ORIGINAL ARTICLE – BREAST ONCOLOGY Validation of a Nomogram to Predict the Risk of Nonsentinel Lymph Node Metastases in Breast Cancer Patients with a Positive Sentinel Node Biopsy: Validation of the MSKCC Breast Nomogram R. F. D. van la Parra, MD 1 , M. F. Ernst, MD, PhD 1 , J. L. B. Bevilacqua, MD, PhD 2 , S. J. J. Mol, MD 3 , K. J. Van Zee, MS, MD 4 , J. M. Broekman, MD, PhD 3 , and K. Bosscha, MD, PhD 1 1 Department of Surgery, Jeroen Bosch Hospital, 5200 ME ‘s-Hertogenbosch, The Netherlands; 2 Department of Breast Surgery, Hospital Sirio Libanes, Sa ˜o Paulo, Brazil; 3 Department of Pathology, Jeroen Bosch Ziekenhuis, ‘s- Hertogenbosch, The Netherlands; 4 Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York ABSTRACT Background. Completion axillary lymph node dissection (ALND) remains the standard of care for patients with disease-positive sentinel lymph nodes (SLN). However, approximately two-thirds will have no additional disease- positive nodes. To identify the patient’s individual risk for non-SLN metastases, the Memorial Sloan-Kettering Can- cer Center (MSKCC) developed a nomogram. Methods. The records of 182 breast cancer patients who underwent SLN and ALND were selected. Serial hema- toxylin and eosin (HE) analysis and immunohistochemistry were routinely performed on each sentinel node. For application of the nomogram, the detection method was assigned in two ways: for all metastases visible by serial HE, the method of detection was scored as ‘‘serial HE’’ (method 1), independent of the tumor size, and by a combination of size and staining method (method 2); so macrometastasis were scored as detected by routine HE, micrometastasis by serial HE, and isolated tumor cells by immunohistochemistry. A receiver operating characteristic curve (ROC) was drawn, and the area under the curve was calculated to assess the discriminative power of the nomogram. Results. The area under the ROC was .71 (range, .64–.79) according to method 1 and .75 (range, .67–.88) according to method 2. Conclusions. Because the variable ‘‘method of detection’’ in the MSKCC nomogram is a surrogate for SLN metas- tasis size, the size category of the SLN metastasis can be used in applying the nomogram to patients in whom the SLN histologic analysis is performed by a much different procedure than that used to develop the MSKCC nomo- gram. This results in an improved predictive accuracy. Sentinel lymph node (SLN) biopsy is found to be accurate for assessing regional lymph node involvement in breast cancer patients. The technique is safe and simple, and the morbidity is less with respect to lymph edema, sensory disturbances, and shoulder dysfunction compared with axillary lymph node dissection (ALND). The high negative predictive value allows ALND to be safely avoi- ded in SLN-negative patients. Because of its prognostic (need for adjuvant therapy) and therapeutic implications (better locoregional disease control), ALND remains the standard of care for SLN-positive patients according to the Dutch guidelines 1 . However, approximately 50% to 70% of patients with disease-positive SLNs will have no additional positive nodes, which means that axillary dissection might also be avoided in selected patients 2–25 . Many studies have been conducted to identify predictive parameters to select those patients who would benefit most from ALND. This This article was presented as a poster at the SSO 2008 in Chicago. Ó Society of Surgical Oncology 2009 First Received: 11 March 2008; Published Online: 28 February 2009 R. F. D. van la Parra, MD e-mail: rfdvanlaparra@tiscali.nl Ann Surg Oncol (2009) 16:1128–1135 DOI 10.1245/s10434-009-0359-y