If you have a specific type of rectal cancer, known as dMMR or MSI-H (deficient mismatch repair or microsatellite instability-high) you may be eligible for immunotherapy. Immunotherapy is different from chemotherapy in that it helps the person’s own immune system recognize and destroy cancer cells. Immunotherapy may be administered for around 6 months. If there is not cancer detectable at the end of this regimen, therapy is discontinued. If the cancer is persistent, then a combination of radiation, chemotherapy, and surgery may be given.

The current standard of care for stage II and III rectal cancer is chemotherapy and radiation, but advances in chemotherapy have led researchers to investigate whether some patients with stage II or III rectal cancer could be treated with FOLFOX without radiation before having surgery. This research was performed in a trial called the PROSPECT study.

The PROSPECT study was a unique type of trial called a “de-escalation” study, which means a standard of care treatment was removed to see if it was necessary.

The study found that, depending on tumor location, some patients with stage II or III rectal cancer may not benefit from radiation.

If you’re receiving radiation therapy for rectal cancer, it’s likely in one of these two intervals:

Ask your radiation oncologist what’s recommended for you and why. Lower dose radiation spread out over several weeks may give tumors time to shrink and save bowel function.

While you’re receiving radiation, it’s also possible to receive continuous chemotherapy through a pump. This is called chemoradiation.

When chemotherapy and/or radiation are administered before surgery, this approach is known as neoadjuvant therapy. In some cases, doctors will recommend total neoadjuvant therapy where a full course of chemotherapy and radiation are administered prior to surgery.

In other cases, chemotherapy may be recommended without radiation, and radiation may be reserved for after surgery in cases with high-risk features in their tumors noted when the pathologist examines the surgical specimen.

Patients who cannot tolerate chemoradiation at first, may go directly to surgery with no additional treatment, and then onto adjuvant chemotherapy and/or chemoradiation after surgery.

For rectal cancer, abdominal surgery is often required to remove tumors. You may be treated with radiation and/or chemotherapy before surgery.

Removal of all or part of your colon through an incision or incisions (laparoscopic surgeries often require several small incisions while open surgery is usually done using a single, larger incision).

When a surgeon makes a few small incisions in your abdomen through which they pass a tiny camera and tools to access your colon.

Watch and wait is an approach that some patients with stage II or III rectal cancer may be eligible for after undergoing neoadjuvant chemoradiation. Watch and wait aims to avoid rectal surgery and the side effects associated with surgical resection of rectal tumors.