Merkel cell carcinoma of the head and neck: emphasizing the risk of undertreatment

Interdisciplinary management of skin cancer

The interdisciplinary treatment of skin cancer in the head and neck area requires close collaboration between different specialist disciplines. The most common non-melanoma skin cancer tumor entities are cutaneous squamous cell carcinoma and basal cell carcinoma as well as their precursor lesions. One of the less common tumors is Merkel cell carcinoma, which also occurs primarily in light-exposed areas and, in contrast to squamous and basal cell carcinoma, is more likely to metastasize. Due to the low tendency of basal cell carcinoma as well as cutaneous squamous cell carcinoma to metastasize, a cure can often be achieved by surgery. If the tumor growth exceeds certain levels it may require collaboration between dermatology and otorhinolaryngology. The primary goal of this interdisciplinary collaboration is to achieve a functional, cosmetically and aesthetically acceptable result in addition to adequate tumor treatment. Depending on the stage of the tumor and the clinical course, a case may be discussed in an interdisciplinary tumor board in order to determine a personalised, appropriate and adequate treatment concept for each patient, including prevention, therapy and follow-up.

S2k Guideline - Merkel cell carcinoma (MCC, neuroendocrine carcinoma of the skin) - Update 2022

Merkel cell carcinoma (MCC, ICD-O M8247/3) is a rare, malignant, primary skin tumor with epithelial and neuroendocrine differentiation. The tumor cells share many morphologic, immunohistochemical, and ultrastructural features with cutaneous Merkel cells. Nevertheless, the cell of origin of MCC is unclear. MCC appears clinically as a reddish to purple spherical tumor with a smooth, shiny surface and a soft to turgid, elastic consistency, usually showing rapid growth. Spontaneous and often complete regressions of the tumor are observed. These likely immunologically-mediated regressions explain the cases in which only lymph node or distant metastases are found at the time of initial diagnosis and why the tumor responds very well to immunomodulatory therapies even at advanced stages. Due to its aggressiveness, the usually given indication for sentinel lymph node biopsy, the indication of adjuvant therapies to be evaluated, as well as the complexity of the necessary diagnostics, clinical management should already be determined by an interdisciplinary tumor board at the time of initial diagnosis.

Mohs Micrographic Surgery Versus Wide Local Excision in the Treatment of Merkel Cell Carcinoma: A Systematic Review

BACKGROUND

Merkel cell carcinoma (MCC) is an aggressive neoplasm with high rates of recurrences. Current guidelines recommend wide local excision (WLE) with 1 to 2 cm margins. However, Mohs micrographic surgery (MMS) offers a potential advantage over WLE because of its ability of sparing healthy tissue and assessing 100% of margins.

OBJECTIVE

To systematically evaluate the surgical modalities for the treatment of MCC.

MATERIALS AND METHODS

Eligible articles were identified using MEDLINE, Scopus, EMBASE, and Cochrane Library. All available studies investigating surgical treatment of MCC with WLE or MMS were considered.

RESULTS

Forty studies met the inclusion criteria. Thirty-one studies described patients treated with WLE, 3 with MMS, and 6 with either WLE or MMS. Subgroup analysis of Stage I MCC showed recurrence rates similar in both surgical modalities with local recurrence rate of 6.8% for WLE versus 8.5% for MMS (p = .64) and a regional recurrence rate of 15.2% for WLE versus 15.3% for MMS (p = .99).

CONCLUSION

Overall WLE cases were at a higher stage at presentation. Subgroup analysis showed that MMS is not inferior to WLE excision for the treatment of Stage I MCC and is a reasonable option for anatomic locations where tissue sparing is important.

Recurrence and mortality rates with different treatment approaches of Merkel cell carcinoma: a systematic review and meta-analysis

BACKGROUND

Comprehensive treatment recommendations for Merkel cell carcinoma are complex. We aimed to systematically review the published data on recurrence and mortality rates associated with various treatment approaches for Merkel cell carcinoma.

METHODS

Search of MEDLINE, Embase, Web of Science, and Scopus from inception to August 2015. Studies were included that reported comparative survival and recurrence data for two or more treatment modalities. Two reviewers independently reviewed and abstracted recurrence and mortality rates. Event rates for individual treatment arms in each study were pooled and meta-analyzed across studies using a random-effects model.

RESULTS

Fifty-two retrospective studies met inclusion criteria, revealing a total of 1,804 patients with primary Merkel cell carcinoma with data available for analyses. The recurrence rate was higher for surgery alone (55.0%) versus a combination of surgery and radiotherapy (39.0%) (odds ratio, 2.089; 95% CI, 1.374-3.177; P < 0.001). Combination therapy including surgery, radiotherapy, and chemotherapy had a higher mortality rate (44.6%) than did combined surgery and radiotherapy (23.2%) (odds ratio, 2.688; 95% CI, 1.196-6.037; P = 0.02).

CONCLUSIONS

The treatment of Merkel cell carcinoma with surgery plus adjuvant radiotherapy may produce lower recurrence rates.

Surgical Management of Merkel Cell Carcinoma

The incidence of Merkel cell carcinoma (MCC) continues to increase. Understanding of MCC biology has advanced rapidly, with current staging providing valuable prognostic information. MCC treatment often is multidisciplinary. Surgery remains an important component in the staging and treatment, most commonly involving wide excision of the cancer and sentinel lymph node biopsy. Lymphadenectomy is used to treat nodal disease. Radiotherapy enhances locoregional control and possibly survival. Systemic therapies, in particular novel immunotherapies, may be promising in the treatment of advanced or recurrent and metastatic disease.

Frequency and prognosis of metastasis to liver, lung, bone and brain from Merkel cell carcinoma

Aim: To describe the factors affecting distant metastasis of Merkel cell carcinoma (MCC) and the prognosis of metastatic MCC. Materials & methods: The MCC patient information was downloaded from the SEER database. Logistic regression and Cox proportional hazard models were conducted to screen for significant factors. Results: A total of 3449 patients were enrolled. Surgery and chemotherapy were significantly correlated with the occurrence of distant metastasis. In the cause-specific survival rate of MCC, regional lymph node removal, sentinel lymph node biopsy, radiation and chemotherapy can significantly reduce the prognostic risk of patients with distant metastases. Conclusion: Our study screened out the factors affecting the distant metastasis and prognosis of MCC and more prospective studies are needed to verify our findings.

Merkel Cell Carcinoma: A 28-Year Experience

OBJECTIVE

To evaluate the management and recurrence outcomes of head and neck Merkel cell carcinoma (HN-MCC) at a single institution.

STUDY DESIGN

A retrospective review of outcomes in patients with HN-MCC.

SETTING

A tertiary center from May 1990 to December 2018.

SUBJECTS AND METHODS

Electronic medical records of patients with HN-MCC were reviewed.

RESULTS

Sixty cases were included, with 67% (40 of 60) males and a mean age of 73.3 years. Imaging had a moderate sensitivity and specificity for detection of occult disease when compared with histopathologic analysis. Forty-two percent (25 of 60) of patients underwent neck dissection, and 12% (7 of 60) had a sentinel lymph node biopsy (SLNB). There was a high rate of negative SLNB findings. The majority of patients were treated with surgery alone (29 of 60), followed by a cohort (21 of 60) treated with surgery plus adjuvant treatment, and 10 of 60 patients were treated with radiation therapy with or without chemotherapy. Recurrence-free survival was 50%, 45%, and 42% at 1, 2, and 5 years.

CONCLUSIONS

We report higher recurrence rates and higher negative SLNB result rates than other studies. Our results affirm that imaging may not be a substitute for SLNB and that it had an intermediate ability to identify the occult disease. Traditional predictors, including SLNB and cervical node pathology, may not identify patients at risk for recurrence in HN-MCC. We report similar recurrence rates in patients who had treatment of the cervical nodes by radiation therapy or neck dissection as compared with those who did not receive neck treatment.

S2k guidelines for Merkel cell carcinoma (MCC, neuroendocrine carcinoma of the skin) - update 2018

Merkel cell carcinoma (MCC, ICD-O M8247 / 3) is a rare malignant primary skin tumor with epithelial and neuroendocrine differentiation. The neoplastic cells share many morphological, immunohistochemical and ultrastructural characteristics with Merkel cells of the skin. The diagnosis of MCC is rarely made on clinical grounds. Histological and immunohistochemical studies are usually required to confirm the clinical suspicion. Given the frequent occurrence of occult lymph node metastasis, sentinel lymph node biopsy should be performed once distant metastasis has been ruled out by cross-sectional imaging. Primary tumors without evidence of organ metastases are treated with complete surgical excision with appropriate surgical margins. Radiation therapy should be considered at all stages of the disease. For advanced MCC that is no longer amenable to curative treatment by surgery or radiation therapy, there is currently no established systemic therapy for which an improvement in recurrence-free survival or overall survival has been demonstrated in a prospective randomized trial. However, immunotherapy using PD-1/PD-L1 blockade seems to be superior to chemotherapy. Various factors warrant that further diagnostic and therapeutic interventions be determined by an interdisciplinary tumor board. These factors include the tumor's aggressiveness, the frequent indication for sentinel lymph node biopsy along with the frequent occurrence in the head and neck region, the potential indication for adjuvant radiation therapy as well as the complexity of the required diagnostic workup.

Systematic review of sentinel lymph node biopsy in Merkel cell carcinoma of the head and neck

BACKGROUND

Merkel cell carcinoma (MCC) is a rare and aggressive cutaneous neuroendocrine tumor arising on the head and neck in 40%-50% of patients. Between 20% and 40% will harbor subclinical nodal metastasis.

METHODS

Using search terms 'Merkel AND sentinel', MEDLINE, PUMED, and EMBASE databases were systematically reviewed for publications regarding sentinel lymph node biopsy (SLNB) in classification I and II MCC of the head and neck.

RESULTS

Twenty-nine publications encompassing 136 patients were included. The SLNB finding was positive in 42 patients (30.9%). Primary MCC was located on the malar/zygomatic (34.4%), forehead/frontal (13.5%), and nasal (13.5%) regions. Recurrence in an SLNB negative nodal basin result occurred in 10 patients (false negative rate of 19.2%). Site of primary MCC was not associated with a false-negative SLNB result; however, there was a non-statistically significant trend for increased frequency among midline lesions.

CONCLUSIONS

Sentinel lymph node biopsy (SLNB) is recommended for eligible patients with classification I and II head and neck MCC.