Merkel Cell Carcinoma Guidelines

Primary Treatment Selection for Clinically Node-Negative Merkel Cell Carcinoma of the Head and Neck

OBJECTIVE

Merkel cell carcinoma practice guidelines recommend sentinel lymph node biopsy after wide local excision for the initial management of clinically node-negative disease without distant metastases (cN0M0). Despite guideline publication, treatment selection remains variable. We hypothesized that receipt of guideline-recommended care would be more common in patients evaluated at academic centers and institutions with high melanoma case volumes and that such therapy would be associated with improved overall survival.

STUDY DESIGN

Retrospective cohort analysis.

SETTING

The National Cancer Database from 2004 to 2015.

METHODS

A total of 3500 patients were included. We utilized Kaplan-Meier analysis and logistic and Cox proportional hazard regressions. Survival analysis was performed on inverse probability-weighted cohorts.

RESULTS

There has been a trend toward evaluation at academic programs at a rate of 1.58% of patients per year (95% CI, 1.06%-2.11%) since 2004. However, the percentage of patients receiving guideline-compliant primary tumor excision and lymph node evaluation has plateaued at approximately 50% since 2012. Guideline-compliant surgical management was more commonly provided to patients evaluated at academic programs than nonacademic programs but only when those institutions had a high melanoma case volume (odds ratio, 2.01; 95% CI, 1.62-2.48). Receipt of guideline-compliant primary tumor excision and lymph node evaluation was associated with improved overall survival (hazard ratio, 0.70; 95% CI, 0.64-0.76).

CONCLUSION

Facility factors affect rates of receipt of guideline-compliant initial surgical management for patients with node-negative Merkel cell carcinoma. Given the survival benefit of such treatment, patients may benefit from care at hospitals with high melanoma case volumes.

Focus on Merkel cell carcinoma: diagnosis and staging

Merkel cell carcinoma is a rare lymphophilic skin tumor of neuroendocrine origin with the potential for rapid progression. Small, localized lesions are diagnosed and treated clinically, but advanced tumors often undergo imaging evaluation. Due to its rarity, radiologists are unaware of evocative imaging features and usually do not consider Merkel cell carcinoma in the differential diagnosis of soft tissue tumors. Appropriate staging is important to determine appropriate treatment and has an impact on patient prognosis. Multimodality imaging is usually needed, and there is no consensus on the optimal imaging strategy. The purpose of this article is to review various aspects of Merkel cell carcinoma imaging and look in detail at how optimal multimodality staging should be carried out.

Merkel cell polyomavirus in merkel cell carcinoma: clinical and therapeutic perspectives

Merkel cell carcinoma (MCC) is a rare and often aggressive cutaneous cancer with a poor prognosis. The incidence of this cancer increases with age, immunodeficiency and sun exposure. Merkel cell polyomavirus (MCPyV), a new human polyomavirus identified in 2008, is detected in the majority of the MCCs and there is a growing body of evidence that healthy human skin harbors resident or transient MCPyV. A causal link between MCPyV and MCC has been evidenced and this is the first polyomavirus to be clearly implicated as a causal agent underlying a human cancer, and MCPyV was recently classified as a 2A carcinogen. MCC is thus a rare tumor caused by a very common viral skin infection. The aim of this review is to provide a basic overview of the epidemiological, clinical, and pathological characteristics of MCC, to present the current knowledge on MCPyV polyomavirus and its causal association with MCC development, and to describe the therapeutic implications of this causal link.

Prognostic significance of sentinel lymph node mapping in Merkel cell carcinoma: systematic review and meta-analysis of prognostic studies

Aim. To assess through a systematic review and meta-analysis of the literature the prognostic implication of sentinel lymph node mapping in Merkel cell carcinoma (MCC). Materials and Methods. PubMed and SCOPUS databases were searched by using “Merkel AND sentinel” as keywords. All studies with prognostic information regarding SLN mapping in cN0 MCC patients were included. Hazard ratio (HR) for overall survival (OS) and disease free survival (DFS) was used as effect size. Results. SLN biopsy predicted better DFS and OS as compared to the nodal observation in cN0 MCC patients (pooled HR for DFS: 1.61 (95% CI: 1.05–2.46), P = 0.028; pooled HR for OS: 1.08 (95% CI: 0.55–2.10), P = 0.8). Pathologically negative SLN (SLN−) patients had better OS (pooled HR: 4.42 (95% CI: 1.82–10.7), P = 0.0009) and DFS (pooled HR: 2.58 (95% CI: 1.78–3.73)) as compared to SLN+ patients. Conclusion. SLN mapping can provide strong prognostic information regarding OS and DFS in cN0 MCC patients. More importantly, SLN mapping can improve DFS and possibly OS in cN0 MCC patients as compared to nodal observation. As MCC is a rare tumor, large multicenter prospective studies are still needed to validate the survival benefit of SLN mapping.

Benefits of combined modality treatment of Merkel cell carcinoma of the head and neck: single institution experience

BACKGROUND

There is ongoing debate surrounding the roles of surgery and adjuvant radiotherapy in the management of primary and recurrent Merkel cell carcinoma of the head and neck. This study assessed the influence of local excision, margin status, adjuvant radiotherapy and chemotherapy on locoregional recurrence and survival.

METHOD

A retrospective review of 54 consecutive cases of head and neck Merkel cell carcinoma at a single institution.

RESULTS

Median disease-specific survival time was 120 months. Forty-four per cent of patients developed locoregional recurrence. Combined treatment with surgery and locoregional radiotherapy improved diseasespecific survival. Radiotherapy was associated with longer time to recurrence and regional recurrence. Irradiation of the regional nodes improved regional control, irrespective of clinical status. Margin-negative excision was not associated with improved local control. Combined modality treatment of recurrent disease resulted in a four-fold improvement of local control, but small numbers prevented this trend from reaching statistical significance.

CONCLUSION

Surgical excision of the primary disease and clinically involved regional nodes, plus adjuvant radiotherapy to the surgical bed and regional nodes are recommended for all patients with Merkel cell carcinoma of the head and neck, irrespective of clinical status. Recurrent disease should be aggressively treated with combined modality treatment.

Merkel cell carcinoma: review

Merkel cell carcinoma (MCC) is synonymous with primary cutaneous neuroendocrine carcinoma. It tends to affects elderly whites, but there is also an increased incidence among immunosuppressed patients. The recent identification of a novel polyomavirus associated with the tumor has stimulated renewed interest in its pathogenesis. MCC tends to show classic histologic features of a neuroendocrine carcinoma and is often positive for CK20, but nonclassic cytologic findings and unusual immunophenotypes may be observed and can lead to a diagnostic confusion. MCC needs to be distinguished from other primary cutaneous tumors with a small cell appearance and metastatic tumors. Surgical excision is the treatment of choice, but radiation therapy has also found to be effective. Sentinel lymph node biopsy has become an integral part of the staging of patients with MCC.

Analysis of Radiation Therapy for the Control of Merkel Cell Carcinoma of the Head and Neck Based on 36 Cases and a Literature Review

Merkel cell carcinoma (MCC) is a rare and aggressive epidermal cancer. We conducted a retrospective study and literature review to investigate the impact that radiation therapy has on local, regional, and distant control as part of the oncologic management of MCC of the head and neck and to further elucidate the role of radiation therapy with regard to regional control for the clinically uninvolved neck. We reviewed all registered cases of head and neck MCC that had occurred at four institutions from January 1988 through December 2005. Treatment and outcomes data were collected on patients with American Joint Committee on Cancer stage I, II, and III tumors. Local, regional, and distant control rates were calculated by comparing variables with the Fisher exact test; Kaplan-Meier analysis was used to report actuarial control data. Stage I to III head and neck MCC was identified in 36 patients— 22 men and 14 women, aged 43 to 97 years (mean: 71.6) at diagnosis. Patients with stage I and II tumors were combined into one group, and their data were compared with those of patients with stage III tumors. Twenty-sixpatients(72%) had clinical stage I/II disease and 10 patients (28%) had clinical stage III disease. Median follow-up was 41 months for the stage I/II group and 19 months for the stage III group. Based on examination at final follow-up visits, local recurrence was seen in 7 of the 36 patients (19%), for a local control rate of 81 %. The 2-year actuarial local control rate for all stages of MCC was 83%; by treatment subgroup, the rates were 95% for those who had undergone radiation therapy to the primary site and 69%) for those who had not— a statistically significant difference(p = 0.020). Based on information obtained at final follow-ups, 10 of the 36 patients (28%) experienced a regional recurrence, for a regional control rate of 72%. The 2-year actuarial regional control rate among all patients was 70%; by subgroup, rates were 82%) for patients who had undergone regional node radiation therapy and 60% for those who had not— not a statistically significant difference (p = 0.225). Nine patients (25%) overall developed a distant metastasis, for a distant control rate of 75%. Salvage therapies included chemotherapy and/or radiation therapy to the metastatic site, but neither had any significant effect on survival. Regardless of treatment, the Kaplan-Meier survival curves leveled off at 30 months with 82% survival for the stage I/II group and at 19 months with 60% survival for the stage III group. We conclude that radiation therapy to the primary tumor site (either following resection or definitively) results in a local control rate of more than 90% in patients with head and neck MCC. We also found a trend toward improved regional control of the clinically negative neck with the addition of radiation therapy.

Merkel cell carcinoma: critical review with guidelines for multidisciplinary management

Merkel cell carcinoma (MCC) is a relatively rare cutaneous malignancy that occurs predominantly in the older white population. The incidence of MCC appears to have tripled during the past 20 years; an increase that is likely to continue because of the growing number of older Americans. The pathogenesis of MCC remains largely unknown. However, ultraviolet radiation and immunosuppression are likely to play a significant pathogenetic role. Many questions currently remain unanswered regarding the biologic behavior and optimal treatment of MCC. Large, prospective, randomized studies are not available and are unlikely to be performed because of the rarity of the disease. The objective of this review was to provide a comprehensive reference for MCC based on a critical evaluation of the current data. The authors investigated the importance of sentinel lymph node biopsy as a staging tool for MCC to assess the status of the regional lymph node basin and to determine the need for additional therapy to the lymph node basin. In an attempt to standardize prospective data collection with the intention to define prognostic indicators, the authors also present histopathologic profiles for primary MCC and sentinel lymph nodes. The controversies regarding the appropriate surgical approach to primary MCC, the use of adjuvant radiation therapy, and the effectiveness of adjuvant chemotherapy were examined critically. Finally, the authors have provided treatment guidelines based on the available evidence and their multidisciplinary experience.

An unusual case of Merkel cell carcinoma

PURPOSE

Merkel cell carcinoma (MCC) is a rare aggressive neuroendocrine tumor of the skin mainly found in elderly white patients. Due to its poor prognosis with distant metastases in up to 33% and local recurrence in 25-33% and a 5 year disease-specific survival of 64% (1-2) its early diagnosis and appropriate treatment is mandatory.

METHODS

The study is an exceptional clinical case of a patient with a large inoperable MCC unable to be treated according to treatment guidelines due to her old age. We review the literature addressing treatment options.

RESULTS

The patient was treated with palliative definitive radiotherapy to her large MCC of the left lower leg. She showed a rapid clinical response to four palliative radiation doses of 7 Gy each, necrosis of tumor mass and persistent clearing at a follow-up of 32 weeks. Our patient was very unusual in terms of her extensive MCC and her rapid and complete response to palliative radiotherapy lasting for 6 months at present.

CONCLUSIONS

As MCC is an aggressive tumor, best survival is achieved with early diagnosis in a localized stage and prompt adequate surgery and further stage-adjusted treatment. Thus, the differential diagnosis of MCC should not be dismissed in a reddish nodule on the leg, and every excision should be submitted to pathology. In accordance with the literature we demonstrate here that definitive radiotherapy is an effective treatment option for inoperable MCC, which in this individual patient produced necrosis of the extensive tumor mass after only four palliative doses.