Methodological guide for assessing the carbon footprint of external beam radiotherapy: A single-center study with quantified mitigation strategies

Background and purposes

Data on the carbon footprint of external beam radiotherapy (EBRT) are scarce. Reliable and exhaustive data, including a detailed carbon inventory, are needed to determine effective mitigation strategies.

Materials and methods

This study proposes a methodology for calculating the carbon footprint of EBRT and applies it to a single center. Mitigation strategies are derived from the carbon inventory, and their potential reductions are quantified whenever possible.

Results

The average emission per treatment and fraction delivered was 489 kg CO₂eq and 27 kg CO₂eq, respectively. Patient transportation (43 %) and the construction and maintenance of linear accelerators (LINACs) and scanners (17 %) represented the most significant components. Electricity, the only energy source used, accounted for only 2 % of emissions.Derived mitigation strategies include a data deletion policy (reducing emissions in 30 years by 12.5 %), geographical appropriateness (-12.2 %), transportation mode appropriateness (-9.3 %), hypofractionation (-5.9 %), decrease in manufacturers' carbon footprint (-5.2 %), and an increase in machine durability (-3.5 %).

Conclusion

Our findings indicate that a significant reduction in the carbon footprint of a radiotherapy unit can be achieved without compromising the quality of care.This study provides a methodology and a starting point for comparison and proposes and quantifies mitigation strategies, paving the way for others to follow.

Clinical characteristics and radiation therapy modality of younger patients with early-stage endometrial cancer, a multicenter study in China's real world

BACKGROUND

Endometrial cancer is a prevalent gynecologic malignancy found in postmenopausal women. However, in the last two decades, the incidence of early-stage has doubled in women under 40 years old. This study aimed to investigate the clinical and pathological characteristics and adjuvant therapeutic modalities of both young and not -young patients with early-stage endometrial cancer in China's real world.

METHODS

This retrospective study analyzed patients with early-stage endometrial cancer at 13 medical institutions in China from 1999 to 2015. The patients were divided into two groups: young (≤ 45 years old) and non-young (> 45 years old). Statistical comparisons were conducted between the two groups for clinical characteristics, pathological features, and survival. The study also identified factors that affect local recurrence-free survival (LRFS) using Cox proportional risk regression analysis. Propensity score matching (1:1) was used to compare the effects of local control between vaginal brachytherapy (VBT) alone and pelvic external beam radiotherapy (EBRT) ± VBT.

RESULTS

The study involved 1,280 patients, 150 of whom were 45 years old or younger. The young group exhibited a significantly higher proportion of stage II, low-risk, lower uterine segment infiltration (LUSI), and cervical invasion compared to the non-young group. Additionally, the young patients had significantly larger maximum tumor diameters. The young group also had a significantly higher five-year overall survival (OS) and a five-year LRFS. Age is an independent risk factor for LRFS. There was no significant difference in LRFS between young patients with intermediate- to high-risk early-stage endometrial cancer who received EBRT ± VBT and those who received VBT alone.

CONCLUSIONS

In the present study, young patients had better characteristics than the non-young group, while they exhibited higher levels of aggressiveness in certain aspects. The LRFS and OS outcomes were better in young patients. Age is an independent risk factor for LRFS. Additionally, VBT alone may be a suitable option for patients under 45 years of age with intermediate- to high-risk early-stage endometrial cancer, as it reduces the risk of toxic reactions and future second cancers while maintaining similar local control as EBRT.

Outcomes and complications of intraoperative radiotherapy versus external beam radiotherapy for early breast cancer

BACKGROUND

Intraoperative radiotherapy (IORT) is an alternative for external beam radiotherapy (EBRT) for early stage breast cancer (BC). Herein, we compared outcomes, postoperative and post-radiation complications of IORT and EBRT.

METHODS

We conducted a cohort study to compare complications of IORT and EBRT in patients. A checklist of the complications of IORT and EBRT, was used to assess and post-radiation complications and outcomes.

RESULTS

Overall, 264 women (121 in IORT and 143 in EBRT group) with a mean (SD) age of 55 ± 8.6 years analyzed in this study. The IORT group (quadrantectomy + SLNB + IORT) had more severe post-operative pain compared to the EBRT group (quadrantectomy + SLNB) (OR = 1.929, 95% CI: 1.116-3.332). Other postoperative complications, including edema, erythema, seroma, hematoma, and wound complications were not significantly different between the IORT and EBRT groups. EBRT was associated with higher rates post-radiation complications, including erythema (95.8% vs. 21.5%), skin dryness (30.8% vs. 12.4%), pruritus (26.6% vs. 17.4%), hyperpigmentation (48.3% vs. 9.9%), and telangiectasia (1.4% vs. 0.8%). Multivariate analysis showed that erythema, skin dryness and pruritus, and hyperpigmentation were more severe in the EBRT group, while breast induration was higher in the IORT group (OR = 4.109, 95% CI: 2.242-7.531). Excellent, good, and fair cosmetic outcome was seen in 11.2%, 72%, and 16.8% of the patients in the EBRT group and 29.8%, 63.6%, and 6.6% in the IORT group, respectively, suggesting that the cosmetic outcome was significantly better in the IORT group (P < .001). There wasn't statistically significant difference in recurrence-free survival and overall survival rates between two groups of patients who received either IORT or EBRT (P = .953, P = .56).

CONCLUSION

IORT is considered to have lower post-radiation complications and better cosmetic outcomes in breast cancer patients. Therefore, IORT might be used as the treatment of choice in eligible patients.

Radiosensitising effect of iron oxide-gold nanocomplex for electron beam therapy of melanoma in vivo by magnetic targeting

Melanoma is a dangerous type of skin cancer sometimes treated with radiotherapy. However, it induces damage to the surrounding healthy tissue and possibly further away areas. Therefore, it is necessary to give a lower dose to the patient with targeted therapy. In this study, the radio-sensitising effect of gold-coated iron oxide nanoparticles on electron beam radiotherapy of a melanoma tumour with magnetic targeting in a mouse model was investigated. Gold-coated iron oxide nanoparticles were prepared in a steady procedure. The melanoma tumour model was induced in mice. Animals were divided into five groups: (1) normal; (2) melanoma; (3) gold-coated iron oxide nanoparticles alone; (4) electron beam radiotherapy; (5) electron beam radiotherapy plus gold-coated iron oxide nanoparticles. The magnet was placed on the tumour site for 2 h. The tumours were then exposed to 6 MeV electron beam radiotherapy for a dose of 8 Gy. Inductively coupled plasma optical emission spectrometry test, hematoxylin and eosin staining, and enzyme-linked immunosorbent assay blood test were also performed. Gold-coated iron oxide nanoparticles with magnetic targeting before electron beam radiotherapy reduced the growth of the tumour compared to the control group. Blood tests did not show any significant toxicity. Deposition of nanoparticles was more in the tumour and spleen tissue and to a lesser extent in the liver, kidney, and lung tissues. The synergistic effect of nanoparticles administered by the intraperitoneal route and then concentrated into the tumour area by application of an external permanent magnet, before delivery of the electron beam radiotherapy improved the overall cancer treatment outcome and prevented metal distribution side effects.

Hit and Run: Bilateral Massive Intraocular Lymphomatous Infiltration after CAR-T Therapy

PURPOSE

We report a case of bilateral intraocular infiltration of DLBCL after CAR-T therapy.

METHODS

Retrospective case report.

RESULTS

A 62-year-old Caucasian male with medical history of high-grade DLBCL presented with papillitis and vitritis upon completion of CAR-T therapy. Thorough infectious and diagnostic work-ups were performed. Diagnostic vitreous tap revealed intraocular lymphoma. The patient received external beam radiotherapy to both orbits with dramatic improvement in disc edema and vitritis. However, subsequent MRI showed development of intracranial metastatic disease, and the patient died within the same month.

CONCLUSION

Atypical intraocular metastasis of DLBCL may occur following CAR-T therapy and may indicate secondary changes in immunosurveillance within immune-privileged sites such as the eye.

Long-term oncologic outcomes of low dose-rate brachytherapy compared to hypofractionated external beam radiotherapy for intermediate -risk prostate cancer

PURPOSE

To compare the long-term oncologic outcomes of intermediate risk (IR) prostate cancer (PCa) patients treated with low dose-rate brachytherapy (LDR-BT) or moderate hypofractionated external beam radiotherapy (HF-EBRT).

METHODS AND MATERIALS

Patients diagnosed with IR PCa and treated with LDR-BT or HF-EBRT between January 2005 and December 2013 were included. Brachytherapy treatment involved a transperineal implant of iodine-125 to a dose of 145 Gy to the PTV, while HF-EBRT was delivered using intensity modulated radiotherapy with 60 Gy in 20 fractions. The Phoenix ''nadir +2'' threshold was used to define biochemical relapse (BR). The cumulative incidence function (CIF) of BR and metastases was reported for each group and compared using the Gray's test to account for the competing risk of death. The Kaplan-Meier (KM) method was used to estimate overall survival (OS) and prostate cancer specific survival (PCSS). Univariate (UVA) and multivariable (MVA) analysis of the CIF of BR and metastases were performed. A 2-tailed p-value ≤ 0.05 was considered statistically significant.

RESULTS

Overall, 122 and 124 patients were treated with LDR-BT and HF-EBRT respectively. Median follow-up was 95 months [interquartile range (IQR): 79-118] in the LDR-BT group and 96 months (IQR: 63-123) in the HF-EBRT group. BR was observed in 5 patients treated with LDR-BT and 34 treated with HF-EBRT. At 60 and 90 months, the CIF of BR was 0.9% and 3.5% in the LDR-BT group vs. 16.6% and 23.7% in the HF-EBRT (p < 0.001). The CIF of metastases at 90 and 108 months, was 0% and 1.6% vs. 3.4% and 9.1% in the LDR-BT and HF-EBRT groups (p = 0.003), respectively. At the last follow-up, 3 patients treated with HF-EBRT died from their cancer [PCSS of 97.5% at 8 years and none died in the LDR-BT group (p = 0.09). On UVA and MVA risk group and treatment modality were independently associated with CIF of BR. On UVA HF-EBRT and ISUP grade group 3 were associated with metastases.

CONCLUSION

LDR-BT was associated with higher biochemical and metastases control in our cohort when compared to moderately HF-EBRT. In the absence of a randomized trial, LDR-BT when feasible should be offered to patients with a life expectancy of >8 years.

Custom-made radiotherapy prosthesis for external and internal radiotherapy in a patient with lip cancer

Definitive radiotherapy is an effective treatment for early-stage lip cancer. The goal of radiotherapy is to irradiate the cancer site effectively while protecting healthy surrounding tissue from the adverse effects of radiation. To this end, radiotherapy prostheses have been widely and effectively used. A maxillofacial prosthodontist working in collaboration with a radiation oncologist can create a custom-made radiotherapy prosthesis that minimizes adverse effects. This report demonstrates the successful use of spacers in external beam radiotherapy and brachytherapy in consideration of the patient's radiation therapy treatment plan and wearing conditions, ensuring adequate availability and preventing radiation-related complications.

Trial Participation is Not Associated with Better Biochemical Recurrence-free Survival in a Large Cohort of External Beam Radiotherapy-Treated Intermediate- and High-Risk Prostate Cancer Patients

AIMS

There is a widespread belief that outcomes of cancer patients treated within clinical trials might not be representative of the outcomes obtained within standard clinical settings. We sought to investigate the effect of trial participation on biochemical recurrence (BCR) in localised, D'Amico intermediate- and high-risk prostate cancer patients treated with external beam radiotherapy (EBRT).

MATERIALS AND METHODS

We relied on a study population treated with EBRT between January 2001 and January 2021 at a single tertiary care centre, stratified according to trial enrolment. Separate Kaplan-Meier and multivariable Cox regression models tested BCR-free survival at 60 months within intermediate- and high-risk EBRT patients, after adjustment for covariables. Additionally, the analyses were refitted after inverse probability treatment weighting was performed separately for both risk subgroups.

RESULTS

Of 932 eligible patients, 635 (68%) and 297 (32%) had intermediate- and high-risk prostate cancer, respectively. Overall, 53% of patients were trial participants. BCR rates were 11 versus 5% (P = 0.27) and 12 versus 14% (P = 0.08) in trial participants versus non-participants for intermediate- and high-risk subgroups, respectively. Differences in patient and clinical characteristics were recorded. Trial participation status failed to reach predictor status in multivariable Cox regression models for BCR in both intermediate-risk (hazard ratio 1.34; 95% confidence interval 0.71-2.49; P = 0.4) and high-risk patients (hazard ratio 1.03; 95% confidence interval 0.45-2.34; P = 0.9). Virtually the same results were recorded in inverse probability treatment weighting cohorts.

CONCLUSIONS

Relying on a large cohort of EBRT-treated intermediate- and high-risk patients, no BCR differences were recorded between trial participants and non-participants after accounting for confounders.

A study of skin marker alignment using different diamond-shaped light fields for prone breast external-beam radiation therapy

For breast cancer patients treated in the prone position with tangential fields, a diamond-shaped light field (DSLF) can be used to align with corresponding skin markers for image-guided radiation therapy (IGRT). This study evaluates and compares the benefits of different DSLF setups. Seventy-one patients who underwent daily tangential kilovoltage (kV) IGRT were categorized retrospectively into four groups: (1) DSLF field size (FS) = 10 × 10 cm² , gantry angle = 90° (right breast)/270° (left breast), with the same isocenter as treatment tangential beams; (2) same as group 1, except DSLF FS = 4 × 4 cm² ; (3) DSLF FS = 4 × 4-6 × 8 cm² , gantry angle = tangential treatment beam, off-isocenter so that the DSLF was at the approximate breast center; and (4) No-DSLF. We compared their total setup time (including any DSLF/marker-based alignment and IGRT) and relative kV-based couch shift corrections. For groups 1-3, DSLF-only dose distributions (excluding kV-based correction) were simulated by reversely shifting the couch positions from the computed tomography plans, which were assumed equivalent to the delivered dose when both DSLF and IGRT were used. For patient groups 1-4, the average daily setup time was 2.6, 2.5, 5.0, and 8.3 min, respectively. Their mean and standard deviations of daily kV-based couch shifts were 0.64 ± 0.4, 0.68 ± 0.3, 0.8 ± 0.6, and 1.0 ± 0.6 cm. The average target dose changes after excluding kV-IGRT for groups 1-3 were-0.2%, -0.1%, and +0.4%, respectively, whereas DSLF-1 was most efficient in sparing heart and chest wall, DSLF-2 had lowest lung D_max ; and DSLF-3 maintained the highest target coverage at the cost of highest OAR dose. In general, the use of DSLF greatly reduces patient setup time and may result in smaller IGRT corrections. If IGRT is limited, different DSLF setups yield different target coverage and OAR dose sparing. Our findings will help DSLF setup optimization in the prone breast treatment setting.

After ASCENDE-RT: Biochemical and survival outcomes following combined external beam radiotherapy and low-dose-rate brachytherapy for high-risk and unfavourable intermediate-risk prostate cancer, a population-based analysis

PURPOSE

To evaluate the outcomes of unfavorable intermediate-risk (UIR) and high-risk (HR) prostate cancer patients treated with combined external beam radiation therapy (EBRT) and low-dose-rate prostate brachytherapy (LDR-PB).

METHODS AND MATERIALS

A population-based cohort of 568 prostate cancer patients treated with combined EBRT and LDR-PB from 2010 to 2016 was analyzed. All patients received EBRT followed by LDR-PB boost. Outcomes were compared with the results for the brachytherapy arm of the ASCENDE-RT trial.

RESULTS

The median followup was 4.5 years. Sixty-nine percent (N = 391) had HR disease. Ninety-four percent of the HR and 57% of UIR were treated with androgen deprivation therapy (ADT) with a median duration of 12 months. The 5-year K-M biochemical progression-free survival (b-PFS), metastasis-free survival (MFS), and overall survival (OS) were 84 ± 2%, 90 ± 2%, and 88 ± 2%, similar to 89 ± 5%, 94 ± 4%, and 92 ± 4% for the ASCENDE-RT LDR-PB arm. The likelihood of achieving a PSA ≤0.2 ng/mL at 4 years was 88%, similar to 86% in the ASCENDE-RT LDR-PB arm. Thirty-three men (5.8%) would have been ineligible for ASCENDE-RT due to high-risk features. The 5-year K-M b-PFS, MFS and OS estimates were 86 ± 2%, 92 ± 1% and 89 ± 2% for the ASCENDE-RT eligible versus 56 ± 10% (p < 0.001), 73 ± 8% (p < 0.001), and 77 ± 9% (p = 0.098) for the ineligible patients.

CONCLUSIONS

In this population-based cohort, combining LDR-PB with pelvic EBRT (+/- ADT) achieves very favorable b-PFS that compares to the LDR-PB arm of the ASCENDE-RT, supporting the generalizability of those results. Men ineligible for ASCENDE-RT, based on prognostic features, have a much higher risk of biochemical recurrence and metastatic relapse.

A systems-based operational assessment of external beam radiotherapy

PURPOSE

Advanced technologies have led to improvements in modern radiotherapy over the years. However, adoption of advanced technologies can present challenges to existing clinical operations and negatively impact safety. The purpose of this work is to perform an assessment of modern radiotherapy for the operational objectives of safety, efficiency, and financial viability.

METHODS

This work focuses on external beam radiotherapy (EBRT). The operational assessment included department management, treatment planning, treatment delivery, and associated workflows for three equipment configurations of Ethos, Halcyon, and TrueBeam with the ARIA information system, Eclipse treatment planning, and IDENTIFY surface guidance. Systems-theoretic process analysis (STPA) was used to analyze the related workflows. Control actions, unsafe contexts of those control actions, and associated causal scenarios that can lead to unsafe radiation and non-radiation physical injury (safety objective), reduced treatment capacity (efficiency objective), and costs that exceed budget (financial viability objective) were identified.

RESULTS

The number of control actions (and causal scenarios) were 18 (254), 18 (267), and 20 (267) for the equipment configurations of Halcyon, TrueBeam, and Ethos, respectively. The extent that safety, efficiency, and financial viability were impacted is similar across the different equipment configurations but there were some noteworthy differences related to information transfer and workflow bottlenecks potentially impacting access to care. Seventy five percent of the scenarios across all three configurations were related to safety. Overall, 29% of the scenarios impacted more than one operational objective and 48% were related to human decisions during the process of care. Planned or unplanned process changes were responsible for 8% of the causal scenarios.

CONCLUSIONS

Broad-based clinical improvements may be realized by addressing causal scenarios that impact multiple objectives. Redesigning the roles and responsibilities of the clinical team and some aspects of the radiotherapy workflow may be helpful to fully realize the benefits of advanced technologies. Radiotherapy may benefit from additional tools to improve the consistency between decisions and actions when system or process changes occur. This article is protected by copyright. All rights reserved.

Alpha-Emitter Radiopharmaceuticals and External Beam Radiotherapy: A Radiobiological Model for the Combined Treatment

Previously published studies combined external beam radiotherapy (EBRT) treatments with different activities of ²²³Ra. The data of two-year overall survival (2y-OS) and neutropenia (TOX) incidence when combining EBRT and ²²³Ra are not homogeneous in literature. We adapted the linear-quadratic model (LQ) to ²²³Ra therapy using brachytherapy formalism for a mixture of radionuclides, considering the contribution of all daughter isotopes in the decay chain. A virtual cohort of patients undergoing ²²³Ra therapy was derived using data from the literature. The doses delivered using ²²³Ra and EBRT were converted into biologically equivalent doses. Fixed-effect logistic regression models were derived for both the 2y-OS and TOX and compared with available literature. Based on the literature search, four studies were identified to have reported the ²²³Ra injection activity levels varying from the placebo (0) to 80 kBq/kg, associated or not with EBRT. Logistic regression models revealed a dose-dependent increase in both the 2y-OS (intercept = -1.364; slope = 0.006; p-value ≤ 0.05) and TOX (-5.035; 0.018; ≤0.05) using the EBRT schedule of 8 Gy in 1 fr. Similar results were obtained for other schedules. Discrepancies between our TOX model and those derived for EBRT combined with chemotherapy are discussed. Radiobiological models allow us to estimate dose-dependent relationships, to predict the OS and TOX following combined ²²³Ra + EBRT treatment, which will guide future treatment optimization.

Survival rates with external beam radiation therapy in newly diagnosed elderly metastatic prostate cancer patients

BACKGROUND

The survival benefit of primary external beam radiation therapy (EBRT) has never been formally tested in elderly men who were newly diagnosed with metastatic prostate cancer (mPCa). We hypothesized that elderly patients may not benefit of EBRT to the extent as younger newly diagnosed mPCa patients, due to shorter life expectancy.

METHODS

We relied on Surveillance, Epidemiology and End Results (2004-2016) to identify elderly newly diagnosed mPCa patients, aged >75 years. Kaplan-Meier, univariable and multivariable Cox regression models, as well as Competing Risks Regression models tested the effect of EBRT versus no EBRT on overall mortality (OM) and cancer-specific mortality (CSM).

RESULTS

Of 6556 patients, 1105 received EBRT (16.9%). M1b stage was predominant in both EBRT (n = 823; 74.5%) and no EBRT (n = 3908; 71.7%, p = 0.06) groups, followed by M1c (n = 211; 19.1% vs. n = 1042; 19.1%, p = 1) and M1a (n = 29; 2.6% vs. n = 268; 4.9%, p < 0.01). Median overall survival (OS) was 23 months for EBRT and 23 months for no EBRT (hazard ratio [HR]: 0.97, p = 0.6). Similarly, median cancer-specific survival (CSS) was 29 months for EBRT versus 30 months for no EBRT (HR: 1.04, p = 0.4). After additional multivariable adjustment, EBRT was not associated with lower OM or lower CSM in the entire cohort, as well as after stratification for M1b and M1c substages.

CONCLUSIONS

In elderly men who were newly diagnosed with mPCa, EBRT does not affect OS or CSS. In consequence, our findings question the added value of local EBRT in elderly newly diagnosed mPCa patients.

The Effect of Maximum Tumor Diameter by MRI on Disease Control in Intermediate and High-risk Prostate Cancer Patients Treated With Brachytherapy Boost

BACKGROUND

Larger maximum tumor diameter (MTD) has been associated with worse prostate cancer (PCa) outcomes. However, the impact of MTD in PCa treated with external beam radiotherapy and brachytherapy boost (EBRT+BB) remains unknown.

MATERIALS AND METHODS

Patients with PCa treated with EBRT+BB were identified from an institutional database. Clinical data including MTD, age, androgen deprivation therapy (ADT) use, prostate specific antigen (PSA), International Society of Urologic Pathology (ISUP) group, clinical T-stage, and presence of adverse pathology on imaging were retrospectively collected. Multivariable and univariable cox proportional hazards models for biochemical failure (BF) and distant metastasis (DM) were produced with MTD grouped by receiver operating characteristic (ROC) cut-point. Cumulative hazard functions for BF and DM were compared with log-rank test and stratified by ISUP group.

RESULTS

Of 191 patients treated with EBRT+BB, 113 had MTD measurements available. Larger MTD was associated with increased ADT use and seminal vesicle involvement. ROC optimization identified MTD of 24 mm as the optimal cut-point for both BF and DM. MTD was independently associated with both BF (HR 8.61, P = .048, 95% CI 1.02-72.97) and DM (HR 8.55, P = .05, 95% CI 1.00-73.19). In patients with ISUP group 4 to 5 disease, MTD > 24 mm was independently associated with increased risk of DM (HR 10.13, P = .04, 95% CI 1.13-91.12).

CONCLUSIONS

This is the first study to evaluate MTD in the setting of EBRT+BB. These results demonstrate that MTD is independently associated with BF and metastasis. This suggests a possible role for MTD in risk assessment models and clinical decision-making for men receiving EBRT+BB.

Online MR evaluation of inter- and intra-fraction uterus motions and bladder volume changes during cervical cancer external beam radiotherapy

Purpose/objective(s)

The purpose of the study was to assess the uterus motions and bladder volume changes of fractional movements in cervical sites throughout the external beam radiotherapy (EBRT) treatment.

Materials/methods

A prospective online MR imaging tracking study was conducted in EBRT 43 patients with at least 4 scans during each treatment (before: ultrasound scan, MRI scan, CBCT scan, after: MRI scan) were included. In order to improve the treatment repeatability, each patient was instructed to empty the bladder and drink 500 ml water 1 h before CT simulation and each treatment. If the ultrasound scan result reached the CT simulation volume of bladder, the treatment began. Bladder was outlined on the T2 weighted axial sequence and CBCT image by the two observers to avoid the influence of contouring. The data of bladder volume and scanning time were accurately recorded. The bladder volumes, filling rates and uterus motion were retrospectively analyzed by MIM software.

Results

Inter-fraction variation of the bladder volume was significant (p < 0.0001). Intra-fraction mean increase of the bladder volume was modest (30 cc) but significant (p < 0.001). Both inter- and intra-fraction of the uterus motion were significant. The average time between the pre-and post-fraction MRI scans was 27.82 ± 7.12 min (range 10–55 min) for IMRT plans and 24.14 ± 5.86 min (range7-38 min) for VMAT plan. Average bladder filling rate was 3.43 ml/min. The bladder filling rate did not change significantly with the course of treatment, but the bladder was more intolerant.

Conclusion

This is the most detailed assessment of intra-fraction and inter-fraction motion during EBRT for cervical cancer. Finally, this study will inform appropriate treatment margins for online adaptive radiotherapy. We suggest that at least one image scan is needed before the EBRT. The portable US scanner provides a quick but unreliable measurement of the bladder volume. There is a significant statistical difference between the results of ultrasonic scanning and that of image scanning.

Assessing ISUP prostate cancer grade groups in patients treated with definitive dose escalated external beam radiation

PURPOSE

The five grade group system has been validated for men treated with radical prostatectomy. However, the prognostic value for men treated with radiation therapy is uncertain, with prior studies utilising old techniques and doses. We aimed to validate the International Society of Urological Pathology (ISUP) groupings for men treated with contemporary radiation therapy.

METHODS

Men with localised prostate cancer treated with image-guided, dose-escalated (≥78 Gy) external beam radiation were identified across four institutions. Primary outcome was time to biochemical failure. Harrell's C index assessed performance of the ISUP system against other grading stratifications.

RESULTS

2205 men were included, withmedian follow-up of 5.6 years. Seven-year actuarial rates of biochemical failure for grade groups 1-5 were 9.3%, 10.4%, 13.2%, 12.4% and 23.4%. On multivariate analysis, hazard ratios for biochemical failure were1.19, 1.00, 1.10, 1.05 and 2.10 for grade groups 1-5, relative to 2. P values were only significant for grade group 5. Harrell's C index favoured an alternative three group model (comprising Gleason scores [6 and 3 + 4 = 7] vs [4 + 3 = 7 and 8] vs [9 and 10]) over ISUP grade groups.

CONCLUSIONS

The ISUP grade groups were not validated in a contemporary cohort treated with dose-escalated, image-guided radiation therapy. Grade groups 1-4 were not statistically different from each other; however, grade group 5 had a significantly worse prognosis. We identified a new three group model that better predicted biochemical outcomes. Further work is requiredto validate optimal groupings for modern radiation therapy and investigate the contrasting prognostic capability of grade groups in surgical and radiation therapy patients.

Vesico-urethral anastomosis sampling: a forgotten tool for guiding salvage radiation after radical prostatectomy

OBJECTIVE

To review the utility of vesicourethral anastomosis (VUA)-directed biopsy in the setting of biochemical recurrence (BCR) after radical prostatectomy (RP) for prostate cancer (PCa) in patients who have undergone evaluation by gallium-68 prostate-specific membrane antigen positron emission tomography with computed tomography (⁶⁸ Ga-PSMA PET/CT).

METHODS

We completed a retrospective review of a prospectively maintained dataset from January 2015 to August 2020. Patient demographics were recorded for those who experienced BCR, as defined by a rise in prostate-specific antigen (PSA) level to above 0.2 ng/mL, who had a ⁶⁸ Ga-PSMA PET/CT that did not demonstrate recurrence within the prostate bed, and who subsequently underwent a transperineal ultrasonography (TPUS)-guided biopsy directed at the VUA. Histological reporting of the biopsies was undertaken in order to determine whether the benefits of salvage radiation therapy (SRT) could be justified by the presence of cancer cells.

RESULTS

Eighteen patients who had a ⁶⁸ Ga-PSMA PET/CT and underwent VUA-directed biopsy were identified as having BCR. ⁶⁸ Ga-PSMA PET/CT scans demonstrated avidity at the VUA in none of the patients, although two out of 18 patients showed avidity in the seminal vesicles and two out of 18 patients showed avidity within regional lymph nodes. Histology from the TPUS-guided, VUA-directed biopsies demonstrated no prostatic tissue in six out of 18 and presence of prostatic tissue in 12 out of 18 of patients, respectively. In 7 out of 18 cases, there was histological evidence of recurrent PCa at the VUA in the absence of a positive ⁶⁸ Ga-PSMA PET/CT scan.

CONCLUSION

This study highlights the potential value of VUA-directed biopsy. We are reminded that a negative ⁶⁸ Ga-PSMA PET/CT does not exclude local recurrence and that the addition of a VUA-directed biopsy may aid in the decision-making process for patients with BCR following RP, especially when ⁶⁸ Ga-PSMA PET/CT is locally negative. When the result of both ⁶⁸ Ga-PSMA PET/CT and VUA-directed biopsy are negative, it should encourage clinicians to share decision-making in regard to undertaking SRT vs continuing BCR surveillance. This may delay the possible side effects associated with SRT, despite its excellent PSA failure-free survival rate.

Patterns of Clinical Progression in Radiorecurrent High-risk Prostate Cancer

The natural history of radiorecurrent high-risk prostate cancer (HRPCa) is not well-described. To better understand its clinical course, we evaluated rates of distant metastases (DM) and prostate cancer-specific mortality (PCSM) in a cohort of 978 men with radiorecurrent HRPCa who previously received either external beam radiation therapy (EBRT, n = 654, 67%) or EBRT + brachytherapy (EBRT + BT, n = 324, 33%) across 15 institutions from 1997 to 2015. In men who did not die, median follow-up after treatment was 8.9 yr and median follow-up after biochemical recurrence (BCR) was 3.7 yr. Local and systemic therapy salvage, respectively, were delivered to 21 and 390 men after EBRT, and eight and 103 men after EBRT + BT. Overall, 435 men developed DM, and 248 were detected within 1 yr of BCR. Measured from time of recurrence, 5-yr DM rates were 50% and 34% after EBRT and EBRT + BT, respectively. Measured from BCR, 5-yr PCSM rates were 27% and 29%, respectively. Interval to BCR was independently associated with DM (p < 0.001) and PCSM (p < 0.001). These data suggest that radiorecurrent HRPCa has an aggressive natural history and that DM is clinically evident early after BCR. These findings underscore the importance of further investigations into upfront risk assessment and prompt systemic evaluation upon recurrence in HRPCa. PATIENT SUMMARY: High-risk prostate cancer that recurs after radiation therapy is an aggressive disease entity and spreads to other parts of the body (metastases). Some 60% of metastases occur within 1 yr. Approximately 30% of these patients die from their prostate cancer.

Feasibility of Proton Beam Therapy as a Rescue Therapy in Heavily Pre-Treated Retinoblastoma Eyes

Simple Summary

A variety of therapies are available for the treatment of retinoblastomas. Nevertheless, despite exhaustion of all therapeutic methods, refractory or recurrent courses of the disease occur. In eyes with a function worthy of preservation radiation therapy may become unavoidable. Proton beam therapy, compared to conventional photon-based radiotherapy, is a highly conformal form of radiation therapy with a high biological effectiveness with a simultaneously reduced probability of radiation-related side-effects and induction of secondary primary malignancies. The aim of our retrospective study was to evaluate the efficacy of proton beam therapy as rescue therapy in 15 heavily pretreated retinoblastoma eyes. In our retrospective series of a highly negatively selected patient population, we were able to preserve 60% of the eyes with a manageable side effect profile. A cataract, as the most common long-term complication, was evident in 44.4% of the preserved eyes. There was no in-field second tumor manifestation during follow-up, therefore the preliminary data of this study and series published by others suggest that the risk is significantly lower after proton beam therapy compared to conventional external beam radiation therapy using photons.

Abstract

Despite the increased risk of subsequent primary tumors (SPTs) external beam radiation (EBRT) may be the only therapeutic option to preserve a retinoblastoma eye. Due to their physical properties, proton beam therapy (PBT) offers the possibility to use the effectiveness of EBRT in tumor treatment and to decisively reduce the treatment-related morbidity. We report our experiences of PBT as rescue therapy in a retrospectively studied cohort of 15 advanced retinoblastoma eyes as final option for eye-preserving therapy. The average age at the initiation of PBT was 35 (14–97) months, mean follow-up was 22 (2–46) months. Prior to PBT, all eyes were treated with systemic chemotherapy and a mean number of 7.1 additional treatments. Indication for PBT was non-feasibility of intra-arterial chemotherapy (IAC) in 10 eyes, tumor recurrence after IAC in another 3 eyes and diffuse infiltrating retinoblastoma in 2 eyes. Six eyes (40%) were enucleated after a mean time interval of 4.8 (1–8) months. Cataract formation was the most common complication affecting 44.4% of the preserved eyes, yet 77.8% achieved a visual acuity of >20/200. Two of the 15 children treated developed metastatic disease during follow-up, resulting in a 13.3% metastasis rate. PBT is a useful treatment modality as a rescue therapy in retinoblastoma eyes with an eye-preserving rate of 60%. As patients are at lifetime risk of SPTs consistent monitoring is mandatory.

External beam radiotherapy for prostate cancer: What are the current research trends and hotspots?

Background

The external beam radiotherapy (EBRT) applied for prostate cancer (PCa) has been one of the most important and hottest research fields over recent decades. This study aimed to explore the research hotspots of EBRT in PCa and help the researchers have a clear and intuitive reference basis for later researches.

Methods

The literature scientometric analysis related to “EBRT applied for PCa” was conducted via the Web of Science Core Collection from 2010 to 2019. The Microsoft Office Excel 2019 and CiteSpace V. 5.7.R1 software were introduced for visualizing and analyzing the data.

Results

A total of 7860 relevant papers were extracted and downloaded. A total of 7828 papers were extracted and analyzed after data cleansing by CiteSpace. The tendency of published papers was comprehensively increasing from 2010 to 2019. Among all 73 countries/regions, USA published the most papers, accounting for 39%, which was the most active contributor with most publications. Australia (Centrality: 0.18), England (Centrality: 0.12) were cooperating most cohesively with other countries. Univ Toronto was the most productive institute (229), while Harvard Univ (Centrality: 0.67) had extensive collaborations with other institutes. The International journal of Radiation Oncology Biology Physics had the largest number of publications and the highest number of co‐citations. Briganti A had the largest volume of publications. D'Amico AV had the highest number of co‐citations. Four latest and largest clusters were identified as oligometastases, salvage therapy (SRT), prostate‐specific membrane antigen (PSMA), and hypofractionation. Thirteen references became strongest burst citations lasting until 2019. The studies of “oligometastases,” “SRT,” “PSMA,” “hypofractionation,” “postoperative radiotherapy,” and “dose and fraction regimen changes” were prevailing in the recent years.

Conclusion

The “oligometastases,” “SRT,” “PSMA,” “hypofractionation,” “postoperative radiotherapy,” and “dose and fraction regimen changes” may be the state‐of‐art research frontiers, and related studies will advance in this field over time.

Radioactive Iodine Therapy in Patients With Thyroid Carcinoma With Distant Metastases: A SEER-Based Study

Distant metastasis (DM) is the dominant negative prognosis for thyroid carcinoma. Radioactive iodine (RAI) therapy serves as an effective treatment for thyroid carcinoma. However, resistance to RAI occurs in patients with DMs. The present study aims to discriminate patients who may benefit from RAI. We extracted patients with thyroid cancer in the Surveillance, Epidemiology, and End Results program and analyzed thyroid cancer–specific survival after radiotherapy based on age and grade subgroups. A total of 1608 patients having DMs were eligible, including 521 (32.4%) cases with bone metastasis, 90 (5.6%) cases with brain metastasis, 158 (9.8%) cases with liver metastasis, 995 (61.9%) cases with lung metastasis, and 50 (3.1%) cases with other metastases. Advanced age, poor differentiation, follicular carcinoma, lymphatic metastasis, tumor size >10 mm, and extracapsular invasion are associated with pulmonary metastases. With respect to patients with DM, RAI therapy improved the survival in the age <45 years group and the well-/moderately differentiated group. For patients with pulmonary metastasis, RAI improved the survival in the higher grade group but did not have a strong effect in the better grade group. Our data indicate that the disparity of metastatic sites has different risk factors. Similarly, this finding indicates that RAI should be precisely applied to patients who undergo DM but are young and have well-/moderately differentiated tumors and may improve survival in pulmonary metastasis patients with poor grade tumors.

Patient-reported outcomes after external beam radiotherapy versus brachytherapy for palliation of dysphagia in esophageal cancer: A matched comparison of two prospective trials

BACKGROUND AND PURPOSE

A matched comparison of external beam radiotherapy (EBRT) versus brachytherapy recently demonstrated that EBRT appears at least as effective for palliating dysphagia in patients with incurable esophageal cancer. The aim of this analysis was to compare patient-reported outcomes (PROs) after EBRT versus brachytherapy.

MATERIALS AND METHODS

In a multicenter prospective cohort study, patients with incurable esophageal cancer requiring palliation of dysphagia were included to undergo EBRT (20 Gy in 5 fractions). This EBRT cohort was compared to the single-dose 12 Gy brachytherapy cohort of the previously reported SIREC-trial. Propensity score matching was applied to adjust for baseline imbalances. The primary endpoint of dysphagia improvement was reported previously. PROs were secondary outcomes and assessed at baseline and 3 months after treatment using EORTC QLQ-C30 and QLQ-OES18 questionnaires.

RESULTS

A total of 115 enrolled EBRT patients and 93 brachytherapy patients were eligible. After matching, 69 well-balanced pairs remained. At follow-up, significant deteriorations in functioning (i.e. physical, role, social), pain, appetite loss, and trouble with taste were observed after brachytherapy. In the EBRT group, such deterioration was observed only for role functioning, while significant improvements in trouble with eating and pain were found. Between-group comparison showed mostly comparable PRO changes, but significantly favored EBRT with regard to nausea, vomiting, pain, and appetite loss.

CONCLUSION

Short course EBRT results in similar or better PROs at 3 months after treatment compared to single-dose brachytherapy for the palliation of malignant dysphagia. These findings further support its use and inclusion in clinical practice guidelines.

Relationships between rectal and perirectal doses and rectal bleeding or tenesmus in pooled voxel-based analysis of 3 randomised phase III trials

BACKGROUND AND PURPOSE

This study aimed to identify anatomically-localised regions where planned radiotherapy dose is associated with gastrointestinal toxicities in healthy tissues throughout the pelvic anatomy.

MATERIALS AND METHODS

Planned dose distributions for up to 657 patients of the Trans Tasman Radiation Oncology Group 03.04 RADAR trial were deformably registered onto a single exemplar computed tomography dataset. Voxel-based multiple comparison permutation dose difference testing, Cox regression modelling and LASSO feature selection were used to identify regions where dose-increase was associated with grade ≥2 rectal bleeding (RB) or tenesmus, according to the LENT/SOMA scale. This was externally validated by registering dose distributions from the RT01 (n = 388) and CHHiP (n = 241) trials onto the same exemplar and repeating the tests on each of these data sets, and on all three datasets combined.

RESULTS

Voxel-based Cox regression and permutation dose difference testing revealed regions where increased dose was correlated with gastrointestinal toxicity. Grade ≥2 RB was associated with posteriorly extended lateral beams that manifested high doses (>55 Gy) in a small rectal volume adjacent to the clinical target volume. A correlation was found between grade ≥2 tenesmus and increased low-intermediate dose (∼25 Gy) at the posterior beam region, including the posterior rectum and perirectal fat space (PRFS).

CONCLUSIONS

The serial response of the rectum with respect to RB has been demonstrated in patients with posteriorly extended lateral beams. Similarly, the parallel response of the PRFS with respect to tenesmus has been demonstrated in patients treated with the posterior beam.

Vertebral body fracture rates after stereotactic body radiation therapy compared with external-beam radiation therapy for metastatic spine tumors

OBJECTIVE

Stereotactic body radiation therapy (SBRT) is utilized to deliver highly conformal, dose-escalated radiation to a target while sparing surrounding normal structures. Spinal SBRT can allow for durable local control and palliation of disease while minimizing the risk of damage to the spinal cord; however, spinal SBRT has been associated with an increased risk of vertebral body fractures. This study sought to compare the fracture rates between SBRT and conventionally fractionated external-beam radiation therapy (EBRT) in patients with metastatic spine tumors.

METHODS

Records from patients treated at the University of California, San Francisco, with radiation therapy for metastatic spine tumors were retrospectively reviewed. Vertebral body fracture and local control rates were compared between SBRT and EBRT. Ninety-six and 213 patients were identified in the SBRT and EBRT groups, respectively. Multivariate analysis identified the need to control for primary tumor histology (p = 0.003 for prostate cancer, p = 0.0496 for renal cell carcinoma). The patient-matched EBRT comparison group was created by matching SBRT cases using propensity scores for potential confounders, including the Spinal Instability Neoplastic Score (SINS), the number and location of spine levels treated, sex, age at treatment, duration of follow-up (in months) after treatment, and primary tumor histology. Covariate balance following group matching was confirmed using the Student t-test for unequal variance. Statistical analysis, including propensity score matching and multivariate analysis, was performed using R software and related packages.

RESULTS

A total of 90 patients met inclusion criteria, with 45 SBRT and 45 EBRT matched cases. Balance of the covariates, SINS, age, follow-up time, and primary tumor histology after the matching process was confirmed between groups (p = 0.062, p = 0.174, and 0.991, respectively, along with matched tumor histology). The SBRT group had a higher 5-year rate of vertebral body fracture at 22.22% (n = 10) compared with 6.67% (n = 3) in the EBRT group (p = 0.044). Survival analysis was used to adjust for uneven follow-up time and showed a significant difference in fracture rates between the two groups (p = 0.044). SBRT also was associated with a higher rate of local control (86.67% vs 77.78%).

CONCLUSIONS

Patients with metastatic cancer undergoing SBRT had higher rates of vertebral body fractures compared with patients undergoing EBRT, and this difference held up after survival analysis. SBRT also had higher rates of initial local control than EBRT but this difference did not hold up after survival analysis, most likely because of a high percentage of radiosensitive tumors in the EBRT cohort.

Analysis of long-term outcome of image-guided volumetric modulated arc therapy (VMAT) for primary malignant tumor of the cervical spine

OBJECTIVE

Retrospective analysis of the long-term clinical outcome and acute toxicity of the primary malignant tumor of cervical spine receiving CBCT image-guided VMAT.

METHODS

Thirty patients with primary malignant tumor of the cervical spine included in our center, from December 2013 to January 2016, 28 patients were retrospectively studied. The prescription dosage 95% PTV volume dose was 44 Gy, 2.0 Gy/fraction, and a total of 22 times. The median PGTV synchronized volume dose was 60 Gy (45-62.1 Gy), median 2.5 Gy (2-2.7 Gy)/fraction. In volumetric modulated, two arc volumetric modulated arc therapy (VMAT) was used, with spinal cord dosage D_MAX< 45 Gy. Early response rate and acute toxicities were analyzed.

RESULT

The follow-up duration was 6-76 months (median 53 months). At the end of follow-up of June 1, 2019, 78.6% (22/28) patients were still alive. 3 and 5-y local control rates were 67.3% and 56.5% while 3 and 5-y OS were both 78.6% in the whole group of patients, respectively. Fourteen patients with chordoma 5-y local control rates and OS were 57.1% and 85.7%, respectively. Nine patients with giant-cell tumor of bone had a 5-y local control rate and OS were 77.8% and 85.7%, respectively. The response rate for moderate pain or above was 80% (8/10). Eleven patients (39.3%) suffered from grade 1 acute skin toxicity. Twenty-four patients (85.7%) had grade 1/2 mucositis. No radiation-induced spinal cord injury was found.

CONCLUSION

The image-guided VMAT for primary malignant tumor of the cervical spine provided a satisfactory long-term local control rate.

Nervous System Hemangiopericytoma

The management of patients harboring central nervous system (CNS) hemangiopericytomas (HPCs) is a partially answered challenge. These are rare locally aggressive lesions, with potential for local recurrence, distal neural metastasis (DNM), and extraneural metastasis (ENM). Resection, when feasible, remains the initial treatment option, providing histological diagnosis and immediate relief of tumor-related mass effect. Patients receiving surgery alone or surgery and external beam radiotherapy (EBRT) show improved overall survival (OS) and progression-free survival as compared to those undergoing a biopsy alone (p = 0.01 and p = 0.02, respectively). Yet, in many instances, patient and tumor-related parameters preclude complete resection. EBRT or stereotactic radiosurgery (SRS) shares a significant role in achieving local tumor control, not shown to impact OS in HPC patients. The benefits of SRS/EBRT are clearly limited to improved local tumor volume control and neurologic function, not affecting DNM or ENM development. SRS provides acceptable rates of local tumor volume control coupled with treatment safety and a patient-friendly apparatus and procedure. Single-session SRS is most effective for lesions measuring <2 cm in their largest diameter (10 cm3 volume), with prescription doses of at >15 Gy. Systemic HPC disease is managed with various chemotherapeutic, immunotherapeutic, and anti-angiographic agents, with limited success. We present a short discussion on CNS HPCs, focusing our discussion on available evidence regarding the role of microsurgical resection, EBRT, SRS, chemotherapy, and immunotherapy for upfront, part of adoptive hybrid surgery approach or for recurrent HPCs.

Cherenkov-excited luminescence scanned imaging using scanned beam differencing and iterative deconvolution in dynamic plan radiation delivery in a human breast phantom geometry

PURPOSE

The purpose of this study was to demonstrate high resolution optical luminescence sensing, referred to as Cherenkov excited luminescence scanning imaging (CELSI), could be achieved during a standard dynamic treatment plan for a whole breast radiotherapy geometry.

METHODS

The treatment plan beams induce Cherenkov light within tissue, and this excitation projects through the beam trajectory across the medium, inducing luminescence where there can be molecular reporter. Broad beams generally produce higher signal but low spatial resolution, yet for dynamic plans the scanning of the multileaf collimator allows for a beam-narrowing strategy by recursively temporal differencing each of the Cherenkov images and associated luminescence images. Then reconstruction from each of these size-reduced beamlets defined by the differenced Cherenkov images provides a well-conditioned matrix inversion, where the spatial frequencies are limited by the higher signal-to-noise ratio beamlets. A built-in stepwise convergence relies on stepwise beam size reduction, which is associated with a widening of the bandwidth of Cherenkov spatial frequency and resultant increase in spatial resolution. For the phantom experiments, europium nanoparticles were used as luminescent probes and embedded at depths ranging from 3 to 8 mm. An intensity modulated radiotherapy (IMRT) plan was used to test this.

RESULTS

The Cherenkov images spatially guided where the luminescence was measured from, providing high lateral resolution, and iterative reconstruction convergence showed that optimization of the initial and stopping beamlet widths could be achieved with 15 and 4.5 mm, respectively, using a luminescence imaging frame rate of 5/s. With the IMRT breast plan, the original lateral resolution was improved 2X, that is, 0.08-0.24 mm for target depths of 3-8 mm. In comparison, a dynamic wedge (DW) plan showed an inferior image fidelity, with relative contrast recovery decreasing from 0.86 to 0.79. The methodology was applied to a three-dimensional dataset to reconstruct Cherenkov excited luminescence intensity distributions showing volumetric recovery of a 0.5 mm diameter object composed of 0.5 μM luminescent microbeads.

CONCLUSIONS

High resolution CELSI was achieved with a clinical breast external beam radiotherapy (EBRT) plan. It is anticipated that this method can allow visualization and localization for luminescence/fluorescence tagged vasculature, lymph nodes, or superficial tagged regions with most dynamic treatment plans.

Maximizing rectal dose sparing with hydrogel: A retrospective planning study

External beam radiation therapy for prostate cancer can result in urinary, sexual, and rectal side effects, often impairing quality of life. A polyethylene glycol‐based product, SpaceOAR© hydrogel (SOH), implanted into the connective tissue between the prostate gland and rectum can significantly reduce the dose received by the rectum and hence risk of rectal toxicity. The optimal way to manage the hydrogel and rectal structures for plan optimization is therefore of interest. In 13 patients, computerized tomography (CT) scans were taken pre‐ and post‐SpaceOAR© implant. A prescription of 60 Gy in 20 fractions was planned on both scans. Six treatment plans were produced per anonymized dataset using either a structure of rectum plus the hydrogel, termed composite rectum wall (CRW), or rectal wall (RW) as an inverse optimization structure and intensity modulated radiotherapy (IMRT) or volumetric modulated arc therapy (VMAT) as a treatment technique. Dose‐volume histogram metrics were compared between plans to determine which optimization structure and treatment technique offered the maximum rectal dose sparing. RW structures offered a statistically significant decrease in rectal dose over CRW structures, whereas the treatment technique (IMRT vs VMAT) did not significantly affect the rectal dose. There was improvement seen in bladder and penile bulb dose when VMAT was used as a treatment technique. Overall, treatment plans using the RW optimization structure offered the lowest rectal dose while VMAT treatment technique offered the lowest bladder and penile bulb dose.

A Comparative Study of Two Chemo-Radiation Regimens for the Cancer of Larynx

The region of head and neck is critical for respiration, nutrition, and speech. The management of laryngeal tumours can stimulate mutilations and cosmetic deformities and worsen the life. A “non-operative approach” is preferred for patients to whom radiation following surgery, possibly, will direct severe functional destruction predominantly in advanced stage patients having a bulk of carcinoma larynx. The case material for the study was selected from the cross-section of patients registered at the J. K. Cancer Institute, Kanpur. Histologically squamous cell carcinoma 64 patients were registered and equally and randomly placed into Arm I and Arm II. “Arm I” patients and “Arm II” was comprised of randomly selected 64 patients, having histopathologically proven squamous cell carcinoma of the larynx. All patients (32 patients) belonging to “Arm I” received concurrent chemoradiotherapy of Inj. Cisplatin 100 mg/m² for three-weekly underwent EBRT with 60 Co/LINAC and photon radiation of 70 Gy in 35 fractions for 7 weeks (2 parallel opposed fields). All the patients (32 patients) belongs to “Arm II” received chemo boost as Inj. Cisplatin 6 mg/m2 on last 15 fractions of treatment underwent EBRT with 60 Co/ LINAC photon radiation of 70 Gy in 35 fractions for 7 weeks. Radiotherapy was delivered in supine position by parallel opposing fields including the primary tumour, disease extension, and neck nodes. The study concluded that the loco-regional responses are analogous in Arm I and Arm 2, however Arm II had additional treatment allied toxicities and resulting from numerous of treatment breaks.

Evaluating the Use of 18F-FDG PET CT for External Beam Radiotherapy Planning in Gynaecological Malignancies

PURPOSE OF REVIEW

To evaluate the evidence for the use of fluorine-18-fluorodeoyglucose (18F-FDG) PET CT in external beam radiotherapy planning for treatment of gynaecological malignancies.

RECENT FINDINGS

Our review confirms that the incorporation of 18F-FDG PET CT during radiotherapy planning may decrease inter-observer variability during target delineation. It can also provide useful functional information regarding the tumour, which may facilitate the development of techniques for dose escalation and 'dose painting' not only for primary disease, especially in cervical cancer, but also nodal metastasis. The utilisation of this functional modality in external beam radiotherapy planning, particularly in locally advanced cervical malignancy, is an exciting topic that warrants further prospective research. Perhaps the most valuable role may be the potential to deliver dose escalation to 18F-FDG PET CT avid targets previously limited by organ at risk constraints, now that we have significantly more advanced radiotherapy planning tools at our disposal.

125I seed brachytherapy versus external beam radiation therapy for the palliation of painful bone metastases of lung cancer after one cycle of chemotherapy progression

Purpose

This study aimed to compare the outcomes of ¹²⁵I seed brachytherapy versus external beam radiation therapy (EBRT) for the palliation of painful bone metastases of lung cancer after one cycle of chemotherapy progression.

Materials and methods

We analyzed retrospectively 158 patients with painful bone metastases secondary to lung cancer after one cycle of chemotherapy progression treated between June 2013 and May 2016. Seventy-six patients with 96 lesions received ¹²⁵I brachytherapy (Group A), whereas 82 patients with 98 metastases received EBRT (Group B). Pain intensity on Brief Pain Inventory, percentage of patients with pain severity, and quality of life were recorded prior to treatment (T₀), 2, 4, 6, 8, 12, 16, 20, and 24 weeks (T₂, T₄, T₆, T₈, T₁₂, T₁₆, T₂₀, and T₂₄) after treatment during a 24-hour period. Cost-effectiveness and number of treatment appointments were also compared between groups.

Results

One hundred and fifty-eight patients had been treated. Visual analog scale for worst pain in Group A was significantly lower than in Group B at T₂, T₄, T₆, T₁₆, T₂₀, and T₂₄. Group A was superior to group B concerning quality of life scores (T₂, T₄, T₂₀, and T₂₄), cost-effectiveness, and number of treatment appointments. No significant differences were observed for complications.

Conclusion

Compared with EBRT, ¹²⁵I seed brachytherapy can be an alternative method for painful bone metastases from lung cancer after one cycle of chemotherapy progression.

Venous invasion by hepatic tumors: imaging appearance and implications for management

Venous invasion by hepatic tumors most commonly occurs with hepatocellular carcinoma and is associated with worse patient prognosis. Imaging plays an important role in the diagnosis of tumor thrombus in the liver. Moreover, differentiating between bland and tumor thrombus in the liver has important diagnostic, staging, therapeutic, and prognostic implications and may require a multimodal imaging approach including ultrasound, computed tomography, and/or magnetic resonance imaging. Treatment of hepatic malignancies with associated tumor thrombus is dependent on tumor type, disease extent within the liver, liver hemodynamics, and underlying liver function. Treatment of such tumors may involve surgical, locoregional and/or systemic therapies. The current review will focus on the imaging characteristics of venous invasion by hepatic tumors. The imaging findings most useful for differentiating hepatic venous tumor thrombus and bland thrombus will be highlighted and demonstrated with imaging examples. Imaging findings with implications for subsequent patient management will be described.

Vaginal brachytherapy for endometrial cancer

BACKGROUND

There is limited information about survival effect of vaginal brachytherapy (VBT) and its comparison to external beam pelvic radiotherapy (EBRT) and no radiotherapy (no-RT) of endometrial cancer patients.

PATIENTS AND METHODS

We performed a multicenter retrospective registry study of 1550 patients with endometrial cancer treated by no-RT (n = 702), VBT (n = 430) and EBRT ± VBT (n = 418). The outcome measure was overall survival.

RESULTS

RT did not improve the overall survival of patients with a low risk of recurrence. In univariate analysis, the survival effect of VBT was significant in patients with intermediate and high risk of recurrence (HR 0.42, CI 0.29-0.60, p < 0.0001). EBRT ± VBT demonstrated no survival effect in these groups. Multivariate analysis showed that VBT (HR 0.50, CI 0.36-0.71) significantly reduced the mortality risk in patients with an intermediate and high risk compared with no-RT after adjustment for age, tumor grading, tumor stage, lymphadenectomy, adjuvant therapy and comorbidities. Matching for age, histological type, tumor stage, tumor grade, and performance status between patients treated with no-RT and VBT was performed. The matching analysis again demonstrated the favorable survival effect of VBT compared to no-RT on overall survival with an absolute risk reduction of 17.7%. Notably, in a further 106 matched pairs, EBRT ± VBT did not demonstrate any survival effect over VBT among patients at intermediate and high risk of recurrence.

CONCLUSIONS

VBT should be performed in patients at intermediate and high risk of recurrence of endometrial cancer, after operative determination of lymph node status.

Survival outcomes of radical prostatectomy and external beam radiotherapy in clinically localized high-risk prostate cancer: a population-based, propensity score matched study

OBJECTIVE

This study was aimed to compare survival outcomes in high-risk prostate cancer (PCa) patients receiving external beam radiotherapy (EBRT) or radical prostatectomy (RP).

MATERIALS AND METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was used to identify PCa patients with high-risk features who received RP alone or EBRT alone from 2004 to 2008. Propensity-score matching (PSM) was performed. Kaplan-Meier survival analysis was used to compare cancer-specific survival (CSS) and overall survival (OS). Multivariate Cox regression analysis was used to identify independent prognostic factors.

RESULTS

A total of 24,293 patients were identified, 14,460 patients receiving RP and 9833 patients receiving EBRT. Through PSM, 3828 patients were identified in each group. The mean CSS was 128.6 and 126.7 months for RP and EBRT groups, respectively (P<0.001). The subgroup analyses showed that CSS of the RP group was better than that of the EBRT group for patients aged <65 years (P<0.001), White race (P<0.001), and married status (P<0.001). However, there was no significant difference in CSS for patients aged ≥65 years, Black race, other race, and unmarried status. Similar trends were observed for OS. Multivariate analysis showed that EBRT treatment modality, T3-T4 stage, Gleason score 8-10, and prostate-specific antigen >20 ng/mL were significant risk factors for both CSS and OS.

CONCLUSION

This study suggested that survival outcomes might be better with RP than EBRT in high-risk PCa patients aged <65 years; however, RP and EBRT provided equivalent survival outcomes in older patients, which argues for primary radiotherapy in this older cohort.

Combined external beam radiotherapy and vaginal brachytherapy versus vaginal brachytherapy in stage I, intermediate- and high-risk cases of endometrium carcinoma

Purpose

Randomized trials on the effect of external beam radiotherapy (EBRT) with or without vaginal brachytherapy (VBT) for endometrial carcinoma are very few. In view of this, the current study was conducted with the hypothesizes: whether the escalated dose of 26 Gy (VBT alone) in comparison with various major international trials (PORTEC-2) has any difference in rates of disease-free and overall survival with fewer adverse effects in low resource setting like India.

Material and methods

An open-labeled, non-inferiority, randomized control trial was undertaken at a regional cancer center among patients with stage IA or IB high-intermediate risk endometrial carcinoma. A total of 50 patients were divided equally among two arms of combined EBRT with VBT (arm I) and VBT alone (arm II). A dose of 50-50.4 Gy in 25-28 fractions of EBRT with 2 fractions of VBT 6.5 Gy each were delivered to patients in arm I and 4 fractions of VBT 6.5 Gy each to patients in arm II, and were followed up for 60 months.

Results

During the median follow-up of 36.5 months, two patients developed loco-regional recurrence in arm II, three (arm II), and one (arm I) developed distant metastasis. The 5-year survival rates for arms I and II were 96.0% vs. 92.0% overall, and 88.0% vs. 84.0% disease-free, respectively, and were not found to be statistically significantly different. Dermatological, gastro-intestinal toxicities, and cystitis were lower in the VBT group compared to combined group.

Conclusions

VBT alone is as effective as EBRT+VBT in ensuring loco-regional control and achieving comparable survival rates, with fewer toxic effects for patients with stage I intermediate- and high-risk endometrial carcinoma. The dose escalation did not make a difference in the survival rates and was like in the other major trials (PORTEC-2).

External Beam Radiotherapy in the Treatment of Gastroenteropancreatic Neuroendocrine Tumours: A Systematic Review

AIMS

External beam radiotherapy (EBRT) is infrequently used to treat gastroenteropancreatic neuroendocrine tumours (GEPNETS), with little published data to date. We carried out a systematic review to assess the activity of EBRT for GEPNETS.

MATERIALS AND METHODS

Major databases were searched for papers including at least five patients treated with contemporary EBRT techniques. Eligible studies underwent dual independent review. The primary end points were response rate for lesions treated with definitive intent and recurrence-free survival for primary lesions treated with neoadjuvant or adjuvant intent.

RESULTS

Of 11 included studies (all retrospective), seven investigated pancreatic neuroendocrine tumours (PNETs, 100 patients, 14% grade 3) and four studies investigated extra-pancreatic neuroendocrine tumours (84 patients, 14% grade 3). Trials investigating PNETs administered a median of 50.4 Gy via three-dimensional conformal radiotherapy and intensity-modulated radiotherapy. EBRT was given with neoadjuvant or adjuvant intent in 56 patients, with a recurrence rate of 15%. For the 44 patients not undergoing surgery, the radiological response rate was 46%. Grade 3 + toxicity rates were 11% (acute) and 4% (late). Twelve patients with anorectal neuroendocrine carcinoma received 58 Gy to the primary tumour. Seventy-two patients were treated to sites of metastatic disease (34 bone, 27 brain, 11 soft tissue). Local and distant control were poorly reported. Overall survival ranged from 9 to 19 months. No studies in this group reported toxicity outcomes.

CONCLUSIONS

There are limited, retrospective data on the overall activity and safety of EBRT in GEPNETS. EBRT generally seems to be well tolerated in selected PNET patients with encouraging activity. Well-designed prospective studies in clearly defined populations are required to clarify the role of EBRT in neuroendocrine tumours.

Experimental study of beam distortion due to fiducial markers during salvage HIFU in the prostate

Background

Prostate cancer is frequently treated using external beam radiation therapy (EBRT). Prior to therapy, the prostate is commonly implanted with a small number of permanent fiducial markers used to monitor the position of the prostate during therapy. In the case of local cancer recurrence, high-intensity focused ultrasound (HIFU) provides a non-invasive salvage treatment option. However, the impact of the fiducial markers on HIFU treatment has not been thoroughly studied to date. The objective of this study was to experimentally investigate the effect of a single EBRT fiducial marker on the efficacy of HIFU treatment delivery using a tissue-mimicking material (TMM).

Methods

A TMM with the acoustic properties of the prostate was developed based on a polyacrylamide hydrogel containing bovine serum albumin. Each phantom was implanted with a cylindrical fiducial marker and then sonicated using a 3.3 MHz focused bowl HIFU transducer. Two sets of experiments were performed. In the first, a single lesion was created at different positions along either the anteroposterior or left-right axes relative to the marker. In the second, a larger ablation volume was created by raster scanning. The size and position of the ablated volume were assessed using a millimetre grid overlaid on the phantom.

Results

The impact of the marker on the position and size of the HIFU lesion was significant when the transducer focus was positioned within 7 mm anteriorly, 18 mm posteriorly or within 3 mm laterally of the marker. Beyond this, the generated lesion was not affected. When the focus was anterior to the marker, the lesion increased in size due to reflections. When the focus was posterior, the lesion decreased in size or was not present due to shadowing.

Conclusions

The presence of an EBRT fiducial marker may result in an undertreated region beyond the marker due to reduced energy arriving at the focus, and an overtreated region in front of the marker due to reflections. Depending on the position of the targeted regions and the distribution of the markers, both effects may be undesirable and reduce treatment efficacy. Further work is necessary to investigate whether these results indicate the necessity to reconsider patient selection and treatment planning for prostate salvage HIFU after failed EBRT.

Lifetime cost-effectiveness analysis of intraoperative radiation therapy versus external beam radiation therapy for early stage breast cancer

Background

To date no one has examined the quality of life and direct costs of care in treating early stage breast cancer with adjunct intraoperative radiation therapy (IORT) versus external beam radiation therapy (EBRT) over the life of the patient. As well no one has examined the effects of radiation exposure with both therapies on the longer term sequelae. The purpose of this analysis was to examine the cost-effectiveness of IORT vs. EBRT over the life of the patient.

Methods

A Markov decision-analytic model evaluated these treatment strategies in terms of the direct costs in treating patients over their lifetime (including the downstream costs associated with radiation exposure) and the resultant quality of life of these patients. Medicare reimbursement amounts in treating patients were used for acute, steady state, recurrent cancer(s), and complications associated with radiation exposure. Quality adjusted life years (QALYs) derived from the medical literature were assessed with each of these states. Life expectancies as well were derived from the medical literature. Cost-effectiveness was evaluated for dominance and net monetary benefit [at a willingness to pay (WTP)] of $50,000/QALY. Sensitivity analysis was also performed.

Results

IORT was the dominant (least costly with greater QALYs) versus EBRT: total costs over the life of the patient = $53,179 (IORT) vs. $63,828 (EBRT) and total QALYs: 17.86 (IORT) vs. 17.06 (EBRT). At a willingness to pay of $50,000 for each additional QALY, the net monetary benefit demonstrated that IORT was the most cost effective option: $839,815 vs. $789,092. The model was most sensitive to the probabilities of recurrent cancer and death for both IORT and EBRT.

Conclusion

IORT is the more valuable (lower cost with improved QALYs) strategy for use in patients presenting with early stage ER+ breast cancer. It should be used preferentially in these patients.

Outcome of extraocular retinoblastoma in a resource limited center from low middle income country

Retinoblastoma (RB) is the most common ocular malignancy in children, and is managed by multimodal treatment. There is a paucity of data regarding the clinical profile and outcome of children with extraocular retinoblastoma from Low Middle Income Countries (LMIC) including India. Case records of children with newly diagnosed extraocular RB from January 2013 to August 2016 treated at our unit were analysed for clinical profile, treatment, and outcome. Over the 44 month study period, 91 children were diagnosed with RB, out of which 41 had extraocular disease. While 26 children had extraocular spread limited to orbit (IRSS stage III), 15 had a distant spread to brain (IRSS stage IV). Median lag period for diagnosis was eight months. Treatment abandonment rates were 38.5% and 46.6% in International Retinoblastoma Staging System (IRSS) stage III and IV respectively. With a median follow up of 31.5 months, the projected overall survival for IRSS III at one, two, and three years was 87.5%, 55.6%, and 39.7%. All patients with stage IV disease died after a median follow up duration of three months. High treatment abandonment rates and limited availability of resources lead to suboptimal survival in children with extraocular RB from LMIC. Initiatives aimed at improving early diagnosis, so that the disease is detected in the intraocular stage, are critical to improve the survival in children with RB.

Low-risk Prostate Cancer: Identification, Management, and Outcomes

CONTEXT

The incidence of low-risk prostate cancer (PCa) has increased as a consequence of prostate-specific antigen testing.

OBJECTIVE

In this collaborative review article, we examine recent literature regarding low-risk PCa and the available prognostic and therapeutic options.

EVIDENCE ACQUISITION

We performed a literature review of the Medline, Embase, and Web of Science databases. The search strategy included the terms: prostate cancer, low risk, active surveillance, focal therapy, radical prostatectomy, watchful waiting, biomarker, magnetic resonance imaging, alone or in combination.

EVIDENCE SYNTHESIS

Prospective randomized trials have failed to show an impact of radical treatments on cancer-specific survival in low-risk PCa patients. Several series have reported the risk of adverse pathologic outcomes at radical prostatectomy. However, it is not clear if these patients are at higher risk of death from PCa. Long-term follow-up indicates the feasibility of active surveillance in low-risk PCa patients, although approximately 30% of men starting active surveillance undergo treatment within 5 yr. Considering focal therapies, robust data investigating its impact on long-term survival outcomes are still required and therefore should be considered experimental. Magnetic resonance imaging and tissue biomarkers may help to predict clinically significant PCa in men initially diagnosed with low-risk disease.

CONCLUSIONS

The incidence of low-risk PCa has increased in recent years. Only a small proportion of men with low-risk PCa progress to clinical symptoms, metastases, or death and prospective trials have not shown a benefit for immediate radical treatments. Tissue biomarkers, magnetic resonance imaging, and ongoing surveillance may help to identify those men with low-risk PCa who harbor more clinically significant disease.

PATIENT SUMMARY

Low-risk prostate cancer is very common. Active surveillance has excellent long-term results, while randomized trials have failed to show a beneficial impact of immediate radical treatments on survival. Biomarkers and magnetic resonance imaging may help to identify which men may benefit from early treatment.

Detection Efficacy of Hybrid 68Ga-PSMA Ligand PET/CT in Prostate Cancer Patients with Biochemical Recurrence After Primary Radiation Therapy Defined by Phoenix Criteria

The aim of this retrospective study was to evaluate the detection rate of Glu-NH-CO-NH-Lys-(Ahx)-[⁶⁸Ga(HBED-CC)] (⁶⁸Ga-PSMA ligand; PSMA is prostate-specific membrane antigen) PET/CT in patients with biochemical recurrent prostate cancer defined by Phoenix criteria after external-beam radiotherapy or brachytherapy as primary treatment. Methods: One hundred eighteen patients with a median prostate-specific antigen (PSA) of 6.4 ng/mL (range, 2.2-158.4 ng/mL; interquartile range, 4.2-10.2 ng/mL) were finally eligible for this retrospective analysis. Seventy-seven and 41 patients had been treated by external-beam radiotherapy or brachytherapy, respectively. Of the 118 patients, 45 were receiving androgen-deprivation therapy (ADT) within at least 6 mo before the PET/CT. The detection rates were stratified by PSA. The influence of primary Gleason score and ADT was assessed. Relationships between SUV and clinical as well as pathologic features in patients with positive findings were analyzed using univariate and multivariable linear regression models. Results: One hundred seven of 118 patients (90.7%) showed pathologic findings indicative for tumor recurrence in ⁶⁸Ga-PSMA ligand PET/CT. The detection rates were 81.8% (36/44), 95.3% (41/43), and 96.8% (30/31) for PSA of 2 to <5, 5 to <10, and ≥10 ng/mL, respectively (P = 0.0377). ⁶⁸Ga-PSMA ligand PET/CT indicated local recurrence in 68 of 107 patients (63.5%), distant lesions in 64 of 107 patients (59.8%), and local recurrence as well as distant lesions in 25 of 107 patients (23.4%). The detection rate was significantly higher in patients with ADT (97.7%) versus without ADT (86.3%, P = 0.0381), but independent from primary Gleason score ≥ 8 (92.0%) versus ≤ 7 (90.2%, P = 0.6346). SUV_max and SUV_mean were significantly associated with PSA and ADT (P = 0.018 and 0.004 for SUV_max, respectively; P = 0.025 and 0.007 for SUV_mean, respectively). Conclusion:⁶⁸Ga-PSMA ligand PET/CT demonstrates high detection rates in patients with biochemical recurrence of prostate cancer after primary radiation therapy. The detection rate was positively associated to increasing PSA as well as concomitant ADT. ⁶⁸Ga-PSMA ligand PET/CT enables discrimination of local versus metastatic disease and thus might have a crucial impact on further clinical management. A major limitation of this study is the lack of histopathologic proof in most patients.

Brachytherapy boost for prostate cancer: Trends in care and survival outcomes

PURPOSE

Androgen suppression combined with elective nodal and dose-escalated radiation therapy recently demonstrated an improved biochemical failure-free survival in men who received external beam radiation therapy (EBRT) plus a brachytherapy boost (BB) compared with dose-escalated external beam radiotherapy (DE-EBRT). We sought to analyze the factors predictive for use of EBRT + BB as compared with DE-EBRT and report resulting survival outcomes on a national level using a hospital-based registry.

METHODS AND MATERIALS

We identified 113,719 men from the National Cancer Database from 2004 to 2013 with intermediate- or high-risk prostate cancer who were treated with EBRT + BB or DE-EBRT. We performed univariate and multivariate analyses of all available factors potentially predictive of receipt of treatment selection. Survival was evaluated in a multivariable model with propensity adjustment.

RESULTS

For intermediate-risk patients, utilization of BB decreased from 33.1% (n = 1742) in 2004 to 12.5% (n = 766) in 2013 and for high-risk patients, utilization dropped from 27.6% (n = 879) to 10.8% (n = 479). Numerous factors predictive for use of BB were identified. Cox proportional hazards analysis was performed-adjusting for age, Charlson-Deyo comorbidity score, T stage, prostate-specific antigen, Gleason score, and sociodemographic factors-and demonstrated BB use was associated with a hazard ratio of 0.71 (95% confidence interval, 0.67-0.75; p < 0.0005) and 0.73 (95% confidence interval, 0.68-0.78; p < 0.0005) for intermediate- and high-risk patients, respectively.

CONCLUSIONS

There has been a concerning decline in the utilization of BB for intermediate- and high-risk prostate cancer patients despite an association with improved on overall survival. Numerous factors predictive for use of BB have been identified.

Beam distortion due to gold fiducial markers during salvage high-intensity focused ultrasound in the prostate

PURPOSE

High intensity focused ultrasound (HIFU) provides a non-invasive salvage treatment option for patients with recurrence after external beam radiation therapy (EBRT). As part of EBRT the prostate is frequently implanted with permanent fiducial markers. To date, the impact of these markers on subsequent HIFU treatment is unknown. The objective of this work was to systematically investigate, using computational simulations, how these fiducial markers affect the delivery of HIFU treatment.

METHODS

A series of simulations was performed modelling the propagation of ultrasound pressure waves in the prostate with a single spherical or cylindrical gold marker at different positions and orientations. For each marker configuration, a set of metrics (spatial-peak temporal-average intensity, focus shift, focal volume) was evaluated to quantify the distortion introduced at the focus. An analytical model was also developed describing the marker effect on the intensity at the focus. The model was used to examine the marker's impact in a clinical setting through case studies.

RESULTS

The simulations show that the presence of the marker in the pre-focal region causes reflections which induce a decrease in the focal intensity and focal volume, and a shift of the maximum pressure point away from the transducer's focus. These effects depend on the shape and orientation of the marker and become more pronounced as its distance from the transducer's focus decreases, with the distortion introduced by the marker greatly increasing when placed within 5 mm of the focus. The analytical model approximates the marker's effect and can be used as an alternative method to the computationally intensive and time consuming simulations for quickly estimating the intensity at the focus. A retrospective review of a small patient cohort selected for focal HIFU after failed EBRT indicates that the presence of the marker may affect HIFU treatment delivery.

CONCLUSIONS

The distortion introduced by the marker to the HIFU beam when positioned close to the focus may result in an undertreated region beyond the marker due to less energy arriving at the focus, and an overtreated region due to reflections. Further work is necessary to investigate whether the results presented here justify the revision of the patient selection criteria or the markers' placement protocol.

External beam boost versus interstitial high-dose-rate brachytherapy boost in the adjuvant radiotherapy following breast-conserving therapy in early-stage breast cancer: a dosimetric comparison

Purpose

This study aims to compare the dosimetric data of local tumor's bed dose escalation (boost) with photon beams (external beam radiation therapy – EBRT) versus high-dose-rate interstitial brachytherapy (HDR-BT) after breast-conserving treatment in women with early-stage breast cancer.

Material and methods

We analyzed the treatment planning data of 136 irradiated patients, treated between 2006 and 2013, who underwent breast-conserving surgery and adjuvant whole breast irradiation (WBI; 50.4 Gy) and boost (HDR-BT: 10 Gy in one fraction [n = 36]; EBRT: 10 Gy in five fractions [n = 100]). Organs at risk (OAR; heart, ipsilateral lung, skin, most exposed rib segment) were delineated. Dosimetric parameters were calculated with the aid of dose-volume histograms (DVH). A non-parametric test was performed to compare the two different boost forms.

Results

There was no difference for left-sided cancers regarding the maximum dose to the heart (HDR-BT 29.8% vs. EBRT 29.95%, p = 0.34). The maximum doses to the other OAR were significantly lower for HDR-BT (D_max lung 47.12% vs. 87.7%, p < 0.01; rib 61.17% vs. 98.5%, p < 0.01; skin 57.1% vs. 94.75%, p < 0.01; in the case of right-sided breast irradiation, dose of the heart 6.00% vs. 16.75%, p < 0.01).

Conclusions

Compared to EBRT, local dose escalation with HDR-BT presented a significant dose reduction to the investigated OAR. Only left-sided irradiation showed no difference regarding the maximum dose to the heart. Reducing irradiation exposure to OAR could result in a reduction of long-term side effects. Therefore, from a dosimetric point of view, an interstitial boost complementary to WBI via EBRT seems to be more advantageous in the adjuvant radiotherapy of breast cancer.

Nanoparticle-aided external beam radiotherapy leveraging the Čerenkov effect

This study investigates the feasibility of exploiting the Čerenkov radiation (CR) present during external beam radiotherapy (EBRT) for significant therapeutic gain, using titanium dioxide (titania) nanoparticles (NPs) delivered via newly designed radiotherapy biomaterials. Using Monte Carlo radiation transport simulations, we calculated the total CR yield inside a tumor volume during EBRT compared to that of the radionuclides. We also considered a novel approach for intratumoral titania delivery using radiotherapy biomaterials (e.g. fiducials) loaded with NPs. The intratumoral distribution/diffusion of titania released from the fiducials was calculated. To confirm the CR induced enhancement in EBRT experimentally, we used 6MV radiation to irradiate human lung cancer cells with or without titania NPs and performed clonogenic assays. For a radiotherapy biomaterial loaded with 20μg/g of 2-nm titania NPs, at least 1μg/g could be delivered throughout a tumor sub-volume of 2-cm diameter after 14days. This concentration level could inflict substantial damage to cancer cells during EBRT. The Monte Carlo results showed the CR yield by 6MV radiation was higher than by the radionuclides of interest and hence greater damage might be obtained during EBRT. In vitro study showed significant enhancement with 6MV radiation and titania NPs. These preliminary findings demonstrate a potential new approach that can be used to take advantage of the CR present during megavoltage EBRT to boost damage to cancer cells. The results provide significant impetus for further experimental studies towards the development of nanoparticle-aided EBRT powered by the Čerenkov effect.

Clinical comparison of brachytherapy versus hypofractionated external beam radiation versus standard fractionation external beam radiation for non-melanomatous skin cancers

Purpose

Non-melanomatous skin cancer (NMSC) is the single most common cancer in the US. Radiation therapy is an excellent treatment alternative to surgery. High-dose-rate (HDR) brachytherapy and external beam radiotherapy (EBRT) are commonly used radiation treatment modalities but little data is published comparing these modalities. We present our institution's experience and outcomes with these therapeutic options.

Material and methods

From June 2005 to March 2013, 61 patients were treated with HDR brachytherapy (n = 9), hypofractionated EBRT (n = 30), or standard fractionation EBRT (n = 22) for NMSC. The primary outcome measure was local control at most remote follow-up and secondary outcome measures were overall survival, cosmetic outcome, and toxicity. Univariate analysis was performed to compare outcomes between treatment modalities. Kaplan-Meier analysis and log-rank test were used to compare overall survival.

Results

Median follow-up was 30 months. The most common histologies were BCC (47%) and SCC (44%); mean patient age was 83.3 years. Local control was 81% and 2-year actuarial overall survival was 89%. There was no statistical difference in local control or overall survival between treatment modalities. There was no statistical difference in cosmetic outcome or toxicity between treatment modalities, although five of six “poor” cosmetic outcomes and the only grade 3 toxic events were found in the standard fractionation EBRT group.

Conclusions

All modalities investigated represent effective treatments for NMSC and have good cosmetic outcomes and acceptable toxicity profiles. The finding of higher grade toxicity and a greater portion of patients experiencing toxicity among standard fractionation therapy is counter to expectations. There was no statistical significance to the finding and it is not likely to be meaningful.