Postoperative radiotherapy in stage I-III Merkel cell carcinoma.

BACKGROUND: Postoperative radiotherapy (PORT) is currently recommended for the treatment of Merkel cell carcinoma. Nevertheless, deviations occur frequently due to the generally elderly and frail patient population. We aimed to evaluate the influence of PORT on survival in stage I-III MCC patients treated in the Netherlands. METHODS: Patients were included retrospectively between 2013 and 2018. Fine-Gray method was used for cumulative incidence of recurrence and MCC-related death, cox regression was performed for overall mortality. Analyses were performed in patients with clinical (sentinel node biopsy [SN] not performed) stage I/II (c-I/II-MCC), pathologic (SN negative) stage I/II (p-I/II-MCC) and stage III MCC (III-MCC), separately. Propensity score matching (PSM) was performed to assess confounding by indication. RESULTS: In total 182 patients were included, 35 had p-I/II-MCC, 69 had c-I/II-MCC and 78 had III-MCC. Median follow up time was 53.5 (IQR 33.4-67.4), 30.5 (13.0-43.6) and 29.3 (19.3-51.0) months, respectively. Multivariable analysis showed PORT to be associated with less recurrences and reduced overall mortality, but not with MCC-related mortality. In stage III-MCC, extracapsular extension (sub-distribution hazard [SDH] 4.09, p = 0.012) and PORT (SDH 0.45, p = 0.044) were associated with recurrence, and ≥ 4 positive lymph nodes (SDH 3.24, p = 0.024) were associated with MCC-related mortality. CONCLUSIONS: PORT was associated with less recurrences and reduced overall mortality in patients with stage I-III MCC, but not with MCC-related mortality. Trends in overall survival benefit are likely to be caused by selection bias suggesting further refinement of criteria for PORT is warranted, for instance by taking life expectancy into account.

Merkel cell carcinoma: Clinical outcome and prognostic factors in 351 patients.

BACKGROUND: Merkel cell carcinoma (MCC) is a rare and aggressive neuroendocrine carcinoma of the skin. AIM: To describe clinical outcome and prognostic factors of MCC patients in two expert-centers. METHOD: Patients with histologically confirmed MCC in 1990-2014 were included. Data on patient, tumor characteristics and treatment were retrospectively collected. RESULTS: A total of 351 Patients were evaluated, 153 (44%) males, median age 74 years (range 28-94). Median follow-up time was 28 months (IQR 13-58). Median primary tumor size was 17 mm (range 2-135). At time of diagnosis 112 (32%) patients had lymph node metastases. The cohorts' 5-year overall survival (OS) was 58%. Using a competing risk analysis the 5-year relapse and MCC related death was 42% and 22%. Adjuvant radiation therapy (XRT) was associated with reduced recurrence (SDH 0.54; CI 0.3-0.9). Nodal involvement (SDH 2.7; CI 1.1-6.6) and the male gender were associated with higher MCC related death (SDH 3.1; CI 1.2-7.9) CONCLUSION: In a large cohort a low MCC related death, in the presence of a low OS was seen. This indicates that a significant number of MCC patients die due to other causes than MCC. Adjuvant XRT was associated with relapse. Male gender and nodal metastasis were associated with MCC related death.

Pigmentation in the sentinel node correlates with increased sentinel node tumor burden in melanoma patients.

The prognosis of sentinel node (SN)-positive melanoma patients is predicted by a number of characteristics such as size and site of the metastases in the SN. The pathway and prognosis of strong pigmentation of melanoma metastases in the SN is unclear. The aim of this study is to evaluate the role of pigmentation and growth pattern of metastases in the SN with respect to survival. A total of 389 patients underwent an SN procedure (1997-2011). Ninety-five patients had a positive SN and material from 75 patients was available for review. The median follow-up time was 75 months (range 6-164). Pigmentation was scored from 0 to 2 using the following scale: 0=absent, 1=slight, and 2=strong. Growth pattern was scored as either eccentric (1) or infiltrative (2). SN tumor burden was measured according to the Rotterdam criteria. The primary melanoma had a median Breslow thickness of 2.90 mm (0.8-12.00 mm). Ulceration was present in 34 patients (45.3%). There was a median SN tumor burden of 0.5 mm (0.05-7.00 mm). In a total of 75 patients, 59 patients (79%) had no pigmentation, 13 patients (17%) had slight pigmentation, and three patients (4%) had strong pigmentation in the SN. Because of the small numbers, the classification was modified to either absent 59 (79%) or present 16 (21%) pigmentation, respectively. The SN tumor burden was significantly higher (P=0.031) for patients with pigmentation. Patients with pigmentation had a 5-year melanoma-specific survival (MSS) of 47% and a 10-year MSS of 33%. Patients without pigmentation had a 5-year MSS of 70% and a 10-year MSS of 59% (P=0.06). There was no difference in MSS for patients with an eccentric or an infiltrative growth pattern, nor did it correlate with other prognostic factors. Multivariate analysis for MSS showed five significant factors associated with worse prognosis: male sex (P=0.036), nodular melanoma (P=0.001), truncal site (P=0.0001), SN tumor burden more than 1.0 mm (P=0.022), and positive completion lymph node dissection (P=0.004). The 5-year MSS for SN tumor burden is 94% for 0.1 mm or less, 66% for 0.1-1.0 mm, and 41% for more than >1.0 mm (P<0.001). The 10-year MSS for SN tumor burden is, respectively, 94, 51, and 35% (P<0.001). This preliminary exploratory retrospective study showed that pigmentation within the SN seems to correlate with increased SN tumor burden.