Chemoradiation an Effective But Toxic Therapy for Colorectal Cancer

Chemoradiation is effective in controlling anal and rectal cancers but causes significant side effects and complications, according to three independent teams of colorectal surgeons in Australia and the United States.

The surgeons presented their findings at the annual meeting of the American Society of Colon and Rectal Surgeons (ASCRS). They all agreed that chemoradiation, either alone or following surgery, is still the best way to prevent the recurrence of colon and rectal cancers. However, each study team felt that further research is needed to examine dosage amounts, mix of therapies, and delivery methods of chemoradiation to reduce the incidence of side effects.

Study from Nebraska

In a study of patients with anal cancer treated with chemoradiation, Harry Liberman, MD, Creighton University School of Medicine, Omaha, Nebraska, reported that when patients received more than 3,000 cGy of radiation, the frequency of complications increased, with no significant benefit achieved in terms of tumor recurrence or survival.

Of 336 patients studied, roughly 11% received £ 3,000 cGy of radiation and almost 89% received > 3,000 cGy. Among patients receiving the larger doses of radiation, 75% had complications. The incidence dropped in those who received smaller doses, but was still significant at 59%.

Complications related to radiation included diarrhea (35.4%), skin excoriation (35.1%), inflammation of the rectum (15.8%), incontinence (12.2%), rectal narrowing (5.4%), impotence (1.8%), and loss of libido (1.5%).

Australian Study

In another study focusing on the use of chemoradiation in addition to surgery, Dr. David Schache of Princess Alexandra Hospital, Brisbane, Australia, reported that while chemoradiation is successful in controlling tumors in rectal cancer, “the side effects are significant.”

Of 80 patients from the Queensland Radium Institute enrolled in the study, 1 in 4 developed severe side effects during radiotherapy. Chemotherapy was discontinued in 29% of patients because of severe side effects, such as small bowel obstruction, diarrhea, nausea, and vomiting. In 11 other patients, the dose of chemotherapy was reduced due to complications. In a 3-year follow-up of the 80 patients, 30% experienced late side effects.

Review of Randomized Trials

Reporting on a review of all existing randomized, controlled trials of adjuvant chemotherapy and radiotherapy for resectable rectal cancer, Joe Tjandra, MD, of the Royal Melbourne Hospital in Australia, noted that pelvic floor function and quality of life were impaired in 30% to 70% of patients treated with chemotherapy and radiotherapy in addition to surgery.

“The patient could develop very poor sphincter control. Almost invariably, younger women will become postmenopausal, which can have an impact on osteoporosis,” said Dr. Tjandra. “The implications are enormous. We need to change the mix of therapies, the amount, and the method of administration.”