Initial data from a multi-institutional Italian study (Studio Terapia Adiuvante Retto, or STAR) has shown that oxaliplatin can be added to a standard preoperative fluorouracil-based chemoradiotherapy regimen for rectal cancer safely and without affecting the dosage of radiotherapy or the ability to perform surgery.

Chemotherapy and radiation are sometimes offered before surgery for colon and rectal cancers to shrink tumors, making them easier to remove. The addition of oxaliplatin has been shown to increase the efficacy of chemotherapy in both early-stage and metastatic colon cancer, either following or as a substitute for surgery, but it was not known whether it was safe and effective to add oxaliplatin to chemotherapy and radiation regimens given prior to surgery.

The current study reported preliminary safety data from the first 250 patients and will ultimately report on the efficacy of the approach. Approximately half of the patients received standard preoperative 5-fluorouracil and radiation, while the other half received chemoradiotherapy combined with oxaliplatin therapy.

The large majority of patients in both groups had surgery following their preoperative treatments. The study was an open-label, multicenter, randomized phase III trial with the primary purpose of comparing the activity (pathological response rate) and efficacy (overall and disease-free survival) of preoperative chemoradiotherapy with and without oxaliplatin.

Although oxaliplatin regularly resulted in more severe acute toxicity, there were no major unexpected adverse events. The most common side effects were diarrhea (59 percent in the oxaliplatin group versus 47 percent in the control group), neurosensory problems (40 percent vs. 0 percent), nausea (36 percent vs. 19 percent), and vomiting (24 percent vs. 6 percent). With the exception of a slight increase in severe (grade 3 or 4) diarrhea, none of the side effects were severe enough to result in major changes in the treatment program.

“These data show that adding oxaliplatin to preoperative chemotherapy and radiation for rectal cancer is safe and could, if proven effective, provide an important new tool for treating this disease,” said Carlo Aschele, MD, PhD, Attending Physician and Lead Clinician in Colorectal/Gastrointestinal Cancer in the Department of Medical Oncology and Cancer Prevention, E.O. Ospedali Galliera in Genoa, Italy, and the study's lead author.

“The doses of oxaliplatin used in this study are in the same range as those used in the treatment of metastatic cancer, and thus are likely to be active in this population of patients as well. Our group is continuing to enroll patients in the study to determine whether the addition of oxaliplatin improves both tumor response and overall and disease-free survival in these patients.”