The role of radiation therapy in melanoma

Survival and Prognosis for Patients with Rectal Melanomas in the United States: A SEER-Based Study

PURPOSE

Limited attention was paid to focus on rectal melanomas (RM). This study aimed to evaluate the survival rate and prognostic factors of RM.

METHODS

The data for patients with RM from Surveillance, Epidemiology, and End Results (SEER) database were used to analyze tumor survival. Kaplan-Meier method and log-rank test were employed to estimate cancer-specific survival (CSS) and overall survival (OS). A nomogram was established based on the risk factors of survival by the forest plot for multivariate Cox regression analysis. Receiver operating characteristic (ROC) and calibration curve were conducted for validation.

RESULTS

A total of 187 patients with RM were selected to perform survival analyses. The median survival time of OS was 12 months (range: 0-146 months), and the median survival time of CSS was 12 months (range: 0-74 months). Patients' age, tumor size, stage, the number of nodes examined, surgery, and radiation were identified as prognostic indicators for CSS by the forest plot for multivariate Cox regression analysis. The nomogram was validated as a reliable model for CSS.

CONCLUSION

Clinicopathologic relevance with tumor prognosis was confirmed in this study. Our nomogram can provide a relatively accurate prediction of the survival rate of patients with RM.

Recent advances in radiosensitivity determinants in melanoma

PURPOSE OF REVIEW

Radiotherapy has been proven to be useful but insufficient in melanoma management due to the intrinsic radioresistance of melanoma cells. Elucidation of the molecular mechanisms and pathways related to resistance/sensitivity to radiotherapy in melanoma is of paramount importance. In this review, we will summarize and discuss the recent 'discoveries' and advances in radiosensitivity determinants in melanoma.

RECENT FINDINGS

The different levels of radiosensitivity among the various melanoma tumors could be attributed to the DNA damage signaling and repair proteins, tumor microenvironment, hypoxia, cell metabolism, glutathione and redox balance, protein kinase signaling pathways as well as pigmentation and melanin content.

SUMMARY

It is therapeutically important to elucidate the factors involved in radiation resistance/sensitivity of melanoma. More importantly, improving radiosensitivity may 'widen the clinical utility' in melanoma of this important therapeutic modality.

Melanoma, Melanin, and Melanogenesis: The Yin and Yang Relationship

Melanin pigment plays a critical role in the protection against the harmful effects of ultraviolet radiation and other environmental stressors. It is produced by the enzymatic transformation of L-tyrosine to dopaquinone and subsequent chemical and biochemical reactions resulting in the formation of various 5,6-dihydroxyindole-2-carboxylic acid (DHICA) and 5,6-dihydroxyindole (DHI) oligomers-main constituents of eumelanin, and benzothiazine and benzothiazole units of pheomelanin. The biosynthesis of melanin is regulated by sun exposure and by many hormonal factors at the tissue, cellular, and subcellular levels. While the presence of melanin protects against the development of skin cancers including cutaneous melanoma, its presence may be necessary for the malignant transformation of melanocytes. This shows a complex role of melanogenesis in melanoma development defined by chemical properties of melanin and the nature of generating pathways such as eu- and pheomelanogenesis. While eumelanin is believed to provide radioprotection and photoprotection by acting as an efficient antioxidant and sunscreen, pheomelanin, being less photostable, can generate mutagenic environment after exposure to the short-wavelength UVR. Melanogenesis by itself and its highly reactive intermediates show cytotoxic, genotoxic, and mutagenic activities, and it can stimulate glycolysis and hypoxia-inducible factor 1-alpha (HIF-1α) activation, which, combined with their immunosuppressive effects, can lead to melanoma progression and resistance to immunotherapy. On the other hand, melanogenesis-related proteins can be a target for immunotherapy. Interestingly, clinicopathological analyses on advanced melanomas have shown a negative correlation between tumor pigmentation and diseases outcome as defined by overall survival and disease-free time. This indicates a "Yin and Yang" role for melanin and active melanogenesis in melanoma development, progression, and therapy. Furthermore, based on the clinical, experimental data and diverse effects of melanogenesis, we propose that inhibition of melanogenesis in advanced melanotic melanoma represents a realistic adjuvant strategy to enhance immuno-, radio-, and chemotherapy.

Skin Dosimetry with EBT3 Radiochromic Film in Radiotherapy of Parotid Cancer

Background

Skin is a sensitive organ and should be spared in radiotherapy and irradiation of skin in radiotherapy can cause to acute and late skin effects such as erythema, desquamation, epilation, color change, or even necrosis.

Objective

The aim of the present study is to do skin dosimetry in radiotherapy of parotid cancer using Gafchromic EBT3 radiochromic film. EBT3 radiochromic films were calibrated in 0.2-5 Gy dose range.

Material and Methods

This is an experimental study in the field of radiotherapy physics. Treatment planning was performed on a RANDO phantom for treatment of parotid cancer by a clinical oncologist. Based on the treatment planning, the skin dose at various points in the overlapping region of right anterior-oblique and right posterior-oblique fields were measured using EBT3 radiochromic film.

Results

The minimum and maximum skin doses in a fraction (with 2.0 Gy prescribed dose) were 0.50 Gy and 0.97 Gy, respectively. Based on these values, the total skin dose in 30 treatment fractions (for removed tumor) or in 35 treatment fractions (for unremoved tumor) was in the range of 15-33 Gy.

Conclusion

Based on the skin dosimetry results of parotid cancer radiotherapy using EBT3 films, it is predicted that there will occur mild skin reactions and these reactions can be neglected due to being mild.

Adjuvant Radiation Does Not Affect Locoregional Control Following Resection of Melanoma Satellitosis or In-Transit Disease

BACKGROUND

This study evaluates the association of adjuvant radiation therapy (RT) with improved locoregional (LR) recurrence for resected melanoma satellitosis and in-transit disease (ITD).

MATERIALS AND METHODS

Data were collected retrospectively for resected melanoma satellitosis/ITD from 1996 to 2017.

RESULTS

99 patients were identified. 20 patients (20.2%) received adjuvant RT while 79 (79.8%) did not. Mean follow-up in the RT group was 4.3 years and 4.7 years in the non-RT group. 80% of patients who underwent RT suffered a complication, most commonly dermatitis. Locoregional recurrence occurred in 9 patients (45%) treated with adjuvant RT and 30 patients (38%) in the non-RT group (P = 0.805). Median LR-DFS was 5.8 years in the RT group and 9.5 years in the non-RT group (P = 0.604). On multivariable analysis, having a close or positive margin was the only independent predictor of LR-DFS (HR 3.8 95% CI 1.7-8.7). In-transit disease was associated with improved overall survival when compared to satellitosis (HR 0.260, 95% CI 0.08-0.82).

DISCUSSION

The use of adjuvant RT is not associated with improved locoregional control in resected melanoma satellitosis or ITD. Close or positive margin was the only treatment-related factor associated with decreased LR-DFS after surgical resection of satellitosis/ITD.

Treatment of Clinically Positive Cervical Lymph Nodes by Limited Local Node Excision and Adjuvant Radiotherapy in Melanoma Patients with Major Comorbidities

INTRODUCTION

When cervical lymph nodes are clinically positive for metastatic melanoma, surgeons may be hesitant to recommend a therapeutic complete lymph node dissection if the patient is elderly or has major comorbidities. A limited local node excision of the clinically positive nodes only, followed by adjuvant radiotherapy to the entire node field, may be an effective alternative in such patients.

METHODS

All patients who had presented with a primary head and neck melanoma or an unknown primary site and had subsequently undergone limited local node excision and adjuvant radiotherapy for macroscopically involved cervical nodes between 1993 and 2010 at a tertiary referral center were selected for study.

RESULTS

Twenty-eight patients were identified, with a median age of 78 years and a median of 2 major comorbidities. The 5-year regional control, disease-free survival, and overall survival rates were 69%, 44%, and 50%, respectively. At the time of data analysis, seven patients were alive without evidence of disease. Twenty-one patients had died: 11 of melanoma (4 with neck recurrence) and 10 of other causes (2 with neck recurrence).

CONCLUSIONS

Excision of clinically positive metastatic cervical lymph nodes followed by radiotherapy provides satisfactory regional disease control without risking serious morbidity or mortality in melanoma patients whose general condition is considered a contraindication for therapeutic complete lymph node dissection.

Analysis of patients diagnosed with primary cutaneous melanoma in the last six years in Hospital Erasto Gaertner: epidemiologic profile

BACKGROUND

Melanoma is one of the conditions with greater increase in incidence worldwide in recent decades. It is a skin cancer with potential high lethality and predominates in Caucasian adults. Treatment of primary cutaneous melanoma is essentially surgical and search for sentinel lymph node can modify the aggressiveness of the treatment.

OBJECTIVE

To analyze the epidemiological profile of patients diagnosed with primary cutaneous melanoma, histopathological features and compare with literature data.

METHODS

This is a retrospective, observational, single-center, case series study of patients with primary cutaneous melanoma, who underwent surgery between January 2008 and December 2013. The parameters include: Age, sex, clinical stage, date of surgery, tumor location, histological subtype, condition of surgical margins, Breslow thickness, mitotic index, presence of ulceration and metastasis on admission.

RESULTS

We included 321 melanoma patients who were treated at Hospital Erasto Gaertner. The population consisted of 58.9% females and 41.1% males with an average age of 52.8 ± 16.3 years. As for the clinical stage, 51.1% were in the initial stage, 24.3% in the clinical stage II (A, B and C), 21.2% in clinical stage III and 3.4% with distant metastases. The most frequent location of the primary melanoma was the trunk, and the histological subtype was superficial spreading pattern. Intermediate and thick melanomas were the most frequent.

STUDY LIMITATIONS

This is a retrospective study and some information and data could be incomplete or absent.

CONCLUSION

The diagnosis and treatment of melanoma in early stages provides less morbidity and improved survival of patients. Understanding the biological behavior of tumor and knowing the local epidemiology guide health strategies.

The potential complementary role of targeted alpha therapy in the management of metastatic melanoma

Standard treatments for metastatic melanoma have recently extended survival although many patients still succumb. Targeted alpha therapy (TAT) is a new therapeutic approach in which a cancer-targeting vector is labeled with an alpha-emitting radioisotope. Alpha-particles have the shortest range and highest energy transfer, and produce localized, high-density and lethal ionization damage to DNA. Thus, the targeted radiation can kill isolated cancer cells circulating in blood and lymphatic vessels, regress metastatic cancer cell clusters, and disrupt the vasculature of solid tumors. Preclinical and clinical studies of TAT for metastatic melanoma demonstrate its safety and anti-tumor activity. We recommend ways in which TAT can be used to treat small-volume disease sometimes in conjunction with cytoreductive anti-melanoma therapies.

An unusual case of desmoplastic malignant melanoma

Desmoplastic malignant melanoma is a rare variant of spindle cell melanoma, commonly seen in older adults, on sun-exposed areas. It accounts for 1-4% of all cases of cutaneous melanoma. The common location of the desmoplastic melanoma is the head and neck region, whereas, other sites are less common. Regional lymph node involvement is reported in 0 to 13.7% of the cases, which is less frequent than other cutaneous melanomas. A 75-year-old male presented with an ulceroproliferative growth on the left foot that was diagnosed as desmoplastic melanoma with regional lymph node metastasis and in transit metastasis, with extensive pulmonary metastasis.