Waddle, Mark R.

126 Background: Palliative radiation treatment (pRT) is a common and effective treatment for patients with symptomatic bone metastases. However, patients receiving RT for bone metastases often may have a poor performance status and are more likely to experience toxicity during or after treatment. This study aims to investigate the number and type of toxicity event occurring during or after pRT for bone metastases. Methods: Patients treated with RT for bone metastases at Mayo Clinic from 2007 to 2016 were included in this study. Demographic, disease, treatment, and toxicity information were collected. Specifically, toxicity events were identified as emergency department (ED) visits and inpatient hospitalization (IH) within 90 days, breaks in treatment >4 days, and excessive 30 day financial toxicity defined as standardized Medicare costs >1 standard deviation above the mean. RT treatment was compared by dose and fractionation via descriptive statistics. Results: A total of 538 patients treated with pRT were identified, 124 receiving 8Gy x1, 204 receiving 4Gy x5, and 210 receiving 3Gy x10. Patients with breast and prostate cancer were most likely to be treated with 3Gy x10 and patients with GI and Lung cancer were most likely to be treated with 8Gy x1. A description of the patient characteristics and toxicities are shown in Table 1. For 8Gy x1, 4Gy x5, and 3Gy x10 breaks in treatment were rare (0%, 2%, and 3.3%), ED visits (15%, 24%, & 28%), IH (12%, 23%, & 19%), and financial toxicity (13%, 18%, & 21%) were common. A total of 22.6%, 27.5%, and 38.6% of patients were alive two years following pRT from each group. Conclusions: Toxicity during or shortly after pRT of bone metastases is common. This study confirms that additional steps should be taken to monitor and mitigate toxicity in this vulnerable patient group. [Table: see text]

AbstractPurposeLeverage the National Cancer Database (NCDB) to evaluate trends in management of nonmetastatic squamous cell cancer (SCC) of the rectum and their effect on survival for this uncommon tumor.Methods and MaterialsRetrospective data was obtained from the NCDB for patients diagnosed with SCC of the rectum between 2004 and 2014, including cT1‐4, cN0‐2, cM0 tumors (cohort A, n = 2296). A subgroup analysis was performed on locally advanced tumors (cT1‐T2, N+ or cT3, N any, subcohort B, n = 883), treated with chemoradiation (n = 706) or trimodality therapy (n = 177) including chemotherapy, radiation, and surgery. Pathological complete response rate following neoadjuvant therapy was obtained. Univariate and multivariate logistic regression analyses were performed to generate hazard ratios (HR) investigating factors associated with overall survival. Kaplan‐Meier (K‐M) method was used to estimate overall surviving proportion at 5 and 10 years.ResultsThe K‐M estimated 5 and 10 year overall survival for stage I disease was 71.3% and 57.8%, respectively; stage II disease was 57.0% and 38.9%, respectively; stage III disease was 57.8% and 41.5%, respectively. On multivariate analysis, higher cT category (P < 0.001) resulted in worse survival. For locally advanced tumors (subcohort B), there was no significant difference in survival between chemoradiation alone compared to trimodality therapy (P = 0.909 on multivariate analysis).ConclusionsMost providers manage locally advanced SCC of the rectum similar to anal cancer, which results in equivalent overall survival and spares patients from the additional morbidity associated with surgical resection.

It is an exciting time for big data efforts in radiation oncology. The use of big data to help aid both outcomes and decision‐making research is becoming a reality. However, there are true challenges that exist in the space of gathering and utilizing performance and outcomes data. Here, we summarize the current state of big data in radiation oncology with respect to outcomes and discuss some of the efforts and challenges in radiation oncology big data.

147 Background: Prostate cancer patients treated with external beam radiation therapy are instructed to present daily with a full bladder to decrease small bowel and bladder toxicity and to increase reproducibility of treatment. However, older patients may have difficulty presenting with full bladders and variation of bladder volume with treatment is unknown. The objective of this study was to assess bladder filling at the time of radiation treatment (RT) using a bladder ultrasound in patients undergoing treatment for prostate cancer. Methods: Patients with prostate cancer were prospectively enrolled prior to CT simulation from January to August 2017. Bladder volume was recorded during CT simulation and daily immediately prior to RT. Patients were instructed to drink 8-12 ounces of water 30-60 minutes prior to RT. Three bladder volume measurements were recorded daily and averaged at the time of each treatment. Average bladder volume during treatment and the number of treatments with low bladder volumes ( < 50cc, < 60cc, and < 100cc) were reported using descriptive statistics. Results: A total of 13 patients completed a median of 42 days of RT during the study period, resulting in 550 daily bladder volumes. Ten patients were treated definitively and 3 with salvage radiation after prostatectomy. The median age of patients in the study was 72 years. Older patients were statistically more likely to present with low bladder volumes, with percentage of treatments with a bladder volume less than 50cc, 60cc, and 100cc being 29%, 42%, and 66% compared to only 4%, 7%, and 18% in patients aged < 70 (P < 0.01). The average bladder volume at the time of CT simulation was 176cc ± 57cc and the average volume during treatment was 140cc± 93cc, which was not statistically different (P = 0.28). The bladder volume did not significantly change over the course of treatment. Conclusions: Older patients (age 70+) with prostate cancer were more likely to present for RT with low bladder volumes in this prospective study. Our findings suggest that older patients should receive extra counseling about bladder filling and/or may require less bladder filling at the time of CT simulation to provide more accurate bowel dosimetry measurements.