Rectal Cancer

The rectum is the part of the bowel that connects the colon to the anus. Symptoms of rectal cancer include a change in bowel pattern, blood in the stool, pain with bowel movements, and chronic diarrhea. There are approximately 40,000 cases of rectal cancer diagnosed in the US each year.

Rectal cancers are usually diagnosed with a biopsy dome at the time of colonoscopy. Adenocarcinoma is the most common type of rectal cancer. Additional staging studies may include an endorectal ultrasound, a CT scan, an MRI, or a PET/CT scan.

Treatment of rectal cancer is largely determined by the depth of invasion through the wall of the rectum and the presence or absence of lymph nodes. Tumors that have not invaded through the wall of the rectum and have not spread to lymph nodes can often be treated with surgery alone with no requirement for chemotherapy or radiation. Occasionally, combined chemotherapy and radiation will be used to downstage a low lying early stage tumor prior to surgery in order to spare the sphincter and avoid a colostomy bag. More advanced tumors that have invaded through the wall of the rectum or spread to lymph nodes are recommended to undergo neo-adjuvant combined chemotherapy and radiation therapy followed by surgery 4-6 weeks later.

Radiation treatment is delivered each day over the course of 5-6 weeks to a field that includes the rectal tumor and draining pelvic lymph nodes. Chemotherapy is often infused through a pump during the radiation therapy. Side effects of the radiation include rectal pain, diarrhea, abdominal cramping, and nausea. Your radiation oncologist will help you manage these symptoms as you go through your therapy.

Cure rates for rectal cancer are very encouraging with over 85% of early stage tumors cured with surgery alone and 75-85% of advanced tumors cured with a combination of chemotherapy, radiation, and surgery.

Anal Cancer

The anal canal is the 3-4 cm length of bowel extending from the anus up to the muscles of the pelvic floor. The peri-anal region involves a 5-6cm radius of skin around the anal verge.

Cancers of the anus are relatively rare consisting of about 4% (7,000/yr) of all GI cancers each year in the United States. Squamous cell carcinoma is the most common type of anal cancer and is link to HPV (Human Papilloma Virus) exposure.

Symptoms of anal cancer include a palpable firm mass, rectal bleeding, pain, and a change in bowel habits. Diagnosis can often be made with biopsy at the time of proctoscopy, but sigmoidoscopy or colonoscopy should also be performed to rule out involvement elsewhere in the colon. Additional workup should include a pelvic exam for females, and may also include an endorectal ultrasound, CT scan, MRI scan, or PET/CT scan.

Very early stage anal cancers may be treatable with a wide local excision alone. These are often small tumors in the perianal skin that can be completely excised with preservation of the sphincter function.

More advanced tumors require a combination of radiation and chemotherapy for the best chance of cure. Radiation is given on a daily basis over the course of five to seven weeks to include the primary tumor and draining lymph nodes and chemotherapy is given concurrently.

Potential side effects of treatment include anorectal pain, diarrhea, severe irritation of the skin of the perineum (skin outside the pelvis), and swelling of the legs. You radiation oncologist will help you manage these symptoms during the course of your treatment.

Cure rates are very encouraging with 85% percent of patients achieving a complete response with preservation of sphincter function.