The effectiveness and safety of proton radiation therapy for indications of the eye : a systematic review

External Beam Radiotherapy in the Management of Uveal Melanoma

OPINION STATEMENT

Uveal melanoma is the most common primary ocular tumor in adults. With the evidence demonstrating that episcleral plaque brachytherapy (EPB) has similar survival rates as enucleation in the Collaborative Ocular Melanoma Study (COMS), eye-sparing treatments have come to the fore today. External radiotherapy techniques (proton beam radiotherapy and stereotactic radiosurgery/fractionated stereotactic radiosurgery) are an important treatment option for globe-sparing treatments. There are no prospective randomized trials comparing these techniques; however, retrospective series, meta-analyses, and reviews indicate that these EPB and external radiotherapy techniques are equal. With this review, we aimed to examine the external radiotherapy techniques used in the treatment of uveal melanoma in detail with reference to the current literature.

Long-term follow-up in patients treated with electrochemotherapy for non-melanoma skin cancer in the head and neck area

BACKGROUND

Electrochemotherapy (ECT) is a cancer treatment modality where the intracellular accumulation of chemotherapeutic agents is enhanced by an applied electrical field.

AIMS/OBJECTIVES

To evaluate the long-term efficacy, safety and functional outcome after ECT treatment in high-risk non-melanoma skin cancer (NMSC) with curative intent.

MATERIALS AND METHODS

Seven patients with SCC or BCC in the head and neck area were treated with ECT with intratumoral bleomycin administration.

RESULTS

Five patients were cured by ECT as a mono-modality treatment after a median 10-year follow-up period. Two patients had recurrences and/or persisting tumors after treatment that required salvage surgery and radiotherapy. In two patients, the eye was spared with no visual impairment. In another patient, full facial nerve function was spared.

CONCLUSIONS

ECT can be a curative as well as an organ and function-sparing mono modality treatment in high-risk NMSC.

SIGNIFICANCE

Today ECT is mostly used as a palliative treatment. Its curative potential should be further investigated. Randomized studies comparing ECT with standard treatment is needed. Hopefully, this small study can encourage such studies.

Appraising the Quality of Systematic Reviews for Age-Related Macular Degeneration Interventions: A Systematic Review

Importance

Age-related macular degeneration (AMD) is a leading cause of vision impairment. It is imperative that AMD care is timely, appropriate, and evidence-based. It is thus essential that AMD systematic reviews are robust; however, little is known about the quality of this literature.

Objectives

To investigate the methodological quality of systematic reviews of AMD intervention studies, and to evaluate their use for guiding evidence-based care.

Evidence Review

This systematic review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. All studies that self-identified as a systematic review in their title or abstract or were categorized as a systematic review from a medical subject heading and investigated the safety, efficacy and/or effectiveness of an AMD intervention were included. Comprehensive electronic searches were performed in Ovid MEDLINE, Embase, and the Cochrane Library from inception to March 2017. Two reviewers independently assessed titles and abstracts, then full-texts for eligibility. Quality was assessed using the Assessing the Methodological Quality of Systematic Reviews (AMSTAR) tool. Study characteristics (publication year, type of intervention, journal, citation rate, and funding source) were extracted.

Findings

Of 983 citations retrieved, 71 studies (7.6%) were deemed eligible. The first systematic review relating to an AMD intervention was published in 2003. More than half were published since 2014. Methodological quality was highly variable. The mean (SD) AMSTAR score was 5.8 (3.2) of 11.0, with no significant improvement over time (r = -0.03; 95% CI, -0.26 to 0.21; P = .83). Cochrane systematic reviews were overall of higher quality than reviews in other journals (mean [SD] AMSTAR score, 9.9 [1.2], n = 15 vs 4.7 [2.2], n = 56; P < .001). Overall, there was poor adherence to referring to an a priori design (22 articles [31%]) and reporting conflicts of interest in both the review and included studies (16 articles [23%]). Reviews funded by government grants and/or institutions were generally of higher quality than industry-sponsored reviews or where the funding source was not reported.

Conclusions and Relevance

There are gaps in the conduct of systematic reviews in the field of AMD. Enhanced endorsement of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement by refereed journals may improve review quality and improve the dissemination of reliable evidence relating to AMD interventions to clinicians.

Stereotactic radiotherapy for choroidal melanomas by means of HybridArc™ : Physics and technique of linac-based photon beam therapy

PURPOSE

Stereotactic radiotherapy (SRT) is suitable to treat ocular tumours. The optimal beam geometry for SRT, however, has not been defined. Here we evaluate a combination technique with dynamic conformal arcs (DCAs) and intensity-modulated static fields (IMRT), known as HybridArc™ (HA).

METHODS

For the first consecutive 25 cases with choroidal melanomas with volumes of 0.02 to 1.18 cm³ treated with 50 Gy in five fractions, the results with respect to dose conformity, homogeneity, and dose distributions were summarised. To describe the dose distribution at the planning target volume (PTV) boundary, we defined a spatially averaged dose gradient (SADG) and compared it with Paddick's gradient index (GI). We made dosimetric comparisons between HA and other irradiation techniques.

RESULTS

The PTVs ranged from 0.42 to 3.37 cm³. The conformity index (CI) was 1.25 ± 0.15, and the homogeneity index (HI) 0.08 ± 0.02. The SADG was (-3.5 ± 0.5) Gy/mm or (-7.0 ± 1.0) %/mm between the isodose levels 95 and 20%; local minima reached -11.5 Gy/mm or -22.9%/mm. The coefficient of determination for a nonlinear regression of GI on SADG was 0.072. After a median follow-up time of 19.6 months, local tumour control was 100% without any case of post-therapeutic enucleation. Two patients (8%) developed liver metastases.

CONCLUSION

SRT of ocular tumours by HA is highly appropriate, and HA is superior to intensity-modulated arc therapy (IMAT) concerning dose reduction in organs at risk (OARs). The novel gradient measure SADG is more informative than Paddick's GI.

Cost-effectiveness of proton beam therapy for intraocular melanoma

Purpose

Proton beam therapy is a commonly accepted treatment for intraocular melanomas, but the literature is lacking in descriptions of patient preferences of clinical outcomes and economic impact. In addition, no economic evaluations have been published regarding the incremental cost-effectiveness of proton beam therapy compared with enucleation or plaque brachytherapy, typical alternative treatments. We, therefore, conducted a cost-utility analysis of these three approaches for the treatment of intraocular melanomas.

Materials and Methods

A Markov model was constructed. Model parameters were identified from the published literature and publicly available data sources. Cost-effectiveness of each treatment was calculated in 2011 US Dollars per quality-adjusted life-year. Incremental cost-effectiveness ratios were calculated assuming enucleation as reference. One-way sensitivity analyses were conducted on all model parameters. A decision threshold of $50,000/quality-adjusted life-year was used to determine cost-effectiveness.

Results

Enucleation had the lowest costs and quality-adjusted life-years, and plaque brachytherapy had the highest costs and quality-adjusted life-years. Compared with enucleation, the base-case incremental cost-effectiveness ratios for plaque brachytherapy and proton beam therapy were $77,500/quality-adjusted life-year and $106,100/quality-adjusted life-year, respectively. Results were highly sensitive to multiple parameters. All three treatments were considered optimal, and even dominant, depending on the values used for sensitive parameters.

Conclusion

Base-case analysis results suggest enucleation to be optimal. However, the optimal choice was not robust to sensitivity analyses and, depending on the assumption, both plaque brachytherapy and proton beam therapy could be considered cost-effective. Future clinical studies should focus on generating further evidence with the greatest parameter uncertainty to inform future cost-effectiveness analyses.

Proton-beam therapy for hepatocellular carcinoma associated with portal vein tumor thrombosis

BACKGROUND AND PURPOSE

The prognosis of patients with advanced hepatocellular carcinoma (HCC) with portal vein tumor thrombosis (PVTT) is extremely poor, as effective treatment options are limited. The authors performed a retrospective review to evaluate the efficacy of proton-beam therapy (PBT) for patients presenting with PVTT in the setting of HCC.

PATIENTS AND METHODS

Between February 1991 and September 2005, 35 patients with HCC and tumor thrombi in the main trunk or major branches of the portal vein presented for consideration of PBT. Their tumor sizes ranged from 25 mm to 130 mm (median, 60 mm). A median total dose of 72.6 GyE in 22 fractions was delivered over 31 days to a target volume that encompassed both the primary hepatic lesion and the PVTT.

RESULTS

32 patients were progression-free during a median follow-up period of 21 months (range, 2-88 months) and three patients experienced disease progression. Local progression-free survival rates were 46% at 2 years and 20% at 5 years, and the median local progression-free survival was 21 months. Acute toxicity > or = grade 3 was observed in three patients, and no patient experienced late toxicity > or = grade 3. None of the patients had to discontinue treatment as a result of toxicity.

CONCLUSION

PBT improved local control and significantly prolonged survival in HCC patients with PVTT.

Technical considerations for noncoplanar proton-beam therapy of patients with tumors proximal to the optic nerve

PURPOSE

To investigate technical feasibilities of noncoplanar proton-beam therapy (PBT) on dose reduction to critical organs.

MATERIAL AND METHODS

The degree of mechanical precision, rotational limitations of the gantry and the treatment couch were evaluated, and dose-volume histograms were compared for noncoplanar and coplanar PBT. Following these studies, three patients with tumors proximal to the optic nerve underwent noncoplanar PBT.

RESULTS

Noncoplanar PBT offered advantage in dose reduction to the optic nerve when compared to coplanar therapy. This advantage was more significant if the tumor reduced in size during treatment. None experienced radiation injury to the optic nerve during a short follow-up time of 7-12 months.

CONCLUSION

Noncoplanar PBT appears to reduce doses to organs at risk.