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Colorectal cancer is the third most common malignancy and the second leading cause of cancer-related deaths in North America. Despite our increasing understanding of the genetics and pathophysiology of this condition, the incidence and prevalence remains unchanged in the Western World. Appropriately, in this issue's first article Dr. Fatima Haggar and I provide a comprehensive look at the geographic variation, incidence, and survival of colorectal cancer. Nutritional, lifestyle, and various chemopreventative strategies are discussed along with supporting evidence.
Approximately 15 to 20% of colorectal cancers are thought to be familial. This includes a spectrum of genetic abnormalities including errors in DNA mismatch repair genes, APC mutations, and genomic instability. Dr. Robert Gryfe examines this complex group of inherited colorectal cancer syndromes and emphasizes the clinically relevant information for the practicing surgeon. Genetic syndromes discussed include hereditary nonpolyposis colorectal cancer (HNPCC), familial adenomatous polyposis (FAP) syndromes, and MYH mutations.
Colorectal cancer takes several years to develop from precursor adenomatous polyps: early detection has been shown to greatly improve the chances of a cure. Despite this, colorectal cancer screening rates are low and there remains tremendous variation among the various professional societies as to the most cost-effective screening modality. Drs. Timothy Geiger and Rocco Ricciardi provide a detailed look at the various screening options and the evidence supporting screening recommendations for colorectal cancer.
In the past decade, we have seen several advances in the surgical approach to patients with colorectal cancer with a trend toward a minimally invasive approach. Initial concerns regarding port site metastasis in patients undergoing laparoscopic colectomy for cancer have been refuted in several prospective studies including the COST and CLASICC trials. Although these large randomized studies have demonstrated oncologic equivalence in patients undergoing laparoscopic colectomy for colon cancer when compared with an open cohort, the use of laparoscopy in the setting of rectal cancer remains under investigation. Dr. Sang Lee highlights the evolution of these laparoscopic technologies for colon and rectal cancer.
Over 20% of patients present with metastatic (stage IV) colorectal cancer at the time of diagnosis; up to 25% of this group will have liver metastases that are potentially resectable. Lesions that undergo curative resection have demonstrated 5-year survival rate outcomes now exceeding 50%. This number is expected to increase with newer induction chemotherapeutic agents, radiofrequency ablation (RFA), cryoablation, and chemoembolization. Drs. Waleed Mohammad and Fady Balaa provide a detailed review for the nonspecialist surgeon with an emphasis on the role of the hepatobiliary surgeon in the treatment of colorectal metastasis. Similarly, Drs. Villeneuve and Sundaresan review the management of colorectal lung metastasis and provide a practical review for the practicing surgeon.
The long-term surveillance of patients having undergone curative resection remains very controversial. Drs. Adena Scheer and Rebecca Auer highlight some of the controversies and provide the reader with an algorithm for following-up on patients based on existing survivorship data.
The past decade has seen the introduction of a large number of new chemotherapeutic and biologic agents for the treatment of colorectal cancer. As a result, there have been improvements in patient survival and/or reduced mortality rates. Drs. Rachel Goodwin and Timothy Asmis provide an overview of the various systemic therapies for colorectal cancer. In addition, they look at novel chemotherapeutic and biologics currently under clinical investigation.
It has been a tremendous honor and pleasure to serve as Guest Editor of this issue. I wish to extend a sincere appreciation to the outstanding group of clinicians who have contributed articles. I hope that the readers find this to be an enjoyable and educational endeavor as well.