Anal canal and perianal tumors are clinically rare, accounting for less than 2% of colon and rectal tumors. The incidence of anal canal cancer is about three times higher than that of perianal cancer. It is more common in women, and perianal cancer is more common in male patients. Common symptoms: change in stool habit, change in stool shape, anal pain, anal itching, mass in anal canal Etiology: The real cause of anal canal cancer is not yet known, but some studies have shown that it is caused by multifactorial multi-gene disorder, and long-term chronic irritation such as anal fistula, warts and immune disorders are also related to the occurrence of anal canal cancer. Clinical manifestations: The early symptoms of anal canal cancer are not obvious, but the clinical manifestations of progressive stage are similar to those of lower rectal cancer, mainly in the following aspects: 1. 2. Change of stool characteristics, thinning or deformation of stool strips, often with mucus or pus and blood. Anal pain is the main feature of anal canal cancer. It starts with anal discomfort and gradually increases to continuous pain, which is more obvious after defecation. 4.Anal itching with secretion, because the secretion of anal canal cancer stimulates the perianal skin, the patient’s anus itches. The secretion is accompanied by fishy odor. 5.Lumps in the anal canal, ulcerated lumps or polyp-like or myxoid lumps in the anal canal can be seen on rectal finger examination or examination with anal speculum, or infiltrated lumps with narrowing of the anal canal. 6. Inguinal lymph nodes may be enlarged on one side or both sides, multiple, firm or with pain. Examination: The diagnosis of anal canal cancer mainly relies on anal canal and rectal finger examination and biopsy. Early rectal finger examination can easily detect lesions. Tissue biopsy is the main basis for definite diagnosis, which can be divided into anal canal squamous carcinoma and adenocarcinoma. Rectal finger examination, ultrasonography in the anal canal and cytological aspiration biopsy of enlarged lymph nodes can help determine the stage of tumor. Ultrasound of liver, lung X-ray and CEA examination can exclude distant metastasis. Treatment 1.Surgical plan should be selected according to the growth site, invasion range, metastasis of anal cancer and patient’s specific conditions. (1) Combined transabdominal perineal radical resection This surgery is mainly used for anal canal cancer or perianal cancer invading the anal canal. The operation method can be referred to the operation related to rectal cancer. (2) Local excision This kind of surgery is suitable for lesions with small scope of anal or anal canal skin cancer, which basically does not extend into the anal canal and does not invade the sphincter muscle in depth, and the pathological examination proves that the cell differentiation is high. 2.Radiation therapy Squamous cell carcinoma and basal cell carcinoma of the anus are very sensitive to radiation. According to the patient’s general condition and the local condition of the tumor, X-ray external radiotherapy, radium radiotherapy, cobalt radiotherapy and electron gas pedal radiotherapy can be used, and it can also be combined with surgery. Pre-operative application can improve the resection rate, while post-operative application can reduce recurrence and improve the efficacy. 3.Chemotherapy High-dose chemotherapy can remove subclinical metastases that cannot be removed by surgery or radiotherapy, and increase the sensitivity of tissue to radiotherapy. Commonly used chemotherapy regimens include cisplatin + 5-FU or 5-FU + mitomycin (MMC). Combination chemotherapy and radiotherapy applied simultaneously can significantly reduce the incidence of distant metastases.