Stereotactic radiotherapy for head and neck paragangliomas: How long should we wait for treatment response?

BACKGROUND AND PURPOSE

Stereotactic radiotherapy (SRT) is an effective treatment for head & neck (H&N) paragangliomas. Nevertheless, the timeline for achieving a tumor-volume-reduction (TVR) remains unclear.

MATERIALS AND METHODS

Sixty-three cases with H&N paragangliomas received definitive SRT and were evaluated retrospectively. Statistical Package for the Social Sciences (SPSS) v23.0 (IBM, Armonk, NY, USA) was used for statistics.

RESULTS

Sixty-eight lesions were irradiated, with glomus jugulotympanicum being the most common location (44 %). Median tumor diameter and volume were 3 cm (range, 1-7.6 cm) and 15.4 cm3 (range,1-185 cm3), respectively. Median dose was 25 Gy (range, 12-37.5 Gy) in 5 fractions (range, 1-5 fractions). Median follow-up was 40 months (range, 3-184 months). Treatment response, evaluated at a median 4.6 months post-SRT (range: 3-11 months), revealed TVR in 26 cases (41 %). During follow-up, 13 additional cases showed TVR, resulting in an overall TVR rate of 62 %. The median duration for attaining TVR was 9 months (range, 3-36 months) after SRT, and TVR occurred ≥ 12 months in 42 % of cases. Patients without prior surgery (p = 0.03) and with a longer follow-up (p = 0.04) demonstrated a higher rate of TVR. The likelihood of TVR tends to increase as the SRT dose increases (p = 0.06). Overall local control (LC) rate was 100 %. No ≥ grade 3 acute or late toxicities were observed.

CONCLUSION

While SRT demonstrates an excellent LC rate for H&N paragangliomas, it's important to note that the response to treatment may require time. TVR may last beyond the initial year of treatment in a substantial proportion of patients.

Preclinical Dosimetry for Small Animal Radiation Research in Proton Therapy: A Feasibility Study

Purpose

To evaluate the feasibility of the three-dimensional (3D) printed small animal phantoms in dosimetric verification of proton therapy for small animal radiation research.

Materials and Methods

Two different phantoms were modeled using the computed-tomography dataset of real rat and tumor-bearing mouse, retrospectively. Rat phantoms were designed to accommodate both EBT3 film and ionization chamber. A subcutaneous tumor-bearing mouse phantom was only modified to accommodate film dosimetry. All phantoms were printed using polylactic-acid (PLA) filament. Optimal printing parameters were set to create tissue-equivalent material. Then, proton therapy plans for different anatomical targets, including whole brain and total lung irradiation in the rat phantom and the subcutaneous tumor model in the mouse phantom, were created using the pencil-beam scanning technique. Point dose and film dosimetry measurements were performed using 3D-printed phantoms. In addition, all phantoms were analyzed in terms of printing accuracy and uniformity.

Results

Three-dimensionally printed phantoms had excellent uniformity over the external body, and printing accuracy was within 0.5 mm. According to our findings, two-dimensional dosimetry with EBT3 showed acceptable levels of γ passing rate for all measurements except for whole brain irradiation (γ passing rate, 89.8%). In terms of point dose analysis, a good agreement (<0.1%) was found between the measured and calculated point doses for all anatomical targets.

Conclusion

Three-dimensionally printed small animal phantoms show great potential for dosimetric verifications of clinical proton therapy for small animal radiation research.

The Effect of Video-Based Education on Anxiety of Patients Receiving Stereotactic Radiosurgery and Stereotactic Body Radiation Therapy

Patients receiving stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT) may have an anxiety due to unknown aspects of the treatment. We aimed to reduce patient anxiety by using video-based education. Forty patients were divided into 2 groups, with one-to-one information session (n = 20) and one-to-one information session plus video-based education (n = 20). The patients completed the State-Trait Anxiety Inventory (STAI) and visual facial anxiety scale before and after information sessions and after treatment. The setup time and disruptions during treatment sessions were recorded for patients receiving treatment with Novalis® and Cyberknife®, respectively. The patient characteristics and STAI scores before education were similar between groups. The anxiety level was significantly lower in group 1 after treatment (median 38, interquartile range (IQR) 27-45) compared to before (median 43, IQR 36-47) (p = 0.003) and after information sessions (median 42, IQR 36-47) (p = 0.004); however, any difference was not observed in anxiety levels between before and after information sessions (p = 0.317). The anxiety level was significantly lower in group 2 after video-based education (median 25, IQR 22-33) and after treatment (median 25, IQR 20-30) compared to before video-based education (median 35, IQR 31-42) (p < 0.001 for both), while there was no significant difference in anxiety levels between after video-based education and after the treatment (p = 0.407). The interruptions during treatment were observed in 9 (60%) patients in group 1 and 6 (40%) patients in group 2 (p = 0.038). Video-based educations significantly reduce patient anxiety before SRS/SBRT and increase their compliance with the treatment.

Stereotactic Body Radiotherapy as an Effective Treatment for Pancreatic Cancer

Background Stereotactic body radiotherapy (SBRT) allows the delivery of an ablative radiation dose to the tumor with minimal toxicity. Although magnetic resonance imaging (MRI)-guided SBRT appears to be a promising approach in the modern era, X-ray image-guided SBRT is still used worldwide for pancreatic cancer. This study aims to evaluate the results of X-ray image-guided SBRT in patients with locally advanced pancreatic cancer (LAPC). Methodology Medical records of 24 patients with unresectable LAPC who underwent X-ray image-guided SBRT between 2009 and 2022 were retrospectively evaluated. SPSS version 23.0 (IBM Corp., Armonk, NY, USA) was utilized for all analyses. Results The median age was 64 years (range = 42-81 years), and the median tumor size was 3.5 cm (range = 2.7-4 cm). The median total dose of SBRT was 35 Gy (range = 33-50 Gy) in five fractions. After SBRT, 30% of patients showed complete and 41% showed partial response, whereas 20% had stable disease and 9% had progression. Median follow-up was 15 months (range = 6-58 months). During follow-up, four (16%) patients had local recurrence, one (4%) had a regional recurrence, and 17 (70%) had distant metastasis (DM). The two-year local control (LC), local recurrence-free survival (LRFS), overall survival (OS), and DM-free survival (DMFS) rate was 87%, 36%, 37%, and 29%, respectively. In univariate analysis, a larger tumor size (>3.5 cm) and higher cancer antigen 19-9 level (>106.5 kU/L) significantly decreased the OS, LRFS, and DMFS rates. No severe acute toxicity was observed. However, two patients had severe late toxicity as intestinal bleeding. Conclusions X-ray image-guided SBRT provides a good LC rate with minimal toxicity for unresectable LAPC. However, despite modern systemic treatments, the rate of DM remains high which plays a major role in survival.

Planning and dosimetric evaluation of three total body irradiation techniques: Standard SSD VMAT, Extended SSD VMAT and Extended SSD Field-in-Field

The aim of this study was to dosimetrically compare three total body irradiation (TBI) techniques which can be delivered by a standard linear accelerator, and to deduce which one is preferable. Specifically, Extended Source to Surface Distance (SSD) Field-in-Field (FiF), Extended SSD Volumetric Modulated Arc Therapy (VMAT), and Standard SSD VMAT TBI techniques were dosimetrically evaluated. Percent depth dose and dose profile measurements were made under treatment conditions for each specified technique. After having generated treatment plans with a treatment planning system (TPS), dose homogeneity and critical organ doses were investigated on a Rando phantom using radiochromic films and optically stimulated luminescence dosimeters (OSLDs). TBI dose of 12 Gy in six fractions was prescribed for each technique. The gamma index (5%/5 mm) was used for the analysis of radiochromic films. Passing rates for Extended SSD FiF, Extended SSD VMAT and Standard SSD VMAT techniques were found to be 90%, 87% and 94%, respectively. OSLD measurements were within ± 5% agreement with TPS calculations for the first two techniques whereas the agreement was found to be within ± 3% for the Standard SSD VMAT technique. TPS calculations demonstrated that mean lung doses in the first two techniques were around 8.5 Gy while it was kept around 7 Gy in Standard SSD VMAT. It is concluded that Standard SSD VMAT is superior in sparing the lung tissue while all three TBI techniques are feasible in clinical practice with acceptable dose homogeneity. In the absence of VMAT-based treatment planning, Extended SSD FiF would be a reasonable choice compared to other conventional techniques.

Post-induction lymph node delineation in nasopharyngeal cancer: A single-center experience

BACKGROUND

We routinely delineate the gross tumor volume (GTV) for the lymph nodes (LN) based on post-induction chemotherapy (IC) MRI in nasopharyngeal carcinoma (NPC). Herein, we investigated the sufficiency of this method, particularly in high-risk LNs.

METHODS

Eighty-one LNs with a high-risk of clinical extranodal extension and/or ≥3-cm diameter in 58 patients were evaluated. A new GTV covering the pre-IC LN volume was delineated for each LN.

RESULTS

The median volume reduction was 72.5% for the GTV and 53.1% for the planning target volume. After a median 43 months, the overall LN local control rate was 97.5%. The 2- and 5-year LN recurrence-free survival, overall survival, and disease-free survival rate was 88.3% and 84.4%, 92.5% and 85.1%, and 86.8% and 79.2%, respectively.

CONCLUSION

IC yields a significant reduction in nodal target volumes, and post-IC nodal volume-based radiotherapy provides excellent LC in NPC, even in high-risk LNs.

Treatment Outcomes of Stereotactic Body Radiotherapy in Patients with Synchronous and Metachronous Oligometastatic Renal Cell Carcinoma

INTRODUCTION

The aim of this study was to investigate the clinical outcomes of metastasis-directed therapy (MDT) using stereotactic body radiotherapy (SBRT) in patients with synchronous or metachronous oligometastatic renal cell carcinoma (RCC).

METHODS

The clinical data of 87 patients with 138 lesions who received MDT between February 2008 and January 2019 were retrospectively analyzed. All patients had ≤5 metastasis at diagnosis (synchronous) or during progression (metachronous) and were treated with SBRT for their metastasis. The primary endpoints were local control (LC) and progression-free survival (PFS). The secondary endpoint was overall survival (OS).

RESULTS

Median follow-up was 20.4 months for entire cohort and 27.2 months for survivors. Synchronous oligometastatic disease was observed in 35 patients (40.2%), and 52 patients (59.8%) had metachronous disease. Seventy-two patients (82.8%) received systemic treatment synchronously or after MDT, while 15 patients (17.2%) did not receive any systemic treatment. The 1- and 2-year OS rates were 79.4% and 58.1%, respectively, and the 1- and 2-year PFS rates were 58.6% and 15.1%, respectively. The 1- and 2-year LC rates per lesion were 96.6% and 91.4%, respectively. There were no significant differences in survival between patients with synchronous oligometastasis and those with metachronous oligometastasis. All disease progressions were observed at a median time of 31.6 months (range: 1.9-196.9 months) after the completion of SBRT. Patients with solitary oligometastasis had significantly better OS compared to patients with >1 metastasis (p = 0.04). No patients experienced grade 3 or higher acute or late toxicities.

CONCLUSION

SBRT is a successful treatment for oligometastatic RCC patients due to its excellent LC and minimal toxicity profile. There were no statistically significant survival differences between patients with synchronous and metachronous oligometastasis. Patients with solitary oligometastasis outlived their counterparts.

Treatment outcomes of postoperative ultra-hypofractionated stereotactic body radiotherapy in prostate cancer

BACKGROUND

This study aimed to evaluate the safety and efficacy of ultra-hypofractionated stereotactic body radiation therapy (SBRT) to prostate bed.

METHODS

Sixty-six prostate cancer patients treated with postoperative ultra-hypofractionated SBRT between 2018 and 2020 were retrospectively reviewed. All patients received a total dose of 35 Gy to prostate bed in 5 fractions. Biochemical complete response (BCR), biochemical failure (BF), acute and late toxicities were assessed.

RESULTS

After a median follow-up of 24.2 months (range, 6.4-37.2), seven patients (10.6%) developed BF, and the 2-year freedom from BF (FFBF) rate was 88.4%. BCR was observed in 57 patients (86.4%). The 2-year FFBF in patients with pre-SBRT PSA value of <0.2 ng/mL was higher than those with pre-SBRT PSA of ≥0.2 ng/mL (100% vs. 81.4%; P = 0.04). The 2-year FFBF in patients with BCR was significantly higher than in those without BCR (94.5% vs. 58.3%; P < 0.001). In multivariate analysis, pre-SBRT PSA and post-SBRT PSA values were prognostic factors for FFBF (P = 0.009 and P = 0.01, respectively). Nine patients (13.6 %) developed acute and late grade 2 genitourinary (GU) toxicities. There was no acute or late grade ≥3 GU toxicity. Acute and late grade ≥2 gastrointestinal (GI) toxicity was observed in 9 (13.6%) and 2 (3%) patients, respectively.

CONCLUSION

Postoperative ultra-fractionated SBRT showed no severe acute toxicity and late toxicity rates of about 15%, in addition to excellent biochemical control rates. Pre- and post-SBRT PSA levels may be a predictor of BCR in patients receiving post-operative ultra-fractionated SBRT.

Transit dosimetry of stereotactic body radiotherapy treatments with electronic portal dosimetry device in patient with spinal implant

In recent years, the use of the Electronic Portal Imaging Device (EPID) as an in vivo dosimeter has become widespread. However, reports of EPID for stereotactic body radiotherapy (SBRT) applications is scarce. There is no data on this topic especially when there are high-density materials in the radiation field. In this study, we aimed to investigate the dose distributions of SBRT treatment plans in patients with spinal implants by transit EPID dosimetry. Implants were inserted in phantoms that mimic the vertebrae, and VMAT plans were created on the phantoms to deliver 16 Gy radiation doses to the target in 1 fraction. Transit EPID measurements were performed for each irradiation. The results were compared with the treatment planning system using the gamma analysis method. According to the gamma analysis results, while the non-implant model met the acceptance criteria with a rate of 95.4%, the implanted models did not pass the test with results between the rates of 70% to 73%. In addition, while the dose difference in the isocenter was 1.3% for the non-implanted model, this difference was observed to be between 7 and 8% in the implanted models. Our study revealed that EPID can be used as transit dosimetry for the VMAT-SBRT applications. However, unacceptable dose differences were obtained by transit EPID dosimetry in the VMAT-SBRT applications of patients with an implant. In the treatment of such patients, alternative treatment methods should be preferred in which the interaction of the implants with radiation can be prevented.

Stereotactic body radiotherapy and tyrosine kinase inhibitors in patients with oligometastatic renal cell carcinoma: a multi-institutional study

PURPOSE

Few studies have determined the viability of stereotactic body radiotherapy (SBRT) and tyrosine kinase inhibitors (TKIs) in the treatment of metastatic renal cell carcinoma (mRCC). We examined the results of RCC patients who had five or fewer lesions and were treated with TKI and SBRT.

METHODS

The clinical data of 42 patients with 96 metastases treated between 2011 and 2020 were retrospectively evaluated. The prognostic factors predicting overall survival (OS) and progression-free survival (PFS) were assessed in uni- and multivariable analyses.

RESULTS

Median follow-up and time between TKI therapy and SBRT were 62.3 and 3.7 months, respectively. The 2‑year OS and PFS rates were 58.0% and 51.3%, respectively, and 2‑year local control rate was 94.1% per SBRT-treated lesion. In univariable analysis, the time between TKI therapy and SBRT and treatment response were significant prognostic factors for OS and PFS. In multivariable analysis, a time between TKI therapy and SBRT of less than 3 months and complete response were significant predictors of better OS and PFS. Only 12 patients (28.6%) had a systemic treatment change at a median of 18.2 months after SBRT, mostly in patients with a non-complete treatment response after this therapy. Two patients (4.8%) experienced grade III toxicity, and all side effects observed during metastasis-directed therapy subsided over time.

CONCLUSION

We demonstrated that SBRT in combination with TKIs is an effective and safe treatment option for RCC patients with ≤ 5 metastases. However, distant metastasis was observed in 60% of the patients, indicating that distant disease control still has room for improvement.

Every other day stereotactic radiation therapy for the treatment of uveal melanoma decreases toxicity

BACKGROUND AND PURPOSE

To report the long-term results of stereotactic radiosurgery and fractionated stereotactic radiation therapy (SRS/FSRT) in patients with uveal melanoma (UM).

MATERIALS AND METHODS

We retrospectively evaluated the results of patients treated between 2007 and 2019. The primary endpoints were local control (LC), local recurrence-free survival (LRFS), enucleation-free survival (EFS) and treatment toxicity.

RESULTS

443 patients with 445 UMs were treated via CyberKnife®. According to the COMS classification, 70% of the tumors were small/medium and 30% were large. Median total RT dose was 54 Gy, median BED10 was 151 Gy. After a median 74-months follow-up, SRS/FSRT yielded an 83% overall LC rate. The 5- and 10-year LRFS rate was 74% and 56%, respectively. Patient age and the COMS size were prognostic for all survival endpoints. An increased SRS/FSRT dose was associated with higher LRFS and EFS rates. SRS/FSRT-related toxicity was observed in 49% of the eyes. Median visual acuity (VA) significantly deteriorated after SRS/FSRT in 76% of the treated eyes. The overall eye preservation rate was 62%, and the 5- and 10-year EFS rate was 64% and 36%, respectively. The delivery of FSRT every other day resulted in a significantly lower rate of toxicity and enucleation compared to FSRT on consecutive days.

CONCLUSION

A total dose of ≥45 Gy and BED_10Gy ≥ 112.5 SRS/FSRT is associated with a higher LC rate in patients with UM. Despite the favorable outcomes, treatment toxicity is the major limitation of this treatment. Toxicity and enucleation can be minimized by treating the eye every other day.

Stereotactic body radiotherapy boost in patients with cervical cancer

Our aim was to evaluate the oncological outcomes of stereotactic body radiotherapy (SBRT) boost in patients with cervical cancer. The data of 21 patients who received SBRT boost after definitive radiotherapy (RT) or chemoradiotherapy (CRT) between March 2012 and April 2019 were retrospectively evaluated. External beam radiotherapy (EBRT) was applied to patients with a total dose of 50.4 Gy in 28 fractions. Kaplan-Meier method was used for survival analysis (IBM SPSS 23 software) and p < .05 value was considered significant. After definitive RT or CRT, there was a complete response in 9 (43%) patients, partial response in 11 (52%) patients and stable disease in 1 (5%) patient. The median follow-up period was 28 months (range, 7.5-88 months). Two-years cancer-specific survival rate was 80%. While 2-year LC rate was 75% in patients with residual tumour size <4 cm, it was 50% when there was ≥4 cm residual tumour after definitive CRT (p = .1). The treatment was well-tolerated and no acute or late toxicity was observed. Although brachytherapy (BRT) is an essential part of the treatment in locally advanced cervical cancer, SBRT may be used in patients with small residual disease who are not candidate for BRT. IMPACT STATEMENTCervical cancer is one of the most common cancers in the world, and external beam radiotherapy (EBRT) and brachytherapy (BRT) are the main treatment options. However, in rare cases where BRT is not feasible, it has been questioned whether stereotactic body radiotherapy (SBRT) as an alternative to BRT.What is already known on this subject? Nowadays, BRT still appears to be the gold standard treatment. However, studies with a small number of patients and short follow-up periods in the literature show that SBRT can be a good alternative in cases where BRT cannot be performed.What do the results of this study add? Our study is one of the series with the largest number of patients in the literature and with the longest follow-up period. In this area where there is no prospective study, we think that retrospective data with high patient numbers are enlightening.What are the implications of these findings for clinical practice and/or further research? Our study shows that SBRT is an alternative option in cases with small residual disease where BRT cannot be applied, and it provides a basis for a prospective randomised study.

Prostate-specific membrane antigen PET response associates with radiographic progression-free survival following stereotactic ablative radiation therapy in oligometastatic castration-sensitive prostate cancer

5011

Background: Emerging data suggest metastasis-directed therapy (MDT) improves outcomes in patients with oligometastatic castration-sensitive prostate cancer (omCSPC). Prostate-specific membrane antigen positron emission tomography (PSMA-PET/CT) can detect occult metastatic disease and has been proposed as a biomarker for treatment response. Herein we identify and validate a PSMA-PET biomarker for clinical outcomes following MDT in omCSPC. Methods: This was an international multi-institutional retrospective study of two completely independent cohorts of men with omCSPC, defined as ≤3 lesions, treated with metastasis-directed stereotactic ablative radiation therapy (SABR) who underwent PSMA-PET/CT prior to and 3-6 months after treatment. Pre- and post-SABR PSMA-PET/CT standardized uptake value (SUV) was measured for all lesions and PSMA response defined discretely using a cutpoint of ≥ 30% decrease in SUVmax. PSMA-PET response was correlated with lesion local control (LLC), radiographic progression-free survival (rPFS) defined using conventional and PET imaging, and metastasis-free survival (MFS) defined by conventional imaging alone. Results: A total of 131 patients with 261 treated metastases were included in the analysis, with median follow-up of 29 months (IQR 18.5-41.3). Following SABR, 78.4% of lesions experienced a partial or complete PSMA response. Multivariable analysis demonstrated SUV response significantly associated with improved LLC (HR = 9.97, 95%CI 3.92-25.4; p < 0.01). Patients with PSMA response in all lesions experienced significantly better rPFS (HR = 0.49, 95%CI 0.26-0.92; p = 0.03) compared to their counterparts and this maintained significance within both the discovery (p < 0.01) and validation (p = 0.01) cohorts. Within the discovery cohort, patients with PSMA response in all lesions also experienced significantly improved MFS (HR = 0.24, 95%CI 0.07-0.85; p = 0.03); analysis of the independent validation cohort is ongoing. Conclusions: Following SABR, PSMA-PET response is a robust and externally validated radiographic biomarker for rPFS and appears to be associated with MFS pending validation. This approach holds promise for guiding clinical management of omCSPC.

Stereotactic body radiotherapy optimization to reduce the risk of carotid blowout syndrome using normal tissue complication probability objectives

Purpose

To determine the possibility of further improving clinical stereotactic body radiotherapy (SBRT) plans using normal tissue complication probability (NTCP) objectives in order to minimize the risk for carotid blowout syndrome (CBOS).

Methods

10 patients with inoperable locally recurrent head and neck cancer, who underwent SBRT using CyberKnife were analyzed. For each patient, three treatment plans were examined: (1) cone‐based without delineation of the ipsilateral internal carotid (clinical plan used to treat the patients); (2) cone‐based with the carotid retrospectively delineated and spared; and (3) Iris‐based with carotid sparing. The dose–volume histograms of the target and primary organs at risk were calculated. The three sets of plans were compared based on dosimetric and TCP/NTCP (tumor control and normal tissue complication probabilities) metrics. For the NTCP values of carotid, the relative seriality model was used with the following parameters: D₅₀ = 40 Gy, γ = 0.75, and s = 1.0.

Results

Across the 10 patient plans, the average TCP did not significantly change when the plans were re‐optimized to spare the carotid. The estimated risk of CBOS was significantly decreased in the re‐optimized plans, by 14.9% ± 7.4% for the cone‐based plans and 17.7% ± 7.1% for the iris‐based plans (p = 0.002 for both). The iris‐based plans had significant (p = 0.02) reduced CBOS risk and delivery time (20.1% ± 7.4% time reduction, p = 0.002) compared to the cone‐based plans.

Conclusion

A significant improvement in the quality of the clinical plans could be achieved through the delineation of the internal carotids and the use of more modern treatment delivery modalities. In this way, for the same target coverage, a significant reduction in the risk of CBOS could be achieved. The range of risk reduction varied depending on the proximity of carotid artery to the target.

The role of stereotactic body radiotherapy in switching systemic therapy for patients with extracranial oligometastatic renal cell carcinoma

BACKGROUND

Targeting oligometastatic lesions with metastasis-directed therapy (MDT) using stereotactic-body radiotherapy (SBRT) may improve treatment outcomes and postpone the need for second-line systemic therapy (NEST). We looked at the results of oligometastatic renal cell carcinoma (RCC) patients who had five or fewer lesions and were treated with SBRT.

METHODS

We examined the treatment outcomes of 70 extracranial metastatic RCC (mRCC) patients treated at two oncology centers between 2011 and 2020. The clinical parameters of patients with and without NEST changes were compared. The prognostic factors for overall survival (OS), progression-free survival (PFS), and NEST-free survival were evaluated.

RESULTS

Median age was 67 years (range 31-83 years). Lung and bone metastasis were found in 78.4% and 12.6% of patients, respectively. With a median follow-up of 21.1 months, median OS was 49.1 months and the median PFS was 18.3 months. Histology was a prognostic factor for OS, BED, and treatment switch for PFS in univariate analysis. In multivariate analysis, the significant predictor of poor OS was clear cell histology, and a lower BED for PFS. Following SBRT for oligometastatic lesions, 19 patients (27.2%) had a median NEST change of 15.2 months after MDT completion. There were no significant differences in median OS or PFS between patients who had NEST changes and those who did not. No patient experienced grade ≥ 3 acute and late toxicities.

CONCLUSIONS

The SBRT to oligometastatic sites is an effective and safe treatment option for ≤ 5 metastases in RCC patients by providing favorable survival and delaying NEST change.

Testicular metastasis in prostate cancer: A rare case of testicular metastasis diagnosed with 68Ga-PSMA and review of the literature

Objective:

Testicular metastasis in prostate cancer is a rare entity. We aimed to report the case where this rare condition was diagnosed with Gallium prostate-specific membrane antigen–positron emission tomography/computed tomography (68Ga-PSMA-PET/CT).

Subjects/patients and methods:

A 68-year-old male with a prostate adenocarcinoma presented with testicular metastasis. The patient was diagnosed with 68Ga-PSMA-PET/CT, and bilateral inguinal orchiectomy was performed. Herein, our case is presented, and a short review of the literature is carried out.

Conclusion:

68Ga-PSMA-PET/CT is an effective imaging method for detecting rare metastases.

Level of evidence:

4

Results of concurrent radiotherapy and immunotherapy in recurrent and metastatic head and neck cancer: A single-center experience

OBJECTIVES

In metastatic and recurrent head and neck cancer (M/R HN-SCC), the median survival is less than a year and locoregional recurrence is the main cause of death. Our aim was to evaluate the results of concurrent stereotactic body radiotherapy (SBRT) and immunotherapy (ICI) in these patients.

MATERIALS AND METHODS

Fifteen patients diagnosed with M/R HN-SCC were evaluated retrospectively. All patients received SBRT (3x8 Gy) to all recurrent and metastatic foci with concurrent ICI.

RESULTS

Six months overall survival (OS) rates and progression-free survival (PFS) rates were 93% and 86%, respectively. Local control (LC) rate in the site of SBRT was 96%. Higher survival and LC rates were achieved with lower doses of radiotherapy with the synergistic effect of SBRT and ICI.

CONCLUSION

Concurrent ICI and SBRT was feasible with excellent LC.

Radiotherapy-induced alterations in vitreous humor: A new potential critical structure

Vitreous humor (VH) is not considered as a critical structure in the radiotherapy planning process. In the present study, an experimental animal model was performed to examine the effects of radiotherapy on VH. The right eyes of twelve New Zealand rabbits were irradiated to 60 Gy in 3 fractions in accordance with the scheme used in the treatment of uveal melanoma in our clinic, and contralateral (left) eyes were considered as control. Weekly ophthalmologic examination was performed after irradiation, for three months. At the end of the third month, enucleation and vitreous collection were conducted. The vitreous samples were subjected to metabolomic analyses, ELISA analyses, viscosity measurements, and electron microscopic examination. In control and experimental vitreous samples, 275 different metabolites were identified, and 34 were found to differ significantly between groups. In multivariate analyzes, a clear distinction was observed between control and irradiated vitreous samples. Pathway analysis revealed that nine pathways were affected, and these pathways were mainly related to amino acid metabolism. A significant decrease was observed in the expressions of type II, V, and XI collagens in protein level in the ELISA. There was a non-significant decrease in type IX collagen and viscosity. Electron microscopic examination revealed disrupted collagen fibrillar ultra-structure and dispersed collagen fragments in the experimental vitreous. An intact vitreous is essential for a healthy eye. In this study, we observed that radiation causes changes in the vitreous that may have long-term consequences.

Clinical parameters and nomograms for predicting lymph node metastasis detected with 68 Ga-PSMA-PET/CT in prostate cancer patients candidate to definitive radiotherapy

BACKGROUND

Defining the extent of disease spread with imaging modalities is crucial for therapeutic decision-making and definition of treatment. This study aimed to investigate whether clinical parameters and nomograms predict prostate-specific membrane antigen (PSMA)-positive lymph nodes in treatment-naïve nonmetastatic prostate cancer (PC) patients.

MATERIALS AND METHODS

The clinical data of 443 PC patients (83.3% high-risk and 16.7% intermediate-risk) were retrospectively analyzed. Receiver operating characteristic (ROC) curves with areas under the curve (AUC) were generated to evaluate the accuracy of clinical parameters (prostate-specific antigen [PSA], T stage, Gleason score [GS], International Society of Urological Pathology [ISUP] grade) and nomograms (Roach formula [RF], Yale formula [YF], and a new formula [NF]) in predicting lymph node metastasis. The AUCs of the various parameters and clinical nomograms were compared using ROC and precision-recall (PR) curves.

RESULTS

A total of 288 lymph node metastases were identified in 121 patients (27.3%) using ⁶⁸ Ga-PSMA-11-positron emission tomography (PET)/computed tomography (CT). Most PSMA-avid lymph node metastases occurred in external or internal iliac lymph nodes (142; 49.3%). Clinical T stage, PSA, GS, and ISUP grade were significantly associated with PSMA-positive lymph nodes according to univariate logistic regression analysis. The PSMA-positive lymph nodes were more frequently detected in patients with PSA >20 ng/ml, GS ≥7 or high risk disease compared to their counterparts. The clinical T stage, serum PSA level, GS, and ISUP grade showed similar accuracy in predicting PSMA-positive metastasis, with AUC values ranging from 0.675 to 0.704. The median risks for PSMA-positive lymph nodes according to the RF, YF, and NF were 31.3% (range: 12.3%-100%), 22.3% (range: 4.7%-100%), and 40.5% (range: 12.3%-100%), respectively. The AUC values generated from ROC and PR curve analyses were similar for all clinical nomograms, although the RF and YF had higher accuracy compared to NF.

CONCLUSION

The clinical T stage, PSA, GS, and ISUP grade are independent predictors of PSMA-positive lymph nodes. The RF and YF can be used to identify patients who can benefit from ⁶⁸ Ga-PSMA-11 PET/CT for the detection of lymph node metastasis. Together with nomograms, ⁶⁸ Ga-PSMA-11 PET/CT images help to localize PSMA-positive lymph node metastases and can thus assist in surgery and radiotherapy planning.

Oligometastatic Bone Disease in Castration-Sensitive Prostate Cancer Patients Treated With Stereotactic Body Radiotherapy Using 68Ga-PSMA PET/CT: TROD 09-004 Study

PURPOSE

To evaluate the outcomes of metastasis-directed treatment (MDT) using stereotactic body radiotherapy (SBRT) for bone-only oligometastasis (OM) detected with gallium prostate-specific membrane antigen (68Ga-PSMA) PET/CT in castration-sensitive prostate cancer (PC) patients.

METHODS

In this multi-institutional study, clinical data of 74 PC patients with 153 bone lesions who were undergoing MDT were retrospectively evaluated. Twenty-seven patients (36.5%) had synchronous, and 47 (63.5%) had metachronous OM. All patients had PC with 5 metastases or fewer detected by 68Ga-PSMA PET/CT and treated using SBRT with a median dose of 20 Gy. The prognostic factors for PC-specific survival (PCSS) and progression-free survival (PFS) were analyzed.

RESULTS

The median follow-up was 27.3 months. Patients with synchronous OM were older and received higher rates of androgen deprivation therapy after SBRT compared with patients with metachronous OM. The 2-year PCSS and PFS rates were 92.0% and 72.0%, respectively. A prostate-specific antigen (PSA) decline was observed in 56 patients (75.7%), and 48 (64.9%) had a PSA response defined as at least 25% decrease of PSA after MDT. The 2-year local control rate per lesion was 95.4%. In multivariate analysis, single OM and PSA response after MDT were significant predictors for better PCSS and PFS. In-field recurrence was observed in 4 patients (6.5%) with 10 lesions at a median of 13.1 months after MDT completion. No serious late toxicity was observed.

CONCLUSIONS

We demonstrated that SBRT is an efficient and well-tolerated treatment option for PC patients with 5 bone-only oligometastases or fewer detected with 68Ga-PSMA PET/CT.

Stereotactic body radiotherapy for oligoprogressive lesions in metastatic castration-resistant prostate cancer patients during abiraterone/enzalutamide treatment

BACKGROUND

Metastasis-directed therapy (MDT) utilizing stereotactic body radiotherapy (SBRT) for oligoprogressive lesions could provide a delay in next-line systemic treatment (NEST) change while undergoing androgen receptor-targeted agents (ARTA) treatment. We evaluated prognostic factors for prostate cancer-specific survival (PCSS) and progression-free survival (PFS) to characterize patients receiving treatment with ARTA who may benefit from MDT for oligoprogressive lesions. The impact of MDT on delaying NEST and the predictive factors for NEST-free survival (NEST-FS) were also assessed.

MATERIALS AND METHODS

The clinical data of 54 metastatic castration-resistant prostate cancer patients with 126 oligoprogressive lesions receiving abiraterone (1 g/day) or enzalutamide (160 mg/day) before or after systemic chemotherapy were analyzed. A median of three lesions (range: 1-5) were treated with MDT. The primary endpoints were PCSS and PFS. The secondary endpoints were time to switch to NEST and NEST-FS.

RESULTS

The median follow-up time was 19.1 months. Univariate analysis showed that the number of oligoprogressive lesions treated with SBRT and the time between the start of ARTA treatment and oligoprogression were significant prognostic factors for PCSS, and the timing of ARTA treatment (before or after chemotherapy) and the prostate-specific antigen (PSA) response after MDT were significant prognostic factors for PFS. Multivariate analysis showed that early MDT for oligoprogressive lesions delivered less than 6 months after the beginning of ARTA and higher PSA levels after MDT were significant predictors of worse PCSS and PFS. The median total duration of ARTA treatment was 13.8 months. The median time between the start of ARTA treatment and the start of MDT for oligoprogressive lesions was 5.2 months, and MDT extended the ARTA treatment by 8.6 months on average. Thirty-two (59.3%) patients continued ARTA treatment after MDT. ARTA treatment after chemotherapy, early oligoprogression requiring MDT, and lower radiation doses for MDT were independent predictors of NEST-FS in multivariate analysis.

CONCLUSIONS

MDT for oligoprogressive lesions is effective and may provide several benefits compared to switching from ARTA treatment to NEST. Patients with early progression while on ARTAs and inadequate PSA responses after MDT have a greater risk of rapid disease progression and poor survival, which necessitates intensified treatment.

Factors affecting post-treatment radiation-induced lung disease in patients receiving stereotactic body radiotherapy to lung

The aim of the study is to investigate factors that may cause radiation-induced lung disease (RILD) in patients undergoing stereotactic body radiotherapy (SBRT) for lung tumors. Medical records of patients treated between May 2018 and June 2019 with SBRT were retrospectively evaluated. All patients should have a diagnosis of either primary non-small cell lung cancer (NSCLC) or less than three metastases to lung from another primary. The median treatment dose was 50 Gy in 4-5 fractions. Tumor response and RILD were evaluated in thoracic computer tomography (CT) using RECIST criteria. 82 patients with 97 lung lesions were treated. The median age was 68 years (IQR = 62-76). With a median follow-up of 7.2 months (3-18 months), three patients had grade 3 radiation pneumonitis (RP). RILD was observed in 52% of cases. Patients who had RILD had a higher risk of symptomatic RP (p = 0.007). In multivariate analyses older age, previous lung radiotherapy history, and median planning treatment volume (PTV) D95 value of ≥ 48 Gy were associated with RILD. Local recurrence (LR) was observed in 5.1% of cases. There was no difference in overall survival and LR with the presence of RILD. Older age, previous lung radiotherapy history, and median PTV D95 value of ≥ 48 Gy seems to be associated with post-SBRT RILD.

A hesitated approach: primary radiotherapy for keloids-a case series

PURPOSE

To assess the efficacy and toxicity of hypofractionated radiotherapy (RT) alone in treatment-resistant symptomatic keloids.

METHODS

Six patients with a total of 13 inoperable large keloid lesions and no response to previous treatments were admitted to our department between 2017 and 2019. All patients were examined for detailed wound localization, size, contour, and color assessment, and for objective and subjective symptoms. Response to treatment was graded as "complete remission" in case of full symptomatic relief and >75% decrease in lesion size, as "partial remission" in case of partial symptomatic relief and 25-75% decrease in lesion size, and as "stable disease" in case of no symptomatic relief or <25% decrease in lesion size. Patients were followed up monthly for the first 3 months and every 3 months thereafter by physical examination.

RESULTS

A total dose of 37.5 Gy external RT in five fractions was prescribed by 6‑MeV electrons in 4 patients and 6‑MV photons in 2 patients. Complete response was obtained in all patients at the 6‑month control. All patients were satisfied with cosmetic results at their last control. Grade 2 dermatitis developed in all patients during the second week of RT but resolved completely in all after 6 months following the end of RT.

CONCLUSION

In keloids that are unresponsive to standard treatment, hypofractionated RT using a total dose of 37.5 Gy in five fractions is feasible.

Parotid gland stem cells: Mini yet mighty

BACKGROUND

Our aim was to evaluate the correlation between the radiation doses to parotid gland (PG) stem cells and xerostomia.

METHODS

Patients diagnosed with head and neck cancer (HNC) were retrospectively evaluated, and xerostomia inventory (XI) was applied to these patients. PG stem cells were delineated on the treatment planning CT, and the mean doses to the PG stem cells calculated.

RESULTS

The total test score and mean doses to bilateral PGs were significantly correlated (r = .34, P = .001), and the mean doses to bilateral PG stem cell niches were significantly correlated with the total test score (r = .32, P = .002).

CONCLUSIONS

In this study, we found that the mean dose to PG stem cells can predict dry mouth as much as the mean dose to the PG.

Stereotactic body radiotherapy in patients with early-stage non-small cell lung cancer: Does beam-on time matter?

PURPOSE

Stereotactic body radiotherapy (SBRT) is an effective treatment option for patients with early-stage non-small cell lung cancer (NSCLC). In this study, we evaluated the treatment results using two different SBRT techniques and the effect of beam-on time (BOT) on treatment outcomes.

METHODS

Between July 2007 and January 2018, 142 patients underwent SBRT for primary NSCLC. We have delivered SBRT using either respiratory tracking system (RTS) or internal-target-volume (ITV)-based motion management techniques. The effect of age, tumor size, pretreatment tumor SUVmax value, presence of tissue diagnosis, histopathological subtype, operability status, tumor location, motion management technique, BED10 value, BOT on overall survival (OS), loco-regional control (LRC), event-free survival (EFS) and primary tumor control (PTC) were evaluated.

RESULTS

Median age of the patients was 70 years (range, 39-91 years). Most of the patients were inoperable (90%) at the time of SBRT. Median BED10 value was 112.5 Gy. With a median follow-up of 25 months, PTC was achieved in 91.5% of the patients. Two-year estimated OS, LRC, PTC and EFS rates were 68, 63, 63 and 53%, respectively. For the entire group, OS was associated with BOT (P = 0.027), and EFS was associated with BOT (P = 0.027) and tumor size (P = 0.015). For RTS group, OS was associated with age (P = 0.016), EFS with BOT (P = 0.05) and tumor size (P = 0.024), LRC with BOT (P = 0.008) and PTC with BOT (P = 0.028). The treatment was well tolerated in general.

CONCLUSION

SBRT is an effective and safe treatment with high OS, LRC, EFS and PTC rates in patients with primary NSCLC. Protracted BOT might deteriorate SBRT outcomes.

Hyaluronic acid spacer in focal prostate reirradiation: A single centre experience

PURPOSE

The optimal management of locally recurrent prostate cancer after curative radiotherapy is still unknown. In this study, we evaluated the preliminary results of reirradiation using stereotactic body radiotherapy for locally recurrent prostate cancer after initial definitive local radiotherapy.

MATERIALS AND METHODS

Between April 2016 and February 2019, 11 patients with recurrent disease at the previously irradiated prostate were treated. Local recurrence was detected by radiological with or without functional imaging modalities including prostate multiparametric/pelvic MRI or positron-emission tomography-computerised tomography with (⁶⁸Ga)-labelled prostate-specific membrane antigen performed after rising prostate specific antigen serum level during follow-up. All patients received stereotactic body radiotherapy to the recurrent nodule to a total dose of 30Gy in five fractions. Hyaluronic acid spacer was injected between prostate and rectum in seven patients to decrease the rectal dose. Acute toxicity was evaluated by using Common Terminology Criteria for Adverse Events version 4.0, and late toxicity was evaluated by using Radiation Therapy Oncology Group/European Organisation for Research and Treatment of Cancer late radiation morbidity scoring schema.

RESULTS

At the diagnosis, the median age was 64 years, and the mean prostate specific antigen serum concentration was 17.7ng/mL. The median interval time between local recurrence and initial definitive radiotherapy was 63 months. Mean prostate specific antigen concentration nadir value during follow-up was 0.43ng/mL. With a median follow up of 19 months, three patients developed either local or distant relapse. One patient had grade 3 acute rectal toxicity, and one patient had grade 2 late urinary toxicity. We did not observe any acute or late toxicity due to hyaluronic acid spacer injection.

CONCLUSION

Reirradiation after local recurrence following initial definitive radiotherapy together with hyaluronic acid spacer use seems to be effective and safe.

Dosimetric comparison of three-dimensional conformal radiotherapy and intensity-modulated radiotherapy for left-sided chest wall and lymphatic irradiation

Introduction

The aim of this study was to compare five different techniques for chest wall (CW) and lymphatic irradiation in patients with left‐sided breast carcinoma.

Methods

Three‐dimensional conformal radiotherapy (3DCRT), forward‐planned intensity‐modulated radiotherapy (FP‐IMRT), inverse‐planned IMRT (IP‐IMRT; 7‐ or 9‐field), and hybrid IP‐/FP‐IMRT were compared in 10 patients. Clinical target volume (CTV) included CW and internal mammary (IM), supraclavicular (SC), and axillary nodes. Planning target volumes (PTVs), CTVs, and organs at risks (OARs) doses were analyzed with dose–volume histograms (DVHs).

Results

No differences could be observed among the techniques for doses received by 95% of the volume (D95%) of lymphatics. However, the FP‐IMRT resulted in a significantly lower D95% dose to the CW‐PTV compared to other techniques (P = 0.002). The 9‐field IP‐IMRT achieved the lowest volumes receiving higher doses (hotspots). Both IP‐IMRT techniques provided similar mean doses (Dmean) for the left lung which were smaller than the other techniques. There was no difference between the techniques for maximum dose (Dmax) of right breast. However, FP‐IMRT resulted in lower Dmean and volume of right breast receiving at least 5 Gy doses compared to other techniques.

Conclusion

The dose homogeneity in CW‐CTV was better using IMRT techniques compared to 3DCRT. Especially 9‐field IP‐IMRT provided a more homogeneous dose distribution in IM and axillary CTVs. Moreover, the OARs volumes receiving low radiation doses were larger with IP‐IMRT technique, while volumes receiving high radiation doses were larger with FP‐IMRT technique. Hybrid IMRT plans were found to have the advantages of both FP‐ and IP‐IMRT techniques.