Reduction of inter-observer differences in the delineation of the target in spinal metastases SBRT using an automatic contouring dedicated system

BACKGROUND

Approximately one third of cancer patients will develop spinal metastases, that can be associated with back pain, neurological symptoms and deterioration in performance status. Stereotactic radiosurgery (SRS) and stereotactic body radiotherapy (SBRT) have been offered in clinical practice mainly for the management of oligometastatic and oligoprogressive patients, allowing the prescription of high total dose delivered in one or few sessions to small target volumes, minimizing the dose exposure of normal tissues. Due to the high delivered doses and the proximity of critical organs at risk (OAR) such as the spinal cord, the correct definition of the treatment volume becomes even more important in SBRT treatment, thus making it necessary to standardize the method of target definition and contouring, through the adoption of specific guidelines and specific automatic contouring tools. An automatic target contouring system for spine SBRT is useful to reduce inter-observer differences in target definition. In this study, an automatic contouring tool was evaluated.

METHODS

Simulation CT scans and MRI data of 20 patients with spinal metastases were evaluated. To evaluate the advantage of the automatic target contouring tool (Elements SmartBrush Spine), which uses the identification of different densities within the target vertebra, we evaluated the agreement of the contours of 20 spinal target (2 cervical, 9 dorsal and 9 lumbar column), outlined by three independent observers using the automatic tool compared to the contours obtained manually, and measured by DICE similarity coefficient.

RESULTS

The agreement of GTV contours outlined by independent operators was superior with the use of the automatic contour tool compared to manually outlined contours (mean DICE coefficient 0.75 vs 0.57, p = 0.048).

CONCLUSIONS

The dedicated contouring tool allows greater precision and reduction of inter-observer differences in the delineation of the target in SBRT spines. Thus, the evaluated system could be useful in the setting of spinal SBRT to reduce uncertainties of contouring increasing the level of precision on target delivered doses.

Radiation treatment for adult rare cancers: Oldest and newest indication

AIM

Aim of this analysis is to review the role of RT in the management of several rare tumors for adult patients.

METHODS

Collection data regarding RT and rare tumors was made by Pubmed.

RESULTS

For mucosal melanomas, RT is prescribed, being associated with lower local recurrence rate. For trachea tumors, RT was used as adjuvant or salvage treatment for unresectable disease. For pNET, RT can be a suitable option for post-surgical or unresectable/borderline. For bronchopulmonary neuroendocrine tumors the role of adjuvant treatments is uncertain. For hepatobiliary and ovarian malignancy, stereotactic body RT (SBRT) is a promising approach. For soft tissue sarcoma, perioperative treatments are indicated, and a growing role of SBRT in oligometastatic disease is recognized. For endocrine tumors, adjuvant RT has demonstrated benefits through reducing recurrence risk.

CONCLUSION

The radiotherapy is a frequent indication in adult rare cancers; thus the role of Radiation Oncologist must not be neglected.

Feasibility and preliminary clinical results of linac-based Stereotactic Body Radiotherapy for spinal metastases using a dedicated contouring and planning system

BACKGROUND

Stereotactic radiosurgery (SRS) and stereotactic body radiotherapy (SBRT) are well established local treatment approaches in several cancer settings. Although SBRT is still under investigation for spinal metastases, promising results in terms of a high effectiveness and optimal tolerability have been recently published on this topic. For spinal SBRT, one of the most relevant issues is represented by the inter-observer variability in target definition. Recently, several technological innovations, including specific tools such as multimodality-imaging (computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET-CT), automated volumes contouring and planning, could allow clinicians to minimize the uncertainties related to spinal SBRT workflow. Aim of this study is to report the feasibility of the clinical application of a dedicated software (Element®, Brainlab™ Germany) for spinal metastases SBRT.

MATERIAL AND METHOD

The patient selection criteria for SBRT in spinal metastases were the following: age > 18 years, diagnosis of spinal metastases (n ≤ 3), life expectancy > 3 months, controlled primary tumor or synchronous diagnosis and Spinal Instability Neoplastic Score (SINS) ≤ 12 points. All radiation target volumes were defined and planned with the support of the dedicated software Elements® (Brainlab™ Germany). Different dose prescription have been used: 12 Gy in single fraction, 12 Gy, 18 Gy, 21 Gy and 24 Gy in 3 fractions. Toxicity was assessed according to the Common Terminology Criteria for Adverse Events (CTCAE) v4.0. SPSS version 20 was used for statistical analysis.

RESULTS

From April 2018 to April 2019, 54 spinal metastases in 32 recruited patients were treated with Linac-based SBRT. With a median follow-up of 6 months (range 3-12), local control rates at 6 months and 9 months were 86 and 86%, respectively. No adverse events ≥3 grade were observed.

CONCLUSIONS

This preliminary experience shows that with respect to acute toxicity and early clinical response, linac-based using Elements® Spine SRS is a feasible and effective approach.

The role of radiotherapy in epithelial ovarian cancer: a literature overview

Ovarian cancer (OC) accounts for 3% of all cancer in women and for 5% of all cancer-related deaths. Epithelial Ovarian Cancer (EOC) is a radiosensitive malignancy with a poor prognosis. In the pre-chemotherapy era, radiation therapy (RT) delivered to the abdominopelvic region (whole abdominal irradiation, WAI) has historically played a role in the adjuvant and consolidation setting. Specific cluster of patients with early-stage disease and definite histologies may take advantage of RT. Platinum-based chemotherapy (CT) has replaced RT and plays a major role in most of the clinical settings. Radiation Therapy for palliation is recommended in patients with localized symptoms. Nevertheless, modern RT represents a reliable treatment option, with a mild toxicity profile, particularly effective for oligo-recurrent or progressive disease. The present literature review aims to highlight the historical role of RT in EOC, the actual lines of evidence, and the future perspectives.

Radiotherapy and immune checkpoints inhibitors for advanced melanoma

INTRODUCTION

The therapeutic landscape of metastatic melanoma drastically changed after the introduction of targeted therapies and immunotherapy, in particular immune checkpoints inhibitors (ICI). In recent years, positive effects on the immune system associated to radiotherapy (RT) were discovered, and radiation has been tested in combination with ICI in both pre-clinical and clinical studies (many of them still ongoing). We here summarize the rationale and the preliminary clinical results of this approach.

MATERIALS AND METHODS

In the first part of this review article, redacted with narrative non-systematic methodology, we describe the clinical results of immune checkpoints blockade in melanoma as well as the biological basis for the combination of ICI with RT; in the second part, we systematically review scientific publications reporting on the clinical results of the combination of ICI and RT for advanced melanoma.

RESULTS

The biological and mechanistic rationale behind the combination of ICI and radiation is well supported by several preclinical findings. Retrospective observational series and few prospective trials support the potential synergistic effect between radiation and ICI for metastatic melanoma.

CONCLUSION

RT may potentiate anti-melanoma activity of ICI by enhancing response on both target and non-target lesions. Several prospective trials are ongoing with the aim of further exploring this combination in the clinical setting, hopefully confirming initial observations and opening a new therapeutic window for advanced melanoma patients.

Diagnostic imaging to detect and evaluate response to therapy in bone metastases from prostate cancer: current modalities and new horizons

Different therapeutic options for the management of prostate cancer (PC) have been developed, and some are successful in providing crucial improvement in both survival and quality of life, especially in patients with metastatic castration-resistant PC. In this scenario, diverse combinations of radiopharmaceuticals (for targeting bone, cancer cells and receptors) and nuclear medicine modalities (e.g. bone scan, SPECT, SPECT/CT, PET and PET/CT) are now available for imaging bone metastases. Some radiopharmaceuticals are approved, currently available and used in the routine clinical setting, while others are not registered and are still under evaluation, and should therefore be considered experimental. On the other hand, radiologists have other tools, in addition to CT, that can better visualize bone localization and medullary involvement, such as multimodal MRI. In this review, the authors provide an overview of current management of advanced PC and discuss the choice of diagnostic modality for the detection of metastatic skeletal lesions in different phases of the disease. In addition to detection of bone metastases, the evaluation of response to therapy is another critical issue, since it remains one of the most important open questions that a multidisciplinary team faces when optimizing the management of PC. The authors emphasize the role of nuclear modalities that can presently be used in clinical practice, and also look at future perspectives based on relevant clinical data with novel radiopharmaceuticals.

Stereotactic ablative radiation therapy as first local therapy for lung oligometastases from colorectal cancer: a single-institution cohort study

PURPOSE

To estimate stereotactic ablative radiation therapy (SABR) efficacy and its potential role as an alternative to surgery for the treatment of lung metastases from colorectal cancer.

METHODS AND MATERIALS

Forty consecutive patients who received SABR as first local therapy at the time of lung progression were included, from 2004 to 2014. The primary study endpoint was overall survival. Secondary endpoints were progression-free survival and safety.

RESULTS

A single nodule was treated in 26 patients (65%), 2 nodules in 10 patients (25%), 3 in 3 patients (7.5%), and 4 in 1 patient (2.5%), for a total of 59 lesions. The median delivered biological effective dose was 96 Gy, in 1 to 8 daily fractions. Median follow-up time was 20 months (range, 3-72 months). Overall survival rates at 1, 2, and 5 years were, respectively, 84%, 73%, and 39%, with 14 patients (35%) dead. Median overall survival was 46 months. Progression occurred in 25 patients (62.5%), at a median interval of 8 months; failure at SABR site was observed in 3 patients (7.5%). Progression-free survival rates were 49% and 27% at 1 and 2 years, respectively.

DISCUSSION

The results of this retrospective exploratory analysis suggest safety and efficacy of SABR in patients affected with colorectal cancer lung oligometastases and urge inclusion of SABR in prospective clinical trials.