Anal+Canal


 * **Epidemiolgy:** || More commonly diagnosed in women, especially over the age of 60. Incidence in younger men is increasing, possibly due to anal intercourse.[1] ||
 * **Etiology:** || Increased risk was seen in patients with greater than 10 sexual partners, certain STDs (genital or anal warts, gonorrhea) or anal sexual intercourse. Other factors include immunosuppression and human papilloma virus.[1,2] ||
 * **Signs & Symptoms:** || Bleeding and anal discomfort is the most common sign of disease. Also, the presence of an anal mass, pruritus, anal discharge and pain. Changes in bowel habits and fecal incontinence are less common.[1,2] ||
 * **Diagnostic Procedures:** || The diagnosis of colon cancer involves an extensive work up including a history and physical examination, laboratory values, colonoscopy and medical imaging studies. A proctoscopy is done to obtain biopsies. An abdominal pelvis computed tomography (CT) is used as a primary imaging study to assess the extent of the primary tumor. A transrectal ultrasound is often used to determine the depth of the tumor. A Positron emission tomography computed tomography (PET-CT) is recommended to evaluate local, regional,and distance metastasis. [2,3] ||
 * **Histology:** || The most common histological type of anal cancer is squamous cell carcinoma. However, there are a varietyof carcinomas are present in the anus.Adenocarcinomas are typically foundin the anal crypts, where tiny epithelium break at the upper end of the anal canal. Also, other rare histologic cell types, such as small cell neuroendocrine carcinomas, lymphoma, and melanomas, can be found in the anal canal. [2] ||
 * **Lymph node drainage:** || Lymph nodes of the anal canalsuperiorly drain from the hemorrhoidal vessels to the perirectal and internal iliac lymph nodes. Below the dental line, it drains from the anal verge to the inguinal lymph nodes. At the time of presentation, pelvic and inguinal lymph node metastasis isfound in more than thirty percent of all cases. Inguinal lymph nodes metastases are mostly unilateral. [3] ||
 * **Metastatic spread:** || May invade into the vaginal septum and mucosa. Extensive tumors may infiltrate the sacrum and coccyx or the pelvic side walls. Metastasis may occur in the superior hemorhoidal nodes, external iliac, obturator, inguinal nodes or hypogastric nodes. May also metastasize to the liver and the lungs.[2] ||
 * **Grading:** || Tumor Grading for Anal Cancer.

G1: Well differentiated (low grade). G2: Moderately differentiated (intermediate grade). G3: Undifferentiated (high grade). || **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
 * **Staging:** || __TNM staging for carcinoma of anal canal__ [2]

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
 * Regional Lymph Nodes (N) **

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

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 || v When the cancer is confined to the pelvis, the size of the primary tumor is the most useful indicator for local control,preservation of anorectal function and survival. v Presence of extrapelvic metastases is the most adverse factor for survival. v Some studies suggest that women have a better prognosis than men. v Poorly differentiated tumors are associated with a worse prognosis than moderately or well differentiated tumors.[2]
 * Stage Grouping **
 * **Radiation side effects:** || Side effects include: moderate leukopenia, thrombocytopenia, proctitis, perineal dermatitis, nausea, vomiting, urgency and frequency of defecation, dyspareunia and sexual impotence.[2] ||
 * **Prognosis:** || v Anatomic extent of the disease provides the most prognostic value.

Figure 2. Field size and borders for anal cancer.[1] || Bladder 65 Gy 80 Gy Rectum 60 Gy  Colon 45 Gy 55Gy Femoral Head 52Gy Spinal cord 47 Gy(20 cm) 50 Gy(10 cm) 50(5 cm).[1] || [2] Chao KS, Perez CA, Brady LW. //Radiation Oncology Management Decisions//. 2nd ed. Lippincott Williams & Wilkins; 2002. [3] Hoppe TR, Phillips LT, Roach M. Leibel and Phillips Textbook of Radiation Oncology. 3rd Edition. Philadelphia: Saunders, Elsevier. 2010 || Figure 1. Lymphatic Drainage of Anal Canal. [3] Back to Week 3
 * The overall 5-year relative survival rate for all patients with anal cancer is 58% for men and 69% for women.
 * For localized stage, the relative 5-year survival is around 80%.
 * For cancers in the regional stage, this rate is about 57%.
 * In those with distant disease, this rate is about 17%.
 * In all stages, the survival rate is slightly higher for women than for men.[1] ||
 * **Treatments:** || * A combination of chemotherapy and radiation therapy is recommended. [2]
 * The most effective chemotherapy used along with irradiation is mitomycin C and 5-FU
 * Patients that are restricted from both irradiation and chemotherapy would only receive radiation.
 * Radiation therapy alone is effective for smaller tumors.
 * **TD 5/5:** || __ ORGAN WHOLE ⅓ __
 * **References:** || [1] Washington CM, Leaver D. //Principles and Practice of Radiation Therapy//. 2nd ed. Mosby; 2004.