48: Predicting Regional Lymph Node Recurrence in the Modern Age of Tumor-positive Sentinel Node Melanoma: The Role of the First Post-operative Ultrasound

Friday, March 11, 2022

1:21 PM – 1:29 PM CST

Location: Chantilly East

Abstract Presenter(s)

Jennifer Keller, MD

Complex General Surgical Oncology Fellow
Saint John's Providence Cancer Institute
Santa Monica, California, United States

Disclosure: I do not have any relevant financial / non-financial relationships with any proprietary interests.

Participants should be aware of the following financial/non-financial relationships:

Jennifer Keller, MD: I do not have any relevant financial / non-financial relationships with any proprietary interests.

Introduction: The Multicenter Selective Lymphadenectomy Trial II (MSLT-II) resulted in a paradigm shift in the management of tumor positive sentinel lymph nodes (SLN) from completion node dissection (CLND) to nodal observation. While there is no apparent survival advantage with CLND this change in practice leaves some patients with nodal disease in the SLN basin. We aimed to evaluate prognostic factors for predicting sentinel node basin recurrence (SNBR).

Methods: 1,939 p</span>atients were randomized within MSLT-II, 968 were assigned to nodal observation. In this study, patients were included if they underwent an ultrasound of the sentinel node basin(s) within four months of surgery. We excluded those with positive SLN by RT-PCR or if SLN pathologic data was incomplete. Primary tumor, patient, and SLN characteristics were evaluated. The first post-operative ultrasound (PSNB-US) was considered abnormal if >1 of the following were true: length:depth >2, hypoechoic center or focal subcapsular lesion. Univariate and multivariate analysis were performed to determine independent factors for predicting SNBR.

Results: 737 patients were included in this study with 193 (26.2%) having SNBR. There were 73 (9.9%) abnormal ultrasounds. 46 of 147 (23.8%) basins with subsequent recurrence vs 27 of 517 (5%) basins without recurrence had an abnormal ultrasound. On multivariate analysis, age (adjusted odds ratio [aOR] 1.02, 95% CI 1.0-1.03), increasing Breslow thickness (aOR 1.14, 95% CI 1.01-1.28), primary tumor ulceration (aOR 2.07, 95% CI 1.42-3.02), and abnormal PSNB-US (aOR 5.00, 95% CI 2.97 -8.64) were significantly (p < 0.05) associated with SNBR. Primary tumor location, SLN burden were not found to be significantly associated with SNBR. By combining all the predictive factors, a multimodal model was created to predict SNBR with an AUC of 0.76.

Conclusions: Both clinical and pathologic factors can be used to predict lymph node recurrence after SLN yet the first post-operative ultrasound may be an important step in determining residual disease in the dissected basin.

Learning Objectives:

To Determine the utility of surveillance ultrasounds of the post-operative sentinel node lymph node basin.
Discuss the patient, and tumor factors that contribute to lymph node basin recurrence after positive sentinel lymph node biopsy.
Discuss the utility of surveillance ultrasounds in the sequencing of surgical and systemic treatment cutaneous melanoma after positive sentinel lymph node biopsy