The Doppler Perfusion Index: Can it Help Select the Best Candidates for Adjuvant Chemotherapy?
February 1, 2000 4 minutes read
The Doppler Perfusion Index: Can it Help Select the Best Candidates for Adjuvant Chemotherapy?
ABSTRACT & COMMENTARY
Synopsis: Presently, Dukes’ staging is the best indicator of likely relapse in patients after resection for colon cancer. Patients with occult metastatic disease have been shown to benefit from adjuvant chemotherapy and this is most demonstrable for patients with Dukes’ C lesions, because they have a 60-70% chance of having occult disease. Patients with Dukes’ A or B lesions and occult metastases probably also benefit, but this is more difficult to prove because the great majority of these were cured surgically and, even without therapy, the relapse rate is small. Thus, a technique that would help determine the presence of occult metastases independent of Dukes’ stage would be an advance toward the discriminate use of adjuvant chemotherapy. Leen and colleagues have shown that the doppler perfusion index (DPI) may well fit this bill. In a series of patients with Dukes’ A, B, or C colon or rectal carcinomas, DPI assessment proved to define more specifically those patients likely to develop recurrent disease. This promising technique needs to be examined in a larger, multi-institutional setting, but may well be a tool soon introduced in the clinical assessment of colorectal cancer patients.
Source: Leen E, et al. Lancet 2000;355:34-37.
Approximately two-thirds of patients with colorectal cancer are treated initially with curative intent surgery, but of these, only about 50% survive five years.1 A common site for relapse is the liver, despite the fact that preoperative and intraoperative evaluations did not reveal disease involvement. Apparently, currently used ultrasound, CT, and MRI scans are not sensitive enough to detect microscopic involvement at its earliest stages.
Leen and colleagues at the Royal Infirmary in Glasgow addressed the question of whether a technique that they have been developing, the doppler perfusion index (DPI), could be used to predict ultimate liver involvement in patients resected for cure with Dukes A, B, or C lesions of the colon or rectum.2,3
The DPI is a technique that allows the estimation of the ratio of hepatic arterial to total liver blood flow. Leen et al had previously shown that liver metastases are associated with an increased ratio of hepatic arterial flow.4 Leen et al have suggested that such alterations in blood flow are present, even with occult metastases. In the current study, they attempted to correlate changes in DPI with long-term outcome in patients who were undergoing potentially curative surgery for colorectal cancer.
Leen et al studied 120 patients undergoing potentially curative surgery for colorectal cancer. Preoperative analysis had not revealed suspicion of liver involvement in these patients. At five years, patients with Dukes’ A or B tumors (n = 61) had recurrence-free survival of 57% and overall survival of 64%, compared with 39% and 42% for patients with Dukes’ C tumors. Of the 120 patients, 47 had normal DPI values and 73 had abnormal values. Patients with normal DPI values had recurrence-free survival of 89% and overall survival of 91%, compared with 22% and 29% for those with abnormal DPI values. In multivariate analysis, which included age, sex, primary tumor site, Dukes’ stage and DPI status as covariates, only DPI status had independent prognostic significance. This led Leen et al to conclude that DPI may be a useful measure to assist in the determination of those for whom adjuvant chemotherapy might be of greatest benefit.
COMMENT By William B. Ershler, MD
Adjuvant chemotherapy has been conclusively shown to benefit some patients after colorectal cancer surgery but, unfortunately, there are associated toxicities.5 Thus, an effort to define those who are likely to benefit is worthwhile. Presently, the most useful measure is Dukes’ staging. Patients with Dukes’ C lesions, for example, have a 60-70% chance of relapse. Thus, 30-40% of these patients do not require adjuvant therapy. However, to date, there is not an established method of determining the likelihood of relapse in this group.
The data presented by Leen et al, if validated in larger studies, will be a step in the right direction. It was clear from their series that patients with normal DPI results had much lower relapse and much better survival rates than those with abnormal patterns—independent of Dukes’ stage. Extrapolating from this data, one could argue that patients with abnormal DPI (independent of Dukes’ stage) would be the best candidates for adjuvant chemotherapy.
Before implementing such a strategy, additional confirmatory studies will be needed. This is a report from a single institution with developed expertise in this technique. In fact, all DPI assessments were performed by a single investigator. Thus, it remains to be seen if similar excellent results will be achieved when the technique is applied generally.
References
1. McArdle CS, et al. Br J Surg 1990;77:206-208.
2. Leen E, et al. Br J Cancer 1991;63:323-325.
3. Leen E, et al. Ann Surg 1991;214:599-604.
4. Leen E, et al. Radiology 1995;195:113-116.
5. NIH Consensus Conference. JAMA 1990;264: 1444-1450.
Which one of the following statements about the hepatic doppler perfusion index is true?
a. It is a technique that may determine the size of primary colon cancers.
b. It is a technique that may determine which patients with Dukes’ D colon cancer should receive chemotherapy for metastatic disease.
c. It is a technique that may prove useful in patients with Dukes’ A, B, or C colorectal carcinomas to help determine which patients would be the best candidates for adjuvant chemotherapy.
d. It is a technique that may prove useful in patients with Dukes’ C (but not Dukes’ A or B) colorectal carcinoma to help determine which patients would be the best candidates for adjuvant chemotherapy.
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