J Plast Surg Hand Surg, 2013; 47: 139–143 © 2013 Informa Healthcare ISSN: 2000-656X print / 2000-6764 online DOI: 10.3109/2000656X.2012.736386 ORIGINAL ARTICLE Positive sentinel lymph node biopsy predicts local metastases during the course of disease in Merkel cell carcinoma Maria Kouzmina 1 , Junnu Leikola 2 , Tom Böhling 3 & Virve Koljonen 2 1 Department of Oral and Maxillofacial Surgery, 2 Department of Plastic Surgery, Helsinki University Central Hospital, Helsinki, Finland, 3 Department of Pathology, Helsinki University and HUSLAB, Helsinki, Finland Abstract The purpose was to investigate the predictive power of sentinel lymph node biopsy (SLNB) in Merkel cell carcinoma (MCC) patients, using clinical data collected during treatment. The aim was also to review the treatment protocols for MCC patients in Finland. These data were retrieved and compared after identification in the Finnish Cancer Registry from 1979–2009. Hospital files were reviewed for demographic and treatment- related data. Statistical analysis was performed for survival comparing sentinel lymph node positive and negative patients. Specific inclusion criteria yielded a cohort of 33 patient records, which accounted for 15% of the 225 diagnosed MCC patients during the study period. The male: female ratio was 1:1.5. On average, in the lymphoscintigraphy 2 ± 1.62 sentinel lymph nodes visualised and 2 ± 2.4 sentinel lymph nodes were removed in the operation. The mean primary tumour size in sentinel lymph node positive patients was 12.7 mm and in sentinel lymph node negative patients it was 19 mm. Nine patients had micrometastases in their removed sentinel lymph nodes. The patients with positive sentinel lymph node developed local metastases during the course of disease more often than sentinel lymph node negative patients (p < 0.003). However, there was no statistical difference in overall survival in sentinel lymph node negative and positive patients (p > 0.12). This study emphasises that SLNB appears to be a useful tool in determining the stage of MCC patients regardless of tumour size. A positive sentinel lymph node predicts the metastatic course of disease. Key Words: Merkel cell carcinoma, sentinel lymph node biopsy, survival, tumour size, mortality, metastases Introduction Merkel cell carcinoma (MCC) is a rare, potentially aggressive cutaneous neuroendocrine malignancy, affecting mainly the elderly. The disease progression is defined with a high incidence to early and frequent locoregional, distant metastasis, and relapses [1]. The vast majority of patients (70%) present with clinically localised disease to the skin (American Joint Com- mittee on Cancer stage I or II), 25% present with palpable regional lymphadenopathy (stage III), and 5% with distant metastasis (stage IV) [2–4]. Patients diagnosed with localised, regional, and distant MCC have a 5-year relative survival rate of 75%, 59%, and 25%, respectively [5]. Few patients diagnosed with distant metastases survive for 3 years or longer [2]. In the past, MCC was frequently defined as “lethal” with an extremely high tendency to metastasise. This maxim led to significantly over-treat early lesions and to extensive surgical attempts both in primary tumours as well as draining lymph basins. Numerous clinical, histological, and immunohistochem- ical factors have been studied for prognostic power to subgroup those patients most likely to have an untoward course of the disease and/or to target specific treatment modalities. Some prognostic factors have indeed been established. The Surveil- lance, Epidemiology, and End Results (SEER) series based on 3470 cases demonstrated that the stage of disease is an important prognostic factor in MCC [6]. The morphological features of the primary tumour seem to predict the survival. Large tumour size (‡2 cm in diameter) at the time of the diagnosis has been known to have a negative influence on survival and is mentioned most frequently in published reports as the factor with the greatest negative influence on survival. Smaller tumours (£1 cm in diameter) were unlikely to harbour regional lymph node metastases in a series of 346 MCC patients [7]. Nowadays there is wide agreement that the most important prognostic factor in MCC, for the survival and development of distant metastases, is the presence of lymph node involvement [2,8,9]. The most common location of metastasis in MCC is the draining lymph node basin in 27%–60% of the cases [2]. As it seems that the course of MCC follows the orderly progression of lymphatic metastatic spread and nodal involvement proceeds distant dissemination [10], it is concurred that sentinel lymph node biopsy (SLNB) is a valuable aid to select those patients with occult metastasis for staging and further treatments [11,12]. The positive sentinel lymph node bears a risk of recurrence or metastasis 19-times as great in sentinel lymph node positive patients as in sentinel lymph node negative MCC patients [12]. Allen et al. [2] found a significant 5-year disease-specific survival difference between patients clinically staged as node- negative and those pathologically node-negative by SLNB. Further supporting the role of SLNB, Gupta et al. [9] found the 3-year recurrence rate to be 3-times higher in patients with a positive SLNB compared with those with a negative sentinel node. Increasing clinical size, tumour thickness, mitotic rate, infiltrative tumour growth pattern [13], and the presence of Correspondence: Maria Kouzmina, DDS, Department of OMFS, Helsinki University Hospital, Kasarminkatu 11-13, POB 263, FI-00029 HUS, Helsinki, Finland. Tel: +358 443068743. Fax: +358 9 4718853. E-mail: maria.kouzmina@fimnet.fi (Accepted 29 May 2012) Journal of Plastic Surgery and Hand Surgery Downloaded from informahealthcare.com by EBSCO on 08/08/14 For personal use only.