Chemosensitivity testing of primary cultures of Merkel cell cancer

High-throughput three-dimensional spheroid tumor model using a novel stamp-like tool

Spheroid culture is a widely used three-dimensional culture technology that simulates the three-dimensional structure of tumors in vivo and has been considered a good model for tumor research. However, current commercialized spheroid culture tools have the shortcomings of high cost or relatively poor spheroid-forming results for some special cells. To solve such problems, we designed a 3D printed, reusable, stamp-like resin mold that could shape microstructures for spheroid culture of tumor cells on the surface of agarose substrate in a 96-well plate. We applied this homemade three-dimensional culture tool in spheroid formation for hepatocellular carcinoma cells. The experimental data show that the effect of spheroid culture on four hepatocellular carcinoma cell lines in our homemade spheroid culture plate is better than that of the commercialized ultralow attachment spheroid culture plate, and compared to two-dimensional culture, three-dimensional culture improves cell functions. In addition, the drug-sensitive test based on patient-derived hepatocellular carcinoma cells showed a different pattern between spheroid and two-dimensional cultures. In conclusion, our spheroid culture tool is characterized by its low cost, reusability, low cell consumption, convenience in medium exchange, and good effect of spheroid formation, suggesting that this technique could be widely used in individual treatment and high-throughput drug screening.

Merkel Cell Carcinoma: Current Issues Regarding Diagnosis, Management, and Emerging Treatment Strategies

Merkel cell carcinoma (MCC) is a rare but aggressive cutaneous tumor with a predilection for the head and neck of elderly Caucasian patients. Although much less common than melanoma, MCC has higher rates of sentinel lymph node involvement, local and regional recurrences, and mortality. The majority of MCC cases have been linked to the relatively newly discovered Merkel cell polyomavirus, which is a ubiquitous constituent of the skin flora. Recent discoveries regarding viral integration and carcinogenesis and the immunologic features of MCC have expanded the understanding of MCC. These discoveries have led to the development and application of emerging therapies such as somatostatin analogs, immune checkpoint inhibition, adoptive cell therapy, and other exciting possibilities for targeted therapy.

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.

Merkel cell carcinoma of skin: diagnosis and management strategies

Merkel cell carcinoma (MCC) of the skin is a rare form of cutaneous malignancy of neuroendocrine origin with a propensity to affect predominately elderly patients in sun-exposed areas. The tumour has an extremely aggressive growth pattern with the potential to seed into the dermal lymphatics at an early stage as well as spread to nodes and distant sites. Successful outcomes can be achieved with early diagnosis and a multidisciplinary approach to management. Patients with MCC should be carefully staged to exclude distant metastatic disease. Treatment should be approached with both the primary site and the lymph nodes in mind. The primary site should be excised with clear margins, followed by postoperative radiotherapy to the primary site and affected nodes. Addition of chemotherapy to patients perceived to be at high-risk of distant recurrence (e.g. those with involved nodes) has been considered, but evidence supporting this approach is relatively scant. This treatment strategy needs to be approached with caution in the elderly because of the risk of myelosuppression. An aggressive treatment approach is warranted at the first attempt to treat MCC as treatment for recurrent disease is less likely to be successful.

Treatment of Merkel Cell Carcinoma

PURPOSE

The purpose of this study was to evaluate the treatment of Merkel cell carcinoma.

MATERIALS AND METHODS

We reviewed 85 cases of Merkel cell carcinoma. There were 68 males and 17 females. The majority of cases involved head and neck sites (48%), followed by the extremities (38%) and trunk (14%). Sixty-seven percent of the patients had stage I disease that was localized to the skin of origin at presentation. Twenty-five percent and 8% were stage II (nodal metastasis) and stage III (distant metastasis), respectively. Surgical intervention included local or wide local excision +/- nodal dissection (68%), radical resection +/- nodal dissection (22%), and amputation (4%). Five patients (6%) underwent biopsy only because of metastatic disease or unresectability at presentation. Fifty-one percent received adjuvant therapy consisting of external beam radiation therapy and/or combination chemotherapy.

RESULTS

With an average follow-up time of 39.5 months, 12% had persistent disease and 40% had recurrent disease. The median time to recurrence was 8 months with a mean of 10.6 months. Although the addition of adjuvant therapy did not affect survival, the recurrence rate was 32.5% for surgery +/- adjuvant radiation therapy +/- chemotherapy as compared with 52.7% for surgery-only patients. Although the 40.7% recurrence rate for patients receiving surgery and adjuvant radiation therapy was approximately the same as for patients receiving surgery and adjuvant chemotherapy (40%), the effect of systemic chemotherapy on recurrence is less clear as a result of the small number of patients who received such therapy. Although tumor size and site of presentation were not observed to be statistically significant in overall survival, significant differences were observed based on sex and tumor stage. For females, the median survival time was 96 months (mean, 94.5 months) compared with 63 months (mean, 76.8 months) for males. This difference was significant (P < 0.01). Patients presenting with low-stage (stage I) disease had a significant (P < 0.01) survival benefit when compared with high-stage individuals (stages II and III). The 5-year actuarial survival rates were 68% and 42%, respectively.

CONCLUSION

In this retrospective study, surgery remains the primary modality for Merkel cell carcinoma, and adjuvant radiation therapy +/- systemic chemotherapy reduces local recurrence. Female patients and those who present with early-stage disease appear to have a better prognosis.

Merkel cell carcinoma--current therapeutic options

Merkel cell carcinoma (MCC) is a rare, highly malignant skin tumour of neuroendocrine origin that occurs predominantly in elderly people in sun-exposed areas. It exhibits high levels of radiosensitivity and chemosensitivity both in vivo and in vitro. A variety of adverse prognostic factors have been identified which allow more aggressive therapy to be delivered to patients who are at higher risk of recurrence. The most powerful prognostic factor is the presence of nodal secondaries. Local disease should be excised, but there is some controversy over how wide the margins should be. Wide resection margins are not required provided postoperative radiotherapy is used. In the event of inoperable disease, patient refusal of surgery or frailty, radiotherapy can be used as the sole treatment modality, with a high likelihood of achieving local control. Patients with involved nodes have a higher risk of distant disease. Traditionally, involved nodes have been managed with resection but, currently, there are protocols exploring the use of synchronous chemoradiotherapy as definitive treatment. Although adjuvant chemotherapy has been used in this setting to reduce the risk of distant metastases, its role still remains under investigation. The presence of distant disease carries a grave outlook with responses to chemotherapy occurring frequently, albeit of short duration.

Merkel cell carcinoma: report of ten cases with emphasis on clinical course, treatment, and in vitro drug sensitivity

BACKGROUND

Merkel cell carcinoma (MCC) is an uncommon primary neuroendocrine skin tumor most often seen in the elderly. The clinical course varies. Treatment is controversial and few data on drug sensitivity are available.

OBJECTIVE

We evaluated the clinical course and treatment of 10 MCC patients and determined MCC chemosensitivity.

METHODS

Clinical records as well as laboratory and histopathologic data from 10 patients with MCC treated in our department were examined. Chemosensitivity to various chemotherapeutic agents and interferons of MCC cells from four patients was determined in a soft agar clonogenic assay.

RESULTS

MCC behaved as an aggressive tumor with early and frequent local relapses (4 of 10 patients at a 2.2-month average), regional (4 of 10 patients at 2.5 months), and distant metastases (5 of 10 patients 9.6 months after excision of the primary tumor). In all but one patient, regional metastases preceded distant ones. Metastatic spread was associated with an average survival of 21 months from the initial diagnosis. Long-term survival (53+ and 65+ months) was observed in two women. Wide excision of the primary tumor, alone or combined with adjuvant chemotherapy and radiotherapy, was the most effective treatment. In advanced disease, chemotherapy and radiotherapy were not able to induce long-term remission. In vitro assays for MCC drug sensitivity revealed cisplatin, doxorubicin, and vindesine to be the most active.

CONCLUSION

MCC has a poor prognosis in advanced stages; therefore the primary tumor should be aggressively treated. The in vitro clonogenic assay may help to identify the chemosensitivity profile of MCC and to optimize chemotherapy protocols.

The importance of postoperative radiation therapy in the treatment of Merkel cell carcinoma

PURPOSE

To determine the role of postoperative radiation therapy in the treatment of Merkel cell carcinoma (MCC).

METHODS AND MATERIALS

Eighty patients with MCC of the skin were treated with curative intent at the Queensland Radium Institute between 1981 and 1991. Fifty-one patients (63.7%) were referred after initial biopsy for further treatment and 29 patients (36.3%) were referred with locally recurrent disease following primary surgery elsewhere. Thirteen patients (16.3%) presented with nodal disease without a clinically definable primary skin lesion.

RESULTS

Of the 80 patients, 38 had undergone surgery (S) alone, 34 surgery plus radiotherapy (S + RT), 7 RT after incomplete S, and 1 patient had chemotherapy (CT) plus RT. Overall survival at 36 months for all patients was 68%. All of the 38 patients treated with S alone relapsed. The median time to recurrence was 5.5 months. Ten of the 34 patients treated with S + RT relapsed. The median time to recurrence was 16.5 months. Of the 80 patients, 55 have relapsed after primary treatment, 25 have developed systemic metastases, and 26 patients have died as a direct result of MCC.

CONCLUSION

Our large series confirms earlier reports from this Institute and highlights the importance of S + RT over S alone in preventing local recurrence of this highly malignant skin cancer.