Patients diagnosed with invasive anal cancer and referred for treatment with chemotherapy and radiation. They are assigned to a physician called a radiation oncologist who specializes in delivering radiation to patients to treat their cancer. Patients are also assigned to a physician called a medical oncologist who specializes in treating cancer patients with chemotherapy. 

The physicians will perform a history and physical examiniation including an assessment of where the cancer is located along with inguinal nodes asessment (lymph nodes in the groin). 

Combined Modality Therapy (CMT)

With the use of radiation and chemotherapy, known as combined modality therapy (CMT), these two types of treatment can work together to cure your cancer.

Radiation therapy 

Energy called ionizing radiation or X-rays to kill cancer cells and shrink tumors. It destroys cells in the area by damaging their genetic material. When damaged, the cells can no longer divide and multiply. Although radiation damages both cancer cells and normal cells, most normal cells are able to recover and function normally. The goal of radiation therapy is to carefully target the abnormal tissue, sparing or limiting damage to the neighboring tissue as much as possible. The radiation is delivered similar to the way a regular X-ray is taken, except that the energy is much higher than a regular X-ray. The treatment plan will include a total dose of radiation to be adminstered per day.

Radiation is given once a day for 5 to 6 weeks and patients will receive supportive care including anti-naseau and pain medications. Common side effects of therapy include fatigue, mild nausea, loss of appetite, irritation of the rectum and anal area, diarrhea, increased frequency of urination, loss of pubic hair, redness, drying, irritation, burning, and occasionally blistering and weeping of the skin around the anus. Long-term side effects which are uncommon include ulcers, obstruction of the bowel, obstruction of the ureters, and the development of fistulas or abnormal connections or tracts between the pelvic tissues.

Chemotherapy 

These drugs are administered through an intravenous catheter placed into the vein to kill cancer cells that are multiplying rapidly. One type of catheter used to administer chemotherapy is called a PICC (peripherally inserted central catheter) line which is a long catheter that is threaded through a vein in the arm into the large veins near the heart.

Side effects of chemotherapy include nausea, vomiting, hair loss, mouth sores, diarrhea, and low blood cell counts including low white blood cells, red blood cells and/or platelets. In some cases, the treatment can be complicated by severe bleeding episodes that may require blood transfusions and there is also a higher risk for life-threatening infections when these blood levels are abnormal. 

Chemotherapy and radiation are not always necessary

Surgery

Standard of care for invasive anal cancer is radiation and chemotherapy, however in some cases, CMT may not always be required.

Cancers of the anal margin or perianal skin can sometimes be considered fully treated by removing the tumor and a small amount of healthy tissue that surrounds it. These cancers are very small and the surgeon will try to excise the tumor without damaging the anal sphincter muscles that surround the anal canal. Anal sphincter muscles help us control bowel movements and these small cancers do not invade these areas.

In most cases, the anal canal can often have tumors and internal anal HSIL. The goal is to eradicate both through surgery. thus avoiding chemotherapy and radiation.

Surgery for cancer that has not responded to chemotherapy or radiation sometimes require an extensive operation called an abdominoperineal resection (APR) where the surgeon will remove the anal canal, rectum and portion of the colon. The large intestine is then brought out through a hole in the lower abdomen (stoma) and covered with a plastic bag (colostomy).