Is targeted chemotherapy for stage II/III rectal cancer before surgery effective?

This study examined the effect of pre-surgical chemotherapy without radiotherapy in stage II/III rectal cancer. The study showed that combined targeted chemotherapy was effective in these patients.

Rectal cancer is a cancer of the end part of the digestive system. In stage II and III, the cancer has begun to spread through the area. Chemotherapy combined with radiation is commonly used before surgery to remove the tumor. Chemotherapy treatment for this type of cancer involves 3 agents (FOLFOX) – Folinic acid (Leucovorin), 5-Fluoruracil (Adrucil) and oxaliplatin (Eloxatin). Bevacizumab (Avastin) is a type of targeted chemotherapy. It is known as a vascular endothelial growth factor (VEGF) inhibitor. This type of treatment stops the growth of new blood vessels  for tumors. This is important to shrink a tumor before surgical removal.

Radiation is generally used to control the tumor locally. Whether radiation before surgery improves survival is not clear. It is also associated with many side effects. It is not clear whether chemotherapy and targeted therapy are as effective.

The current study examined whether chemotherapy with targeted therapy was effective in patients with stage II/III rectal cancer. The study included 60 patients (80% male). 40 patients without the KRAS gene mutation (a gene abnormality that can lead to cancer growth) were treated with cetuximab (another type of targeted therapy). Bevacizumab was given to the 20 patient who had KRAS gene mutations. Patients were treated with up to 6 cycles of treatment before surgery.

98.3% of patients achieved an R0 resection. This was defined as no evidence of tumor cells at the edges of the removed tissue. This did not differ for patients with or without the KRAS mutation. 16.7% of patients saw a complete response, meaning there were no cancer cells found in the surrounding lymph nodes.

21.7% of patients experienced moderate to severe complications. These included leakage at the surgical site (11.6%), infection (6.7%), and urinary problems (3.3%). 

This study concluded that chemotherapy combined with targeted therapies was effective at shrinking rectal tumors before surgery.  

This study was not a randomized comparison of treatments. Further, larger studies are needed to directly compare chemotherapy and targeted therapy with chemotherapy and radiation, as well as the different types of targeted therapy. Survival rates and complications also need to be compared. 

Discuss with your doctor the use of a targeted therapy combined with chemotherapy before surgical removal of the tumor.