Selective sentinel lymphadenectomy for malignant melanoma, Merkel cell carcinoma, and squamous cell carcinoma

Merkel Cell Carcinoma of the Head and Neck

Merkel cell carcinoma (MCC) of the head and neck is a rare and aggressive non-melanoma skin cancer. The objective of this study was to assess the oncological outcome of MCC by retrospective review of electronic and paper records of a population-based cohort of 17 consecutive cases of the head and neck MCC without distant metastasis, diagnosed in Manitoba between 2004 and 2016. The average age of the patients at initial presentation was 74.1 ± 14.4 years with 6 patients presenting with stage I, 4 with stage II, and 7 with stage III disease. Both surgery or radiotherapy alone were the primary treatment modalities in 4 patients each and the remaining 9 patients had a combination of surgery with adjuvant radiotherapy. During the median follow-up of 52 months, 8 patients had recurrent/residual disease and 7 eventually died of it (P = .001). Metastatic spread of disease to the regional lymph nodes was observed in 11 patients either at presentation or during the follow-up and to the distant sites in 3 patients. At the time of the last contact on November 30, 2020, 4 patients were alive and disease-free, 7 had died of disease, and 6 had died of other causes. The case fatality rate was 41.2%. Five-year disease-free and disease-specific survivals were 51.8% and 59.7%, respectively. The 5-year disease-specific survival was 75% for early stage MCC (stage I and II) and 35.7% for stage III MCC. Early diagnosis and intervention are crucial for disease control and improving survival.

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 carcinoma

Merkel cell carcinoma (MCC) is a rare, clinically aggressive cutaneous neuroendocrine neoplasm with a high mortality rate. Though the etiology is not precisely known, Merkel cell polyomavirus DNA has been found recently in a large percentage of MCC tumors. Other suggested risk factors include sun exposure, immunosuppression, and a history of prior malignancy. Work up of patients with MCC most notably includes nodal staging via clinical examination or sentinel lymph node biopsy. The prognosis for most patients with MCC is poor, and the rarity of MCC precludes the prospective, randomized clinical trials necessary to elucidate optimum treatment protocols. Most published data support the use of a multimodality approach centered around surgical excision with negative margins, sentinel lymph node biopsy to establish the presence or absence of nodal metastases, adjuvant radiothearpy to decrease the risk of recurrence, and systemic chemotherapy in the case of widespread disease.

A practical update of surgical management of merkel cell carcinoma of the skin

The role of surgeons in the treatment of Merkel cell carcinoma (MCC) of the skin is reviewed, with respect to diagnosis and treatment. Most of the data in the literature are case reports. Surgery is the mainstay of treatment. A wide local excision, with sentinel node (SLN) biopsy, is the recommended treatment of choice. If SLN is involved, nodal dissection should be performed; unless patient is unfit, then regional radiotherapy can be given. Surgeons should always refer patients for assessment of the need for adjuvant treatments. Adjuvant radiotherapy is well tolerated and effective to minimize recurrence. Adjuvant chemotherapy may be considered for selected node-positive patients, as per National Comprehensive Cancer Network guideline. Data are insufficient to assess whether adjuvant chemotherapy improves survival. Recurrent disease should be treated by complete surgical resection if possible, followed by radiotherapy and possibly chemotherapy. Generally results of multimodality treatment for recurrent disease are better than lesser treatments. Future research should focus on newer chemotherapy and molecular targeted agents in the adjuvant setting and for gross disease.

Role of sentinel lymph node biopsy in the management of merkel cell carcinoma

Merkel cell carcinoma (MCC) is a rare and typically aggressive form of skin cancer. It most commonly affects the elderly and has a predilection for the sun-exposed skin of the head and neck region. Other etiological factors include immune suppression, organ transplantation, and polyoma virus infection. MCC has a propensity to spread to regional lymphatics with a high locoregional recurrence rate. Since its discovery in 1972, treatment paradigms have shifted, with no consensus on optimal management strategies. Currently, standard of care includes surgical intervention to the primary and locoregional site with adjuvant radiotherapy for high-risk disease. In this paper, we discuss the history, pathology, and epidemiology of this rare disease with a focus on the evidentiary basis of treatment protocols. The use of sentinel lymph node biopsy as a management option will be the focus of this paper.

A comprehensive review of the treatment of Merkel cell carcinoma

Merkel cell carcinoma (MCC) is an uncommon but malignant cutaneous neuroendocrine carcinoma with a high incidence of local recurrence, regional lymph node metastases, and subsequent distant metastases. The etiology of MCC remains unknown. It usually occurs in sun-exposed areas in elderly people, many of whom have a history of other synchronous or metachronous sun-associated skin lesions. The outcome for most patients with MCC is generally poor. Surgery is the mainstay of treatment. The role of adjuvant therapy has been debated. However, data from recent development support a multimodality approach, including surgical excision of primary tumor with adequate margins and sentinel lymph node dissection followed by postoperative radiotherapy in most cases, as current choice of practice with better locoregional control and disease-free survival. Patients with regional nodal involvement or advanced disease should undergo nodal dissection followed by adjuvant radiotherapy and, perhaps, systemic platinum-based chemotherapy in most cases.

Sentinel node staging of primary melanoma by the “10% rule”: pathology and clinical outcomes

BACKGROUND

Surgical staging of clinically node-negative primary melanoma involves identification and removal of "sentinel" lymph nodes (SLNs). Although some suggest removal of only the "hottest" SLN, the "10% rule" dictates that nodes are removed until the background count is 10% or less of the count of the "hottest" node.

METHODS

To determine the utility of the 10% rule, a university database of clinically node-negative melanomas surgically staged by using this rule was examined.

RESULTS

Twenty-two of 177 cases (12.5%; 15% of T2 and T3 lesions) were SLN positive. Among the SLN-positive cases, use of the rule resulted in removal of 21 additional nodes, 7 of which contained tumor. In 3 cases (14%), the positive SLN was not the "hottest" node. At 49 months of mean follow-up time, overall survival was 63% for SLN-positive patients versus 92% for SLN-negative patients (P = .01).

CONCLUSIONS

Sentinel node staging of melanoma by the 10% rule provides significant prognostic information and a modest increase in tumor detection compared with removal of only the "hottest" node.

Evidence-based principles and practices in pathology: selected problem areas

Contrary to the intuitive impression of most pathologists, there are still many areas in laboratory medicine where evidence-based medicine (EBM) principles are not applied. These include aspects of both anatomic and clinical pathology. Some non-EBM practices are perpetuated by clinical "consumers" of laboratory services, because of inadequate education, habit, or over-reliance on empirical factors. Other faulty procedures are pathologist-driven, with similar underpinnings. This overview considers several exemplary problem areas representing non-EBM practices in the hospital laboratory. Such examples include ideas and techniques centering on metastatic malignancies, "targeted" oncological therapy, analysis of surgical margins in the excision of neoplasms, general laboratory testing and data utilization, evaluation of selected coagulation defects, administration of blood products, and analysis of hepatic iron-overload syndromes. The concepts illustrating departures from EBM are discussed for each of those topics.