[Rectal cancer: diagnosis, screening and treatment]

Rectal cancer is one of the primary malignant neoplasms occurring in Mexican patients of reproductive age. Unfortunately, randomized studies in rectal cancer do not exist as they do with well-recognized colon cancer. We must individualize the epidemiology, risk factors, diagnostic approach, staging and treatment because management is different in rectal cancers affecting the mid- and lower third of the rectum than in the upper third and in colon cancers. Histological staging is the primary prognostic factor. TNM staging (tumor, node, and metastasis) is used internationally by the American Joint Committee on Cancer (AJCC). Staging is done with the assistance of endorectal ultrasound, which is best used in early-stage cancer; however, there are certain disadvantages in detecting node involvement. Magnetic resonance, on the other hand, allows for the evaluation of stenotic tumors and node involvement. Once the correct diagnosis and staging have been made, the next step is correct treatment. Neoadjuvant treatment has demonstrated to be better than adjuvant treatment. Abdominoperineal resection is rarely practiced currently, with sphincter preservation being the preferred procedure. Laparoscopic approach has conferred the advantages of the approach itself when performed by experts in the procedure but there is insufficient evidence to make it the "gold standard." Rectal cancer is a complex pathology that must be considered totally different from colon cancer for diagnosis and treatment. The patient must be staged completely and appropriately for individualizing correct treatment. More long-term studies are needed for optimizing treatment modalities.