Can SOX and mFOLFOX6 chemotherapies be given without radiotherapy before surgery for advanced rectal cancer?

This study evaluated the safety and effectiveness of two chemotherapy regimens (SOX and mFOLFOX6) before surgery for rectal cancer (RC) without radiotherapy. The study found that both regimens were safe and effective in these patients.  

RC is commonly treated with surgery to remove the tumor. Patients with locally advanced RC (LARC) have a high risk of spread of the tumor (metastasis). These patients need additional therapy. Patients with LARC are usually given chemotherapy (CT) and radiotherapy (RT) before surgery to shrink the tumor. However, RT before surgery often has many side effects that affect the quality of life of patients.

One strategy to improve the risk of side effects is to remove RT from this treatment regimen. Chemotherapy regimens such as SOX (S-1 and oxaliplatin) and mFOLFOX6 (folinic acid, 5-fluorouracil, and oxaliplatin) have shown good effectiveness in patients with colorectal cancer. However, it is not clear if these regimens alone would be safe or effective in shrinking LARC tumors enough before surgery.

This study included 103 patients with LARC who were planning rectal cancer surgery. 53 patients received SOX CT before surgery. 50 patients were given mFOLFOX6 before surgery. The average follow-up time was 43.3 months.

Overall, 98.1% of the patients had their tumors completely removed during surgery (100% in the SOX group and 96% of the mFOLFOX6 group). After 3 years, 69.4% of the SOX group and 73.4% of the mFOLFOX6 group were alive without any signs of cancer.

92.3% of patients in the SOX group and 91.8% in the mFOLFOX6 group were alive after 3 years.

29.5% of the SOX group and 34.2% of the mFOLFOX6 group reported severe side effects. The most common were low levels of platelets (blood cells involved in clotting) and white blood cells. No life-threatening surgical complications were seen in either group.

This study concluded that SOX and mFOLFOX6 chemotherapies are safe and effective when used alone before surgery in patients with LARC.

The sample size was very small. A larger sample size with a longer follow-up time could tell us more about how effective SOX and mFOLFOX6 are alone. Also, there was no control group to compare the outcome of patients also treated with RT. Further studies are needed.