Importance of findings on the initial evaluation for cancer in patients with symptomatic idiopathic deep venous thrombosis

Authors: Cornuz J, Pearson S, Creager M, Cook E, Goldman L.
Source: Annals of Internal Medicine. 125:785-93. November 15, 1996.
Institutions: Harvard medical school; UCSF.
Financial support: National Heart Lung and Blood Institute; Swiss National Science Foundation.



Cancer is known to be a risk factor for deep venous thrombosis of the lower extremities (DVT). Similarly, DVT without obvious precipitating cause may be a marker for unrecognized cancer. How high is the risk of unrecognized cancer in patients with idiopathic DVT? What is the appropriate initial work-up of such patients? What is the subsequent incidence of cancer in these patients, after prevalent cancers have been diagnosed? This retrospective cohort study was designed to look at these issues.



Authors' Discussion

The authors conclude that, based on their results (and on other data and consensus guidelines), the appropriate initial work-up for patients with idiopathic deep venous thrombosis of the legs should include a detailed history, physical examination, routine labwork, chest x-ray, urinalysis, stool for occult blood and mammography (where appropriate). More extensive investigation should be limited to and guided by abnormalities found on the above evaluation. They also conclude that, once prevalent cancers have been detected by the above work-up, the incidence of cancer during follow-up is not greater than in the general population.

They compare their results to other studies. A Scandinavian study of 1383 patients with DVT confirmed their finding that simple clinical and diagnostic methods were sufficient to detect prevalent cancers, but found that the incidence of cancer was higher during follow-up. A smaller cohort study, on the other hand, confirmed their finding that the incidence of subsequent cancer was not higher in patients with DVT. Several other studies did not confirm these results, however. The authors feel that these discrepancies may be due to improper selection of controls, to a heightened awareness of physicians in their study group of the association between DVT and cancer (leading to more careful clinical screening), and to a lack of adjustment for smoking in some of the other studies (patients who smoke have both a higher incidence of cancer and of DVT).


I have two comments about the study presented here. First, from a methodological standpoint, although the 86-item form for data collection from hospital charts appears to have been designed before the study was actually carried out, the same is not explicitly stated for the items that were included in the four abnormality categories (history, physical, lab, chest x-ray). If these four categories were specified and developed after the data was gathered and analyzed, this constitutes a post-hoc analysis, weakens the statistical validity of the study and would require a confirmatory, prospective trial for validation.

The second comment relates to the results themselves. Only 56 out of 142 patients with DVT had no abnormalities on the four components of the initial evaluation. This means that, based on this study, only 39% of patients with DVT would be eligible for "no further work-up". Over 60% would require further evaluation. This represents a fairly large number of patients.

Finally, on a more philosophical note, we live in a time when the cry of "where's the evidence?" meets the cost-cutting imperatives of managed care. Studies demonstrating that expensive diagnostic tests are not supported by evidence are increasingly in vogue, and we can expect to see more of them in the future. We need to subject them to the same scrutiny as those reporting a benefit from new, expensive, diagnostic and therapeutic strategies.

November 26, 1996

Reader comments

January 15, 1996

The following responses were submitted by Dr. Jacques Cornuz, first author of the article:

1. Methodological standpoint

The four items were designed before the study was carried out. However, we do believe that our results must be confirmed by a prospective study.

2. Results

I agree that, based on our study, about 60% of patients with DVT would be eligible for further workup. However, 60% is considerably less than all patients, i.e. 100%.

3. Philosophical note

I do agree with this point. However, in the recent past, scrutiny was not always met in clinical cancer screening, e.g., in screening for prostate cancer with prostatic specific antigen.

Submit a comment about this article


References related to this article from the NLM's PubMed database.

Return to Journal Club home page

Site Meter