I Johansson1, D Tempel2, J T Dwarkasing2, B Rentroia-Pacheco2, J Mattsson3, L Ny4, R Olofsson Bagge5. 1. Department of Pathology, Sahlgrenska University Hospital, Gothenburg, Sweden; Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, Sahlgrenska University Hospital, Gothenburg, Sweden. 2. SkylineDx, Rotterdam, the Netherlands. 3. Department of Surgery, Sahlgrenska University Hospital, Gothenburg, Sweden. 4. Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, Sahlgrenska University Hospital, Gothenburg, Sweden. 5. Department of Surgery, Sahlgrenska University Hospital, Gothenburg, Sweden; Sahlgrenska Center for Cancer Research, Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Sweden. Electronic address: roger.olofsson.bagge@gu.se.
Abstract
BACKGROUND: In patients with cutaneous melanoma, sentinel lymph node biopsy (SLNB) serves as an important technique to asses disease stage and to guide adjuvant systemic therapy. A model using clinicopathologic and gene expression variables (CP-GEP; Merlin Assay) has recently been introduced to identify patients that may safely forgo SLNB. Herein we present data from an independent validation cohort of the CP-GEP model in Swedish patients. METHODS: Archival histological material (primary melanoma tissue) from a prospectively collected cohort of 421 consecutive patients with pT1-T4 melanoma undergoing SLNB between 2006 and 2014 was analyzed using the CP-GEP model. CP-GEP combines Breslow thickness and patient age with the expression levels of eight genes from the primary melanoma. Stratification is based on their risk for nodal metastasis: CP-GEP Low Risk or CP-GEP High Risk. RESULTS: The SLNB positivity rate was 13%. Of 421 primary melanomas, the CP-GEP model identified 86 patients as having a low risk for nodal metastasis. In patients with pT1-2 melanomas, the SLNB reduction rate was 35.4% (95% CI: 29.4-41.8) with a negative predictive value (NPV) of 96.5% (95% CI: 90.0-99.3). Among patients with pT1-3 melanomas, CP-GEP suggested a SLNB reduction rate of 24.0% (95% CI: 19.7-28.8) and a NPV of 96.5% (95% CI: 90.1-99.3). Only one of 118 pT3 tumors was classified as CP-GEP Low Risk, and all pT4 tumors were classified as being high risk for nodal metastasis. CONCLUSION: This study demonstrates that CP-GEP can identify patients with a low risk for nodal metastasis. Patients with pT1-2 melanomas have the highest clinical benefit from using the test, where 35% of the patients could forgo a SLNB procedure.
BACKGROUND: In patients with cutaneous melanoma, sentinel lymph node biopsy (SLNB) serves as an important technique to asses disease stage and to guide adjuvant systemic therapy. A model using clinicopathologic and gene expression variables (CP-GEP; Merlin Assay) has recently been introduced to identify patients that may safely forgo SLNB. Herein we present data from an independent validation cohort of the CP-GEP model in Swedish patients. METHODS: Archival histological material (primary melanoma tissue) from a prospectively collected cohort of 421 consecutive patients with pT1-T4 melanoma undergoing SLNB between 2006 and 2014 was analyzed using the CP-GEP model. CP-GEP combines Breslow thickness and patient age with the expression levels of eight genes from the primary melanoma. Stratification is based on their risk for nodal metastasis: CP-GEP Low Risk or CP-GEP High Risk. RESULTS: The SLNB positivity rate was 13%. Of 421 primary melanomas, the CP-GEP model identified 86 patients as having a low risk for nodal metastasis. In patients with pT1-2 melanomas, the SLNB reduction rate was 35.4% (95% CI: 29.4-41.8) with a negative predictive value (NPV) of 96.5% (95% CI: 90.0-99.3). Among patients with pT1-3 melanomas, CP-GEP suggested a SLNB reduction rate of 24.0% (95% CI: 19.7-28.8) and a NPV of 96.5% (95% CI: 90.1-99.3). Only one of 118 pT3 tumors was classified as CP-GEP Low Risk, and all pT4 tumors were classified as being high risk for nodal metastasis. CONCLUSION: This study demonstrates that CP-GEP can identify patients with a low risk for nodal metastasis. Patients with pT1-2 melanomas have the highest clinical benefit from using the test, where 35% of the patients could forgo a SLNB procedure.
Authors: Evalyn E A P Mulder; Iva Johansson; Dirk J Grünhagen; Dennie Tempel; Barbara Rentroia-Pacheco; Jvalini T Dwarkasing; Daniëlle Verver; Antien L Mooyaart; Astrid A M van der Veldt; Marlies Wakkee; Tamar E C Nijsten; Cornelis Verhoef; Jan Mattsson; Lars Ny; Loes M Hollestein; Roger Olofsson Bagge Journal: Cancers (Basel) Date: 2022-06-09 Impact factor: 6.575