Laura A. Vallow

Skull-base chordoma and chondrosarcoma are rare radioresistant tumors treated with surgical resection and/or radiotherapy. Because of the established dosimetric and biological benefits of heavy particle therapy, we performed a systematic and evidence-based review of the clinical outcomes of patients with skull-base chordoma and chondrosarcoma treated with carbon ion radiotherapy (CIRT). A literature review was performed using a MEDLINE search of all articles to date. We identified 227 studies as appropriate for review, and 24 were ultimately included. The published data illustrate that CIRT provides benchmark disease control outcomes for skull-base chordoma and chondrosarcoma, respectively, with acceptable toxicity. CIRT is an advanced treatment technique that may provide not only dosimetric benefits over conventional photon therapy but also biologic intensification to overcome mechanisms of radioresistance. Ongoing research is needed to define the magnitude of benefit, patient selection, and cost-effectiveness of CIRT compared to other forms of radiotherapy.

Surgical treatment of pelvic sarcoma involving the bone is the standard of care but is associated with several sequelae and reduced functional quality of life (QOL). Treatment with photon and proton radiotherapy is associated with relapse. Carbon ion radiotherapy (CIRT) may reduce both relapse rates and treatment sequelae. The PROSPER study is a tricontinental, nonrandomized, prospective, three-arm, pragmatic trial evaluating treatments of pelvic sarcoma involving the bone. Patients aged at least 15 years are eligible for inclusion. Participants must have an Eastern Cooperative Oncology Group Performance Status score of two or less, newly diagnosed disease, and histopathologic confirmation of pelvic chordoma, chondrosarcoma, osteosarcoma, Ewing sarcoma with bone involvement, rhabdomyosarcoma (RMS) with bone involvement, or non-RMS soft tissue sarcoma with bone involvement. Treatment arms include (1) CIRT (n = 30) delivered in Europe and Asia, (2) surgical treatment with or without adjuvant radiotherapy (n = 30), and (3) proton therapy (n = 30). Arms two and three will be conducted at Mayo Clinic campuses in Arizona, Florida, and Minnesota. The primary end point is to compare the 1-year change in functional QOL between CIRT and surgical treatment. Additional comparisons among the three arms will be made between treatment sequelae, local control, and other QOL measures.

BNCT is a high LET radiation therapy modality that allows for biologically targeted radiation delivery to tumors while reducing normal tissue impacts. Although the clinical use of BNCT has largely been limited to phase I/II trials and has primarily focused on difficult-to-treat malignancies such as recurrent head and neck cancer and recurrent gliomas, recently there has been a renewed interest in expanding the use of BNCT to other disease sites, including breast cancer. Given its high LET characteristics, its biologically targeted and tumor specific nature, as well as its potential for use in complex treatment settings including reirradiation and widespread metastatic disease, BNCT offers several unique advantages over traditional external beam radiation therapy. The two main boron compounds investigated to date in BNCT clinical trials are BSH and BPA. Of these, BPA in particular shows promise in breast cancer given that is taken up by the LAT-1 amino acid transporter that is highly overexpressed in breast cancer cells. As the efficacy of BNCT is directly dependent on the extent of boron accumulation in tumors, extensive preclinical efforts to develop novel boron delivery agents have been undertaken in recent years. Preclinical studies have shown promise in antibody linked boron compounds targeting ER/HER2 receptors, boron encapsulating liposomes, and nanoparticle-based boron delivery systems. This review aims to summarize the physical and biological basis of BNCT, the preclinical and limited clinical data available to date, and discuss its potential to be utilized for the successful treatment of various breast cancer disease states.

Aim/Objective: Prone positioning is often used to reduce the dose to organs at risk during adjuvant breast irradiation. High tangents are used with supine treatments in patients with the low-volume nodal disease to increase nodal coverage while minimizing toxicities. Our study aims to evaluate nodal coverage for patients treated in the prone position with high tangents. Materials and Methods: Our study analyzed the plans for 20 patients with early-stage, left-sided breast cancers treated at our institution from 2018 to 2019. All patients were treated in the prone position. Axillary nodal levels I-III were contoured, and treatment plans were generated using high tangents. The heart, bilateral lungs, and breast tissue were retrospectively contoured. All plans were evaluated to a dose of 42.4 Gy in 16 fractions. Results: Level I lymph node levels had a mean coverage of 99% of the prescription dose (range: 98-100%). Similarly, level II coverage was approximately 88% (range: 65-100%). The mean coverage for level III was approximately 25% (range: 0-52%). The mean heart dose, mean lung volume receiving ≥20 Gy (V20) for the bilateral lungs, and ipsilateral V20 were 1.69 Gy, 1.64%, and 3.56%, respectively. Conclusion: Treating patients in the prone position with high tangents provides excellent coverage of axillary levels I and II, although there is minimal coverage of axillary level III. Prospective trials are needed to evaluate the clinical outcomes when treating patients with high tangents in the prone position.

Brain metastases traditionally carried a poor prognosis with an overall survival of weeks to months in the absence of treatment. Radiation therapy modalities include whole brain radiation therapy (WBRT) and stereotactic radiosurgery (SRS). WBRT delivers a relatively low dose of radiation, has neurocognitive sequelae, and has not been investigated for its immunostimulatory effects. Furthermore, WBRT exposes the entire intracranial tumor immune microenvironment to radiation. SRS delivers a high dose of conformal radiation with image guidance to minimize dose to surrounding normal brain tissue, and appears to promote anti-tumor immunity. In parallel with many of these discoveries, immune checkpoint inhibitors (ICIs) have demonstrated a survival advantage in multiple malignancies commonly associated with brain metastases (e.g., melanoma). Combination SRS and ICI are theorized to be synergistic in anti-tumor immunity directed to brain metastases. The purpose of this review is to explore the synergy of SRS and ICIs, including pre-clinical data, existing clinical data, and ongoing prospective trials.

182 Background: The purpose of this study was to examine the associations of three different measures of anxiety and depression with patient reported distress (PRD) level and survival after radiotherapy (RT). Methods: 518 patients who underwent RT between 2012 and 2016 were included in this retrospective study. PRD was assessed at the time of RT using the NCCN thermometer and a 30 question survey of distress related items. PRD and clinical and demographic data was retrospectively collected and analyzed. The three measures this study focused on that assessed patient anxiety and depression involved asking patients about their level of concern regarding feeling down, regarding loss of interest, and regarding feeling nervous. Associations between baseline patient characteristics and survival after start of RT were evaluated using single variable Cox proportional hazards regression models. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated. Associations of level of concern regarding patient anxiety/depression with survival after RT were evaluated using single variable and multivariable Cox proportional hazards regression models. Results: Overall, PRD level and concern regarding anxiety/depression were positively correlated (p < 0.001). Additionally, there was a significant association between level of concern regarding feeling down and palliative patients (p = 0.03). There was also a significant association between level of concern regarding loss of interest and palliative patients (p = 0.03), with level of concern highest for thorax, breast, and head and neck. There was also a significant different between level of concern regarding feeling nervous and gender (p = 0.05). There was not a significant difference between any of the three measures and survival after RT (all p ≥ 0.21). Conclusions: Anxiety and depression in patients receiving palliative and curative RT was associated with overall distress. Baseline screening of PRD may identify patients who would benefit from intervention to address the causes of their underlying anxiety and depression.

Objective: High GATA2 expression has been associated with an increased risk of poor clinical outcomes after radical prostatectomy; however, this has not been studied in relation to risk of biochemical recurrence (BCR) after salvage radiation therapy (SRT) for recurrent prostate cancer after radical prostatectomy. Our aim was to evaluate the association between protein expression levels of GATA2 in primary prostate cancer tumour samples and the risk of BCR after SRT. Methods: 109 males who were treated with SRT were included. The percentage of cells with nuclear staining and GATA2 staining intensity were both measured. These two measures were multiplied together to obtain a GATA2 H-score (range 0–12) which was our primary GATA2 staining measure. Results: In unadjusted analysis, the risk of BCR was higher for patients with a GATA2 H-score >4 (hazard ratio = 2.04, p = 0.033). In multivariable analysis adjusting for SRT dose, pre-SRT PSA, pathological tumour stage and Gleason score, this association weakened substantially (hazard ratio = 1.45, p = 0.31). This lack of an independent association with BCR appears to be the result of correlations between GATA2 H-score >4 and higher pre-SRT PSA (p = 0.021), higher Gleason score (p = 0.044) and more severe pathological tumour stage (p = 0.068). Conclusion: Higher levels of GATA2 expression appear to be a marker of prostate cancer severity; however, these do not provide independent prognostic information regarding BCR beyond that of validated clinicopathological risk factors. Advances in knowledge: A higher GATA2 expression level appears to be correlated with known measures of prostate cancer severity and therefore is likely not an independent marker of outcome after SRT.

764 Background: Psychosocial distress screening and assessment in patients with gastrointestinal (GI) cancers has an established importance due to the distress experienced during and post treatment. GI cancer patients receiving radiotherapy (RT) for curative or palliative measures were reviewed in order to determine if there was a relationship between patient reported distress (PRD) and survival. Methods: Patients at our institution who receive external beam RT for GI cancers completed a 30 question PRD survey that also included a linear analog measure of overall distress, the National Comprehensive Cancer Network (NCCN) Distress Thermometer, which ranged from 1 (low overall distress) to 10 (high overall stress) at the start of and/or during treatment. Each question on the PRD questionnaire concentrated on a possible cause of distress. It allowed patients to rate distress levels for each question from 1 to 5 (1 being the least distressed and 5 being the most distressed), and also overall distress according. The reported clinical results of the PRD questionnaire were retrospectively reviewed in patients receiving RT for GI cancers from Jan 2012 to Aug 2015. Patients were considered distressed if their overall PRD score was 5 or greater (PRD+) or not distressed (PRD-) if their score was 4 or under. Overall survival between PRD+ and PRD- was compared using the Kaplan-Meier method. Results: PRD surveys were completed by 134 consecutive patients, 67 (50%) male and 67 (50%) female within 30 days of starting RT. The median age was 65 years (range 28 to 93). The top histological finding was adenocarcinoma, 90 patients (60%). 113 (84%) received chemotherapy and 64 (48%) underwent surgery. 102 (75%) treatments were curative and 32 (25%) were palliative. Overall NCCN distress thermometer results ranged from 0 to 10, with a median of 4. Median follow-up was 2.7 years. Distressed patients (PRD+) had inferior survival to those not distressed (PRD-) at 2 years, 52% vs. 72%, p

E18084 Background: Patient reported distress (PRD) is well recognized in cancer patients receiving treatment; regrettably, it is not always assessed in clinical practice. The failure to assess PRD might affect treatment, decrease patient’s quality of life (QoL), increase burden of suffering, and increases health care costs. Patients receiving palliative RT usually have a severe disease that requires an intervention to help ease symptom burden, especially pain. Methods: All RT patients in our clinic are asked to complete a PRD survey during treatment course. PRD forms consist of 30 categorical questions that assess distress subscales. Patients have the option to rate each question from 1 (low distress) to 5 (high distress). The survey also includes the National Comprehensive Cancer Network distress thermometer, which allows patients to rate overall distress level from 0 (no distress) to 10 (extreme distress). Patients’ records were retrospectively reviewed to abstract the needed information to assess survivorship. Results: 270 patients were included from March 2012-May 2015. Overall PRD was analyzed as a continuous and a categorical variable (low: 0-3, moderate: 4-6, high: 7-10). A correlation was noted in moderate distress category (RR: 1.51, P = 0.034), however, this was not noted in high distress category (RR: 1.25, P = 0.33). Age (P: 0.079) and primary site (P = 0.022) had the strongest correlation with survival. However, when combining patients with a moderate or high distress level, we observed a significantly increased risk of death compared to patients with low distress in single variable analysis (RR: 1.45, P = 0.046). This finding weakened slightly in multivariable analysis and was no longer quite significant (RR: 1.43, P = 0.066). Conclusions: This study suggests that 64% of patients receiving palliative RT were under moderate to severe distress that affected their QoL The results provide evidence that patients who have a score of 4 or higher on the patient reported distress level questionnaire have poorer survival after palliative RT. This finding was statistically significant without adjustment for potentially confounding variables, however was no longer quite significant after such multivariable adjustment.

88 Background: There is not yet a consensus on the efficacy and safety of IMRT for the treatment of patients with esophageal carcinomas. We report on our experience with outcomes and toxicity with IMRT for these patients. Methods: Fifty-five patients with esophageal carcinoma were treated with IMRT at our institution from 12/2008 and 12/2014. Medical records were retrospectively reviewed. All patients received concurrent chemotherapy (majority 5-FU with oxaliplatin). Thirty-one (56%) patients underwent surgery. Fifty (91%) received 50.4 Gy in 28 fractions. Seventy-three percent of cases were adenocarcinoma. Regions include mid-thoracic (15%), lower thoracic (64%), and GE junction (22%). Clinical uT-stages were as follows: T1 (2%), T2 (20%), T3 (69%), and T4a (5%). Clinical N-stages were as follows: N0 (33%), N1 (53%), N2 (13%), and N3 (2%). Results: Median follow-up for all patients was 15 months (1.5 - 64.5) and 25.5 months (1.5 - 64.5) for patients who were alive at follow-up (n = 31). Fifty-one (93%) patients completed RT. Of the 31 patients who underwent surgery, 9 (29%) were found to have a complete pathologic response. Site of first recurrence was local (n = 2, 4%), regional (n = 3, 6%), and distant (n = 14, 26%). At 12 and 24 months, overall survival was 72% and 58%, freedom from recurrence was 78% and 65%, and freedom from distant recurrence was 78% and 68%. On univariate analysis, improved OS was noted with patients who underwent surgery (RR 0.29) or were cN0 (RR 0.27). Twenty eight patients (51%) experienced > / = CTCAE v.4grade 3 acute toxicity; notable were hematologic (n = 14, 25%), esophagitis (n = 6, 11%), acute coronary event (n = 1, 2%), and post-chemoRT pneumonia (n = 1, 2%). Fifteen patients (31%) experienced > grade 3 late toxicity; notable were esophageal stricture (n = 7, 14%), post-op pneumonia (n = 3, 6%), post-CRT pneumonia (n = 2, 4%), and COPD exacerbation (n = 1, 2%). Conclusions: Patient receiving IMRT with concurrent chemotherapy for esophageal carcinomas have good LC rates, with or without surgery. Majority of patients are able to finish treatment with acceptable rates of late toxicity. Patient who underwent surgery or were cN0 had better OS.