Historically, rectal cancer was treated with 3 modalities: chemotherapy, radiation and surgery.
Recent advances in rectal cancer research afford patients choices for treatment that often spare them the need for either radiation, surgery and occasionally chemotherapy.
This means patients need to be offered both options, then allowed to choose which is right for them.
Uncommon cases of rectal cancer:
MSI High disease: A small percentage of rectal cancers (6-7%) have a genetic trait called MSI High. People with these cancers have a high probability of cure with one modality, immunotherapy. All rectal cancers diagnosed in our community are tested for this trait so that patients may receive immunotherapy instead of chemotherapy, radiation and surgery.
Some rectal cancers are diagnosed when they are small, small cancers without involvement of lymph nodes and far enough from the sphincter to preserve sphincter function: These tumors may be treated with surgery as a single modality and without radiation or chemotherapy.
Common presentations of rectal cancer:
Most rectal cancers diagnosed in our community do not have the above traits. They are either close to the anal sphincter (in which case we would like to avoid surgery) have penetrated deeply into the wall of the rectum or have spread to nearby lymph nodes (but not to distant sites, such as liver or lung). Patients with these rectal cancers historically were treated with chemotherapy, radiation and surgery. Cure rates were fairly high, as were side effects. In an effort to reduce side effects, research proceeded with efforts to eliminate either surgery or radiation.
Avoidance of surgery:
By 2011 we were finding a fair number of patients who underwent preoperative chemotherapy and radiation and had complete responses of their cancer before going to the OR for surgery. A paper was published in 2011 describing a “wait and see” strategy for 21 patients with complete responses after chemotherapy and radiation and reported that only 1 of these 21 patients suffered relapse. Eventually, enough data was published that patients with CR after chemo-radiotherapy could be offered avoidance of surgery. About 54% of patients (OPRA Trial) are able to avoid surgery and retain all of their rectums.
Avoidance of radiation:
By 2024 3 studies were published comparing chemo-radiotherapy (followed by surgery) with chemotherapy (no radiation) followed by surgery. Radiation was reserved for those patients who did not achieve sufficient responses to preoperative chemotherapy. Only 9% of patients in one of these trials required radiation. Thus 91% of patients are able to avoid radiation with a chemotherapy first approach.
David Palchak MD