Outcome of Patients with Microscopic and Macroscopic Metastatic Nodal Merkel Cell Carcinoma: An Australian Experience

Merkel cell carcinoma in Taiwan: A series of 24 cases and literature review

Merkel cell carcinoma (MCC) is a rare but aggressive neuroendocrine carcinoma of the skin. The available reports of MCC in Asia are limited; in this study, we report the largest series of MCC in Taiwan to date.The series is composed by 24 pathologically proven MCC cases, which were retrospectively reviewed in Chang Gung Memorial Hospital in Taiwan between 2000 and 2018.The tumor occurred predominantly in men (80%) and in the elderly (median 74.8 years). Twenty-one patients had locoregional MCC and 3 had metastatic MCC at the time of diagnosis. Patients with pathologically proven negative nodes by sentinel lymph node biopsy (SLNB) showed better survival time than those without SLNB in 16 clinically node-negative MCC cases undergoing primary surgery. Salvage surgery for loco-regional recurrence lengthened the survival time and possibly cured recurrent MCC. Palliative chemotherapy with cisplatin and etoposide showed a response rate of 25%, progression-free survival of 3.6 months, and overall survival of 14.8 months in 4 metastatic/recurrent MCC. Avelumab treatment was effective in 1 patient, who achieved a durable disease control.This observational cohort of MCC patients in Taiwan suggests aggressive surgical intervention including wide excision and lymph node management, salvage operation is critical for early MCC patients, and palliative chemotherapy and immunotherapy showed their efficacy for advanced MCC patients.

Frequency and locations of systemic metastases in Merkel cell carcinoma by imaging

Background

The primary neuroendocrine skin cancer, Merkel cell carcinoma (MCC), has a well-known predilection to metastasize systemically. However, the experience of systemic metastases in MCC is mainly disseminated through case reports due to the rarity of MCC.

Purpose

To elucidate the frequency and locations of systemic metastasis in MCC by reviewing the imaging of patients with metastatic MCC in a national cohort.

Material and Methods

Patients with diagnosed metastatic MCC by imaging studies in Finland during 1999–2012 were included in this study. We reviewed their imaging studies to evaluate the most frequent sites for systemic metastasis and determined the latency between the primary tumor diagnosis and systemic metastasis. The material includes 30 MCC patients with complete imaging series and 187 examinations, of which 102 (54%) were CT images.

Results

The mean latency from the primary tumor diagnosis to systemic metastasis was 2.1 years and the mean latency between the radiologic diagnosis of the metastases and death was 299 days. Metastases were recorded in several organ systems in most of the cases, and at least two separate metastatic sites in 63% of the cases. Metastatic spread was noted in 60% of the cases in distant lymph nodes. Liver and lungs were the most affected solid organs.

Conclusion

Systemic metastasis in MCC has no predilection site, basically every organ system can be involved. Most of the systemic metastases were recorded during the first two years after the MCC diagnosis.

Analysis of Prognostic Factors from 9387 Merkel Cell Carcinoma Cases Forms the Basis for the New 8th Edition AJCC Staging System

BACKGROUND

The first consensus Merkel cell carcinoma (MCC) staging system was published in 2010. New information on the clinical course prompts review of MCC staging.

METHODS

A total of 9387 MCC cases from the National Cancer Data Base Participant User File with follow-up and staging data (1998-2012) were analyzed. Prognostic differences based on clinical and pathological staging were evaluated. Survival estimates were compared by disease extent.

RESULTS

Sixty-five percent of cases presented with local disease, whereas 26 and 8 % presented with nodal and distant disease. Disease extent at presentation was predictive of 5-year overall survival (OS) with estimates of 51, 35, and 14 % for local, nodal, and distant disease. Tumor burden at the regional nodal basin was predictive of 5-year OS with estimates of 40 and 27 % for clinically occult and clinically detected nodal disease. For local disease, we confirm improved prognosis when the regional nodal basin was negative by pathological compared with clinical staging. We identified 336 cases with clinically detected nodal disease and unknown primary tumor and showed improved prognosis over cases presenting with concurrent primary tumor (OS estimates of 42 vs. 27 %).

CONCLUSIONS

Analysis of a national dataset of MCC cases validates the predictive value of disease extent at presentation. Separation of clinical and pathological stage groups and regrouping of unknown primary tumors are supported by the analysis. The revised staging system provides more accurate prognostication and has been formally accepted by the AJCC staging committee for inclusion in the 8th edition.

Lack of clinical impact of 18 F-fluorodeoxyglucose positron emission tomography with simultaneous computed tomography for stage I and II Merkel cell carcinoma with concurrent sentinel lymph node biopsy staging: A single institutional experience from Westmead Hospital, Sydney

BACKGROUND/OBJECTIVE

¹⁸ F-fluorodeoxyglucose (FDG) positron emission tomography with simultaneous computed tomography (PET-CT) FDG PET-CT plays an important clinical role in the staging and management of Merkel cell carcinoma (MCC) although its role in stage I and II disease relative to a sentinel lymph node biopsy (SLNB) is undefined. This study aimed to compare the clinical impact of FDG PET-CT and SLNB on management in stage I and II MCC.

METHODS

This was a retrospective observational study. Between 2000 and 2014, 65 patients with biopsy-proven MCC (all stages) underwent a staging FDG PET-CT as part of their investigations in Westmead Hospital, Sydney. Since 2006, 26 patients have had an SLNB and of these, 16 underwent both an SLNB and FDGPET-CT. All 16 patients had a histological diagnosis consistent with MCC without clinical evidence of regional or distant metastases prior to SLNB and FDG PET-CT (stages IB and IIB). These patients were assessed with respect to MCC staging and the subsequent change of patient management post-SLNB and FDG PET-CT.

RESULTS

The SLNB identified occult lymph node metastases in 10 patients (63%), with FDG PET-CT positive in only one patient (6%). Of the six SLNB-negative patients, none demonstrated additional metastases on the FDG PET-CT.

CONCLUSIONS

In patients with stage I and II MCC, FDG PET-CT is less sensitive than an SLNB in detecting occult metastatic lymph nodes. The routine use of FDG PET-CT in these patients may not be justified.