Routine sentinel lymph node biopsy (SLNB) may help predict prognosis in patients with extramammary Paget disease (EMPD) of the genital area without clinical lymph node enlargement, according to study results published in the Journal of Dermatology.
Researchers sought to determine whether clinical characteristics and biomarkers before primary tumor resection could predict the invasion level of primary tumors and sentinel lymph node (SLN) metastasis in patients with EMPD. They retrospectively reviewed the data of patients who had primary tumor resection and SLNB for EMPD in the genital region from August 2002 to December 2024 at a single center.
Invasion level of the primary site was classified as intraepidermal (IE), microinvasion into the papillary dermis (MI), or deep invasion into or beyond the reticular dermis (DI). Multiple logistic regression was used to assess associations of clinical factors with DI of the primary lesion and SLN metastasis. Kaplan-Meier method and log-rank testing were used to evaluate overall survival (OS).
The cohort included 121 patients who were a median age of 71 years and 57.9% were men. Of the 121 total patients, 50 (41.3%) patients had IE lesions, 34 (28.1%) had MI, and 37 (30.6%) had DI.
Among the total patients, 20.7% had SLN metastasis, with the positivity rate of SLN metastasis increasing significantly with deeper tumor invasion of the primary lesion (P <.001). The proportion of patients with positive SLN metastasis was 0% in the IE group, 5.9% in the MI group, and 62.2% in the DI group (P <.001).
The most sensitive and specific cutoff for neutrophil-to-lymphocyte ratio (NLR) to predict DI of the primary lesion was 3.03 with the receiver operating characteristic curve. Nodules (odds ratio [OR], 6.820; P =.001) and a NLR of 3.03 or greater (OR, 4.260; P =.009) were independent predictive factors for DI of the primary lesion in the multivariate analysis. A total of 83 patients had a NLR of less than 3.03 and no nodules, of whom 70 (84.3%) had IE lesions or MI. In addition, 38 patients had either a NLR of 3.03 or greater or a nodule at the primary site, of whom 23 (60.5%) had DI.
Nodules (OR, 8.460; P <.001) and a NLR of 2.87 or greater (OR, 3.870; P =.016) were independent predictive factors for SLN metastasis in the multivariate analysis.
No difference in OS was found between the IE and MI groups, with a median OS not reached in either group. However, the DI group had a significantly worse prognosis compared with the other 2 groups (73.0 months; P <.001). The SLN-positive group had significantly worse OS compared with the SLN-negative group, with a median OS of 27.6 months vs no median OS reached, respectfully (P <.001). In a comparison of OS by SLN metastasis in the MI and DI groups, it was significantly worse for the SLN-positive group than the SLN-negative group with a median OS of 27.6 months vs no median OS reached, respectfully (P <.001).
Limitations of the study include the retrospective cohort design from a single institution and the small sample size. Also, the NLR may be affected by diseases and conditions other than EMPD, which was not accounted for.
“[T]he likelihood of sentinel lymph node metastasis is extremely low in intraepidermal and microinvasive primary lesions. It may be reasonable to proactively recommend SLNB, particularly in cases with a confirmed deep invasion lesion, the presence of nodules, or elevated NLR,” the researchers stated.
References:
Horisaki K, Yoshikawa S, Omata W, Tsutsumida A, Kiyohara Y. Predictors of dermal invasion and sentinel lymph node metastasis in patients with extramammary Paget’s disease without clinical lymph node enlargement. J Dermatol. Published online May 23, 2025. doi:10.1111/1346-8138.17795