An unusual case of diffuse Merkel cell carcinoma successfully treated with low dose radiotherapy

Radiotherapy for inoperable Merkel cell carcinoma: a systematic review and pooled analysis

Background

Cumulative data on radiation monotherapy for Merkel cell carcinoma (MCC) is lacking.

Objective

We sought to synthesize all available data on treatment outcomes for radiation monotherapy for inoperable stage I-III MCC.

Methods

We performed a systematic review of the current literature. Articles published in English in the PubMed database up to July 29, 2016, were evaluated.

Results

Eight case reports, 4 case series, and 6 retrospective studies, yielding 68 patients, were included in our analysis. Of the 24 stage I/II patients treated with local irradiation, 6 (25%) relapsed and 1 (4%) died from MCC. Of the 24 stage I/II patients treated with local and regional nodal irradiation, 5 (21%) relapsed and 2 (8%) died from MCC. Of the 20 stage III patients treated with local and regional nodal irradiation, 12 (60%) relapsed and 7 (35%) died from MCC.

Conclusions

Radiation monotherapy appears to be a reasonable treatment modality for patients with inoperable stage I-III MCC. Further investigation with prospective studies is needed to draw definitive conclusions.

Metronomic and metronomic-like therapies in neuroendocrine tumors - Rationale and clinical perspectives

Metronomic therapy is characterized by the administration of regular low doses of certain drugs with very low toxicity. There have been numerous debates over the empirical approach of this regimen, but fewest side effects are always something to consider in order to improve patients' quality of life. Neuroendocrine tumors (NETs) are rare malignancies relatively slow-growing; therefore their treatment is often chronic, involving several different therapies for tumor growth control. Knowing that these tumors are highly vascularized, the anti-angiogenic aspect is highly regarded as something to be targeted in all patients harboring NETs. Additionally the metronomic schedule has proved to be effective on an immunological level, rendering this approach as a multi-targeted therapy. Rationalizing that advanced NETs are in many cases a chronic disease, with which patients can live for as long as possible, a systemic therapy with regular low doses and a very low toxicity is in many cases a judicious manner of pursuing stabilization. Metronomic schedule is usually correlated with chemotherapy in oncology, but other therapies, such as radiotherapy and biotherapy can be delivered in a metronomic like manner. This review describes clinical trials and case series involving metronomic therapies alone or in combination in patients with advanced NETs. Nowadays level of evidence about metronomic therapy in NETs is quite low, therefore future prospective clinical studies are needed to validate the metronomic approach in specific clinical settings.

Multiple Primary Merkel Cell Carcinomas Presenting as Pruritic, Painful Lower Leg Tumors

Merkel cell carcinoma (MCC) is a rare and highly aggressive neuroendocrine tumor of the skin which almost exclusively presents as a solitary tumor. It is most often seen on sun-exposed regions, historically almost exclusively on the head and neck, with only rare case reports on the extremities. Although recent studies have shown increased incidence with up to 20% on the extremities, here we present one of these rare emerging presentations, with the addition of a unique treatment option. Our patient is an 80-year-old male with a 3-month history of multiple raised, rapidly enlarging tumors on the right ankle. Two separate biopsies were performed and demonstrated sheets and clusters of small blue cells filling the dermis with scant cytoplasm, dusty chromatin, and nuclear molding. Subsequent immunohistochemical stains confirmed the diagnosis of multiple primary MCC. Despite the characteristic immunohistochemical profile of primary MCC, the possibility of a metastatic neuroendocrine carcinoma from an alternate primary site was entertained, given his unusual clinical presentation. A complete clinical workup including CT scans of the chest, abdomen, and pelvis showed no evidence of disease elsewhere. Instead of amputation, the patient opted for nonsurgical treatment with radiation therapy alone, resulting in a rapid and complete response. This case represents an unusual presentation of primary MCC and demonstrates further evidence that radiation as monotherapy is an effective local treatment option for inoperable MCC.