S1-based chemotherapy improves the outcomes of patients with advanced colorectal cancer

This study compared the effectiveness and safety of two different chemotherapies in the treatment of advanced colorectal cancer (CRC). Researchers suggested that S1-based chemotherapy is a good option for the treatment of these patients.

CRC is one of the most common cancers worldwide. The standard treatment is surgery and chemotherapy. Chemotherapy consists of one or more combined drugs that prolong the survival of patients with cancer. It targets and kills cancer cells and stops the tumor from growing.

FOLFOX (folinic acid, fluorouracil, oxaliplatin) and FOLFIRI (folinic acid, fluorouracil, irinotecan) chemotherapies are the recommended first-line therapies for advanced CRC. However, receiving these therapies comes with considerable discomfort for cancer patients. To continuously receive these therapies, a port is implanted into a large vein in the chest or arm. This port will remain in the patient's body for the delivery of chemotherapy into the bloodstream. This is associated with an increased risk of infection and blood clots.

Therefore, oral drugs such as S-1 agents have been considered as an option to treat these patients. This consists of a combination of tegafur, gimeracil, and oteracil potassium. Prior studies showed its antitumor activity against advanced CRC. These studies also show that S-1 therapy is associated with fewer side effects when compared to other chemotherapies. However, some trials present contradictory results. The effectiveness of S-1 therapy as a first-line therapy against advanced CRC is still not clear.

This study reviewed 10 other studies including information about 2807 CRC patients. Of these, 1399 patients received S-1 therapy (group 1) and 1408 received other types of chemotherapy (group 2). Progression-free survival (PFS; time from treatment to progression) and overall survival (OS; time from treatment to death by any cause) were assessed.

Overall, patients in group 1 had a 10% better PFS compared to group 2. Patients from group 1 had an 8% improvement in the odds of a better PFS when compared to 5-fluorouracil-based therapy. When compared to capecitabine-based therapy, group 1 had a 15% improvement in the odds of a better PFS. No significant difference was seen in OS and in response rate between groups 1 and 2.

Group 1 was also associated with fewer moderate side effects. Patients from this group had a 70% improvement in the odds of having leucopenia (decrease of white blood cell counts). For the hand-foot syndrome (redness, pain, and swelling of hands and foot) these was a 76% improvement in group 1.  

This study concluded that S-1-based chemotherapy is a good and safe option in the treatment of advanced CRC.

The studies analyzed had different methodologies. This makes it difficult to compare results.