Unresectable rectal cancer is another term for metastatic rectal cancer that has been rendered inoperable or one that cannot fully be removed by surgery. This generally occurs due to the size or location of the tumor. It is diagnosed in nearly 15% of rectal cancer cases and may require other interventions to manage symptoms. When cancer cannot be removed by surgery, oncologists may recommend one or more of the following therapies:

Laser removal of the rectal tumor
Lasers may be used in the early stages of diagnosis to remove any polyps that may become cancerous in the colon and rectum. Generally, CO2 and Nd:YAG lasers are used to shrink or destroy tumors in the body with the help of an endoscope.

Cryotherapy
Some studies have also reported using cryotherapy (treatment with extreme cold) for palliation to reduce tumor bulk in the body. This led to improvements such as more effective control of bleeding, relieving the obstruction, and avoiding colostomy. This is a form of ablation therapy used for small tumors (4 cm or less).

Elective colostomy to bypass the tumor (diverting colostomy)
A colostomy is an opening that is made in the abdominal wall during surgery. The end of the colon is brought through this opening to form a stoma that allows fecal matter to be removed from the body. This procedure is required when the rectum, anus, or surrounding sphincter muscle has been removed, such as during abdominoperineal resection.

Rectal stent
In some cases, doctors may recommend adding a rectal stent or a flexible hollow metal tube to keep the rectum open. This procedure does not require surgery. Once the doctors locate the blockage using a colonoscope, they may use X-rays and fluoroscopic imaging technology to place the stent accurately and help expand the colon or rectum.

Chemotherapy
People battling advanced stages of cancer may be offered chemotherapy, which is a treatment option used to kill fast-growing cancer cells. It may be offered intravenously at the hospital or by administering a course of treatment at home called oral therapy.

Radiation
Radiation therapy may be offered in combination with chemotherapy to decrease the size of the tumor. The most commonly used techniques of radiation therapy for colorectal cancers include:

External beam radiation: This may be intensity-modulated radiation therapy or image-guided radiation therapy conducted to deliver targeted doses of treatment.
Brachytherapy: This high-dose therapy is delivered directly into or near the tumor.

When seeking unresectable rectal cancer treatment, one will work with a team of doctors, including a surgeon, oncologist, radiation oncologist, and gastroenterologist. Based on the progression of cancer and the overall health of the patient, the team will recommend the best possible treatment options and discuss the possible outcomes to help patients make a more informed decision.