCCN Guidelines are available free of charge at NCCN.org.

SOURCE National Comprehensive Cancer Network