This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Tanis, P.J. Articles by Kroon, B.B. R. Search for Related Content PubMed PubMed Citation Articles by Tanis, P.J. Articles by Kroon, B.B. R. Related Collections Sentinel lymph node Sentinel lymph node

The Illusion of the Learning Phase for Lymphatic Mapping

From the Departments of Surgery (PJT, OEN, BBRK) and Radiotherapy (AAMH), The Netherlands Cancer Institute, Amsterdam, the Netherlands.

Correspondence: Address correspondence and reprint requests to: P. J. Tanis, MD, Department of Surgery, the Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands; Fax: 31-20-512-2554; E-mail: ptanis{at}nki.nl

Background: We provide a statistical analysis of the learning phase for sentinel node biopsy.

Methods: Four learning phases were analyzed: 25, 50, 75, and 150 procedures with a corresponding number of 10, 20, 30, and 60 tumor-positive cases. Critical values of nonidentification rate and false-negative rate were defined. The binomial distribution was used to calculate the probabilities of correctly or incorrectly accepting the quality of the performance, given a certain long-term nonidentification or false-negative rate.

Results: The chance of incorrectly reaching a favorable false-negative rate of <10% (critical value) in 20 metastasized patients was 18% for a surgeon with a long-term probability of false-negative procedures of 15%. This chance was reduced to 10% with a learning phase of 60 tumor-positive cases. When this chance has to be further reduced to 5%, the critical value has to be lower in smaller groups of patients: 5% false-negative rate in 20 tumor-positive procedures.

Conclusions: A learning phase of at least 150 procedures with 60 tumor-positive cases is needed to draw any reliable conclusion about the quality of sentinel node biopsy. In general, a compromise has to be made between the reliability of the results and the practically achievable number of procedures.

Key Words: Sentinel node • Learning phase • Sensitivity • Identification rate • Binomial distribution • Critical value

This article has been cited by other articles:

				S. H. Estourgie, O. E. Nieweg, R. A. Valdes Olmos, C. A. Hoefnagel, and B. B. R. Kroon Review and Evaluation of Sentinel Node Procedures in 250 Melanoma Patients With a Median Follow-Up of 6 Years Ann. Surg. Oncol., July 1, 2003; 10(6): 681 - 688. [Abstract] [Full Text] [PDF]