Curative Radiation Treatment Research Articles

Does the presence of emphysema increase the risk of radiation pneumonitis in lung cancer patients?

Radiotherapy (rt) plays an important role in the treatment of lung cancer. One of the most common comorbidities in patients with lung cancer is pulmonary emphysema. The literature offers conflicting data about whether emphysema increases the occurrence and severity of radiation pneumonitis (rp). As a result, whether high doses of rt (with curative intent) should be avoided in patients with emphysema is still unclear. We measured the documented incidence of rp in patients with and without emphysema who received curative radiation treatment. This retrospective cohort study considered patients in the lung cancer clinical database of the Peter Brojde Lung Cancer Centre. Data from the database has been used previously for research studies, including a recent publication about emphysema grading, based on the percentage of lung occupied by emphysema on computed tomography (ct) imaging. Using previously published methods, chest ct imaging for 498 patients with lung cancer was scored for the presence of emphysema. The analysis considered 114 patients who received at least 30 Gy radiation. Of those 114 patients, 64 (56%) had emphysema, with approximately 23% having severe or very severe disease. The incidence of rp was 34.4% in patients with emphysema (n = 22) and 32.0% in patients with no emphysema (n = 16, p = 0.48). No difference in the incidence of rp was evident between patients with various grades of emphysema (p = 0.96). Similarly, no difference in the incidence of rp was evident between the two treatment protocols-that is, definitive rt 17 (37%) and combined chemotherapy-rt 21 (31%, p = 0.5). In our cohort, the presence of emphysema on chest ct imaging was not associated with an increased risk of rp. That finding suggests that patients with lung cancer and emphysema should be offered rt when clinically indicated. However, further prospective studies will be needed for confirmation.

Outcomes of Curative (Chemo)Radiotherapy for Patients Who Are Borderline for Curative Management of Squamous Cell Carcinoma of Head and Neck

Appropriate selection of head and neck cancer (HNC) patients for curative versus palliative treatment is one of the most difficult clinical decisions. The aims of this study were to 1) review the outcomes of curative intent treatment of HNC patients with borderline curability, and 2) assess the utility of a previously devised patient selection algorithm for curative treatment. A single institution retrospective review of patients with mucosal squamous cell carcinoma treated with curative intent between January 1 2004 and December 31 2011. Criteria for borderline curability included one or more of;1) T4 and/or N3 disease; 2) ECOG performance status >/=2; 3) age >/=80 years. A total of 199 patients were identified. One hundred thirty-seven had T4/N3 disease, 48 were >/=80 years, and 40 were >/=ECOG 2. Overall survival (OS) at 2 and 5 years was 67% (95% CI:60-74) and 45% (95% CI: 39-53) respectively. The 2-year and 5-year progression free survival (PFS) were 62% (95% CI: 55-69) and 39% (95% CI: 33-47), respectively. On multivariate analysis, independent predictive factors for overall survival were adult comorbidity evaluation-27 (ACE-27) grade and ECOG status. Thirty-three of the 199 patients should not have received curative intent treatment according to the algorithm. These patients had significantly poorer treatment completion rates and OS and PFS. ACE-27 and ECOG status are a strong and independent prognostic factors for survival among HNC patients of borderline curability. Our patient selection algorithm seems a useful tool to appropriately select patient who are borderline for curative (chemo)radiation treatment.

Customized Text Messaging to Assist Cancer Patients with Diet, Nutrition and Activity: a Pilot Study

There is ample evidence supporting the significance of diet and nutrition in cancer prevention and management. Yet providing comprehensive nutritional support presents with challenges. In this study, we tested the feasibility of providing patients with a cost-effective, hands-on text-messaging platform, in order to implement nutritional support and increase patient engagement throughout the course of radiation therapy cancer treatment. Patients to receive curative radiation treatment for head and neck (H&N), breast or prostate cancers were screened for eligibility. Those consented were enrolled onto a HIPPA compliant texting platform, and set to receive 3-5 text messages a day. Messages sent were specific to diagnosis and treatment time point. Patient responses triggered automated texts from the platform, and notifications were sent to providers when there was a more personalized patient need. Weekly quality of life and post-treatment feedback surveys were collected. Patient engagement was measured by number of text responses and end of treatment feedback score. Of the 25 patients enrolled, 22 completed the program and 3 were screen fails. Breakdown by diagnosis included 7 H&N, 9 breast and 6 prostate. Prostate cancer patients showed the highest engagement, at a mean 59.3 (IQR 60-8.25) total responses throughout treatment. Of the breast and prostate patients, only 1 was referred to a nutritional specialist during the study. Overall feedback scores averaged at 81.3% (IQR 91.7-71.9). On a categorical level, “ease of use” scored the highest rating at 94% (IQR 100-87.5). Impact of the recommendations on changing eating habits scored 59.5% (IQR 75-37.5). Ninety-five percent of patients said they would recommend the program to others. There were no significant weight changes for the breast or prostate patients. Weight expectedly dropped for H&N patients, but returned to baseline by month 3 post treatment and study intervention. There are many challenges to providing comprehensive nutritional support for cancer patients. While most H&N patients receive dietary guidance per standard of care, the same is not always true for breast and prostate patients. A simple texting program can provide the nutritional education and motivation needed for these patients, with minimal costs or time required. Feedback from patients supported a comfortable, appropriate, and easy to use platform. Use increased patient engagement with their clinical care. A future program can tie in activity monitoring and be more tailored to specific needs of each patient, controlling for treatment course or concurrent therapies. Such could offer all types of oncology patients the nutritional and dietary support needed to tolerate treatment and maintain long-term, healthy habits throughout recovery.

Safety and Feasibility of a Pragmatic Pre-planned, Hypofractionated High Dose Rate Brachytherapy Approach to Carcinoma of the Cervix in Low and Middle Income Countries

The burden of cervical cancer is high in low and middle income countries (LMIC) where access to curative radiation treatment is limited. A nonprofit organization donated a high dose rate (HDR) brachytherapy afterloading unit to the sole cancer center in Senegal in 2013. We describe the initial experience of a novel treatment approach using pre-planned brachytherapy as a component of curative chemoradiation in Senegal.

Prostate Clinical Outlook Visualization System for Patients and Clinicians Considering Cyberknife Treatment—A Personalized Approach

Background: When a patient presents with localized prostate cancer, referral for radiation oncology consultation includes a discussion of likely outcomes of therapy. Among current radiation treatments for prostate cancers, hypo-fractionated stereotactic body radiation therapy (SBRT) has gained clinical acceptance based on efficacy, short duration of treatment, and the potential radiobiological advantages. The Prostate Clinical Outlook Visualization System (PCOVS) was developed to provide the patient and the clinician with a tool to visualize probable treatment outcomes using institutional, patient specific data for comparing results of treatment. Methods: We calculated the prostate cancer outcomes—for each prospective patient using the EPIC-26 quality of life parameters based on clinical outcomes data of 580 prostate cancer patients who were treated with SBRT. We applied Kaplan-Meier analysis using the ASTRO definition for biochemical recurrence (BCR) free survival and likely outcome and the PCOVS nomogram to calculate parameters for quality of life. Open-source R, RShiny, and MySQL were used to develop a modularized architecture system. Results: The PCOVS presents patient specific risk scores in a gauge chart style and risk free probability bar plots to compare the treatment data of patients treated with SBRT. The PCOVS generates reports, in PDF, which consists of a comparison charts of risk free probabilities late effects and gauge charts of risk scores. This system is now being expanded as a web-based service to patients. Conclusions: The PCOVS visualized patient specific likely outcomes were compared to treatment data from a single department, helping the patient and the clinician to visualize likely outcomes. The PCOVS approach can be expanded to other specialties of oncology with the flexible, modularized architecture, which can be customized by changing independent modules.

P16 and HPV-DNA Tests Discordance in Human Papilloma Virus (HPV)-Associated Oropharyngeal Cancer: Results From a Case-matched Study

HPV-associated oropharyngeal cancer (OPC) has been associated with improved prognosis compared to HPV-negative OPC. Concomitant HPV DNA and p16 testing has been shown to improve sensitivity and specificity; however, the prognostic significance of discordant testing (i.e., p16+/HPV DNA or p16-/HPV DNA+) in OPC patients has not been quantitatively studied due to inadequate sample sizes. We aim to determine whether there is a prognostic significance for discordant p16/HPV-DNA test results for OPC patients receiving curative intent radiation treatment. A case-control study design was used to retrospectively analyze 136 patients with pathologically proven oropharyngeal cancer (OPC) treated with curative intent radiation therapy at our institution between the years 2005 and 2012. HPV DNA status was evaluated using in-situ hybridization (ISH) methods, and p16 status was identified via immunohistochemistry (IHC). Two subgroups were identified: concordant (p16+/HPV DNA+) and discordant (p16+/HPV DNA- or p16-/HPV DNA+) subgroups, with the former serving as control. Characteristics including sex, age at diagnosis, ethnicity, smoking status, cancer stage, and treatment modality were identified. Kaplan-Meier survival analysis and univariate Cox proportional hazard analysis were performed. Patient characteristics, including age, sex, smoking status, stage, pathological grade, tumor subsite within oropharynx, treatment modality, and follow-up duration were well-matched between the concordant and discordant subgroups. Survival analysis failed to show any statistically significant difference between the concordant and discordant subgroups in terms of overall survival, local, locoregional, or distant control. The discordant subgroup was comprised entirely of p16+/HPV DNA- patients; no patients in the discordant subgroup were found to be p16-/HPV DNA+. Univariate analysis demonstrated statistically significant correlation between overall survival and N-category in the discordant group (P = .024 by Effect Wald Test), in contrast to the concordant group (P = .18). This study suggests that HPV test discordance is not correlated with differential treatment outcomes as compared to HPV test concordance. p16 testing by IHC has been previously shown to be more sensitive and specific than HPV DNA testing by ISH. This study further validates this observation and suggests that p16 may be used as a standalone test in the diagnosis of HPV in HNC patients.

Prognostic Significance of Human Papilloma Virus and p16 Expression in Patients with Vulvar Squamous Cell Carcinoma who Received Radiotherapy

AimsHuman papilloma virus (HPV) has been identified as an aetiological agent in a subset of patients with vulvar squamous cell carcinoma (VSCC). The prognostic role of HPV status in VSCC patients treated with radiotherapy has not yet been determined. We investigated the associations between HPV, p16 and clinical outcome in these women. Materials and methodsPatients undergoing potentially curative radiation treatment for VSCC at a single institution from 2000 to 2009 were retrospectively identified. Those who received definitive or peri-operative radiotherapy as part of treatment, and who had available pathological specimens, were included for analysis. HPV infection was detected using Roche Linear array hybridisation and p16 by immunohistochemistry. The locoregional relapse (LRR) rate was estimated using a cumulative incidence function to account for competing risks. Disease-free survival (DFS) and overall survival were analysed using the Kaplan–Meier method. The median follow-up was 4.9 years. ResultsForty patients were suitable for analysis, with a median age of 69.5 years. HPV was detected in 14/40 (35%) patients, HPV16 being the most common serotype (79%). Patients with HPV-positive tumours had lower 5 year LRR compared with those with HPV-negative tumours (14.3% versus 79.3%, Gray test P = 0.003). Tumour p16 positivity was also associated with lower 5 year LRR (15.4% versus 81.2%, Gray test P = 0.002). Patients with p16-positive tumours had higher 5 year DFS compared with those with p16-negative tumours (62% versus 7%, Log-rank test P = 0.02). ConclusionsWe have identified a favourable prognostic group in VSCC, with p16-positive patients showing improved outcomes. p16 has the potential to be a predictive marker allowing the identification of women more likely to have a favourable response to radiotherapy.

Complications of curative radiation treatment for early prostate cancer.

To report the incidence of urological complications following curative radiation treatment for early prostate cancer, including minimally invasive urological procedures (MUIP), hospital admissions and open surgical procedures. Second malignancies following radiation are also reported and compared with patients undergoing a prostatectomy. Included were patients receiving curative intent external beam radiation treatment for early prostate cancer between January 1, 2002, and December 31, 2009. Medical records were reviewed for baseline characteristics, treatment details and outcomes. Kaplan-Meier methods were used to derive the 5-year cumulative incidence of the urological outcomes and second malignancy. There were 439 patients identified. The median follow-up was 6.96 years. The median age was 69. A total of 56 patients developed a radiation related urological complication, 25 requiring hospital admission. The 5-year cumulative incidence for an MIUP and admission was 3.95% (95% confidence interval (CI), 2.47-6.28) and 2.24% (95% CI, 1.17-4.27), respectively. There were no open surgical procedures. Further malignancy developed in 27 patients during the 5- to 9-year posttreatment period with a cumulative incidence of 10.7% (95% CI, 7.31-15.51). Of the comparator prostatectomy group, of the 265 eligible patients analyzed, 19 patients developed a second malignancy with a cumulative incidence of 9.92% (95% CI, 6.28-15.48). On log-rank testing, there was no difference in the cumulative incidence rates of second malignancy between 5 and 9 years, following respective treatments (P=0.8554). The incidence of MUIP, hospital admissions and open surgical procedures following radiation is reassuringly low. The second malignancy rates are also low and similar to the rates in patients treated with a prostatectomy.

Feasibility of Homeopathic Treatment for Symptom Reduction in an Integrative Oncology Service.

Background: Homeopathy has the potential to reduce symptoms related to cancer treatment. The present study examined the feasibility of a homeopathic consultation and treatment program, provided as part of an integrative oncology service. Methods: The electronic medical files of patients undergoing a homeopathic consultation in an integrative oncology service clinic were examined retrospectively. Adherence to the homeopathic treatment regimen and perceived response to the treatment were evaluated. Results: The files of 124 patient (34 males, 90 females) were examined, of which two-thirds reported acquiring and self-administering the homeopathic remedy as prescribed, and nearly three-quarters reporting a beneficial effect. Adherence to the homeopathic treatment regimen was greatest among patients attending a second visit, as opposed to having only telephone/e-mail follow-up (P < .005). An association was found between a perceived beneficial effect of treatment with attending a follow-up visit (P = .04), female gender (P = .02), younger age (P = .048), diagnosis of breast cancer (P = .014), and current radiation treatment (vs chemotherapy; P = .003). Patients reporting chemotherapy-induced peripheral neuropathy were also more likely to report a beneficial effect (P = .004), as were female patients reporting hot flashes (P = .005) and those referred by an oncologist (P = .046). No adverse effects were attributed to the homeopathic treatment. Conclusions: Homeopathy can be successfully incorporated within a supportive care integrative oncology service. In addition to demographic and cancer-related characteristics, as well as symptoms, patients attending a second visit (vs only telephone/e-mail follow-up) were more likely to adhere to and perceive a beneficial effect from the homeopathic regimen.

Effects of an interactive mHealth innovation for early detection of patient-reported symptom distress with focus on participatory care: protocol for a study based on prospective, randomised, controlled trials in patients with prostate and breast cancer

BackgroundCancer patients are predominantly treated as out-patients and as they often experience difficult symptoms and side effects it is important to facilitate and improve patient-clinician communication to support symptom management and self-care. Although the number of projects within supportive cancer care evaluating mobile health is increasing, few evidence-based interventions are described in the literature and thus there is a need for good quality clinical studies with a randomised design and sufficient power to guide future implementations. An interactive information and communications technology platform, including a smartphone/computer tablet app for reporting symptoms during cancer treatment was created in collaboration with a company specialising in health care management. The aim of this paper is to evaluate the effects of using the platform for patients with breast cancer during neo adjuvant chemotherapy treatment and patients with locally advanced prostate cancer during curative radiotherapy treatment. The main hypothesis is that the use of the platform will improve clinical management, reduce costs, and promote safe and participatory care.MethodThe study is a prospective, randomised, controlled trial for each patient group and it is based on repeated measurements. Patients are consecutively included and randomised. The intervention groups report symptoms via the app daily, during treatment and up to three weeks after end of treatment, as a complement to standard care. Patients in the control groups receive standard care alone. Outcomes targeted are symptom burden, quality of life, health literacy (capacity to understand and communicate health needs and promote healthy behaviours), disease progress and health care costs. Data will be collected before and after treatment by questionnaires, registers, medical records and biomarkers. Lastly, participants will be interviewed about participatory and meaningful care.DiscussionResults will generate knowledge to enhance understanding about how to develop person-centred care using mobile technology. Supporting patients’ involvement in their care to identify problems early, promotes more timely initiation of necessary treatment. This can benefit patients treated outside the hospital setting in regard to maintaining their safety.Clinical trial registrationJune 12 2015 NCT02477137 (Prostate cancer) and June 12 2015 NCT02479607 (Breast cancer).

Prostate clinical outlook visualization for patients and clinicians considering cyberknife treatment: A personalized approach.

e16549 Background: When a patient presents with localized prostate cancer, referral for radiation oncology consultation includes a discussion of likely outcomes of therapy. Among current radiation treatments for prostate cancers, hypo-fractionated stereotactic body radiation therapy (SBRT) has gained clinical acceptance based on efficacy, short duration of treatment and potential radiobiological advantages. The prostate Clinical Outlook (PCO) visualization system was developed to provide the patient and the clinician with a tool to visualize probable treatment outcomes using institutional, patient specific data for comparing results of treatment. Methods: We calculated the prostate cancer outlooks for each prospective patient using the EPIC-26 quality of life parameters based on clinical outcomes data of 580 cyberknife SBRT treated prostate cancer patients. We applied Kaplan-Meier analysis using the ASTRO method for disease free likely outcome and the PCO nomogram to calculate parameters for quality of life. Open source R, R/Shiny, and MySQL were used to develop a modularized architecture system. Results: PCO presents patient specific risk scores in a gauge chart style and risk free probability bar plots to compare treatment data of cyberknife patients. PCO generates reports, in PDF and HTML, which consist of a comparison chart of risk free probabilities and gauge charts of risk scores. This system is now being expanded as a web-based service to patients. Conclusions: PCO visualized patient specific likely outcomes were compared to treatment data from a single department, helping the patient and the clinician to visualize likely outcomes. The PCO approach can be expanded to other specialties of oncology with the flexible, modularized architecture which can be customized by changing parameter variables for the modules.

General health status of long-term cervical cancer survivors after radiotherapy.

To evaluate the global health status of long-term cervical cancer survivors (LCCS) who survived for more than 4years after curative radiation treatment (RT). Medical records of 562women treated with RT in our institution between 2003 and 2010 were reviewed. Excluding 259women who died of disease or were lost to follow-up, disease status and late morbidities were evaluated in 303LCCS. Quality of life (QoL) was analyzed in 168LCCS using aquestionnaire from the European Organization for the Research and Treatment of Cancer, and the results were compared with an age-matched healthy Korean female population. Median follow-up was 6.8years (range4.1-12.5 years). There were 14deaths (7cancer specific) and 14recurrences (5local recurrences and 9distant metastases). The median time to recurrence was 6.0years (range4.1-8.2years). Grade≥2 late toxicities were frequently observed in the bladder (19%) and small/large intestine (15%). Multivariate analysis revealed ahigher rate of late toxicity in patients aged ≥51years at diagnosis (small/large intestine: hazard ratio, HR, 2.5[1.2-5.5]; bladder: HR 2.4 [1.3-4.5]; and bone: HR 4.3 [1.2-15.8]) than patients aged <51years. Compared to the general population, LCCS exhibited asignificantly higher rate of body image concerns, sexual dysfunction, lymphedema, and peripheral neuropathy. New recurrences occurred in 5% of LCCS and grade≥2 treatment-related morbidities were present in 33%. Asignificant proportion of LCCS also showed decreased cervical-cancer-specific QoL. These results suggest the need for long-term surveillance and follow-up care for LCCS.

110 - Clinical Application of Human Adipose Derived Regenerative Cells (ADRCs) in Tissue Repair of Severe Side Effects Following Curative Radiotherapy Treatment

110 - Clinical Application of Human Adipose Derived Regenerative Cells (ADRCs) in Tissue Repair of Severe Side Effects Following Curative Radiotherapy Treatment

Treatment of Locally Recurrent and Metastatic Squamous Cell Carcinoma of Head &amp; Neck

The survival rate at 3 years after potentially curative surgical or radiation treatment for locally advanced squamous cell carcinoma of head and neck (SCCHN) remains quite poor at 30 to 50%. Over 50% of these patients relapse locally or at distant sites and with a median survival of 6-9 months. This review focuses on the established and experimental strategies seeking to improve this outcome. Cetuximab is a chimeric immunoglobulin G1 monoclonal antibody engineered specifically to compete with the natural ligand for EGFR binding sites on the external surface of the cell membrane. This antibody have demonstrated significant disease control rate of over 45% as single agent in the locally recurrent/metastatic disease setting. The combination of cetuximab with platinum-based and taxane-based chemotherapy regimens has resulted in disease control rate of up to 80%. Studies are currently ongoing to assess the activity of immunotherapeutic agents like CTLA-4, PD-1, and PD-L1 inhibitors in the treatment of advanced SCCHN both in biomarker selected and unselected patient population with encouraging preliminary results. Moreover, the combination of these agents with standard chemotherapy regimens, and with cetuximab in the treatment of SCCHN is also being explored.

Piloting prostate cancer patient-reported outcomesin clinical practice.

The expanded prostate cancer index composite-26 (EPIC-26) instrument is a validated research tool used for capturing patient-reported quality-of-life outcomes related to the domains of bowel, bladder, and sexual functioning for men undergoing curative treatment for prostate cancer. The purpose of this pilot study was to explore the perceptions and experiences of clinicians with using EPIC-26 in a clinical setting for patients receiving curative radiotherapy. Ten clinicians reviewed EPIC-26 scores either before or during weekly clinical encounters with patients receiving curative radiation treatment for prostate cancer. After a period of 2 months, clinicians underwent individual semi-structured interviews where they were asked about their views on measuring patient-reported outcomes in practice, the value of EPIC-26, impressions on patient acceptability, and operational issues. There was a general willingness and acceptance by clinicians to use EPIC-26 for routine clinical practice. Clinician participants found EPIC-26 to be generally informative, and added value to the clinical encounter by providing additional information that was specific to prostate cancer patients. EPIC-26 was also felt to improve overall communication and provide additional insight into the patient experience. Our qualitative findings suggest that there may be a role for incorporating patient-reported outcome measure assessment tools like EPIC-26 routinely into clinical practice. However, further qualitative and quantitative research is required in order to assess the impact of patient-reported outcome information on communication, patient and clinician satisfaction, and how these and other related outcomes can be used for guiding treatment decision-making.

RT-13 * OPTIMIZING RADIATION THERAPY FOR GLIOBLASTOMA PATIENTS: A COMPARATIVE STUDY OF USING DIFFERENT MRI MODALITIES TO MINIMIZE RADIATION INJURY

Glioblastoma multiforme is the most common and lethal primary malignant brain tumor and radiation therapy is considered the standard of care in the adjuvant setting. Current radiation treatment planning guidelines recommend FLAIR MRI sequence with a 2 cm margin to encompass the subclinical tumor spread. However, the FLAIR modality extensively visualizes the surrounding edema, possibly leading to unnecessary radiation toxicity to healthy brain tissue. We hypothesize that we can optimize radiation therapy by using alternative MRI modalities or by decreasing clinical tumor volume margins to minimize toxicity without compromising accurate tumor targeting. We retrospectively collected data for 21 patients with pathology confirmed recurrence and created radiation treatment plans using ADC, ADC without FLAIR shine-through (ADCst), DWI, T1, and FLAIR. For the FLAIR both a 1 cm and 2 cm margin was used (FLAIR1 and FLAIR2). Boolean operators were used to calculate the accuracy of targeting tumor recurrence and excessive radiation volume compared to the standard FLAIR2 treatment plan. All MRI modalities had complete coverage of the recurrent tumor and the mean differences in accuracy between the different MRI modalities and FLAIR2 was not significant. However, there was a significant reduction in the excessive radiation volume compared to FLAIR2. ADCst had a 51.3% reduction, DWI 42.3%, T1 42.6%, and FLAIR1 44.6% reduction of excessive radiation volume compared to FLAIR2 (p < 0.05). ADC did not have a significant reduction of excessive radiation volume compared to FLAIR2. Our data support the hypothesis that using MRI modalities other than the standard FLAIR or decreasing the margin by 1cm may optimize radiation therapy for GBM patients by reducing unnecessary radiation dose to healthy brain tissue without compromising accuracy. By using new MRI modalities in radiation treatment planning or modifying clinical tumor volume margins we can decrease radiation toxicity to patients to improve their quality of life.

WE-G-18A-02: Calibration-Free Combined KV/MV Short Scan CBCT

Purpose: To combine orthogonal kilo-voltage (kV) and Mega-voltage (MV) projection data for short scan cone-beam CT to reduce imaging time on current radiation treatment systems, using a calibration-free gain correction method. Methods: Combining two orthogonal projection data sets for kV and MV imaging hardware can reduce the scan angle to as small as 110° (90°+fan) such that the total scan time is ∼18 seconds, or within a breath hold. To obtain an accurate reconstruction, the MV projection data is first linearly corrected using linear regression using the redundant data from the start and end of the sinogram, and then the combined data is reconstructed using the FDK method. To correct for the different changes of attenuation coefficients in kV/MV between soft tissue and bone, the forward projection of the segmented bone and soft tissue from the first reconstruction in the redundant region are added to the linear regression model. The MV data is corrected again using the additional information from the segmented image, and combined with kV for a second FDK reconstruction. We simulated polychromatic 120 kVp (conventional a-Si EPID with CsI) and 2.5 MVp (prototype high-DQE MV detector) projection data with Poisson noise using the XCAT phantom. The gainmore » correction and combined kV/MV short scan reconstructions were tested with head and thorax cases, and simple contrast-to-noise ratio measurements were made in a low-contrast pattern in the head. Results: The FDK reconstruction using the proposed gain correction method can effectively reduce artifacts caused by the differences of attenuation coefficients in the kV/MV data. The CNRs of the short scans for kV, MV, and kV/MV are 5.0, 2.6 and 3.4 respectively. The proposed gain correction method also works with truncated projections. Conclusion: A novel gain correction and reconstruction method was developed to generate short scan CBCT from orthogonal kV/MV projections. This work is supported by NIH Grant 5R01CA138426-05.« less

PO-0995: Fatigue in breast cancer patients undergoing curative radiotherapy treatment

PO-0995: Fatigue in breast cancer patients undergoing curative radiotherapy treatment

High resolution ultrasound features of prostatic rib metastasis: A prospective feasibility study with implication in the high-risk prostate cancer patient

ObjectiveIn a prior study, high resolution ultrasound (US) was shown to be accurate for evaluating rib metastasis detected on bone scan. However, that study did not address the specific US appearance typical of osteoblastic rib metastasis. Our objective was to determine the specific US imaging appearance of osteoblastic prostate carcinoma rib metastasis using osteolytic renal cell carcinoma rib metastasis as a comparison group. Materials and methodsThe Institutional Review Board approval and informed consent were obtained for this prospective feasibility study. We performed high resolution US of 16 rib metastases in 4 patients with prostate carcinoma metastases and compared them to 8 rib metastases in 3 male patients with renal cell carcinoma. All patients had rib metastases proven by radiographs and computed tomography (CT). High resolution US scanning was performed by a musculoskeletal radiologist using a 12–5MHz linear-array transducer. Transverse and longitudinal scans were obtained of each rib metastasis. ResultsAll 16 prostate carcinoma metastases demonstrated mild cortical irregularity of the superficial surface of the rib without associated soft tissue mass, cortical disruption, or bone destruction. 7 of 8 (88%) renal cell carcinoma rib metastases demonstrated cortical disruption or extensive bone destruction without soft tissue mass. One of 8 (12%) renal cell carcinoma rib metastases demonstrated only minimal superficial cortical irregularity at the site of a healed metastasis. ConclusionOsteoblastic prostate carcinoma rib metastases have a distinctive appearance on US. Our success in visualizing these lesions suggests that US may be a useful tool to characterize isolated rib abnormalities seen on a bone scan in high-risk prostate cancer patients who are being evaluated for curative surgery or radiation treatment.

Constrained‐beam inverse planning for intensity‐modulated radiation therapy of prostate cancer patients with bilateral hip prostheses

Hip prostheses present a technical challenge in the planning of curative external beam radiation treatment for patients with prostate cancer. Bilateral prostheses compel planners to compromise between target coverage and avoidance of beam entry through the prostheses. Inverse planning systems given objectives to avoid dose to prostheses are overly restricted from allowing exit dose to them. We report a novel inverse planning technique for intensity-modulated radiation therapy of patients with prostate cancer and bilateral hip prostheses, by constraining beam characteristics rather than dose in the inverse planning process.