Anal+Canal

Jake, Dustin , Bret , Eyob , Faleesa , Nick, Holly • Rectal bleeding • Rectal itching • Pain in the anal area • Change in the diameter of stool • Abnormal discharge from the anus • Swollen lymph nodes in the anal or groin areas || G1: The cells look more like normal tissue cells (well differentiated). 4  G2: The cells are somewhat different from normal cells (moderately differentiated). G3: The cellsdo not look like normal cells (poorly differentiated). G4: The cells barely resemble normal cells (undifferentiated). ||
 * **Epidemiolgy:** || Anal cancer is more common among women vs. men and makes up about 1% to 2% of all large bowel cancer. 1 The age range varies from 30 to 90 years old, with the median age being 60. An increase in cases involving males under age 45 has been observed and most likely due to homosexuality and anal intercourse. ||
 * **Etiology:** || The development of anal cancer can be associated with genital warts, genital infections, human papillomaviruses (HPV), immunosupression, and cigarette smoking. 1 ||
 * **Signs & Symptoms:** || Some cases of anal cancer cause no symptoms at all. 2 In more than half of patients, bleeding occurs and is often the first sign of the disease. The bleeding is usually minor. Important symptoms of anal cancer include:
 * **Diagnostic Procedures:** || The odds that anal cancer can be found early depend on the location and type of the cancer. 2 Anal cancer is often fairly easy to diagnose because it is in a fairly easy-to-reach area. Cancers that begin higher up in the anal canal are less likely to be found early. Some cases of anal cancer in people at high risk for that disease are diagnosed by screening tests, such as the digital rectal exam and/or anal Pap test, but most people are diagnosed after their cancer starts to cause symptoms. Diagnostic procedures include a physical exam, a digital rectal exam, endoscopy, biopsy, ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET). ||
 * **Histology:** || The most common histologies in anal canal cancers are 1 :
 * Squamous Cell (80% of all anal canal cancer)
 * Large cell keratinizing
 * Large cell nonkeratinizing
 * Basaloid
 * Adenocarcinoma
 * Mucoepidermoid
 * Melanoma ||
 * **Lymph node drainage:** || The major lymph node pathways drain to 3 lymph node groups in the anal canal, including the perianal skin, anal verge, and canal distal. 3 Those nodal groups drain to the superficial inguinal nodes, and then to the external iliac system. The lymphatics from above the dentate line follow the route of the rectal lymph node groups, going to the obturator nodes and then the internal iliac system. The proximal canal drains through the inferior mesenteric system. ||
 * **Metastatic spread:** || The most common distant metastatic site for anal cancer is liver. 4 ||
 * **Grading:** || GX: The tumor grade cannot be identified.
 * **Staging:** || TNM staging for carcinoma of anal canal 3 :

Primary Tumor (T) TX Primary tumor cannot be assessed T0 No evidence of primary tumor Tis Carcinoma in situ T1 Tumor <2cm in greatest dimension T2 Tumor >2cm but not >5cm in greastest dimension T3 Tumor >5cm in greatest dimension T4 Tumor of any size invades adjacent organs

Regional Lymph Nodes (N) NX Regional lymph nodes cannot be assessed N0 No regional lymph node metastasis N1 Metastasis in perirectal lymph nodes N2 Metastasis in unilateral internal iliac or inguinal lymph nodes N3 Metastasis in perirectal and inguinal lymph nodes and/or bilateral internal iliac and/or inguinal lymph nodes

Distant Metastasis (M) MX Distant metastasis cannot be assessed M0 No distant metastasis M1 Distant metastasis

Stage Grouping Stage 0 Tis N0 M0 Stage I T1 N0 M0  Stage II T2 N0 M0  T3 N0 M0  Stage IIIA T1 N1 M0  T2 N1 M0  T3 N1 M0  T4 N1 M0  Stage IIIA T4 N1 M0  Any T N2 M0  Any T N3 M0  Stage IV Any T Any N M1 || - Bladder 6000 cGy contracture - Rectum 6000 cGy ulcer, stricture -Intestine 4500 cGy ulcer, perforation, hemorrhage -Femoral heads 6000 cGy necrosis, fracture || Reprinted from //Treatment Planning in Radiation Oncology//, 3rd Edition. 6
 * **Radiation side effects:** || The possibleside effects of radiation of the anal canal include perineal dermatitis, entro proctitis, nausea and vomiting, urgency and frequency of defection, dyspareunia, sexual impotence, and acute toxicity, usually due to neutropenia with sepsis. 3 ||
 * **Prognosis:** || The most efficient method of determining prognosis of anal cancer is to look at the tumor extent. 5 For a tumor that remains in the pelvis, the size of the lesion is the key factor. Also, like many disease types, the presence of metastatic disease outside of the pelvis creates the worst prognosis. The 5 year survival rate for anal cancer patients for men is 58%, and 69% for women. If the stage is localized, the 5 year survival rate jumps up to 80%. On the other hand, if distant metastasis does occur, the survival rate plummets to 17%. ||
 * **Treatments:** || For patients with anal cancer, besides possible inguinal node dissection, surgery is not very common. 5 The most common treatment modalities to improve survival is to concurrently treat chemotherapy and radiation therapy. Typically 5-FU or Cisplatin combined with a dose of 30-50 Gray (Gy) will show the most improvement in patient survival. For patients with a poor prognosis a whole pelvis technique of anterior-posterior (AP), posterior-anterior (PA) is a common method of treatment. The field spans from the lumbosacral junction on the superior aspect and 3 centimeters (cm) distal of the lesion for the inferior border. While there are no standard borders for the width of the field, it is important that the inguinal and external iliac nodes are included. The other option is to use a 3 field technique if it is necessary to spare the anterior perineum. In this case the included inguinal nodes will be treated with an electron technique. ||
 * **TD 5/5:** || Organs at Risk 1 :
 * **Additional images:** || [[image:figure_24.1.jpg width="560" height="322"]]

Image A in the figure above shows a T2N0 squamous cell cancer of the anal canal treated with an eight-field intensity-modulated radiation therapy (IMRT) technique. Image B shows the lower pelvis and image C shows the mid-pelvis. The clinical target volume (CTV) is shown in blue. The red, yellow, green, and purple lines represent 95%, 90%, 85%, and 65% isodose lines, respectively. ||
 * **References:** || # Washington CM, Leaver D. // Principles and Practice of Radiation Therapy // . 3rd ed. St. Louis, MO: Mosby Elsevier; 2010.
 * 1) Anal Cancer. American Cancer Society Web site. [] . Accessed June 14, 2013.
 * 2) Chao KS, Perez CA, Brady LW. // Radiation Oncology Managements Decisions // . 3rd ed. Philadelphia, PA: Lippincott William and Wilkins; 2011.
 * 3) Anal cancer. Cancer.net Web site. http://www.cancer.net/cancer-types/anal-cancer/stages-and-grades. Accessed June 11, 2013.
 * 4) Chao KS, Perez CA, Brady LW. // Radiation Oncology Managements Decisions // . 2nd ed. Philadelphia, PA: Lippincott William and Wilkins; 2002.
 * 5) Khan FM, Gerbi BJ. //Treatment Planning in Radiation Oncology//. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2012. ||

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