Local Control Following Stereotactic Body Radiation Therapy for Liver Oligometastases: Lessons from a Quarter Century

The utilization of stereotactic body radiation therapy for the treatment of liver metastasis has been widely studied and has demonstrated favorable local control outcomes. However, several predictive factors play a crucial role in the efficacy of stereotactic body radiation therapy, such as the number and size (volume) of metastatic liver lesions, the primary tumor site (histology), molecular biomarkers (e.g., KRAS and TP53 mutation), the use of systemic therapy prior to SBRT, the radiation dose, and the use of advanced technology and organ motion management during SBRT. These prognostic factors need to be considered when clinical trials are designed to evaluate the efficacy of SBRT for liver metastases.

Design, Synthesis and Anticancer Evaluation of Nitroimidazole Radiosensitisers

The role of hypoxic tumour cells in resistance to radiotherapy, and in suppression of immune response, continues to endorse tumour hypoxia as a bona fide, yet largely untapped, drug target. Radiotherapy innovations such as stereotactic body radiotherapy herald new opportunities for classical oxygen-mimetic radiosensitisers. Only nimorazole is used clinically as a radiosensitiser, and there is a dearth of new radiosensitisers in development. In this report, we augment previous work to present new nitroimidazole alkylsulfonamides and we document their cytotoxicity and ability to radiosensitise anoxic tumour cells in vitro. We compare radiosensitisation with etanidazole and earlier nitroimidazole sulfonamide analogues and we identify 2-nitroimidazole and 5-nitroimidazole analogues with marked tumour radiosensitisation in ex vivo assays of surviving clonogens and with in vivo tumour growth inhibition.

Automated detection, delineation and quantification of whole-body bone metastasis using FDG-PET/CT images

Non-small cell lung cancer (NSCLC) patients with the metastatic spread of disease to the bone have high morbidity and mortality. Stereotactic ablative body radiotherapy increases the progression free survival and overall survival of these patients with oligometastases. FDG-PET/CT, a functional imaging technique combining positron emission tomography (PET) with 18 F-fluorodeoxyglucose (FDG) and computer tomography (CT) provides improved staging and identification of treatment response. It is also associated with reduction in size of the radiotherapy tumour volume delineation compared with CT based contouring in radiotherapy, thus allowing for dose escalation to the target volume with lower doses to the surrounding organs at risk. FDG-PET/CT is increasingly being used for the clinical management of NSCLC patients undergoing radiotherapy and has shown high sensitivity and specificity for the detection of bone metastases in these patients. Here, we present a software tool for detection, delineation and quantification of bone metastases using FDG-PET/CT images. The tool extracts standardised uptake values (SUV) from FDG-PET images for auto-segmentation of bone lesions and calculates volume of each lesion and associated mean and maximum SUV. The tool also allows automatic statistical validation of the auto-segmented bone lesions against the manual contours of a radiation oncologist. A retrospective review of FDG-PET/CT scans of more than 30 candidate NSCLC patients was performed and nine patients with one or more metastatic bone lesions were selected for the present study. The SUV threshold prediction model was designed by splitting the cohort of patients into a subset of 'development' and 'validation' cohorts. The development cohort yielded an optimum SUV threshold of 3.0 for automatic detection of bone metastases using FDG-PET/CT images. The validity of the derived optimum SUV threshold on the validation cohort demonstrated that auto-segmented and manually contoured bone lesions showed strong concordance for volume of bone lesion (r = 0.993) and number of detected lesions (r = 0.996). The tool has various applications in radiotherapy, including but not limited to studies determining optimum SUV threshold for accurate and standardised delineation of bone lesions and in scientific studies utilising large patient populations for instance for investigation of the number of metastatic lesions that can be treated safety with an ablative dose of radiotherapy without exceeding the normal tissue toxicity.

Local treatment of metastases plus systemic chemotherapy on overall survival of patients with metastatic nasopharyngeal carcinoma

Background

To investigate the effect of local treatment of metastases on overall survival (OS) of patients with metastatic nasopharyngeal carcinoma (NPC).

Methods

One hundred and forty‐seven patients were included. The association between local treatment and OS was examined with propensity score matching (PSM) method.

Results

In entire cohort, the median OS was significantly longer in patients with local treatment of metastases plus chemotherapy compared to those with chemotherapy alone (71.7 vs. 16.2 months; p < 0.001). In PSM cohort, similar OS benefit of patients with local treatment was observed (55.6 vs. 17.6 months; p = 0.011). The survival benefit of local treatment remained regardless of the number of metastatic lesions and metastatic sites. Patients received radiation doses of >60 Gy had longer OS than those who received less.

Conclusions

Local treatment of metastases could improve OS of patients with metastatic NPC and could be considered in their treatment in addition to chemotherapy.

Personalized treatment for differentiated thyroid cancer: current data and new perspectives

More conservative and personalized treatment options have been developed in recent years to face the rising diagnosis of low-risk differentiated thyroid carcinoma (DTC). The present review describes the change towards a more risk-adapted management either in the treatment or in the follow-up of DTC. Particular attention is given to the innovations introduced by the latest guidelines for low-risk tumors, starting from the most appropriate extension of surgery up to the postoperative management. The emerging role of active surveillance for low-risk microcarcinoma is discussed, as well as the development of percutaneous strategies in the setting of malignant thyroid disease. The recent use of approved new systemic target therapies for advanced radioiodine refractory thyroid cancer is reported, together with the description of new compounds in trial. Finally, we provide some considerations to improve the risk evaluation in a presurgical setting, especially related to the rising role of genetics, to enable better risk-based cancer management and personalized treatment choices.

Characteristic And Novel Therapeutic Strategies Of Nasopharyngeal Carcinoma With Synchronous Metastasis

Nasopharyngeal carcinoma (NPC) is rare in Western countries, but its incidence in China and Southeast Asia is notably high. NPC shows a high rate of distant metastasis including metachronous metastasis (mmNPC, metastasis after definitive chemo-radiotherapy) and synchronous metastasis (smNPC, metastasis at initial diagnosis). 4–10% of patients would be diagnosed as smNPC annually, and the survival outcomes of these patients are quite poor. As with few clinical trials exclusively focusing on this population, treatment on smNPC is not unified and many problems remain unsolved. To date, systematic chemotherapy (CT) still remains a fundamental treatment in smNPC. Although no randomized trial has been conducted to compare different CT regimens in smNPC, gemcitabine and taxanes in combination with platinum seem optimal in first-line setting. In second-line CT, there is no consensus: mono-chemotherapy with drugs such as gemcitabine, taxanes or capecitabine could be taken into consideration. Immunotherapy based on checkpoint inhibitors shows promising efficacy both in first-line and in the following lines of therapy. In addition to CT, local therapy in smNPC is also very important. Locoregional radiotherapy (RT) for primary tumor in combination with CT could strikingly increase OS with acceptable toxicities. And local treatment, such as surgery and RT, for metastatic lesions could bring extra survival benefit in patients with solitary or limited metastases. Overall, the present study provides an overview of the literature on the various studies of smNPC.

NRG Oncology/RTOG 0438: A Phase 1 Trial of Highly Conformal Radiation Therapy for Liver Metastases

PURPOSE

This study aimed to determine the feasibility and maximally tolerated dose of hypofractionated, conformal radiation therapy (RT) in patients with liver metastases.

METHODS AND MATERIALS

Nonsurgical patients with ≤5 liver metastases (sum of maximal diameter of all lesions ≤8 cm) were included in the study. There were 4 dose levels: 35 Gy, 40 Gy (starting level), 45 Gy, and 50 Gy, in 10 fractions. The clinical target volume included metastases identified on contrast computed tomography or magnetic resonance imaging with a 5-mm margin within the liver. The planning target volume margin ranged from 4 to 30 mm, depending on breathing motion. Dose-limiting toxicities were defined as RT-related grade ≥4 hepatic or gastrointestinal toxicities or thrombocytopenia occurring within 90 days of the start of RT.

RESULTS

A total of 26 patients with metastases from colorectal (8 patients), breast (7 patients) and other malignancies (11 patients) were enrolled between November 2005 and December 2010. Twenty-three patients were evaluable (8, 7, and 8 on the 40, 45, and 50 Gy dose levels, respectively). Two patients assigned to 50 Gy received 35 Gy owing to normal tissue limits, so 2 additional patients were treated to 50 Gy. There were no dose-limiting toxicities on any of the dose levels. On the 45 Gy dose level, 1 patient developed reversible grade 3 enteritis (37 days from RT start) and diarrhea (22 days); another patient developed grade 3 lymphopenia (23 days). At the 50 Gy dose level, 1 patient had grade 3 hyperglycemia (74 days), and another patient developed grade 3 lymphopenia (13 days), colonic hemorrhage (325 days), and colonic gastrointestinal obstruction (325 days). With a potential median follow-up of 66.1 months (range, 34.6-89.0 months), no other late toxicities were observed.

CONCLUSIONS

Treatment of liver metastases with 50 Gy in 10 fractions was feasible and safe in a multi-institutional setting.

The Impact of Zoledronic Acid and Radioactive Iodine Therapy on Morbi-Mortality of Patients with Bone Metastases of Thyroid Cancer Derived from Follicular Cells

OBJECTIVE

Bone metastases bring greater morbi-mortality to patients with differentiated thyroid carcinoma (DTC). Treatment was limited to radioactive iodine (RAI) and local approaches. Currently, bisphosphonates are included in the therapeutic arsenal. The aim of this study is to evaluate the impact of bone metastases and their treatment with zoledronic acid (ZA) and RAI therapy.

METHODS

We retrospectively review 50 DTC patients with structurally evident bone metastases followed in a tertiary cancer center from 1994 to 2018. Clinical-pathologic characteristics, skeletal related events (SRE), and therapeutic approaches were recorded.

RESULTS

Among the 50 patients analyzed, 22 underwent ZA adjuvant therapy and 28 did not. Mortality rate was 44%. Those patients presented SREs more frequently (90.9 vs. 67.9% the survival group, p = 0.05) and also had a greater number of bone lesions (40.9 vs. 10.7% had more than 6 metastatic sites, p = 0.03). The same group of patients was analyzed before and after therapy with ZA and the incidence of SRE decreased from 1.81 (0-8) before therapy to 0.29 (0-7) after therapy (p = 0.006). Comparing similar groups of 22 patients treated with ZA with 28 patients not treated, there was a trend of better overall survival (OS) in the group that received this drug (147 vs. 119 months, p = 0.06) and significantly improvement when bone metastases were RAI avid 155 (125-185) versus 120 (85-157) months, p < 0.01. Conclusion : ZA can successfully diminish the chance of having new SRE and possibly affect OS in DTC patients with bone metastases. The positive impact of RAI adjuvant treatment on OS is directly associated with RAI uptake.

Radiosurgical techniques for the treatment of brain neoplasms: A short review

Radiotherapy has long been used as an adjunct to neurosurgery for the treatment of malignant and benign intracranial tumors and other intracranial lesions. Intracranial tumors can be irradiated in three different ways: I) fractional radiotherapy, II) stereotactic radiotherapy and III) stereotactic radiosurgery. The third is most often by means of a gamma knife or a specially designed linear accelerator. Additionally, radiosurgery is increasingly used in combination with systemic therapy to treat metastases.

A matched-pair analysis of stereotactic body radiotherapy (SBRT) for oligometastatic lung tumors from colorectal cancer versus early stage non-small cell lung cancer

BACKGROUND

The use of stereotactic body radiotherapy (SBRT) for early-stage primary non-small cell lung cancer (NSCLC) reported excellent local control rates. But the optimal SBRT dose for oligometastatic lung tumors (OLTs) from colorectal cancer (CRC) has not yet been determined. This study aimed to evaluate whether SBRT to a dose of 48-60 Gy in 4-5 fractions could result in similar local outcomes for OLTs from CRC as compared to early-stage NSCLC, and to examine potential dose-response relationships for OLTs from CRC.

METHODS

OLTs from CRC and primary NSCLCs treated with SBRT to 48-60 Gy in 4-5 fractions at a single institution were evaluated, and a matched-pair analysis was performed. Local recurrence-free survival (LRFS) was estimated by the Kaplan-Meier method. Univariate Cox regression was performed to identify significant predictors.

RESULTS

There were 72 lung lesions in 61 patients (24 OLTs from CRC in 15 patients and 48 NSCLCs in 46 patients) were analyzed with a median follow-up of 30 months. LRFS for OLTs from CRC was significantly worse than that of NSCLC when treated with 48-60 Gy/4-5 fx (p = 0.006). The 1, 3 and 5-year LRFS of OLTs from CRC vs NSCLC were 80.6% vs. 100%, 68.6% vs. 97.2%, and 68.6% vs. 81.0%, respectively. On univariate analysis, OLTs from CRC treated with higher dose (BED₁₀ = 132 Gy) exhibited significantly better local recurrence-free survival than those treated to lower doses (BED₁₀ ≤ 105.6 Gy) (p = 0.0022). The 1 and 3-year LRFS rates for OLTs treated to a higher dose (BED₁₀ = 132 Gy) were 88.9% and 81.5%, vs 33.3%, and not achieved for lower doses (BED₁₀ ≤ 105.6 Gy).

CONCLUSION

The LRFS of OLTs from CRC after SBRT of 48-60 Gy/4-5 fx was significantly worse than that of primary NSCLC. Lower dose SBRT appeared to have inferior control for OLTs of CRC in this cohort. Further studies with larger sample sizes are needed.

Ablative stereotactic radiotherapy for oligometastatic colorectal cancer: Systematic review

BACKGROUND

SBRT is a novel modality in treatment for oligometastatic colorectal cancer. We aimed to perform a systematic review of results of SBRT in maintaining LC (local control) for CRC liver and lung oligometastases.

MATERIALS AND METHODS

The review was performed according to PRISMA and PICO guidelines. Database search using keywords: stereotactic, colon, colorectal, cancer, sbrt, sabr returned 457 results. 15 were included in the study. Only cohorts with CRC histology and reported LC were included.

RESULTS

For liver LC rates ranged from 50% to 100% after 1 year and 32% to 91% after 2 years. BED range 40.5-262.5 Gy (Gray). For lung LC rates ranged from 62% to 92% after 1 one year and from 53% to 92% after 2 years. BED range 51.3-262.5 Gy.

CONCLUSIONS

SBRT of oligometastatic CRC offers high LC with low morbidity and toxicity. It requires more observational studies and randomized trials but available data on clinical efficacy is promising, however not yet matured.

Solitary Pulmonary Lesion in Patients with History of Malignancy: Primary Lung Cancer or Metastatic Cancer?

BACKGROUND

Defining the status of solitary pulmonary lesion (SPL) in patients with history of malignancy is important because primary lung cancer (PLC) or intrapulmonary metastasis might indicate different surgical strategies. The aim of this study is to identify factors related to the status of these lesions and construct a clinical model to estimate the pretest probability of PLC.

METHODS

From January 2005 to January 2016, 104 patients with previous malignancy and suitable for surgery were retrospectively studied. Univariate and multivariate analyses were performed to identify possible factors related to SPLs. A nomogram was constructed to differentiate PLC from intrapulmonary metastasis.

RESULTS

Ninety-seven (93.3%) patients were diagnosed as malignant postoperatively, including 61 patients with intrapulmonary metastasis and 36 patients with PLC. Multivariate analysis showed that site of primary tumor [head and neck squamous cell cancer: odds ratio (OR) = 28.509, P = 0.006; genitourinary cancer: OR = 23.928, P = 0.012], negative lymph node status of primary tumor (OR = 3.154, P = 0.038), spiculation of SPL (OR = 3.972, P = 0.022), and central location of SPL (OR = 4.679, P = 0.026) were four independent factors differentiating PLC from intrapulmonary metastasis. All of these were included in the nomogram. The C-index of the nomogram for predicting probability was 0.82.

CONCLUSIONS

Incidence of malignant SPLs was fairly high in patients with history of malignancy. A nomogram including site and lymph node status of primary tumor, and spiculation and location of SPL might be a good tool for differentiating PLC from intrapulmonary metastasis preoperatively and guiding treatment.

A phase II randomized trial of Observation versus stereotactic ablative RadiatIon for OLigometastatic prostate CancEr (ORIOLE)

Background

We describe a randomized, non-blinded Phase II interventional study to assess the safety and efficacy of stereotactic ablative radiotherapy (SABR) for hormone-sensitive oligometastatic prostate adenocarcinoma, and to describe the biology of the oligometastatic state using immunologic, cellular, molecular, and functional imaging correlates. 54 men with oligometastatic prostate adenocarcinoma will be accrued. The primary clinical endpoint will be progression at 6 months from randomization with the hypothesis that SABR to all metastases will forestall progression by disrupting the metastatic process. Secondary clinical endpoints will include local control at 6 months post-SABR, toxicity and quality of life, and androgen deprivation therapy (ADT)-free survival (ADT-FS). Further fundamental analysis of the oligometastatic state with be achieved through correlation with investigational ¹⁸F–DCFPyL PET/CT imaging and measurement of circulating tumor cells, circulating tumor DNA, and circulating T-cell receptor repertoires, facilitating an unprecedented opportunity to characterize, in isolation, the effects of SABR on the dynamics of and immunologic response to oligometastatic disease.

Methods/design

Patients will be randomized 2:1 to SABR or observation with minimization to balance assignment by primary intervention, prior hormonal therapy, and PSA doubling time. Progression after 6 months will be compared using Fisher’s exact test. Hazard ratios and Kaplan-Meier estimates of progression free survival (PFS), ADT free survival (ADT-FS), time to locoregional progression (TTLP) and time to distant progression (TTDP) will be calculated based on an intention-to-treat. Local control will be assessed using Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria. Withdrawal from the study prior to 6 months will be counted as progression. Adverse events will be summarized by type and grade. Quality of life pre- and post- SABR will be measured by Brief Pain Inventory.

Discussion

The ORIOLE trial is the first randomized, non-blinded Phase II interventional study in the North America evaluating the safety and efficacy of SABR in oligometastatic hormone-sensitive prostate cancer. Leading-edge laboratory and imaging correlates will provide unique insight into the effects of SABR on the oligometastatic state.

Trial registrations

ClinicalTrials.gov Identifier: NCT02680587.

URL of Registry: https://clinicaltrials.gov/show/NCT02680587

Date of Registration: 02/08/2016.

Date of First Participant Enrollment: 05/23/2016.

Pattern of Failure Analysis in Metastatic EGFR-Mutant Lung Cancer Treated with Tyrosine Kinase Inhibitors to Identify Candidates for Consolidation Stereotactic Body Radiation Therapy

INTRODUCTION

The role of stereotactic body radiation therapy (SBRT) in patients with metastatic lung cancer harboring epidermal growth factor receptor (EGFR) mutations is not defined. We evaluated the pattern of failure in patients receiving tyrosine kinase inhibitor (TKI) therapy to identify candidates for consolidation SBRT.

METHODS

Computed tomography scans were reviewed in a cohort of EGFR-mutant patients enrolled on prospective TKI trials. Initial progression in sites of original disease (primary/metastatic) or new sites was classified as original site failure (OF) or distant site failure (DF), respectively. Simultaneous OF/DF was labeled ODF. Disease characteristics were analyzed for associations with patterns of failure using actuarial competing risks methodology.

RESULTS

Complete serial imaging was available in 49 patients with measurable disease. Median time to any progression was 8.3 months. The majority failed initially in original disease sites with OF, ODF, and DF frequencies being 47.0%, 32.6%, and 20.4%, respectively. Primary tumor size was the most significant predictor of OF in univariate and multivariate analysis (p = 0.004). Median time to progression was 3 months shorter in patients with OF compared with DF. Ten patients (20%) were retroactively classified as consolidation SBRT candidates based on the extent of disease at time of best response to TKI therapy, and in seven of these, initial progression occurred in original tumor sites.

CONCLUSION

Initial progression of TKI-treated cancers occurred predominantly in original disease sites. Consolidation SBRT was judged feasible in a subset of patients following maximum TKI response and may have prevented oligoprogression in most of these. In addition, we hypothesize that consolidation SBRT for residual disease could delay subsequent metastatic reseeding.

[Not Available]

OLIGOMETASTASIS AND OLIGOPROGRESSION

Oligometastic progression (or solitary metastases) can justify ablative treatment for metastatic treatment. When such a strategy is discussed, it is important to notice that definition of oligometastases is not consensual both in terms of clinical presentation than on the biological basis. Does a specific biological background truly exist and are there markers that could predict for additional occult disease and its oligo or polymetastatic profile in individuals with demonstrated oligometastasis. This article provides a summary of the state of the art in this field and highlights some current areas of controversies.

Clinical applications of stereotactic radiation therapy for oligometastatic cancer patients: a disease-oriented approach

Oligometastases from solid tumors are currently recognized as a distinct clinical entity, corresponding to an intermediate state between local and widespread disease. It has been suggested that local ablative therapies (including surgery, radiofrequency ablation and radiation therapy) play an important role in this setting, in combination or not with systemic therapies, particularly in delaying disease progression and hopefully in increasing the median survival time. Stereotactic body radiation therapy (SBRT) rapidly emerged in recent years as one of the most effective and less toxic local treatment modalities for lung, liver, adrenal, brain and bone metastases. The aim of this review was to focus on its clinical role for oligometastatic disease in four major cancer subtypes: lung, breast, colorectal and prostate. On the basis of the available evidence, SBRT is able to provide high rates of local tumor control without significant toxicity. Its global impact on survival is uncertain; however, in specific subpopulations of oligometastatic patients there is a trend towards a significant improvement in progression-free and overall survival rates; these important data might be used as a platform for clinical decision-making and establish the basis for the current and future prospective trials investigating its role with or without systemic treatments.

Therapeutic options in papillary thyroid carcinoma: current guidelines and future perspectives

The treatment of papillary thyroid cancer is now based on individual patient risk and response to therapies. Molecular techniques are increasingly being used to risk stratify and to guide therapeutic decisions. There have been advances in the treatment of local disease through surgery or radioiodine. Directed techniques can target metastatic disease including bisphosphonates, radiofrequency ablation or radiotherapy. Systemic therapies such as tyrosine kinase inhibitors show great promise although such treatment must be individualized. Future therapies will target treating radioiodine refractory disease.

A multi-national report on stereotactic body radiotherapy for oligometastases: Patient selection and follow-up

Aims Stereotactic body radiotherapy (SBRT) for oligometastases is increasingly used with few evidenced-based guidelines. We conducted a survey to determine patient selection and follow-up practice patterns. Materials and methods Seven institutions from US, Canada, Europe, and Australia that recommend SBRT for oligometastases participated in a 72-item survey. Levels of agreement were categorized as strong (6-7 common responses), moderate (4-5), low (2-3), or no agreement. Results There was strong agreement for recommending SBRT for eradication of all detectable oligometastases with most members limiting the number of metastases to five (range 2-5) and three within a single organ (range 2-5). There was moderate agreement for recommending SBRT as consolidative therapy after systemic therapy. There was strong agreement for requiring adequate performance status and no concurrent chemotherapy. Additional areas of strong agreement included staging evaluations, primary diagnosis, target sites, and follow-up recommendations. Several differences emerged, including the use of SBRT for sarcoma oligometastases, treatment response evaluation, and which imaging should be performed during follow-up. Conclusion Significant commonalities and variations exist for patient selection and follow-up recommendations for SBRT for oligometastases. Information from this survey may serve to help clarify the current landscape.

The use of isodose levels to interpret radiation induced lung injury: a quantitative analysis of computed tomography changes

BACKGROUND

Patients treated with stereotactic body radiation therapy (SBRT) for lung cancer are often found to have radiation-induced lung injury (RILI) surrounding the treated tumor. We investigated whether treatment isodose levels could predict RILI.

METHODS

Thirty-seven lung lesions in 32 patients were treated with SBRT and received post-treatment follow up (FU) computed tomography (CT). Each CT was fused with the original simulation CT and treatment isodose levels were overlaid. The RILI surrounding the treated lesion was contoured. The RILI extension index [fibrosis extension index (FEI)] was defined as the volume of RILI extending outside a given isodose level relative to the total volume of RILI and was expressed as a percentage.

RESULTS

Univariate analysis revealed that the planning target volume (PTV) was positively correlated with RILI volume at FU: correlation coefficient (CC) =0.628 and P<0.0001 at 1(st) FU; CE =0.401 and P=0.021 at 2(nd) FU; CE =0.265 and P=0.306 at 3(rd) FU. FEI -40 Gy at 1(st) FU was significantly positively correlated with FEI -40 Gy at subsequent FU's (CC =0.689 and P=6.5×10(-5) comparing 1(st) and 2(nd) FU; 0.901 and P=0.020 comparing 2(nd) and 3(rd) FU. Ninety-six percent of the RILI was found within the 20 Gy isodose line. Sixty-five percent of patients were found to have a decrease in RILI on the second 2(nd) CT.

CONCLUSIONS

We have shown that RILI evolves over time and 1(st) CT correlates well with subsequent CTs. Ninety-six percent of the RILI can be found to occur within the 20 Gy isodose lines, which may prove beneficial to radiologists attempting to distinguish recurrence vs. RILI.

2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Task Force on Thyroid Nodules and Differentiated Thyroid Cancer

BACKGROUND

Thyroid nodules are a common clinical problem, and differentiated thyroid cancer is becoming increasingly prevalent. Since the American Thyroid Association's (ATA's) guidelines for the management of these disorders were revised in 2009, significant scientific advances have occurred in the field. The aim of these guidelines is to inform clinicians, patients, researchers, and health policy makers on published evidence relating to the diagnosis and management of thyroid nodules and differentiated thyroid cancer.

METHODS

The specific clinical questions addressed in these guidelines were based on prior versions of the guidelines, stakeholder input, and input of task force members. Task force panel members were educated on knowledge synthesis methods, including electronic database searching, review and selection of relevant citations, and critical appraisal of selected studies. Published English language articles on adults were eligible for inclusion. The American College of Physicians Guideline Grading System was used for critical appraisal of evidence and grading strength of recommendations for therapeutic interventions. We developed a similarly formatted system to appraise the quality of such studies and resultant recommendations. The guideline panel had complete editorial independence from the ATA. Competing interests of guideline task force members were regularly updated, managed, and communicated to the ATA and task force members.

RESULTS

The revised guidelines for the management of thyroid nodules include recommendations regarding initial evaluation, clinical and ultrasound criteria for fine-needle aspiration biopsy, interpretation of fine-needle aspiration biopsy results, use of molecular markers, and management of benign thyroid nodules. Recommendations regarding the initial management of thyroid cancer include those relating to screening for thyroid cancer, staging and risk assessment, surgical management, radioiodine remnant ablation and therapy, and thyrotropin suppression therapy using levothyroxine. Recommendations related to long-term management of differentiated thyroid cancer include those related to surveillance for recurrent disease using imaging and serum thyroglobulin, thyroid hormone therapy, management of recurrent and metastatic disease, consideration for clinical trials and targeted therapy, as well as directions for future research.

CONCLUSIONS

We have developed evidence-based recommendations to inform clinical decision-making in the management of thyroid nodules and differentiated thyroid cancer. They represent, in our opinion, contemporary optimal care for patients with these disorders.

A single reference measurement can predict liver tumor motion during respiration

AIM

To evaluate liver tumor motion and how well reference measurement predicts motion during treatment.

MATERIAL AND METHODS

This retrospective study included 20 patients with colorectal cancer that had metastasized to the liver who were treated with stereotactic ablative radiotherapy. An online respiratory tumor tracking system was used. Tumor motion amplitudes in the superior-inferior (SI), latero-lateral (LL), and anterior-posterior (AP) directions were collected to generate patient-specific margins. Reference margins were generated as the mean motion and 95th percentile of motion from measurements recorded for different lengths of time (1, 3, and 5 min). We analyzed the predictability of tumor motion in each axis, based on the reference measurement and intra-/interfraction motions.

RESULTS

About 96,000 amplitudes were analyzed. The mean tumor motions were 9.9 ± 4.2 mm, 2.6 ± 0.8 mm, and 4.5 ± 1.8 mm in the SI, LL, and AP directions, respectively. The intrafraction variations were 3.5 ± 1.8 mm, 0.63 ± 0.35 mm, and 1.4 ± 0.65 mm for the SI, LL, and AP directions, respectively. The interfraction motion variations were 1.32 ± 0.79 mm, 0.31 ± 0.23 mm, and 0.68 ± 0.62 mm for the SI, LL, and AP directions, respectively. The Pearson's correlation coefficients for margins based on the reference measurement (mean motion or 95th percentile) and margins covering 95% of the motion during the whole treatment were 0.8-0.91, 0.57-0.7, and 0.77-0.82 in the SI, LL, and AP directions, respectively.

CONCLUSION

Liver tumor motion in the SI direction can be adequately represented by the mean tumor motion amplitude generated from a single 1 min reference measurement. Longer reference measurements did not improve results for patients who were well-educated about the importance of regular breathing. Although the study was based on tumor tracking data, the results are useful for ITV delineation when tumor tracking is not available.

Advances in veterinary radiation therapy: targeting tumors and improving patient comfort

Newer technology, such as intensity-modulated radiation therapy, can dramatically decrease acute radiation side effects, making patients more comfortable during and after treatment. Stereotactic radiation therapy for definitive treatment can be delivered in 1 to 5 fractions, with minimal radiation-associated effects. Image-guided radiation therapy can be used to direct treatment in locations previously not amenable to radiation therapy. Traditional fractionated radiation therapy remains the most commonly available type in veterinary medicine and is the standard of care for many tumors. This article discusses the role of advancements in the treatment of veterinary cancer patients and reviews more traditional radiation treatment.

Stereotactic Body Radiotherapy of Bone Metastases in Oligometastatic Disease: Prognostic Factors of Oncologic Outcomes

Background

To evaluate the safety of stereotactic body radiotherapy (SBRT) of bone metastases in oligometastatic disease and to investigate prognostic factors of local control (LC), progression/disease-free survival (PDFS), and overall survival (OS).

Methods

Eligibility criteria were number of metastates ≤5, controlled primary tumor without evidence of progression under systemic therapy, exclusion of surgery, and no previous radiotherapy of the lesion of interest. Oligometastatic status was classified into only bone (BOD) and outside bone disease (OBOD), whereas SBRT was delivered to bone lesions using 2 different schedules: 24 Gy/1 fraction or 27 Gy/3 fractions. A positron emission tomography study of the lesion of interest was performed at baseline and at 3 months after SBRT to evaluate metabolic response according to European Organization for Research and Treatment of Cancer (EORTC) criteria. A Cox regression model was used for univariate and multivariate analysis.

Results

Between January 2010 and December 2013, 40 patients were enrolled. Only 1 patient experienced severe late toxicity (radiation-related fracture). Local control was longer among responders’ than nonresponders’ lesions (94.2% and 91.2% versus 63% and 35% at 1 and 2 years, respectively) (p = 0.004; hazard ratio = 9.958). The multivariate analysis of PDFS showed a significant correlation with planning target volume (PTV) size (p = 0.003) and oligometastatic status (p = 0.002). The multivariate analysis of OS confirmed a statistically significant value of the oligometastatic status (p = 0.002) and a significant trend for PTV size (p = 0.065).

Conclusions

Stereotactic body radiotherapy is safe with a low incidence of severe toxicity. Positron emission tomography response was a strong prognostic factor of LC whereas BOD status and small PTV size could identify a subset of oligometastatic patients at better prognosis.

Stereotactic radiation therapy of renal cancer inferior vena cava tumor thrombus

Renal Cell Carcinoma (RCC) is a common malignancy world-wide that is rising in incidence. Up to 10% of RCC patients present with inferior vena cava (IVC) tumor thrombus (IVC-TT). Although surgery is the only treatment with proven efficacy for IVC-TT, the surgical management of advanced (level III and IV) IVC-TT is difficult with high morbidity and mortality, and offers a poor survival outcome. Currently, there are no treatment options in the setting of recurrent or unresectable RCC IVC-TT. Even though RCC may be resistant to conventionally fractionated radiation therapy, hypofractionated radiation has shown excellent control rates for both primary and metastatic RCC. We report our experience treating 2 RCC patients with Level IV IVC-TT -one recurrent and the other unresectable-with stereotactic ablative radiation therapy (SABR). The first patient is a 75-year-old gentleman with a level IV RCC IVC-TT who presented 9 months after his radical nephrectomy and thrombectomy with a growing level IV IVC-TT that became refractory to 4 targeted agents. He received SABR of 50Gy in 5 fractions and at 2-year follow-up is doing well with a significant decrease in the enhancement and size of the IVC-TT. The second patient is an 83-year-old gentleman who presented with metastatic RCC and level IV IVC-TT but was not a surgical candidate. After progression on temsirolimus, he received SABR of 36Gy in 4 fractions to his IVC-TT and survived 18 months post-SABR. Both patients improved symptomatically and did not experience any acute or late treatment-related toxicity. Their survival of 24 months and 18 months are comparable to the reported median survival of 20 months in patients with level IV IVC-TT that underwent surgical resection. Therefore, SABR can be a potentially safe treatment option in the unresectable setting for RCC patients with IVC-TT and should be further evaluated in prospective trials.

Stereotactic body radiotherapy (sbrt) in lung oligometastatic patients: role of local treatments

Background

Data in the literature suggest the existence of oligometastatic disease, a state in which metastases are limited in number and site. Different kinds of local therapies have been used for the treatment of limited metastases and in the recent years reports on the use of Stereotactic Ablative radiotherapy (SABR) are emerging and the early results on local control are promising.

Patients and methods

From October 2010 to February 2012, 76 consecutive patients for 118 lung lesions were treated. SABR was performed in case of controlled primary tumor, long-term of progression disease, exclusion of surgery, and number of metastatic sites ≤ 5. Different kinds of primary tumors were treated, the most common were lung and colon-rectal cancer. The total dose prescribed varied according to tumor site and maximum diameter. Dose prescription was 48 Gy in 4 fractions for peripheral lesions, 60 Gy in 8 fractions for central lesions and 60 Gy in 3 fractions for peripheral lesions with diameter ≤ 2 cm.

Results

Dosimetric planning objectives were met for the cohort of patients with in particular V98% = 98.1 ± 3.4% for the CTV and mean lung dose of 3.7 ± 3.8 Gy. Radiological response was obtained in the vast majority of patients. The local control at 1, 2 and 3 years was 95%, 89% and 89% respectively. No major pulmonary toxicity, chest pain or rib fracture occurred. The median follow up was 20 months (range 6–45 months). Overall Survival (OS) at 1, 2 and 3 years was 84.1%, 73% and 73% respectively.

Conclusions

SABR is feasible with limited morbidity and promising results in terms of local contro, survival and toxicity.

Adenoviral transduction of human acid sphingomyelinase into neo-angiogenic endothelium radiosensitizes tumor cure

These studies define a new mechanism-based approach to radiosensitize tumor cure by single dose radiotherapy (SDRT). Published evidence indicates that SDRT induces acute microvascular endothelial apoptosis initiated via acid sphingomyelinase (ASMase) translocation to the external plasma membrane. Ensuing microvascular damage regulates radiation lethality of tumor stem cell clonogens to effect tumor cure. Based on this biology, we engineered an ASMase-producing vector consisting of a modified pre-proendothelin-1 promoter, PPE1(3x), and a hypoxia-inducible dual-binding HIF-2α-Ets-1 enhancer element upstream of the asmase gene, inserted into a replication-deficient adenovirus yielding the vector Ad5H2E-PPE1(3x)-ASMase. This vector confers ASMase over-expression in cycling angiogenic endothelium in vitro and within tumors in vivo, with no detectable enhancement in endothelium of normal tissues that exhibit a minute fraction of cycling cells or in non-endothelial tumor or normal tissue cells. Intravenous pretreatment with Ad5H2E-PPE1(3x)-ASMase markedly increases SDRT cure of inherently radiosensitive MCA/129 fibrosarcomas, and converts radiation-incurable B16 melanomas into biopsy-proven tumor cures. In contrast, Ad5H2E-PPE1(3x)-ASMase treatment did not impact radiation damage to small intestinal crypts as non-dividing small intestinal microvessels did not overexpress ASMase and were not radiosensitized. We posit that combination of genetic up-regulation of tumor microvascular ASMase and SDRT provides therapeutic options for currently radiation-incurable human tumors.

Esophageal gel-shifting technique facilitating eradicative boost or reirradiation to upper mediastinal targets of recurrent nerve lymph node without damaging esophagus

We developed a new technique using hyaluronic gel injection as a spacer to safely move the esophagus away from the high-dose area during interstitial brachytherapy of a mediastinal target close to the esophagus. We percutaneously injected a high-molecular-weight hyaluronic gel mixed with contrast medium to create a space between the esophagus and the target during interstitial brachytherapy. We applied this technique to two cases of relapsed recurrent nerve lymph node metastasis from esophageal cancer: one refractory tumor after 50 Gy of radiotherapy, and one recurrence after mediastinal radiotherapy of total 64 Gy. We prescribed 20 Gy and 18 Gy in one fraction to each target, with calculated esophageal D2cc (the minimum dose to the most irradiated volume of 2 cc) of 4.0 Gy and 6.8 Gy, respectively. Calculated enhancement factor by gel shifting in equivalent dose was 2.69 and 2.34, respectively. In each patient, accumulated esophageal D1cc (minimum dose to the most irradiated volume of p cc. minimum dose to the most irradiated volume of 1 cc) was 74.4 Gy and 85.6 Gy without shifting, and 59.1 Gy and 37.6 Gy with shifting, respectively. There were no procedure-related complications. Four months after the brachytherapy, each tumor was remarkably diminished. No evidence of recurrences or late complications were observed 8 months and 9 months after the procedure, respectively. The esophageal gel-shifting technique may facilitate eradicative brachytherapy to upper mediastinal targets without damaging the esophagus, and can be used in conjunction with boost irradiation or reirradiation to overcome the problem of salvage failure.

Novel eradicative high-dose rate brachytherapy for internal mammary lymph node metastasis from breast cancer

AIM: To develop a method of delivering an eradicative high radiotherapeutic dose safely preserving the surrounding skin in the treatment of internal mammary lymph node metastasis (IMLNM) of breast cancer.

METHODS: We report a 38-year-old female patient with a solo IMLNM showing no response to 60 Gy in 2.5 Gy fractions of external beam radiotherapy. To eradicate this tumor, a boost brachytherapy plan was created after percutaneous insertion of an applicator needle into the IMLNM lesion avoiding the pleura and vessels under ultrasound monitoring. According to the dose distribution, the required thickness of a spacer between the skin and the tumor was determined, and hyaluronic gel was injected up to this thickness under ultrasound monitoring. We evaluated skin doses, target doses and clinical outcome.

RESULTS: All procedures were performed easily. Sixteen Gy (34.7 Gy equivalent in 2 Gy fractions calculated by the linear quadratic model at α/β = 10: EQD_{2, α/β = 10}, cumulative total was 101.9 Gy EQD10) to 100% of the target volume was irradiated with cumulative maximum skin dose of 70 Gy EQD_{2, α/β = 3} which was 98.7 Gy EQD_{2, α/β = 3} without spacer. No procedure related- or late complications and no local recurrence at the treated site were observed for three years until expiration.

CONCLUSION: We consider that this procedure will provide an eradicative high-dose irradiation to IMLNM of breast cancer, preserving skin from overdose complications.

Stereotactic body radiotherapy for metachronous multisite oligo-recurrence: a long-surviving case with sequential oligo-recurrence in four different organs treated using locally radical radiotherapy and a review of the literature

Stereotactic body radiotherapy (SBRT) for oligometastases represents a recent trend in radiation oncology. While abundant data are available regarding the use of SBRT for the treatment of lung or liver oligometastases from various retrospective series and prospective trials, relatively little information has been accumulated for the treatment of oligometastases at sites other than the lungs and liver, particularly for sequential oligometastases in multiple organs. Oligometastases with primary lesions controlled is called “oligo-recurrence.” We describe herein the case of a lung cancer patient who developed repeated oligo-recurrence at multiple sites that were each controlled by radical radiotherapy and achieved long-term survival and discuss the merits of locally aggressive radiotherapy for this type of disease condition with reviewing the literature. Although further investigation should be undertaken to clarify the benefits, objectives, and methods of SBRT for the treatment of oligometastases, we believe utilization of SBRT may be worthwhile for patients with remote metastases who hope for treatment to acquire better local control and possible longer survival.

Review and uses of stereotactic body radiation therapy for oligometastases

In patients with proven distant metastases from solid tumors, it has been a notion that the condition is incurable, warranting palliative care only. The term "oligometastases" was coined to refer to isolated sites of metastasis, whereby the entire burden of disease can be recognized as a finite number of discrete lesions that can be potentially cured with local therapies. Stereotactic body radiation therapy (SBRT) is a novel treatment modality in radiation oncology that delivers a very high dose of radiation to the tumor target with high precision using single or a small number of fractions. SBRT is the result of technological advances in patient and tumor immobilization, image guidance, and treatment planning and delivery. A number of studies, both retrospective and prospective, showed promising results in terms of local tumor control and, in a limited subset of patients, of survival. This article reviews the radiobiologic, technical, and clinical aspects of SBRT for various anatomical sites.

Stereotactic body radiation therapy for metastasis in the lung: an undervalued treatment option with future prospects

SUMMARY The lung is a common site of metastatic disease from solid tumors. Most cancers can develop lung metastases, and sarcoma and epithelial (especially colorectal) malignancies are prone to metastasize to the lung. In particular, the International Registry of Lung Metastases describes 5206 cases of lung metastasectomy, of which 43% were epithelial and 42% were sarcomatoid. Common presenting symptoms include cough, hemoptysis, shortness of breath, chest pain and back pain. Data in the literature suggest the existence of an oligometastatic state, where metastases are limited in number and location. For selected patients with lung oligometastases, local therapy such as surgery, stereotactic body radiotherapy (SBRT) and radiofrequency ablation may potentially yield prolonged survival. Data from retrospective series and prospective trials on the use of SBRT for lung metastases are emerging, showing promising results. Most studies show high local control rates rivaling those found in studies of surgical management (the usual treatment of choice) for lung metastases, while SBRT also has the benefit of low rates of significant toxicities. This review will provide an overview of the utilization of SBRT in the management of lung oligometastases.

Clinical outcomes of single or oligo-fractionated stereotactic radiotherapy for head and neck tumors using micromultileaf collimator-based dynamic conformal arcs

PURPOSE

To assess the clinical outcomes of single or oligo-fractionated stereotactic radiotherapy (SRT) using dynamic conformal arcs (DCA) for head and neck tumors (HNTs).

METHODS

Thirty-four consecutive patients with 35 lesions treated between 2005 and 2009 were retrospectively evaluated, of whom 85.7 % had recurrent or metastatic disease, and 45.7 and 34.3 % had previous radiotherapy and surgery, respectively. The median SRT dose was 22.3 Gy (11.2-32.8) in 2-4 fractions with a median interval of 7 days and 10.4 Gy (9.2-12.4) in one fraction. SRT was combined with upfront conventionally fractionated RT in 48.6 % of patients.

RESULTS

The median follow-up periods were 18.4 months (2-84.1) for the entire cohort and 49.6 months for the survivors. The 1- and 2-year local control (LC) rates were 84.3 and 70.5 %, with the 1- and 2-year overall survival (OS) rates of 78.6 and 51.6 %. LC was significantly better for tumor volumes <25.6 cm(3) (p = 0.001). OS was significantly longer in patients without any disease outside the SRT site (p < 0.001), whereas LC after the SRT did not affect the OS. Late adverse events occurred in 9 patients, including cranial nerve (CN) injury (grade 3/4) in 2, brain radionecrosis in 5 (grade 1), and fatal bleeding in 2 patients harboring uncontrolled lesions abutting the carotid artery.

CONCLUSIONS

DCA-based SRT can confer relatively long-term LC with acceptable toxicity in selected patients with HNTs. The patients with CN involvement or tumor volume ≥25.6 cm(3) were deemed unsuitable for this treatment regimen.

Pathological vertebral fracture after stereotactic body radiation therapy for lung metastases. Case report and literature review

Background

Stereotactic body radiation therapy (SBRT) is a radiation technique used in patients with oligometastatic lung disease. Lung and chest wall toxicities have been described in the patients but pathological vertebral fracture is an adverse effect no reported in patients treated with SBRT for lung metastases.

Case presentation

A 68-year-old woman with the diagnosis of a recurrence of a single lung metastatic nodule of urothelial carcinoma after third line of chemotherapy. The patient received a hypo-fractionated course of SBRT.A 3D-conformal multifield technique was used with six coplanar and one non-coplanar statics beams. A total dose of 48 Gy in three fractions over six days was prescribed to the 95% of the CTV. Ten months after the SBRT procedure, a CT scan showed complete response of the metastatic disease without signs of radiation pneumonitis. However, rib and vertebral bone toxicities were observed with the fracture-collapse of the 7^th and 8^th vertebral bodies and a fracture of the 7^th and 8^th left ribs. We report a unique case of pathological vertebral fracture appearing ten months after SBRT for an asymptomatic growing lung metastases of urothelial carcinoma.

Conclusion

Though SBRT allows for minimization of normal tissue exposure to high radiation doses SBRT tolerance for vertebral bone tissue has been poorly evaluated in patients with lung tumors. Oncologists should be alert to the potential risk of fatal bone toxicity caused by this novel treatment. We recommend BMD testing in all woman over 65 years old with clinical risk factors that could contribute to low BMD. If low BMD is demonstrated, we should carefully restrict the maximum radiation dose in the vertebral body in order to avoid intermediate or low radiation dose to the whole vertebral body.

Oligometastases treated with stereotactic body radiotherapy: long-term follow-up of prospective study

PURPOSE

To analyze the long-term survival and tumor control outcomes after stereotactic body radiotherapy (SBRT) for metastases limited in number and extent.

METHODS AND MATERIALS

We prospectively analyzed the long-term overall survival (OS) and cancer control outcomes of 121 patients with five or fewer clinically detectable metastases, from any primary site, metastatic to one to three organ sites, and treated with SBRT. Freedom from widespread distant metastasis (FFDM) was defined as metastatic disease not amenable to local therapy (i.e., resection or SBRT). Prognostic variables were assessed using log-rank and Cox regression analyses.

RESULTS

For breast cancer patients, the median follow-up was 4.5 years (7.1 years for 16 of 39 patients alive at the last follow-up visit). The 2-year OS, FFDM, and local control (LC) rate was 74%, 52%, and 87%, respectively. The 6-year OS, FFDM, and LC rate was 47%, 36%, and 87%, respectively. From the multivariate analyses, the variables of bone metastases (p = .057) and one vs. more than one metastasis (p = .055) were associated with a fourfold and threefold reduced hazard of death, respectively. None of the 17 bone lesions from breast cancer recurred after SBRT vs. 10 of 68 lesions from other organs that recurred (p = .095). For patients with nonbreast cancers, the median follow-up was 1.7 years (7.3 years for 7 of 82 patients alive at the last follow-up visit). The 2-year OS, FFDM, and LC rate was 39%, 28%, and 74%, respectively. The 6-year OS, FFDM, and LC rate was 9%, 13%, and 65%, respectively. For nonbreast cancers, a greater SBRT target volume was significantly adverse for OS (p = .012) and lesion LC (p < .0001). Patients whose metastatic lesions, before SBRT, demonstrated radiographic progression after systemic therapy experienced significantly worse OS compared with patients with stable or regressing disease.

CONCLUSIONS

Select patients with limited metastases treated with SBRT are long-term survivors. Future research should address the therapeutic benefit of SBRT for these patients.

Role of radiation therapy in the management of renal cell cancer

Renal cell carcinoma (RCC) is traditionally considered to be radioresistant; therefore, conventional radiotherapy (RT) fraction sizes of 1.8 to 2 Gy are thought to have little role in the management of primary RCC, especially for curative disease. In the setting of metastatic RCC, conventionally fractionated RT has been an effective palliative treatment in 50% of patients. Recent technological advances in radiation oncology have led to the clinical implementation of image-guided radiotherapy, allowing biologically potent doses to the tumors intra- and extra-cranially. As predicted by radiobiologic modeling, favorable outcomes have been observed with highly hypofractionated schemes modeled after the experience with intracranial stereotactic radiosurgery (SRS) for RCC brain metastases with reported local control rates averaging 85%. At present, both primary and metastatic RCC tumors may be successfully treated using stereotactic approaches, which utilize steep dose gradients to maximally preserve function and avoid toxicity of adjacent organs including liver, uninvolved kidney, bowel, and spinal cord regions. Future endeavors will combine stereotactic body radiation therapy (SBRT) with novel targeted therapies, such as tyrosine kinase inhibitors and targeted rapamycin (mTOR) inhibitors, to maximize both local and systemic control.

Normal liver tissue sparing by intensity-modulated proton stereotactic body radiotherapy for solitary liver tumours

BACKGROUND

Stereotactic body radiotherapy (SBRT) is often the preferred treatment for the advanced liver tumours which owing to tumour distribution, size and multi-focality are out of range of surgical resection or radiofrequency ablation. However, only a minority of patients with liver tumours may be candidates for conventional SBRT because of the limited radiation tolerance of normal liver, intestine and other normal tissues. Due to the favourable depth-dose characteristics of protons, intensity-modulated proton therapy (IMPT) may be a superior alternative to photon-based SBRT. The purpose of this treatment planning study was therefore to investigate the potential sparing of normal liver by IMPT compared to photon-based intensity-modulated radiotherapy (IMRT) for solitary liver tumours.

MATERIAL AND METHODS

Ten patients with solitary liver metastasis treated at our institution with multi-field SBRT were retrospectively re-planned with IMRT and proton pencil beam scanning techniques. For the proton plans, two to three coplanar fields were used in contrast to five to six coplanar and non-coplanar photon fields. The same planning objectives were used for both techniques. A risk adapted dose prescription to the PTV surface of 12.5-16.75 Gy × 3 was used.

RESULTS

The spared liver volume for IMPT was higher compared to IMRT in all 10 patients. At the highest prescription dose level, the median liver volume receiving less than 15 Gy was 1411 cm(3) for IMPT and 955 cm(3) for IMRT (p < 0.005); also the mean liver dose was lower with IMPT compared to IMRT (median 9.1 Gy vs. 20.0 Gy; p < 0.005). All IMPT and IMRT plans met the V(D < 15 Gy) > 700 cm(3) constraint. For the D(mean) ≤ 15 Gy constraint, nine of 10 cases could be treated at the highest dose level using IMPT whereas with IMRT, only two cases met this constraint at the highest dose level and six at the lowest dose level.

CONCLUSION

A considerable sparing of normal liver tissue can be obtained using proton-based SBRT for solitary liver tumours.

Uterine sarcomas--recent progress and future challenges

Uterine sarcomas are a group of rare tumours that provide considerable challenges in their treatment. Radiological diagnosis prior to hysterectomy is difficult, with the diagnosis frequently made post-operatively. Current staging systems have been unsatisfactory, although a new FIGO staging system specifically for uterine sarcomas has now been introduced, and may allow better grouping of patients according to expected prognosis. While the mainstay of treatment of early disease is a total abdominal hysterectomy, it is less clear whether routine oophorectomy or lymphadenectomy is necessary. Adjuvant pelvic radiotherapy may improve local tumour control in high risk patients, but is not associated with an overall survival benefit. Similarly there is no good evidence for the routine use of adjuvant chemotherapy. For advanced leiomyosarcoma, newer chemotherapy agents including gemcitabine and docetaxel, and trabectedin, offer some promise, while hormonal therapies appear to be more useful in endometrial stromal sarcoma. Novel targeted agents are now being introduced for sarcomas, and uterine sarcomas, and show some indications of activity. Non-pharmacological treatments, including surgical metastatectomy, radiofrequency ablation, and CyberKnife(®) radiotherapy, are important additions to systemic therapy for advanced metastatic disease.

Stereotactic body radiation therapy: a novel treatment modality

Stereotactic body radiation therapy (SBRT) involves the delivery of a small number of ultra-high doses of radiation to a target volume using very advanced technology and has emerged as a novel treatment modality for cancer. The role of SBRT is most important at two cancer stages-in early primary cancer and in oligometastatic disease. This modality has been used in the treatment of early-stage non-small-cell lung cancer, prostate cancer, renal-cell carcinoma, and liver cancer, and in the treatment of oligometastases in the lung, liver, and spine. A large body of evidence on the use of SBRT for the treatment of primary and metastatic tumors in various sites has accumulated over the past 10-15 years, and efficacy and safety have been demonstrated. Several prospective clinical trials of SBRT for various sites have been conducted, and several other trials are currently being planned. The results of these clinical trials will better define the role of SBRT in cancer management. This article will review the radiobiologic, technical, and clinical aspects of SBRT.