Many persons who have colorectal cancer undergo treatment by surgery. Chemotherapy after the surgery can help some patients avoid a recurrence or metastasis (spreading) of the cancer. However, doctors have not in the past had a reliable technique to determine which patients are likely to have a recurrence or metastasis (and therefore need chemotherapy). Now, researchers in England report that the Doppler Perfusion Index, a value showing the ratio of blood flow in the hepatic artery to total liver blood flow, can be obtained using Doppler ultrasound to help determine which patients are most likely to require chemotherapy after surgery.
Doppler ultrasound has been used to measure blood flow in the artery to the liver (hepatic artery) and total liver blood flow in persons with gastric or colorectal cancer. This measurement is helpful because abnormalities occurring in hepatic arterial blood flow can be used to detect early cancer metastasis to the liver. This technique is particularly important for persons with colorectal cancer because the current cancer staging (extent of cancer at the time of diagnosis) does not allow doctors to accurately predict which patients will experience a recurrence or metastasis.
To study the measurement of hepatic artery and liver blood flow further, researchers in England evaluated 120 patients who underwent curative surgery for colorectal cancer. They determined the Doppler Perfusion Index value for each patient before surgery. Five years later, they analyzed survival rates for the patients by cancer stage and by the Doppler Perfusion Index.
The results showed that patients with Dukes stage A or B cancer had a recurrence-free survival rate of 57%, and patients with Dukes stage C cancer had a recurrence-free survival rate of 39%. In terms of the Doppler Perfusion Index, of the 47 persons who had a normal value before surgery, 89% survived with no recurrence of cancer. Of the 73 persons who had an abnormal value, only 22% survived with no recurrence of cancer. These findings indicate that the Doppler Perfusion Index can more accurately predict cancer recurrence after surgery than does the stage of cancer.
The researchers concluded that the Doppler Perfusion Index may be a useful technique in identifying patients with early colorectal cancer who are at high risk for recurrence, and may benefit most from chemotherapy treatment after surgery. (The Lancet, Vol 355, No 9197, pp 34-37, 2000)