No cancer in the lymph nodes is linked to low rates of local recurrence in rectal cancer patients

This study investigated the rates of cancer return in patients with locally advanced rectal cancer that had not spread to lymph nodes, and whether any factors were linked to increased rates of cancer return.

Locally advanced rectal cancer indicates that the cancer has spread beyond the lining of the rectum, or has spread to the nearby lymph nodes. The standard treatment for patients with locally advanced rectal cancer is chemoradiotherapy followed by surgery. This pre-surgery chemoradiotherapy helps lower the risk of the rectal cancer returning (local recurrence). However, for patients with locally advanced cancer that has not spread to lymph nodes the risk of recurrence is relatively low. For some of these patients routine chemoradiotherapy before surgery may be unnecessary. As chemoradiotherapy leads to negative side effects, predicting the patients who do not need it would improve overall patient care.

The authors analyzed medical data for 166 patients with locally advanced rectal cancer patients that had not spread to lymph nodes. The tumor was located in the middle or upper part of the rectum for all patients and all patients underwent surgery that was intended to cure them. Lymph nodes were also removed during surgery to test for the presence of cancer cells. None of the patients underwent chemoradiotherapy before their surgery but 57% of patients received chemotherapy after surgery. The rate of local and distant recurrence was analyzed after 3 and 5 years.

Rates of local recurrence were low, only 2.5% of patients after 3 years and only 3.4% of patients after 5 years. A higher rate of patients developed cancer in a distant organ, most often the lung or liver. 10.5% had cancer in a distant organ after 3 years and 16.5% after 5 years. Over the follow-up period 9.6% of patients died from cancer recurrence.

The number of lymph nodes removed during surgery was the only factor linked to increased rates of recurrence. The rate of recurrence was higher in patients who had less than 12 lymph nodes removed compared to patients who had more than 12 lymph nodes removed. After 3 years 15.5% of patients who had less than 12 nodes removed had their cancer recur compared to 7.6% of patients who had more than 12 nodes removed.

The authors concluded that in this group of rectal cancer patients local recurrence rates were low. They also suggest that when lower numbers of lymph nodes were removed during surgery there were higher rates of cancer recurrence.