Cancers of the rectum
and anal canal

Symptoms are not always present and are often non-specific: changes in bowel movements, alternating diarrhea and constipation, blood in the stool, and abdominal pain. Sometimes there is unexplained weight loss or fatigue.

In the anal canal, at an early stage, pain in the anus or bleeding, either spontaneous or during defecation, predominate. There may also be a feeling of false urgency. These symptoms may be accompanied by itching, mucous discharge, and loss of bowel control. Sometimes, a tumor can be felt in the anus. At a more advanced stage, unusual weight loss, severe fatigue, and loss of appetite may occur.

A screening test for rectal cancer for people aged 50 to 74 exists. This simple test, which can be done at home, involves checking for blood in the stool every two years.

There is no screening test available for the anal canal. If you experience any of the non-specific symptoms described above, your doctor will check for any abnormalities in the anal canal.

Radiotherapy is usually offered in combination with chemotherapy. For anal canal cancer, it is the only treatment. For rectal cancer, this treatment is usually given in preparation for surgery.

External radiotherapy

This treatment uses X-rays directed through the skin to the area to be treated. These rays are produced by a linear accelerator and gradually destroy the cancer cells.

Your treatment will begin with a scanning session (called virtual simulation) to identify the areas to be treated (target volumes) and the healthy organs around them that must be preserved as much as possible.

Your treatment plan will be tailored to your individual needs (taking into account your specific characteristics and those of your disease) and scheduled over several weeks. Sessions take place from Monday to Friday and last approximately 15 minutes.

The radiation is invisible and painless and does not make you radioactive.

Chemotherapy in combination with radiotherapy

Chemotherapy is a treatment based on drugs that act on the mechanisms of cell division. It is a general treatment (called systemic treatment) that acts throughout the body. This allows cancer cells to be reached wherever they are in the body, even if they are isolated and cannot be detected by diagnostic tests.

Chemotherapy drugs can be administered either orally or by infusion. At Centre François Baclesse, chemotherapy administered concurrently with radiotherapy sensitizes the cells in order to enhance the action of the radiation on the areas to be treated.

Side effects are predictable but not systematic; each situation is unique and each patient reacts differently. We invite patients to report any adverse effects to their referring physician at the CFB during weekly follow-up consultations. Nowadays, the most common acute side effects are very well managed with symptomatic treatments. These will be prescribed by your radiation oncologist if necessary.

During radiotherapy

• Irritation of the rectum and anus (radiation proctitis and anus): Radiation to the rectum causes inflammation and irritation in the rectal and anal areas. This manifests as pain, diarrhea, false urges, and sometimes some bleeding or mucus discharge. Anal pain is similar to that of hemorrhoidal flare-ups.
• Irritation of the bladder (radiation cystitis): The bladder is located in front of the rectum and can be irritated by radiation. This manifests as burning, frequent and urgent need to urinate (similar to a urinary tract infection, which should usually be treated with a urine culture).
• Nausea: This may occur but can be alleviated with medication.
• Skin irritation: The skin may become red, like a sunburn, in the areas exposed to radiation. It may become dry, flaky, and painful. It will heal after treatment is completed.
• La fatigue : This may already be present before treatment and become more pronounced as the weeks of treatment progress.

During chemotherapy

Side effects will depend on the choice of drugs and the doses required to treat the tumor:

• A decrease in white blood cells (leukopenia), red blood cells (anemia), or platelets (thrombocytopenia) is commonly observed and requires an adjustment in chemotherapy doses or even interruption of treatment until blood counts return to normal.
• Hand/foot syndrome: Redness and peeling of the extremities
• Nausea and vomiting are increasingly well managed with antiemetic treatments.
• Diarrhea may occur due to radiation of the rectum or chemotherapy. This should be reported to your doctor and care should be taken to avoid dehydration.

The effects observed during treatment generally fade a few months after the end of treatment. Some signs may appear after several months or years; these are known as "late effects." They may be related to the treatments you received. We encourage you to report any side effects, even late ones, to your radiation oncologist.

Fatigue and side effects often persist for some time. We encourage you to discuss this with your doctor so that they can be treated.

The following side effects may occur:

• Perianal fibrosis
• Vaginal stenosis in patients with a vagina
• Sphincter disorders leading to fecal incontinence