Use Of External Beam Radiotherapy Research Articles

Determinants of the combined use of external beam radiotherapy and brachytherapy for low‐risk, clinically localized prostate cancer

Prostate cancer treatment choices have been shown to vary by physician and patient characteristics. For patients with low-risk, clinically localized prostate cancer, the authors examined the impact of their clinical, sociodemographic, and radiation oncologists' (RO) characteristics on the likelihood that the patients would receive combined external beam radiotherapy and brachytherapy, a treatment regimen that is at variance with clinical guidelines. The Surveillance, Epidemiology and End Results (SEER)-Medicare linked database and the American Medical Association Physician Masterfile were used in a retrospective analysis of 5531 patients with low-risk, clinically localized prostate cancer who were diagnosed between 2004 and 2007, and the 708 ROs who treated them. Hierarchical logistic regression analyses were used to evaluate the relationship between patient and RO characteristics and the use of combined therapy within 6 months of diagnosis. Overall, 356 patients (6.4%) received combined therapy. Nonclinical factors were found to be associated with combined therapy. After adjusting for patient and RO characteristics, the odds of receiving combined therapy for patients residing in Georgia were found to be significantly greater than for all other SEER regions. Black patients were significantly less likely to receive combined therapy (odds ratio, 0.62; 95% confidence interval, 0.40-0.96 [P= .03]) compared with white patients. In addition, ROs accounted for 36.6% of the variation in patients receiving combined therapy. Geographic and sociodemographic factors were found to be significantly associated with guideline-discordant combined therapy for patients diagnosed with low-risk, clinically localized prostate cancer. Which RO a patient consults is important in determining whether they receive combined therapy.

Development and characterization of a three-dimensional film stack dosimeter

A three-dimensional (3D) film stack dosimeter (FSD) using Gafchromic® EBT2 film was characterized for use in external-beam radiotherapy. The FSD was found to have negligible energy dependence and orientation dependence less than 2% using Monte Carlo simulations. Percent-depth-dose measurements with the FSD aligned parallel and perpendicular to the beam axis agreed with Monte Carlo simulations within 2%. Measurements of a 60Co slit field with the FSD and thermoluminescent dosimeters agreed with a gamma passing rate of 97.6% using 1.5%/1.5 mm criteria. Edge artifacts were smaller than 2 mm, minimally affecting the usable measurement volume. The FSD is water equivalent, energy independent and orientation independent within measurement uncertainty at 60Co energies, providing a 3D dosimeter that can be analyzed with a desktop scanner.

In vivo dosimetry in external beam radiotherapy

In vivo dosimetry (IVD) is in use in external beam radiotherapy (EBRT) to detect major errors, to assess clinically relevant differences between planned and delivered dose, to record dose received by individual patients, and to fulfill legal requirements. After discussing briefly the main characteristics of the most commonly applied IVD systems, the clinical experience of IVD during EBRT will be summarized. Advancement of the traditional aspects of in vivo dosimetry as well as the development of currently available and newly emerging noninterventional technologies are required for large-scale implementation of IVD in EBRT. These new technologies include the development of electronic portal imaging devices for 2D and 3D patient dosimetry during advanced treatment techniques, such as IMRT and VMAT, and the use of IVD in proton and ion radiotherapy by measuring the decay of radiation-induced radionuclides. In the final analysis, we will show in this Vision 20∕20 paper that in addition to regulatory compliance and reimbursement issues, the rationale for in vivo measurements is to provide an accurate and independent verification of the overall treatment procedure. It will enable the identification of potential errors in dose calculation, data transfer, dose delivery, patient setup, and changes in patient anatomy. It is the authors' opinion that all treatments with curative intent should be verified through in vivo dose measurements in combination with pretreatment checks.

Haematuria after prostate brachytherapy

To characterize the incidence and clinical history of gross haematuria after prostate brachytherapy. To identify treatment risk factors for the development of gross haematuria in this setting. We reviewed haematuria outcomes collected prospectively in 2454 patients treated with transperineal prostate brachytherapy over a 20-year period at a single institution. Patients were followed for a median of 5.9 years. The association of haematuria with age, pretreatment PSA, ethnicity, clinical tumour stage, Gleason score, prostate volume, isotope (iodine 125 or palladium 103), biologically effective dose (BED), external beam radiation, androgen deprivation, development of urinary retention and occurrence of biochemical failure was investigated. A total of 218 men (8.9%) reported gross haematuria at a median time of 772.2 days after implantation. Haematuria was associated with prostate volume >40 cm(3) (P < 0.01), use of external beam radiation (P < 0.01), Gleason score >7 (P = 0.037), Asian ethnicity (P < 0.001), BED >200 Gy (P = 0.01), and freedom from biochemical failure (P = 0.004). On multivariate analysis, prostate volume >40 cm(3) (P = 0.002), external beam radiation, (P = 0.001), and freedom from biochemical failure (P = 0.035) were predictors of haematuria. Late gross haematuria was observed in a small proportion of men after brachytherapy and may occur with considerable latency. Larger prostate glands, freedom from biochemical failure and external beam radiation are risk factors.

Trends in the diagnosis and treatment of pediatric primary spinal cord tumors

Pediatric primary spinal cord tumors (PSCTs) are rare, with limited comprehensive data regarding incidence and patterns of diagnosis and treatment. The authors evaluated trends in the diagnosis and treatment of PSCTs using a nationwide database. The Surveillance, Epidemiology, and End Results (SEER) registry was queried for the years 1975-2007, evaluating clinical patterns in 330 patients 19 years of age or younger in whom a pediatric PSCT had been diagnosed. Histological diagnoses were grouped into pilocytic astrocytoma, other low-grade astrocytoma, ependymoma, and high-grade glioma. Patient demographics, tumor pathology, use of external beam radiation (EBR), and overall survival were analyzed. The incidence of pediatric PSCT was 0.09 case per 100,000 person-years and did not change over time. Males were more commonly affected than females (58% vs 42%, respectively; p < 0.006). Over the last 3 decades, the specific diagnoses of pilocytic astrocytoma and ependymoma increased, whereas the use of EBR decreased (60.6% from 1975 to 1989 vs 31.3% from 1990 to 2007; p < 0.0001). The 5- and 10-year survival rates did not differ between these time periods. While the incidence of pediatric PSCT has not changed over time, the pattern of pathological diagnoses has shifted, and pilocytic astrocytoma and ependymoma have been increasingly diagnosed. The use of EBR over time has declined. Relative survival of patients with low-grade PSCT has remained high regardless of the pathological diagnosis.

Future directions in palliative thoracic radiotherapy

Recent systematic review, practice guidelines, and consensus statements have summarized the known clinical trial information with regards to the appropriate use of external-beam radiation, brachytherapy, and concurrent chemotherapy (with external-beam radiotherapy) in the palliation of chest symptoms with thoracic radiotherapy. The purpose of this review is to describe our present knowledge with regards to palliative thoracic radiotherapeutic maneuvers and to identify potential areas for future research inquiry consistent with current knowledge gaps. Two systematic reviews, one practice guideline, and one consensus statement based on published prospective clinical trials have demonstrated that palliative thoracic radiotherapy is an effective modality both in terms of symptom palliation and other important cancer outcomes. Evolving areas for future scientific inquiry include the role of advanced technologies such as intensity-modulated radiation therapy and image-guided radiation therapy, economic analyses as well as the creation of a common palliative endpoint that can be used for future clinical trials. Robust clinical trial information and high-level knowledge-translation documents currently exist to guide radiotherapy practitioners to provide standard-of-care treatment for thoracic palliative scenarios.

External Beam Radiation Therapy for PTFE Dialysis Grafts: A Pilot Study

The aim of this study was to identify the effects of external beam radiation on PTFE dialysis graft dysfunction. Seven patients who underwent PTFE dialysis graft angioplasty were randomized to receive either two 8 Gy doses of external beam radiation or no radiation. The primary endpoint was time to graft thrombosis with a secondary endpoint of time to first intervention. There was no statistically significant difference between the two groups in either of the endpoints, although grafts in the radiation group had a shorter time to thrombosis or intervention. Our results demonstrate technical feasibility for use of external beam radiation in the setting of dialysis vascular access graft dysfunction. Larger randomized studies are required to identify whether there is a clinical benefit from this intervention.

Physical Modelling of Proton and Heavy Ion Radiation using Geant4

Protons and heavy ion particles are considered to be ideal particles for use in external beam radiotherapy due to superior properties of the dose distribution that results when these particles are incident externally and due to their relative biological effectiveness. While significant research has been performed into the properties and physical dose characteristics of heavy ions, the nuclear reactions (direct and fragmentation) undergone by He 4 , C 12 and Ne 20 n u c l e i u s e d i n r a d i o t h e r a py i n m a t e r i a l s o t h e r t h a n w a t e r i s s till l a r g e l y unexplored. In the current project, input code was developed for the Monte Carlo toolkit Geant 4 version 9.3 to simulate the transport of several mono-energetic heavy ions through water. The relative dose contributions from secondary particles and nuclear fragments originating from the primary particles were investigated for each ion in both water and dense bone (ICRU) media. The results indicated that the relative contribution to the total physical dose from nuclear fragments increased with both increasing particle mass and with increasing medium density. In the case of 150 MeV protons, secondary particles were shown to contribute less than 0.5% of the peak dose and as high as 25% when using 10570 MeV neon ions in bone. When water was substituted for a bone medium, the contributions from fragments increased by more than 6% for C 12 and Ne 20 .

The risk of bladder cancer in patients diagnosed with other primary neoplasms: Analysis of the SEER database

ObjectiveWe evaluated patients with history of previous malignancy to determine risk of an ensuing bladder cancer. Materials and methodsThe National Cancer Institute's Surveillance, Epidemiology, and End Results 9 registry database from 1973 to 1999 (SEER) was reviewed for patients with initial primary cancers in oral cavity and pharynx, colon and rectum, respiratory system, breast, prostate, testis, or penis. This group of patients was then examined to identify subsequent separate primary malignancies in the bladder. Comparison was made to the incidence of bladder cancer in the general population to determine a standardized incidence ratio (SIR). Additional analysis was performed based on age at diagnosis, stage, gender, race, and use of external beam radiation for treatment of initial cancer. ResultsA total of 7,289 (0.5%) of patients had a bladder cancer following their initial malignancy. Patients with prostate cancer had the largest increase in risk of bladder cancer with a SIR of 8.24, and all initial cancer groups had an elevated risk of bladder cancer relative to the general population. External beam radiation and non-White gender were associated with an increased risk of bladder cancer. Older age at diagnosis of the initial cancer correlated with a lower risk of subsequent bladder cancer. ConclusionsThis study suggests an increased risk of bladder cancer following a separate initial cancer. Lower threshold for working up those patients for bladder cancer may be warranted.

Excellent Local Control and Survival After Intraoperative and External Beam Radiotherapy for Pediatric Solid Tumors

Use of external beam radiotherapy (EBRT) for pediatric solid malignancies is generally limited by the tolerance of normal tissue in developing organs. Intraoperative electron radiotherapy (IOERT) allows a more focal delivery of radiation dose because vital organs can be displaced and avoided during treatment. From February 1983 to July 2003, 20 children underwent IOERT for treatment of locally advanced or recurrent malignancies of the extremity or abdominopelvic area. All patients underwent EBRT and received IOERT doses of 7.5 to 25 Gy with 6-MeV to 15-MeV electrons. At a median follow-up of 11.6 years (range, 2.1 to 25.5 y), 13 patients (65%) were alive and without evidence of disease. Patients who underwent gross total resection had better local control (88% vs. 67%) and survival (71% vs. 33%) than patients for whom the resection was not achieved. Among 7 patients, 11 grade 3 toxicity events were reported. No grade >3 toxicities or second malignancies were observed during follow-up. Use of IOERT in combination with surgery and EBRT in management of pediatric solid malignancies provides excellent local control with reasonable toxicity. IOERT should be considered as an integral part of a multimodality regimen for pediatric solid malignancies, especially for patients with abdominopelvic malignancies.

Emerging trends in radiation therapy use among women older than age 70 with stage I breast cancer from 2000-2007: A population-based analysis.

6094 Background: The use of radiation therapy (RT) after lumpectomy is the standard of care in breast conserving therapy (BCT). A randomized trial published in 2004 suggested that women age ≥70 years with stage I, estrogen receptor (ER) positive breast cancer may not require RT after lumpetomy. We performed a population-based analysis to evaluate changes in patterns of RT usage among women age ≥70 from 2000-2007. Methods: We used the Surveillance, Epidemiology and End Results (SEER) database to identify women diagnosed with stage I invasive ductal breast cancer from 2000 – 2007 who were treated with lumpectomy. We extracted information on patient demographics, tumor characteristics, initial treatment course, and survival. Patients were classified by modality of RT: beam radiation, radioactive implant, other, or none. We used chi-square test for differences in proportion of RT modality usage and linear regression to test for trends in usage. Results: We identified 18,789 women age ≥ 70 (median age 77, range 70-108) diagnosed with stage I breast cancer from 2000 – 2007 and treated with lumpectomy. Overall, 62.8% of these women received external beam RT, 3.2% implant RT, 5.5% other RT, and 28.5% omitted RT. From 2000 to 2007, there has been a decrease in the use of external beam RT from 68.5% to 55.9% (p<0.001) and a simultaneous rise in the use of radioactive implants from 0.5% to 7.7% (p<0.001). Large geographic variations in utilization exist across SEER regions, such as in the percentage of older women who omit RT, from 15.1% (Seattle) to 42.3% (Los Angeles). For patients with known ER status, those with ER positive tumors were more likely to omit RT than those with ER negative tumors (26.9% vs 23.8% p = 0.02). Since 2000, the percentage of older women with ER positive tumors who receive no RT has increased from 24.4% to 29.5% (p=0.02). In contrast, the percentage of older women with ER negative cancers who received no RT did not significantly change. Conclusions: Patterns of RT usage in BCT for women ≥ 70 years with stage I breast cancer are changing with increasing use of radioactive implants and more patients with ER positive tumors omitting RT. Further follow-up is required to determine the effect on survival.

Pelvic Nodal Radiotherapy in Patients With Unfavorable Intermediate and High-Risk Prostate Cancer: Evidence, Rationale, and Future Directions

Over the past 15 years, there have been three major advances in the use of external beam radiotherapy in the management of men with clinically localized prostate made. They include: (1) image guided (IG) three-dimensional conformal/intensity modulated radiotherapy; (2) radiation dose escalation; and (3) androgen deprivation therapy. To date only the last of these three advances have been shown to improve overall survival. The presence of occult pelvic nodal involvement could explain the failure of increased conformality and dose escalation to prolong survival, because the men who appear to be at the greatest risk of death from clinically localized prostate cancer are those who are likely to have lymph node metastases. This review discusses the evidence for prophylactic pelvic nodal radiotherapy, including the key trials and controversies surrounding this issue.

Palliative thoracic radiotherapy in lung cancer: An American Society for Radiation Oncology evidence-based clinical practice guideline

PurposeTo provide guidance to physicians and patients with regard to the use of external beam radiotherapy, endobronchial brachytherapy, and concurrent chemotherapy in the setting of palliative thoracic treatment for lung cancer, based on available evidence complemented by expert opinion. Methods and MaterialsA Task Force authorized by the American Society for Radiation Oncology (ASTRO) Board of Directors synthesized and assessed evidence from 3 systematic reviews on the following topics: (1) dose fractionation in thoracic external beam radiotherapy (EBRT); (2) clinical utility of initial and salvage endobronchial brachytherapy (EBB); and (3) use of concurrent chemotherapy (CC) with palliative thoracic radiotherapy. Practice guideline recommendations were produced and are contained herein. ResultsStudies suggest that higher dose/fractionation palliative EBRT regimens (eg, 30 Gy/10 fraction equivalent or greater) are associated with modest improvements in survival and total symptom score, particularly in patients with good performance status. As these improvements are associated with an increase in esophageal toxicity, various shorter EBRT dose/fractionation schedules (eg, 20 Gy in 5 fractions, 17 Gy in 2 weekly fractions, 10 Gy in 1 fraction), which provide good symptomatic relief with fewer side effects, can be used for patients requesting a shorter treatment course and/or in those with a poor performance status. No defined role for EBB in the routine initial palliative treatment of chest disease has been demonstrated; however, EBB can be a reasonable option for the palliation of endobronchial lesions causing obstructive symptomatology including lung collapse, or for hemoptysis after EBRT failure. The integration of concurrent chemotherapy with palliative intent/fractionated radiotherapy is not currently supported by the medical literature. ConclusionThis Guideline is intended to serve as a guide for the use of EBRT, EBB, and CC in thoracic palliation of lung cancer outside the clinical trial setting. Further prospective clinical investigations with relevant palliative endpoints into the respective roles of EBB and CC/targeted therapy in the thoracic palliation of lung cancer are warranted, given the current state of the medical literature in these areas.

Dose-escalated external beam radiotherapy in unresectable hepatocellular carcinoma.

267 Background: Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. Data regarding the use of external beam radiotherapy is limited in patients from populations without endemic viral hepatitis. We examine the outcomes for patients treated with external beam radiotherapy in the modern era at a single institution. Methods: A total of 29 patients with localized HCC treated from 2000 to 2009 were reviewed. Patients with metastatic disease at the time of radiation were excluded. Median radiation dose was 50 Gy (range 30-75 Gy) with a median biologically effective dose (BED) of 80.6 (range 60-138.6). Median tumor size at the time of radiation was 5.2 cm (range 2-25 cm). Results: Median residual tumor following radiation was 80% (range 27%-278%), with a median residual α-fetoprotein of 47% (range 0.8%-8240%). Estimated one-year overall survival (OS) and in-field progression-free survival (PFS) rates for the study population were 56% and 79%, respectively. One year OS in patients treated to a BED &lt;75 was 18% vs. 69% in patients treated to a BED ≥75 (p=0.002). One year in-field PFS rate (60% vs. 88%, p=0.023) and biochemical PFS duration (median 6.5 vs. 1.6 mos., p=0.001) were also significantly improved in patients treated to a BED ≥75. Grade 3 toxicity was seen in only 13.8% of patients. Conclusions: In a population without endemic viral hepatitis, unresectable HCC demonstrates significant response toexternal beam radiotherapy with minimal toxicity. Furthermore, our findings suggest that increased BED is associated with improved survival and local tumor control. No significant financial relationships to disclose.

Impact of double-balloon rectal catheter use in external-beam radiotherapy for prostate cancer

Prostate motion and rectal sparing are important treatment strategy issues in external-beam radiotherapy for localized prostate cancer. To address these issues, we prospectively investigated the feasibility of using a double-balloon rectal catheter. The rectal catheter has inner and outer balloons that wedge the anus between them. Computed tomography (CT) examinations with and without the catheter were conducted in seven patients with localized prostate cancer treated by external-beam radiotherapy. The rectal wall sparing effect was evaluated using virtual three-dimensional conformal radiotherapy plans in each arm. To evaluate interfractional prostate motion, each patient underwent a series of four CT examinations consisting of a planning CT followed by three additional series of CT with and without a catheter during the course of radiotherapy. Virtual plans demonstrated the reduction of the dose to the rectum by expanding the posterior wall to lie outside the high- to intermediate-dose area when a catheter was applied. Interfractional prostate motion in the anteroposterior direction was effectively reduced by catheter usage; the mean±standard deviation (SD) of the displacement was 1.3±0.9mm with a catheter as compared to 2.8±1.8mm without a catheter (P=0.014), and the maximum displacement was successfully suppressed to 3mm with a catheter compared to 6mm without a catheter. Systematic and random components were also reduced with the catheter. These results suggest the feasibility and clinical applicability of the double-balloon rectal catheter.

Endometrial cancer

Endometrial cancers are the most common gynaecological malignancies in the UK with approximately 4500 new cases occur each year and the incidence is rising. Increasingly there is evidence-based management and centralized specialist care of women with endometrial cancer. Women with high grade disease, deep myometrial invasion or lymphadenopathy should be managed by specialist gynaecological oncologists as part of a multi-disciplinary team (MDT). Results from important clinical trials now guide the application of surgical and non-surgical treatments. Surgery remains the cornerstone of management with a trend towards increased use of minimal access surgery. Radiotherapy-related morbidity can now be reduced by the more selective use of external beam radiotherapy. There remain several unresolved issues however and it is important that relevant clinical trials are offered to eligible women. Women must have multi-disciplinary input before treatment, so that up-to-date and evidence-based treatments and inclusion in clinical trials can be considered.

External Beam Radiotherapy for Differentiated Thyroid Cancer

The management of differentiated thyroid cancer involves a combination of surgery, thyroid stimulating hormone suppression and radioactive iodine for most patients. In a small subset of patients, external beam radiotherapy is also used. However, its role remains controversial and there are no randomised controlled trials to guide practice. In this overview we review the evidence from the published literature for the use of external beam radiotherapy in the management of differentiated thyroid cancer and discuss the indications for which it is most commonly used. The technique of external beam radiotherapy, including the emerging role for intensity-modulated radiotherapy, will also be discussed.

Strahlentherapie des Prostatakarzinoms in der neuen S3-Leitlinie

Radiation therapy is a treatment option for curative management of localized and locally advanced prostate cancer. Depending on tumor stage and constellation of risk factors (PSA level, findings on digital rectal examination, and Gleason score), various forms of radiotherapy are applied. In addition to the sole use of external beam radiotherapy, brachytherapy with radioactive seeds is also employed as stand-alone treatment in patients with low risk factors and in early clinical stages. Increasing risk of recurrence requires more intensive therapies which can be accomplished by adding hormone deprivation therapy and/or intensifying radiation therapy (dose escalation). Combined approaches using brachytherapy and percutaneous radiotherapy are also initiated in these cases. If hormone ablation therapy is administered, this should occur over a course of 3-36 months as neoadjuvant, concommitant and/or adjuvant treatment, depending on the risk of recurrence.

Node-Positive Adenocarcinoma of the Endometrium: Outcome and Patterns of Recurrence With and Without External Beam Irradiation

A previous trial reported that systemic chemotherapy had a better outcome than whole abdominal radiotherapy (RT) in the treatment of patients with advanced endometrial cancer. Although these results convinced some physicians to abandon use of external beam radiotherapy in such patients, close examination of the data revealed a number of methodological deficiencies. This retrospective study investigated the outcomes, risk factors, and patterns of tumor recurrence among 71 patients with FIGO node-positive stage IIIC nonserous and nonclear cell uterine adenocarcinoma. The patients had been treated at a major cancer center between 1984 and 2005. All had received total abdominal hysterectomy and bilateral salpingo-oophorectomy and lymphadenectomy. Fifty patients were treated with regional RT (definitive pelvic or extended-field RT with or without systemic therapy) and 18 were treated with systemic chemotherapy or hormonal therapy without external beam radiotherapy. The median follow-up for all patients was 43 months and for those not dying of disease was 67 months. The Kaplan-Meier method was used to calculate survival rates and differences were analyzed with log-rank tests.

Radioembolization for the treatment of unresectable hepatocellular carcinoma: A clinical review

Hepatocellular carcinoma (HCC) is the sixth most common cancer in the world. The majority of patients with HCC present with unresectable disease. These patients have historically had limited treatment options secondary to HCC demonstrating chemoresistance to the currently available systemic therapies. Additionally, normal liver parenchyma has shown intolerance to tumoricidal radiation doses, limiting the use of external beam radiation. Because of these limitations, novel percutaneous liver-directed therapies have emerged. The targeted infusion of radioactive microspheres (radioembolization) represents one such therapy. Radioembolization is a minimally invasive transcatheter therapy through which radioactive microspheres are infused into the hepatic arteries that supply tumor. Once infused, these microspheres traverse the hepatic vascular plexus and selectively implant within the tumor arterioles. Embedded within the arterioles, the 90Y impregnated microspheres emit high energy and low penetrating radiation doses selectively to the tumor. Radioembolization has recently shown promise for the treatment of patients with unresectable HCC. The objective of this review article is to highlight two currently available radioembolic devices (90Y, 188Rh) and provide the reader with a recent review of the literature.