RSS Feeds
Computed Tomography versus Endoscopic Ultrasonography for Staging of Pancreatic Cancer
- John M. DeWitt, MD;
- Thomas F. Imperiale, MD; and
- Stuart Sherman, MD
The Editors welcome submissions for possible publication in the Letters section. Authors of letters should:
•Include no more than 300 words of text, three authors, and five references
•Type with double-spacing
•Send three copies of the letter, an authors' form signed by all authors, and a cover letter describing any conflicts of interest related to the contents of the letter.
Letters commenting on an Annals article will be considered if they are received within 6 weeks of the time the article was published. Only some of the letters received can be published. Published letters are edited and may be shortened; tables and figures are included only selectively. Authors will be notified that the letter has been received. If the letter is selected for publication, the author will be notified about 3 weeks before the publication date. Unpublished letters cannot be returned.
Annals welcomes electronically submitted letters.
IN RESPONSE:
We thank Drs. Tierney, Kochman, and Scheiman for their interest in our article. We apologize for the incorrect reference cited.
We agree that CT and magnetic resonance imaging (MRI) are superior to endoscopic ultrasonography for detection of hepatic metastases from pancreatic cancer, since most of the right lobe of the liver cannot be seen by the latter test. Therefore, endoscopic ultrasonography clearly cannot replace other methods for staging of the liver but may supplement them. However, endoscopic ultrasonography and endoscopic ultrasonography–guided fine-needle aspiration may detect and accurately sample small metastatic liver lesions missed by other imaging methods (1). Endoscopic ultrasonography may also be superior to CT for detection of celiac node metastases (2) and small quantities of peritoneal fluid (3). Therefore, the overall superiority of CT for detecting distant metastases may bias the spectrum of disease for the study but does not bias the analysis. We do not believe that improved multidetector CT imaging of the right lobe of the liver, compared with endoscopic ultrasonography, creates a significant bias in favor of CT. Furthermore, limiting analysis of enrolled patients to those with confirmed locoregional disease diminishes clinical application of our results.
In our study, only 4 patients with pancreatic cancer who underwent surgery did not have complete assessment of vascular invasion. Although it was not stated in our paper, all patients with T4 malignant disease had invasion into vessels other than the splenic artery or splenic vein. Information concerning vascular invasion was omitted from our study principally because of space limitations and to allow us to focus on detection, staging, and resectability. We agree with Tierney and colleagues that this information is critical to determining preoperative staging and intend to publish this information separately.
All patients had either CT or MRI performed outside our institution before enrollment in the study. Furthermore, those with obvious metastatic disease were excluded. Endoscopic ultrasonography–guided fine-needle aspiration was performed before multidetector CT in our study. We believe that this practice is more the rule than the exception among tertiary care centers such as our institution. Although the risk for acute pancreatitis following endoscopic ultrasonography–guided fine-needle aspiration is 1% to 2%, no data support the contention that this potential inflammation may alter accuracy of tumor staging by CT or MRI. In our study, most CT scans were performed the same day as endoscopic ultrasonography, potentially limiting this problem.
We agree that preoperative overstaging of pancreatic tumors would potentially preclude resectable tumors from proceeding to surgery. However, the protocol we employed generally used surgical resection only when one or both tests showed resectability. The more relevant question, however, is whether the use of 2 tests permits a clinically meaningful increase in resectability as compared with 1 study alone. Our study did not demonstrate this but may have been underpowered to demonstrate any difference. Despite a slightly increased positive predictive value of resectability when CT or MRI is used in combination endoscopic ultrasonography (4, 5), this strategy remains debatable, although it could reduce costs (4). The use of endoscopic ultrasonography for pancreatic tumors, however, will probably remain dependent on availability, referral patterns, and local expertise.
John M. DeWitt, MD
Thomas F. Imperiale, MD
Stuart Sherman, MD
Indiana University Medical Center; Indianapolis, IN 46202-5121
The Editors welcome submissions for possible publication in the Letters section. Authors of letters should:
•Include no more than 300 words of text, three authors, and five references
•Type with double-spacing
•Send three copies of the letter, an authors' form signed by all authors, and a cover letter describing any conflicts of interest related to the contents of the letter.
Letters commenting on an Annals article will be considered if they are received within 6 weeks of the time the article was published. Only some of the letters received can be published. Published letters are edited and may be shortened; tables and figures are included only selectively. Authors will be notified that the letter has been received. If the letter is selected for publication, the author will be notified about 3 weeks before the publication date. Unpublished letters cannot be returned.
Annals welcomes electronically submitted letters.
