Materials/Methods: Femoral head CTh maps were constructed from a control scan (1-3 months prior to radiation), the CT simulation scan, and the CT scan ...
Poster Viewing Session E491
Volume 93 Number 3S Supplement 2015 Purpose/Objective(s): Oral mucositis is a commonly observed toxicity during head and neck radiation therapy. Metallic dental restorations produce short-range secondary electrons that deposit dose into nearby tissue causing large, painful ulcers in the adjacent mucosal surfaces. This contributes to patient weight loss during treatment and often leads to breaks in therapy to replan or to allow for recovery. Various protective dental stents have been proposed and tested in very simplified phantoms and 2D beam arrangements. The objective of this project was to quantitatively assess electron scatter using a more anatomically realistic phantom and a modern beam configuration in order to better address our patients’ quality of life during treatment. Materials/Methods: We created a tissue-equivalent phantom to simulate a complete upper and lower jaw with 2 sets of removable gold caps on opposing molars. We also produced a set of 4-mm upper and lower ethylene copolymer (tissue equivalent) dosimetric stents designed to provide space between the mucosae and teeth as well as between the upper and lower jaw. The phantom was placed in a small cylindrical water bath to simulate head and neck soft tissue. A linear accelerator was used to deliver opposing fields of 6MV photons, and we made measurements with and without the dental stents in place. We then treated the phantom with a 9field IMRT plan generated in a treatment planning system with and without the dental stents. We used GafChromic EBT2 film for dosimetric measurement in both the occlusal plane as well as the vertical plane to simulate the mucosal surfaces of the tongue and the buccal mucosa. We then converted the film reading to a 2D digital dose map using quality assurance software for linear accelerators. Results: Our readout of the 2D dose distributions in the occlusal plane clearly demonstrated in the opposed-beam scenario a 26.9% reduction in maximum dose to the “mucosa” near the gold fixtures with the use of the protective dental stent. In the 9-field IMRT plan, maximum dose to the adjacent simulated tissue was reduced by 42.9% with the use of the dental stent. Conclusion: Our observed 42.9% dose reduction implies that patients’ oral mucosae adjacent to dental fixtures could receive doses in excess of 100 Gy during a course of definitive IMRT radiation therapy to the head and neck. In this era of increasing IMRT utilization, our results emphasize the necessity of dosimetric stent use to improve quality of life and reduce treatment breaks for our patients undergoing head and neck radiation therapy. Author Disclosure: E. Allan: None. L. Lu: None. A. Chakravarti: None. M. Van Putten: None. D. Blakaj: None.
3227 Assessment of Symptom Burden and Quality of Life in Radiation Oncology Patients U. Goyal,1 S. Ong,1 M.K. Cheung,1 J. Simmons,1 J. Holt,1 S.T. Dougherty,1 and K.M. O’Donnell2; 1University of Arizona, Tucson, AZ, 2Providence St. Mary Regional Cancer Center, Walla Walla, WA Purpose/Objective(s): The aim of the study was to assess the level of cancer related symptoms and needs in our patients. We evaluated the use of patient surveys in the clinic and whether weekly survey scores improved when their symptomatic needs were brought to the attention of health care providers via surveys. Materials/Methods: In this 2 phase quality improvement project (QUIP) the Edmonton Symptom Assessment System (ESAS) patient survey and a palliative care screening tool were used to assess the overall symptom burden, predominant symptom types and prevalence of palliative care needs in patients receiving radiation treatment for their cancer. Surveys were filled out by patients prior to their weekly on-treatment visits regardless of being treated with definitive or palliative intent. Survey scores were 0-10 (increasing scores indicated worsening symptoms) in 10 different categories. In the phase 1 portion, none of the ESAS surveys were reviewed by the physician or nurse. During phase 2, all ESAS surveys were reviewed by physicians and nursing staff. The survey scores for each phase during each week of treatment were then used for statistical analysis.
Results: Phase 1 patients were treated from 12/19/2013 to 2/17/2014. Eighty-five patients participated, with 307 surveys completed for phase 1. Phase 2 patients were treated from 4/1/2014 to 5/30/2014. One hundred seventy-seven patients participated with about 500 surveys completed for phase 2. When comparing week by week, there was no significant difference between phase 1 versus phase 2 scores from the baseline to 6 weeks of treatment (initial week, PZ.52; week, 1 PZ.75; week 2, PZ.58; week 3, PZ.37; week 4, PZ.91; week 5, PZ.98; and week 6, PZ.82). Within each phase, using linear regression, there seemed to be a moderate positive association between treatment score and week of radiation therapy (phase 1 r2Z0.27; phase 2 r2Z0.35), but this association was not statistically significant in either phase (phase 1 PZ.23; phase 2 PZ.12). Conclusion: In both phase 1 and phase 2, there seemed to be increasing symptom scores with each week of treatment. Phase 1 rose with a velocity of 0.32 points/week (r2Z0.27), and phase 2 rose with a velocity of 0.65 points/week (r2Z0.35); however, this association of rising symptom scores over time could be due to chance (phase 1 PZ.23; phase 2 PZ.12). The effect of asking questions on surveys may have prompted patients to bring symptoms to the physician’s attention, and thus, reduced the impact of the survey. We did not measure patient satisfaction, which may have increased from phase 1 to phase 2. Although there was no significant difference found for this analysis, further screening tools may be of help for improving a patient’s quality of life during radiation therapy. Author Disclosure: U. Goyal: None. S. Ong: None. M.K. Cheung: None. J. Simmons: None. J. Holt: None. S.T. Dougherty: None. K.M. O’Donnell: None.
3228 Acute Cortical Bone Thinning in the Femoral Head After Pelvic Radiation Therapy D.M. Randolph, II,1 C. Okoukoni,1 S. Isom,2 M.T. Munley,1 B.E. Lally,3 A.W. Blackstock,1 and J. Willey1; 1Wake Forest University Medical Center, Winston-Salem, NC, 2Wake Forest School of Medicine, WinstonSalem, NC, 3Wake Forest Baptist Medical Center, Winston-Salem, NC Purpose/Objective(s): Pelvic insufficiency fractures (PIF) occur in 1545% of patients following radiation therapy. Studies have demonstrated regions of cortical bone thinning by 30% at common fracture sites in the pelvis. New image processing techniques facilitate the accurate detection of cortical thickness (CTh) using standard CT scans. Acute changes occurring within 1-2 months of treatment have not been assessed. The objective of this study was to evaluate acute changes of CTh in the proximal femur following external beam radiation therapy (EBRT). Materials/Methods: Femoral head CTh maps were constructed from a control scan (1-3 months prior to radiation), the CT simulation scan, and the CT scan performed within 1-2 months following treatment in patients treated for pelvic malignancies. The CTh values from the control scan and simulation scan were compared to establish baseline pretreatment values. Using the radiation treatment plans, dose regions were created in 10 Gy increments ranging from 0 Gy to 60 Gy. Regions of interest (ROI) were defined as the intersection of the dose regions and femoral head. The pretreatment scans were registered to the posttreatment scan using rigid body transformation, and analogous ROIs were identified. A similar process was performed to obtain the ROI for the control subjects. The mean CTh within each ROI was determined posttreatment and compared to the baseline thickness using a repeated measures ANCOVA model that included patient age, gender, chemotherapy treatment, and radiation exposure as main effects. Results: Fifty-one femoral heads were analyzed from 27 patients (15 female). Median patient age was 54 years (range 30 to 87). Radiation treatment techniques included VMAT, 3-field, and 4-field arrangements. Treatments were performed primarily using 6 or 10 MV photons. Dose to the femoral head ranged from 0-59.2 Gy. Median date to follow-up scans was 15 days (range 0 to 52) from the last radiation treatment. The effect of radiation exposure on CTh was significant (PZ.050). Significant cortical bone thinning versus control was observed in all ROIs that absorbed >20 Gy, with a mean loss of 15.4% (PZ.006), 14.1% (PZ.017), and 14.4%
