Researchers tried to push the envelope in treating rectal and anal cancer by adding new or different chemotherapy to standard chemoradiotherapy. However, two trials in rectal cancer and one in anal cancer were not able to improve complete response rates for chemoradiation. Adding extra chemotherapy after radiation was finished didn’t improve relapse-free survival for anal cancer either.
- The STAR trial from Italy found that adding oxaliplatin to chemoradiotherapy before rectal surgery did nothing to improve the rate of complete responses found at surgery. There was also no decrease in the number of patients who needed a permanent colostomy. Serious diarrhea was significantly worse in the oxaliplatin arm. However, unexpectedly, more distant metastases were found at the time of surgery among patients who didn’t get oxaliplatin (16 patients with spread to lungs, liver, or peritoneal surfaces vs only 2 who got oxaliplatin prior to surgery.) Survival data is not yet available.
- In France, researchers in the ACCORD trial combined both an increase in radiation to 50Gy and the addition of oxaliplatin to standard treatment of 45Gy and capecitabine in an attempt to improve pathological complete response rates for chemoradiotherapy before rectal cancer surgery. However, there was no significant impact on tumor response at surgery and no decrease in colostomies. Serious diarrhea was significant worse (3 percent with no oxaliplatin, 13 percent in the increased radiation with oxaliplatin.) They did show that Xeloda® (capecitabine) can be substituted for infusional 5-FU in chemoradiotherapy regimens.
- A large trial of anal cancer in the United Kingdom tried to improve both complete response to chemoradiation and disease-free and overall survival by using cisplatin instead of standard mitomycin-C during radiotherapy and by randomly giving two doses of cisplatin and 5-FU after radiation treatment ended. Response to chemoradiation was excellent with 95 percent of patients having a complete response with either mitomycin-C or cisplatin. Furthermore, maintenance chemotherapy didn’t change relapse-free survival at three years, with 75 percent of patients without recurrences whether or not they had the extra chemo. The research team concluded that mitomycin-C remains standard treatment for anal cancer.