Radiation Therapy for Local Cutaneous Melanoma

While primary treatment for melanoma consists of surgical resection and chemotherapeutics, radiation can be used as either definitive or adjuvant therapy in certain clinical scenarios. This chapter aims to explore the indications for primary definitive radiotherapy as well as adjuvant treatment following resection. Delivery, dose, fractionation, and toxicity of radiation treatment will be discussed. As our understanding of melanoma tumor biology increases, the role of radiotherapy may expand for more effective treatment of oligometastatic disease.

A combination of high dose rate (10X FFF/2400 MU/min/10 MV X-rays) and total low dose (0.5 Gy) induces a higher rate of apoptosis in melanoma cells in vitro and superior preservation of normal melanocytes

The aim of this study was to determine the apoptotic effects, toxicity, and radiosensitization of total low dose irradiation delivered at a high dose rate in vitro to melanoma cells, normal human epidermal melanocytes (HEM), or normal human dermal fibroblasts (HDF) and to study the effect of mitochondrial inhibition in combination with radiation to enhance apoptosis in melanoma cells. Cells irradiated using 10X flattening filter-free (FFF) 10 MV X-rays at a dose rate of 400 or 2400 MU/min and a total dose of 0.25–8 Gy were analyzed by cell/colony counting, MitoTracker, MTT, and DNA-damage assays, as well as by quantitative real-time reverse transcriptase PCR in the presence or absence of mitochondrial respiration inhibitors. A dose rate of 2400 MU/min killed on average five-fold more melanoma cells than a dose rate 400 MU/min at a total dose of 0.5 Gy and preserved 80% survival of HEM and 90% survival of HDF. Increased apoptosis at the 2400 MU/min dose rate is mediated by greater DNA damage, reduced cell proliferation, upregulation of apoptotic genes, and downregulation of cell cycle genes. HEM and HDF were relatively unharmed at 2400 MU/min. Radiation induced upregulation of mitochondrial respiration in both normal and cancer cells, and blocking the respiration with inhibitors enhanced apoptosis only in melanoma cells. A high dose rate with a low total dose (2400 MU/min, 0.5 Gy/10X FFF 10 MV X-rays) enhances radiosensitivity of melanoma cells while reducing radiotoxicity toward HEM and HDF. Selective cytotoxicity of melanoma cells is increased by blocking mitochondrial respiration.

Novel cyclic pentapeptide H-15 induces differentiation and inhibits proliferation in murine melanoma B16 cells

Sansalvamide A is a cyclic depsipeptide that is isolated from a marine fungus of the Fusarium genus. Sansalvamide A exhibits significant antitumor ability. The molecular formula and molecular weight of the novel sansalvamide A derivative H-15 are C₂₉H₄₄BrN₅O₆ and 637.2475, respectively. In the present study, H-15 was found to inhibit the proliferation and induce the differentiation of murine melanoma B16 cells. A sulforhodamine B colorimetric assay was used to measure the inhibitory effects of 0.1, 1, 10, 50 and 100 µM H-15 on the B16 cells, and the results revealed that the inhibitory effects of H-15 exerted on the B16 cells occurred in a concentration-dependent manner. In addition, the growth curve model of the B16 cells treated with 50 µM H-15 revealed that the effect of H-15 was also time-dependent. The differentiation morphology of the B16 cells was observed subsequent to treating the cells with H-15. An optical microscope was used to observe the differentiation morphology of the cells. In addition, melanin secretion increased in the B16 cells treated with 50 µM H-15. The expression levels of tyrosinase (TYR) were assayed by western blot analysis, and it was found that the cells treated with 50 µM H-15 for 48 h exhibited increased expression of TYR. The results of the present study indicated that H-15 may induce the differentiation of B16 cells.

Photosensitizing and radiosensitizing effects of mitoxantrone: combined chemo-, photo-, and radiotherapy of DFW human melanoma cells

This study evaluated the effects of mitoxantrone (MX), an antitumor agent, as a sensitizer to both photodynamic and radiation therapy in DFW human melanoma cells. Cells were incubated with MX at different concentrations for 90 min and then exposed to non-coherent light at different fluence rates and/or X-ray ionizing radiation at different dose rates. Combinatorial effects of this chemo-, photo-, and radiotherapy were also evaluated. MX had no significant effects on viability at moderate doses but had a strong cytotoxic effect on cancer cells when used as a photosensitizer. MX also acted as a potent radiosensitizer. We observed a dose-dependent effect on cell viability in cells exposed to MX in combination with phototherapy and radiotherapy. Strong synergistic effects were observed for combinations of two or more treatment methods, which, in some cases, induced complete cell death. Thus, a combination of ionizing radiation with MX-mediated photodynamic therapy could serve as a new method for cancer therapy with fewer adverse side effects.

The evolving role of radiation therapy in the management of malignant melanoma

The incidence of melanoma is rising in the United States, leading to an estimated 68,720 new diagnoses and 8,650 deaths annually. The natural history involves metastases to lymph nodes, lung, liver, brain, and often to other sites. Primary treatment for melanoma is surgical excision of the primary tumor and affected lymph nodes. The role of adjuvant or definitive radiation therapy in the treatment of melanoma remains controversial, because melanoma has traditionally been viewed as a prototypical radioresistant cancer. However, recent studies suggest that under certain clinical circumstances, there may be a significant role for radiation therapy in melanoma treatment. Stereotactic radiosurgery for brain metastases has shown effective local control. High dose per fraction radiation therapy has been associated with a lower rate of locoregional recurrence of sinonasal melanoma. Plaque brachytherapy has evolved into a promising alternative to enucleation at the expense of moderate reduction in visual acuity. Adjuvant radiation therapy following lymphadenectomy in node-positive melanoma prevents local and regional recurrence. The newer clinical data along with emerging radiobiological data indicate that radiotherapy is likely to play a greater role in melanoma management and should be considered as a treatment option.

Single photon emission computed tomography/positron emission tomography imaging and targeted radionuclide therapy of melanoma: new multimodal fluorinated and iodinated radiotracers

This study reports a series of 14 new iodinated and fluorinated compounds offering both early imaging ((123)I, (124)I, (18)F) and systemic treatment ((131)I) of melanoma potentialities. The biodistribution of each (125)I-labeled tracer was evaluated in a model of melanoma B16F0-bearing mice, using in vivo serial γ scintigraphic imaging. Among this series, [(125)I]56 emerged as the most promising compound in terms of specific tumoral uptake and in vivo kinetic profile. To validate our multimodality concept, the radiosynthesis of [(18)F]56 was then optimized and this radiotracer has been successfully investigated for in vivo PET imaging of melanoma in B16F0- and B16F10-bearing mouse model. The therapeutic efficacy of [(131)I]56 was then evaluated in mice bearing subcutaneous B16F0 melanoma, and a significant slow down in tumoral growth was demonstrated. These data support further development of 56 for PET imaging ((18)F, (124)I) and targeted radionuclide therapy ((131)I) of melanoma using a single chemical structure.

Non-thermal plasma induces apoptosis in melanoma cells via production of intracellular reactive oxygen species

Non-thermal atmospheric pressure dielectric barrier discharge (DBD) plasma may provide a novel approach to treat malignancies via induction of apoptosis. The purpose of this study was to evaluate the potential of DBD plasma to induce apoptosis in melanoma cells. Melanoma cells were exposed to plasma at doses that did not induce necrosis, and cell viability and apoptotic activity were evaluated by Trypan blue exclusion test, Annexin-V/PI staining, caspase-3 cleavage, and TUNEL® analysis. Trypan blue staining revealed that non-thermal plasma treatment significantly decreased the viability of cells in a dose-dependent manner 3 and 24 h after plasma treatment. Annexin-V/PI staining revealed a significant increase in apoptosis in plasma-treated cells at 24, 48, and 72 h post-treatment (p < 0.001). Caspase-3 cleavage was observed 48 h post-plasma treatment at a dose of 15 J/cm(2). TUNEL® analysis of plasma-treated cells demonstrated an increase in apoptosis at 48 and 72 h post-treatment (p < 0.001) at a dose of 15 J/cm(2). Pre-treatment with N-acetyl-L: -cysteine (NAC), an intracellular reactive oxygen species (ROS) scavenger, significantly decreased apoptosis in plasma-treated cells at 5 and 15 J/cm(2). Plasma treatment induces apoptosis in melanoma cells through a pathway that appears to be dependent on production of intracellular ROS. DBD plasma production of intracellular ROS leads to dose-dependent DNA damage in melanoma cells, detected by γ-H2AX, which was completely abrogated by pre-treating cells with ROS scavenger, NAC. Plasma-induced DNA damage in turn may lead to the observed plasma-induced apoptosis. Since plasma is non-thermal, it may be used to selectively treat malignancies.

Role of postoperative irradiation for patients with bilateral cervical nodal metastases from cutaneous melanoma: a critical assessment

BACKGROUND

The aim of this study was to evaluate the role of regional nodal radiation therapy (RT) for patients with bilateral cervical nodal metastases from melanoma.

METHODS

Between 1998 and 2008, 16 patients with bilateral cervical metastases without distant metastases were treated with postoperative RT (30 Gy in 5 fractions delivered twice weekly).

RESULTS

Median follow-up was 5 months (range, 1-34 months). Median survival was 9 months (95% confidence interval [CI], 0-23 months). Overall survival was 68%, 50%, and 27% at 6, 12, and 24 months, respectively. Regional nodal control was 74% and 64% at 6 and 12 months, respectively. Rates of development of distant metastasis were 60%, 70%, and 90% at 6, 12, and 18 months, respectively. The actuarial rate of RT-related complications was 49% at 12 months.

CONCLUSION

The limited life expectancy of patients observed with this disease combined with the high rate of RT-related complications argue against the routine use of adjuvant RT for regional nodal disease in this setting.

Beta-elemene inhibits melanoma growth and metastasis via suppressing vascular endothelial growth factor-mediated angiogenesis

PURPOSE

It was to assess antiangiogenic effect of β-elemene in vitro and in vivo, and it was involved in inhibiting melanoma growth and metastasis, as well as to elucidate its intrinsic mechanism.

METHODS

Inhibitive effect of β-elemene on B16F10 cells was performed by cell proliferation assay. Angiogenesis assays in vitro including rat aortic ring and chick embryo chorioallantoic membrane were used, as well as melanoma growth and metastasis assay in C57BL/6 mice. Vascular endothelial growth factor (VEGF) expression in vitro and in vivo was measured respectively by western blot analysis and enzyme-linked immunosorbent assay (ELISA). Immunohistochemistry analysis of CD34 and VEGF expression in primary melanoma was also presented.

RESULTS

β-Elemene inhibited B16BF10 cell proliferation starting from 200 μM, but VEGF from 20 μM. Both 20 and 50 μM β-elemene in vitro inhibited VEGF-induced sprouting vessel of rat aortic ring and microvessel formation of chick embryo chorioallantoic membrane. In vivo, tumor size of primary melanoma in mice intraperitoneally treated with β-elemene was significantly smaller than that of the control; CD34 expression of primary melanoma was also suppressed; and the metastatic melanoma colonies and content of melanin in lung were detected obviously decreased in mice of β-elemene-treated groups. Furthermore, results of VEGF expressing in primary melanoma, serum and lung of mice also disclosed that VEGF was inhibited in vivo.

CONCLUSIONS

β-Elemene inhibited melanoma growth and metastasis through suppressing VEGF-mediated angiogenesis. It is a natural potential antiangiogenic agent.

Preclinical evaluation of an 131I-labeled benzamide for targeted radiotherapy of metastatic melanoma

Radiolabeled benzamides are attractive candidates for targeted radiotherapy of metastatic melanoma as they bind melanin and exhibit high tumor uptake and retention. One such benzamide, N-(2-diethylamino-ethyl)-4-(4-fluoro-benzamido)-5-iodo-2-methoxy-benzamide (MIP-1145), was evaluated for its ability to distinguish melanin-expressing from amelanotic human melanoma cells, and to specifically localize to melanin-containing tumor xenografts. The binding of [(131)I]MIP-1145 to melanoma cells in vitro was melanin dependent, increased over time, and insensitive to mild acid treatment, indicating that it was retained within cells. Cold carrier MIP-1145 did not reduce the binding, consistent with the high capacity of melanin binding of benzamides. In human melanoma xenografts, [(131)I]MIP-1145 exhibited diffuse tissue distribution and washout from all tissues except melanin-expressing tumors. Tumor uptake of 8.82% injected dose per gram (ID/g) was seen at 4 hours postinjection and remained at 5.91% ID/g at 24 hours, with tumor/blood ratios of 25.2 and 197, respectively. Single photon emission computed tomography imaging was consistent with tissue distribution results. The administration of [(131)I]MIP-1145 at 25 MBq or 2.5 GBq/m(2) in single or multiple doses significantly reduced SK-MEL-3 tumor growth, with multiple doses resulting in tumor regression and a durable response for over 125 days. To estimate human dosimetry, gamma camera imaging and pharmacokinetic analysis was performed in cynomolgus monkeys. The melanin-specific binding of [(131)I]MIP-1145 combined with prolonged tumor retention, the ability to significantly inhibit tumor growth, and acceptable projected human dosimetry suggest that it may be effective as a radiotherapeutic pharmaceutical for treating patients with metastatic malignant melanoma.

A striking response of anorectal melanoma to radiotherapy (locoregional disease confined to perineum and anal canal)

Anorectal melanoma is a rare disease with an exceedingly poor prognosis. Literature evaluating outcomes is often difficult because of the infrequent diagnosis, delayed presentation and almost universally poor outcome. We describe a case of a 78-year-old woman with a large anorectal melanoma without detectable metastasis following radiological investigation. Due to the patient's co-morbidity, radiotherapy of 36 Gy once weekly over 7 weeks, was given as the sole treatment. The clinical outcome showed a remarkable regression of the tumour without radiological or clinical recurrence at 12 months' follow-up. This is the first case of the successful use of radiotherapy alone in anorectal melanoma.