Clinical outcomes in borderline and locally advanced pancreatic cancer with the addition of low-dose-rate brachytherapy to standard of care therapy

PURPOSE

Surgical resection remains the only curative therapy for pancreatic cancer. Unfortunately, many patients have borderline or unresectable disease at diagnosis due to proximity of major abdominal vessels. Neoadjuvant chemotherapy and radiation are used to down-stage, however, there is a risk that there will be a positive/close surgical margin. The CivaSheet is a low-dose-rate (LDR) brachytherapy device placed at the time of surgery to target the area of highest risk of margin positivity. The purpose of this study is to assess the clinical value of brachytherapy in addition to standard-of-care therapy in pancreatic therapy.

METHODS AND MATERIALS

Between 2017 and 2022 patients with borderline and locally advanced pancreatic cancer treated with neoadjuvant chemotherapy and radiation followed by surgical resection were included. There were 2 cohorts of patients: (1) Those who had the LDR brachytherapy device placed at the time of surgery and (2) those who did not. Sixteen of 19 (84%) patients who had brachytherapy were enrolled in a prospective clinical trial (NCT02843945). Patients were matched for comorbidities, cancer staging, and treatment details. The primary outcome was progression-free survival (PFS).

RESULTS

Thirty-five patients were included in this analysis, 19 in the LDR brachytherapy group and 16 in the comparison cohort. The 2-year PFS was 21% vs. 0% (p = 0.11), 2-year OS was 26% vs. 13% (p = 0.43), and the pancreatic cancer cause-specific survival was 84% vs. 56% (p = 0.13) in favor of the brachytherapy patients.

CONCLUSIONS

Use of LDR brachytherapy at the time of resection shows a trend towards improved progression free and overall survival for patients with borderline or locally advanced pancreatic cancer treated with neoadjuvant chemoradiation.

Prognostic Effect of Mismatch Repair Status in Early-Stage Endometrial Cancer Treated With Adjuvant Radiation: A Multi-institutional Analysis

PURPOSE

The aim of this work was to report the effect of mismatch repair (MMR) status on outcomes of patients with stage I-II endometrioid endometrial adenocarcinoma (EEC) who receive adjuvant radiation therapy.

METHODS AND MATERIALS

This is a multi-institutional retrospective cohort study across 11 institutions in North America. Patients with known MMR status and stage I-II EEC status postsurgical staging were included. Overall survival (OS) and recurrence-free survival (RFS) rates were estimated via the Kaplan-Meier method. Univariable and multivariable analyses were performed via Cox proportional hazard models for RFS and OS. Statistical analyses were conducted using SPSS version 27.

RESULTS

In total, 744 patients with a median age at diagnosis of 65 years (IQR, 58-71) were included. Most patients were White (69.4%) and had Federation of Obstetrics and Gynecology 2009 stage I (84%) and Federation of Obstetrics and Gynecology grade 1 to 2 (73%). MMR deficiency was reported in 234 patients (31.5%), whereas 510 patients (68.5%) had preserved MMR. External beam radiation therapy with or without vaginal brachytherapy was delivered to 186 patients (25%), whereas 558 patients (75%) received vaginal brachytherapy alone. At a median follow-up of 43.5 months, the estimated crude OS and RFS rates for the entire cohort were 92.5% and 84%, respectively. MMR status was significantly correlated with RFS. RFS was inferior for MMR deficiency compared with preserved MMR (74.3% vs 88.6%, P < .001). However, no difference in OS was seen (90.8% vs 93.2%, P = .5). On multivariable analysis, MMR deficiency status was associated with worse RFS (hazard ratio, 1.86; P = .001) but not OS.

CONCLUSIONS

MMR status was independently associated with RFS but not OS in patients with early-stage EEC who were treated with adjuvant radiation therapy. These findings suggest that differential approaches to surveillance and/or treatment based on MMR status could be warranted.

Utilizing a novel hybrid brachytherapy technique FINITO (Freehand Interstitial Needles in addition to Tandem and Ovoid) for locally advanced cervical cancer

PURPOSE

We aimed to assess the clinical feasibility and advantages of using a novel hybrid brachytherapy technique by placing Freehand Interstitial Needles in addition to the Tandem and Ovoid applicator (FINITO) for the treatment of locally advanced cervical cancer (LAC).

METHODS AND MATERIALS

A retrospective analysis was performed on two cohorts of patients with LACC treated at our institution: 29 patients in the FINITO group and 17 patients in the control group using T&O only approach. Clinical outcomes of interest included local control (LC), progression-free survival (PFS), overall survival (OS), and rates of acute and late toxicities. Kaplan-Meier methodology was used to estimate OS, PFS, and LC. Wilcoxon signed-rank test was used to compare the median values for dosimetry parameters. A p-value of ≤ 0.05 was considered statistically significant. All statistical analyses were performed using RStudio.

RESULTS

At a median of 2 years there was no difference in rates of OS, PFS or LC between the FINITO and the control group of patients. The 2-year OS, PFS, and LC for the FINITO group were 59% (95% CI 34%-100%), 58% (95% CI 38%-89%), and 84% (95% CI 69%-100%), respectively. Late toxicities were significantly lower in the FINITO group for both gastrointestinal and genitourinary symptoms (p = 0.001 and 0.01, respectively) as compared to the T&O group.

CONCLUSION

Based on the equivalent LC rate and lower toxicity profile, our FINITO technique appears to be an excellent alternative to the standard intracavitary brachytherapy in patients with advanced disease, especially in resource-limited settings.

Direction Modulated Brachytherapy Tandem Model Applicators for Treatment Planning of Multi-Institutional Cervical Cancer Cases

PURPOSE/OBJECTIVE(S)

Direction Modulated Brachytherapy (DMBT) offers a means of utilizing an anisotropic source to create more conformal dose distributions when integrated with image-guided adaptive brachytherapy (IGABT). Authors sought to validate the implementation of nine unique six-channeled, MRI-compatible, novel DMBT tandem applicators of varying physical dimensions within Varian's BrachyVision® (v16.1) treatment planning system (BV-TPS).

MATERIALS/METHODS

A total of 110 retrospective clinically delivered high-dose-rate (HDR) cervical cancer brachytherapy plans, from three institutions, were re-planned for each of the nine DMBT tandem models within the BV-TPS, using the latest VEGO® inverse optimization algorithm, with dose heterogeneity accounted for through AcurosBV®. Plans consisted of both intracavitary (77 plans) and interstitial (33 plans) cases with an average prescription dose and high-risk clinical target volumes (CTVHR) of 607±113 cGy and 26.96±14.95 [range 6.70-69.58] cm3, respectively. During re-planning, the conventional tandems were replaced by one of the nine DMBT tandem models while leaving ovoids or rings, and needles (if present), in place. A two-step inverse optimization process was performed such that the lowest possible organs at risk (OAR) D2cc doses could be achieved while 1) keeping equivalent target coverage (ΔCTVHR-D90 to within ±0.5%) and, at the same time, 2) maintaining the general pear-shape dose distribution of the original plans.

RESULTS

Noteworthy improvements in plan quality were achieved by all nine DMBT tandem models, which are presented in Table 1. Irrespective of the model, about ∼50 cGy reduction in D2cc across all OARs appear feasible. There is also a general trend of D2cc reductions' magnitude becoming smaller as the CTVHR volume increased due to loss in modulation at distance. Additionally, D2cc reductions in terms of EQD2 [Gy] were calculated assuming each re-plan was delivered throughout the course of treatment, which includes the external beam radiotherapy dose of 45 Gy and showed significant reductions of -6.29±4.38 Gy, -3.80±2.06 Gy, and -4.86±3.02 Gy for the bladder, rectum, and sigmoid, respectively, for DMBT model #9 for example.

CONCLUSION

We have successfully incorporated nine DMBT tandem models into a commercial TPS and re-planned 110 cases, to a total of 990 plans. All nine DMBT tandem models were each able to generate notable D2cc reductions to OARs (∼50 cGy), without compromising target coverage, across plans from multiple institutions with various clinical/optimization practices. The results indicate both a promising impact and smooth integration of DMBT tandem technology into modern clinical IGABT workflow.

How the Underlying Etiology of Cirrhosis Impacts Response to SBRT

PURPOSE/OBJECTIVE(S)

In the US, incidence rates of hepatocellular carcinoma (HCC) have more than tripled and death rates have doubled since 1980. In 2022, it is expected for 41,260 new cases to be diagnosed with 30,520 deaths. Many etiologies contribute to the development of HCC including alcoholic cirrhosis, cryptogenic cirrhosis, HCV, HBV, NASH, and genetic disorders like hereditary hemochromatosis. An increasing number of patients are not candidates for curative options such as resection or transplant and the role of alternative liver directed as therapies has increased. SBRT has emerged as a safe and effective option, but there is little known about the outcomes related to the etiology of the HCC. The purpose of this study is to characterize the rates of toxicity and efficacy between different HCC etiologies in patients who were treated with SBRT.

MATERIALS/METHODS

A single institutional database was compiled of all patients with HCC who were treated with SBRT. Patients with HCC etiologies of HCV, alcoholic cirrhosis, or NASH cirrhosis who received SBRT and monitored with liver function tests and imaging (MRI or CT) and were not transplanted were included Demographic information, disease etiology, all treatment courses, lab values, radiologic response, and follow-up were collected on all patients. SPSS was used to analyze the data.

RESULTS

Consecutive patients (n = 37, 43 courses of radiation) who received SBRT between 2013- January 2022 were included. Most patients were male (n = 32, 86.5%) and average age was 64.73 ± 7.42 years (range: 50-82 years). A majority of patients had either HCV or HCV and alcoholic cirrhosis (n = 28, 75.7%) and there were no baseline difference in child Pugh score, tumor size, or number of prior treatments. Most patients were treated with 50Gy/5 fx (n = 26, 70.3%) with 5 others being treated with 45Gy/5fx to meet mean liver constraints. Most patients had a decrease in ALT (n = 22, 59.5%) while almost half of patients had a decrease in AFP (n = 14, 48.3%) at average follow-up of 11.84 ± 5.35 months. There was a significant correlation between HCC etiology and change in bilirubin with patients with HCV being more likely to have increases in total bilirubin (χ2 (6) = 17.5, p < 0.01).

CONCLUSION

Patients with HCV induced cirrhosis may be more fragile and have a significant increased risk of toxicity after SBRT based on total bilirubin changes. Most patients did have a decrease in ALT showing potential for some improvement in liver function with SBRT. However, almost half of patients have some biologic efficacy with SBRT independent of HCC etiology. Further studies should include looking at the biologic differences in the etiologies and what treatment liver-directed therapies may be best for each population.

Direction Modulated Brachytherapy Tandem Model Applicators for Treatment Planning of Multi-Institutional Cervical Cancer Cases: Removing Needles in Intracavitary-Interstitial Techniques

PURPOSE/OBJECTIVE(S)

To evaluate the potential of nine direction modulated brachytherapy (DMBT) tandem applicator models of various designs to obviate the need for needles during intracavitary-interstitial (IC-IS) cervical cancer brachytherapy.

MATERIALS/METHODS

A cohort of 33 retrospective clinical high dose-rate (HDR) brachytherapy plans, from three institutions, were re-planned with Varian's BrachyVision® (v16.1) treatment planning system (BV-TPS), using the latest VEGO® inverse optimization algorithm, with dose heterogeneity accounted for through the AcurosBV® model-based dose calculation algorithm. All plans consisted of IC-IS cases, with a range of 2-4 freehand-loaded needles, with an average prescription dose of 706±54 cGy and average high-risk clinical target volume (HRCTV) of 36.0±17.4 [range 9.8-69.6] cm3. Nine novel DMBT tandem models of varying physical dimensions were integrated for the first time into the BV-TPS, with thicknesses (4-8 mm). During re-planning, the conventional tandems and all of the needles were replaced by one of the nine DMBT tandem models while leaving the ovoids/rings in place. An optimization process was performed such that the lowest possible organs at risk (OAR) D2cc doses could be achieved while keeping equivalent target coverage (ΔHRCTV-D90 to within ±0.5%) and maintaining a pear-shape dose distribution. The process was repeated for each of the nine DMBT tandem models resulting in (33 × 9 =) 297 plans.

RESULTS

Average ΔHRCTV-D90 was +0.35±0.39% (+2.8±3.1 cGy). OAR D2cc reductions were achieved by all models for all plans. The performance of the thickest DMBT model (8 mm) was the best in terms of achieving the lowest D2cc for all OARs, with 31 out of 33 plans (94%) achieving lower D2cc doses for all three OARs. The two cases in which the D2cc doses could not be reduced had HRCTV volumes ranging between 50 cm3 and 60 cm3. Additionally, D2cc reductions in terms of EQD2 [Gy] were calculated assuming each re-plan was delivered throughout the entire course of a patient's treatment, which included the external beam radiotherapy dose of 45 Gy, showed significant reductions of -2.64±2.67 Gy, -1.65±1.97 Gy, and -2.80±2.20 Gy for bladder, rectum, and sigmoid, respectively.

CONCLUSION

According to the results, it is clinically feasible to replace the conventional IC-IS cases, with 2-4 freehand-loaded needles, with the DMBT tandem technology, effectively avoiding the need for needle involvement.

Prognostic Impact of Mismatch Repair Deficiency on Stage I-II Endometrioid Endometrial Cancer Treated with Adjuvant Radiation Therapy: A Multi-Institutional Analysis

PURPOSE/OBJECTIVE(S)

To report the impact of mismatch repair (MMR) status on outcomes in patients with stage I-II endometrioid endometrial cancer (EEC).

MATERIALS/METHODS

This is a multi-institutional retrospective cohort study across 11 institutions. Preliminary data from 7 centers is available for analysis. Patients with known MMR status and stage I-II EEC status post-surgical staging treated with adjuvant radiation therapy were included. Overall survival (OS) and recurrence-free survival (RFS) rates were estimated by the Kaplan-Meier method. Univariate and multivariate analyses were performed by Cox proportional hazard models for OS/RFS. Statistical analyses were conducted using statistical software.

RESULTS

A total of 573 patients with median age at diagnosis of 65 years (Interquartile Range (IQR) 58-71) were eligible. Most patients were White (79%), had FIGO 2009 Stage I (89.7%) and FIGO grade 1-2 (74.7%). MMR deficiency (dMMR) was reported in 191 patients (33%) while 382 patients (67%) had preserved MMR (pMMR). External beam radiation therapy (EBRT) +/- vaginal brachytherapy (VBT) was delivered to 124 patients (21.6%) while 449 patients (78.4%) received VBT alone. After a median follow-up of 41 months ((IQR) 28-60 months), the estimated OS and RFS rates for the entire cohort were 95.1% and 85%, respectively. On univariate analysis, age >65 (p < 0.001), grade 3 (p < 0.001), presence of lymphovascular space invasion (LVSI) (p = 0.039) and deep myometrial invasion (p = 0.03) were associated with worse OS. The OS was inferior in the dMMR group, however, it did not reach significance (92% vs 96.1%, p = 0.06). On multivariate analysis, older age (p < 0.001) and grade 3 (p = 0.002) were the only predictors for worse OS. On univariate analysis for RFS, age >65 (p = 0.02), grade 3 (p = 0.018) and dMMR (72.9% vs 91%, p < 0.001) were associated with worse RFS. On multivariate analysis, age >65 (p = 0.015) and dMMR (p < 0.001) were significant predictors of worse RFS.

CONCLUSION

Preliminary data from 7 out of 11 participating institutions showed that dMMR status leads to significantly decreased RFS in patients with early-stage EEC. While awaiting the results of NRG GYN020 and RAINBO prospective trials, this large study suggests that treatment intensification could be warranted in patients with dMMR early-stage EEC.

Identification and Management of Radiation-Induced Premature Ovarian Failure

PURPOSE/OBJECTIVE(S)

Premature ovarian failure (POF) is the dysfunction of ovarian follicles resulting in amenorrhea before the natural age of menopause. For women with locally advanced cervical cancer (LACC), POF is caused by chemoradiation due to the cytotoxic effects of radiation on the ovary. The diagnosis is confirmed with an FSH level in the postmenopausal range. The recommendation is for all patients with POF to take hormone replacement therapy (HRT) through the average age of natural menopause (age 50-51). The goal of this study is to determine how POF was managed in a large cohort of premenopausal women with LACC receiving pelvic RT.

MATERIALS/METHODS

We retrospectively reviewed medical charts of premenopausal patients who underwent RT for LACC at an academic hospital from 2010 to 2020. Data regarding the type and duration of RT, demographics, and survival was obtained. The following data points were obtained from clinic notes documented after radiation treatment started: FSH levels, estradiol levels, menstrual history, menopausal symptoms. Additionally, data regarding HRT initiation was extracted, including the type of HRT and the department of the prescribing provider. Descriptive analysis was performed to determine the frequency of each variable of interest including patient characteristics, receipt hormone therapy, type of hormone therapy and menopausal symptoms.

RESULTS

A total of 45 premenopausal patients treated for locally advanced cervical cancer with a median age of 39 (range 22- 50 years) were included. 51% (n = 23) of the patients were started on hormone therapy either during or post radiation treatment. 20 patients had documented menopausal symptoms. Most frequently reported symptoms included hot flashes (80%), fatigue (25%) and anxiety (15%). Most (78%) women received combination oral contraceptive pills (OCP) and some also received an estrogen patch/cream. 38% (n = 7) of patients started the HRT post RT while 61% (11) patients started during RT treatment. Of the available data, HRT was prescribed by a radiation oncologist 39% of the time and a gynecologic oncologist 35% of the time.

CONCLUSION

The onset of POF was identified clinically by the onset of hypo-estrogen vasomotor symptoms. FSH levels were not routinely checked prior to prescribing HRT. The most commonly prescribed HRT was the combination oral contraceptive pill, which was prescribed and managed by both radiation oncologists and gynecologic oncologists. Our study illustrates the need for a standardized method to routinely assess the onset of POF while undergoing radiation treatment. With frequent follow-ups, radiation oncologists have the opportunity to identify early signs POF and provide adequate treatment. Additional studies are needed to evaluate if patients initiated and maintained HRT for the recommended length of time.

Combining Novel Direction Modulated Brachytherapy Tandem-and-Ovoids Applicators for Treatment Planning of Multi-Institutional Cervical Cancer Cases: Removing Needles in Intracavitary-Interstitial Techniques

PURPOSE/OBJECTIVE(S)

Lack of standard guidelines for optimal needle insertion during high-dose-rate (HDR) intracavitary-interstitial (IC-IS) brachytherapy of the cervix means a sophisticated and technical skillset of inserting needles next to IC applicators must be developed to enhance plan quality. This study sought to evaluate the performance of two separate direction modulated brachytherapy (DMBT) tandem applicators used in conjunction with one set of novel DMBT ovoids, uniquely designed to effectively obviate the need for IS needles.

MATERIALS/METHODS

A cohort of 32 retrospective clinical HDR brachytherapy plans, from three institutions, were re-planned with Varian's BrachyVision® (v16.1) treatment planning system (BV-TPS), using the latest VEGO® inverse optimization algorithm, with dose heterogeneity accounted for through the AcurosBV®. All plans consisted of IC-IS cases, with a range of 2-4 freehand-loaded needles, with an average prescription dose of 709±53 cGy, and with an average high-risk clinical target volume (HRCTV) of 36.73±17.15 [range 9.8-69.6] cm3. Two DMBT tandem models of 5.4-mm and 8.0-mm thicknesses along with a novel DMBT ovoids design, introduced for the first time, with 9 equi-angled grooves and 10-mm-diameter thickness. During re-planning, the conventional tandems, ovoids/rings, and all of the needles were replaced by one of the two DMBT tandem models and a set of DMBT ovoids. A two-step inverse optimization process was performed to achieve the lowest possible OAR D2cc doses while 1) keeping equivalent target coverage (ΔHRCTV-D90 to within ±0.5%) and 2) maintaining the general pear-shape dose distribution used by the original plans. For all plans, this process was repeated using each of the two DMBT tandem-and-ovoids combinations for a total re-planning of (32×2 =) 64 cases.

RESULTS

On average, -47.15±29.61 (-40.40±34.90) cGy, -42.98±26.58 (-41.70±27.40) cGy, and -40.47±25.05 (-32.55±25.30) cGy reductions in D2cc across bladder, rectum, and sigmoid, respectively, were achieved for the 8-mm (5.4-mm) DMBT tandem-and-ovoids combinations while the average ΔHRCTV-D90 was +4.3±2.9 cGy (+0.5%±0.4%). Additionally, D2cc reductions in terms of EQD2 [Gy] were calculated and showed significant reductions of -4.05±2.47 (-3.37±2.83) Gy, -2.71±1.79 (-2.59±1.74) Gy, and -3.27±1.96 (-2.65±2.06) Gy for bladder, rectum, and sigmoid, respectively with an average net increase in total dwell times of 241.0±87.6 seconds at the luxury of avoiding IS needle insertions.

CONCLUSION

It is clinically feasible to obviate the need for IS needles by incorporating the DMBT tandem-and-ovoids while producing lower OAR D2cc doses and maintaining equivalent target coverage.

Radiation Oncology Virtual Education Rotation (ROVER) 2.0 for Residents: Implementation and Outcomes

The COVID-19 pandemic catalyzed the integration of a virtual education curriculum to support radiation oncologists in training. We report outcomes from Radiation Oncology Virtual Education Rotation (ROVER) 2.0, a supplementary virtual educational curriculum created for radiation oncology residents globally. A prospective cohort of residents completed surveys before and after the live virtual webinar sessions (pre- and post-surveys, respectively). Live sessions were structured as complex gray-zone cases across various core disease sites. Resident demographics and responses were summarized using means, standard deviations, and proportions. Nine ROVER sessions were held from October 2020 to June 2021. A total of 1487 registered residents completed the pre-survey, of which 786 attended the live case discussion and 223 completed post-surveys. A total of 479 unique radiation oncology residents (of which 95, n = 19.8%, were international attendees) from 147 institutions (national, n = 81, 55.1%; international, n = 66, 44.9%) participated in the sessions. There was similar participation across post-graduate year (PGY) 2 through 5 (range n = 86 to n = 105). Of the 122 unique resident post-surveys, nearly all reported learning through the virtual structure as "very easy" or "easy" (97.5%, n = 119). A majority rated the ROVER 2.0 educational sessions to be "valuable or "very valuable" (99.2%, n = 121), and the panelists-attendee interaction as "appropriate" (97.5%, n = 119). Virtual live didactics aimed at radiation oncology residents are feasible. These results suggest that the adoption of the ROVER 2.0 curricula may help improve radiation oncology resident education.

Sociodemographic and Clinical Factors Associated With Radiation Treatment Nonadherence and Survival Among Rural and Nonrural Patients With Cancer

PURPOSE

Cancer treatment nonadherence is associated with higher rates of cancer recurrence and decreased survival. Rural patients with cancer experience a 10% higher mortality rate compared with their nonrural counterparts; geographic differences in nonadherence may contribute to this increased mortality. The goal of this study was to assess for geographic disparities and determine sociodemographic and clinical factors associated with radiation therapy (RT) nonadherence and survival among rural and nonrural patients with cancer.

METHODS AND MATERIALS

We examined cancer registry, medical records, and billing claims data at a safety net academic medical center. Geographic residence was defined as rural versus nonrural by US Department of Agriculture 2013 Rural-Urban Continuum Codes. Other factors assessed were age, sex, race, marital status, insurance type, employment, area median household income, residential distance to cancer treatment center, clinical stage, cancer type, treatment modality, total radiation dose received, and radiation dose per fraction. We used Cox proportional hazards modeling to examine 7 ways of operationalizing nonadherence and selected the definition that resulted in the best model fit statistics and prediction of mortality. Overall survival rates were estimated with the Kaplan-Meier method. We then examined nonadherence as the main exposure along with additional covariates in least absolute shrinkage and selection operator penalized survival analyses and as the outcome in our multivariable generalized linear regression analyses predicting nonadherence. We considered 2-way interaction terms with the main exposure, geographic residence.

RESULTS

We identified 3,077 patients with cancer who averaged 62 years old, were 59% female, 34% Black, and 14% rural. Twenty-two percent of patients missed at least 2 fractions and missed an average of 10% of their treatment plan. Rural patients experienced a higher mortality rate than nonrural patients (53% vs 42%, P < .0001). Survival was assessed through December 31, 2021, with a mean follow-up of 4.5 years. Proportion of missed fractions as the indicator of nonadherence provided the best model fit statistics and prediction of survival. Marital status, employment status, tumor, nodes, metastases stage, cancer type, and age at diagnosis significantly affected survival, in addition to a treatment delay by geographic residence interaction effect. Specifically, patients residing in rural areas who experienced a treatment delay were more than twice as likely to die as nonrural residents who also experienced a treatment delay, and nearly twice as likely to die as rural residents who did not experience a treatment delay. The 2-year survival rate was 76% for nonrural residents who did not experience a treatment delay versus 27% for rural residents who experienced a treatment delay. Patients who were widowed, had stage 4 cancer, or lung cancer were more likely to be nonadherent. Finally, patients residing in rural areas who experienced a treatment delay were more likely to subsequently be nonadherent.

CONCLUSIONS

In a geographically and racially diverse population, RT nonadherence is a significant concern that affects survival, yet it is a modifiable risk factor. We demonstrated that rural residence was associated with both RT nonadherence and poorer overall survival. Rural patients with a treatment delay had the lowest overall survival, compared with both nonrural survivors and rural survivors without delay. Rural residents who are delayed in starting treatment are at heightened risk for poor outcomes and should receive targeted support to mitigate the observed disparities. Additional patient populations that may benefit from targeted treatment adherence support include widowed patients and those with stage 4 cancer or lung cancer.

The Impact of Racial Disparities on Outcome in Patients With Stage IIIC Endometrial Carcinoma: A Pooled Data Analysis

OBJECTIVE

To report the impact of race on clinical outcomes in patients with stage IIIC endometrial carcinoma.

MATERIALS AND METHODS

A retrospective multi-institutional study included 90 black and 568 non-black patients with stage IIIC endometrial carcinoma who received adjuvant chemotherapy and radiation treatments. Overall survival (OS) and recurrence-free survival (RFS) were calculated by the Kaplan-Meier method. Propensity score matching (PSM) was conducted. Statistical analyses were conducted using SPSS version 27.

RESULTS

The Median follow-up was 45.3 months. black patients were significantly older, had more nonendometrioid histology, grade 3 tumors, and were more likely to have >1 positive paraaortic lymph nodes compared with non-black patients (all P <0.0001). The 5-year estimated OS and RFS rates were 45% and 47% compared with 77% and 68% for black patients versus non-black patients, respectively ( P <0.001). After PSM, the 2 groups were well-balanced for all prognostic covariates. The estimated hazard ratios of black versus non-black patients were 1.613 ( P value=0.045) for OS and 1.487 ( P value=0.116) for RFS. After PSM, black patients were more likely to receive the "Sandwich" approach and concurrent chemoradiotherapy compared with non-black ( P =0.013) patients.

CONCLUSIONS

Black patients have higher rates of nonendometrioid histology, grade 3 tumors, and number of involved paraaortic lymph nodes, worse OS, and RFS, and were more likely to receive the "Sandwich" approach compared with non-black patients. After PSM, black patients had worse OS with a nonsignificant trend in RFS. Access to care, equitable inclusion on randomized trials, and identification of genomic differences are warranted to help mitigate disparities.

PARP inhibitors in the treatment of ARID1A mutant ovarian clear cell cancer: PI3K/Akt1-dependent mechanism of synthetic lethality

Introduction

Poly(ADP-ribose) polymerase (PARP) is a nuclear enzyme involved in the repair of DNA single-strand breaks (SSB). The recent development of poly(ADP-ribose) polymerase inhibitors (PARPi) results from over 45 years of studies. When the activity of PARP1 or PARP2 is compromised, DNA SSB lesions are unresolved and can be converted to DNA double-strand breaks (DSBs) by the cellular transcription mechanisms. ARID1A (also called BAF250a) is an important component of the mammalian Switch/Sucrose Non-Fermentable (SWI/SNF) chromatin-remodeling complex. ARID1A gene demonstrates >50% of mutation rate in ovarian clear-cell carcinomas (OCCC). Mutated or downregulated ARID1A significantly compromises the Homologous Recombination Repair (HRR) of DNA DSB.

Results

The present study demonstrated that downregulated or mutated ARID1A attenuates DNA HRR through stimulation of the PI3K/Akt1 pathway and makes tumor cells highly sensitive to PARPi and PARPi/ionizing radiation (IR) combination. We showed that PI3K/Akt1 pathway plays an important role in the sensitization of cancer cell lines with compromised function of ARID1A to PARPi treatment.

Discussion

We believe that using of PARPi monotherapy or in combination with radiation therapy is an appealing strategy for treating ARID1A-mutated cancers, as well as many other types of PI3K/Akt1-driven cancers.

Radiation Oncology Education Collaborative Study Group Annual Spring Symposium: Initial Impact and Feedback

The Radiation Oncology Education Collaborative Study Group (ROECSG) is an international collaborative network of radiation oncology (RO) professionals with the goal of improving RO education. This report summarizes the first two ROECSG annual symposia including an overview of presentations and analysis of participant feedback. One-day symposia were held in June 2018 and May 2019. Programs included oral and poster presentations, RO education leadership perspectives, and keynote addresses. Post-symposia surveys were collected. Research presentations were recorded and made available online. The 2018 symposium was had 36 attendees from 25 institutions in three countries. The 2019 symposium had 76 individuals from 41 institutions in five countries. Attendees represented diverse backgrounds including attending physicians (46%), residents (13%), medical students (14%), physicists (2%), nurses (1%), and program coordinators (1%). Fifty-five oral presentations were given with 53 released online. Ninety percent of attendees rated the symposium as improving their knowledge of RO educational scholarship, 98% felt the symposium provided the opportunity to receive feedback on RO education scholarship, and 99% felt that the symposium fostered the development of collaborative RO education projects. ROECSG was rated higher than professional organizations in fostering educational scholarship (p<0.001). All attendees felt that the symposium produced new RO education scholarship ideas and provided unique networking opportunities. The first two ROECSG symposia drew a diverse population of attendees and provided unique opportunities for presentation of RO education scholarship. Future ROECSG symposia will be designed to enhance opportunities to present RO education scholarship and to facilitate networking.

Transitioning Roles from Residency to Attending Physician in Radiation Oncology

Moving from the role of resident into that of a young attending is one of the most anticipated transitions in a medical trainee's career path. Radiation oncology residency training is typically apprentice-style focused in the outpatient setting, which carries additional unique challenges. Twenty-seven junior attendings at academic institutions within their first 5 years of practice were sent an online open-ended questionnaire in 2018 regarding aspects of their practice using a snowball sampling method. Responses were collected, and a thematic analysis was conducted in which two independent reviewers coded the responses. Nineteen junior attendings (70%) from 18 institutions completed the questionnaire. General themes included the importance of cultivating relationships for peer support and to be professional and polite as confidence was gained to enable them to be seen as an attending. All respondents felt that bringing an open mind, balance, and adaptability was crucial in their transition. Respondents stayed up to date on literature and practices by subscribing to journals, courses, and participation in resident education. Forty-two percent of young attendings were matched with a mentor at their new institution through a formal mentor-mentee relationship. Respondents wished that they had more autonomy during residency to prepare for independent practice. Transitioning from residency to a junior attending provides unique stressors and challenges. Allowing for residents to have more autonomy during their training, such as a senior resident clinic, may help improve this transition by providing an opportunity for independent decision-making with guidance as appropriate.

Investigation of Isotoxic Dose Escalation and Plan Quality with TDABC Analysis on a 0.35 T MR-Linac (MRL) System in Ablative 5-Fraction Stereotactic Magnetic Resonance-Guided Radiation Therapy (MRgRT) for Primary Pancreatic Cancer

This study investigates plan quality generated by an MR-Linac (MRL) treatment planning system (TPS) for 5-fraction stereotactic body radiation therapy (SBRT) of primary pancreatic cancer (PCa). In addition, an isotoxic dose escalation was investigated with the MRL TPS based on stereotactic MR-guided adaptive radiation therapy (SMART) trial constraints. A clinical workflow was developed for adaptive and non-adaptive treatments with the MRL, on which a time-driven activity-based costing (TDABC) analysis was performed to quantify clinical efficacy. Fifteen PCa patients previously treated with a conventional Linac were retrospectively re-planned for this study. Three plans were generated for each patient using the original prescription dose (PD) and organ at risk (OAR) constraints (Plan 1), following SMART trial's OAR constraints but with the original PD (Plan 2), starting with Plan 2, following an isotoxic dose escalation strategy where the dose was escalated until any one of the SMART trial's OAR constraints reached its limit (Plan 3). Conformity index (CI) and the ratio of the 50% isodose volume to PTV (R50%) conformity metrics were calculated for all 45 MRL plans, in addition to standard dose-volume indices. Forty-five MRL plans were created which met their respective dosimetric criteria described above. For Plan 1, the MRL TPS successfully achieved equivalent or lower OAR doses while maintaining the prescribed PTV coverage for the 15 plans. A maximum dose to the small bowel was reduced on average by 4.97 Gy (range: 1.11-10.58 Gy). For Plan 2, the MRL TPS successfully met all SMART trial OAR constraints while maintaining equivalent PTV coverage. For Plan 3, the MRL TPS was able to escalate the prescription dose from the original 25-33 Gy by, on average, 36 Gy (range: 15-70 Gy), and dose to the PTV was successfully escalated to at least 50 Gy for all 15 plans. These achievements were made possible, in part, due to the omission of the ITV afforded by the MRL's real-time target tracking technology and sharper dose penumbra due to its unique dual-focus MLC design. The 0.35T MRL TPS can generate plans that are equivalent to conventional Linac-based plans for SBRT of PCa. Through analyzing Plan 2 and 3 strategies, and due to the real-time target localization capabilities of the MRL system, increased OAR sparing and/or target dose escalation are possible.

Education in gynecological brachytherapy

Brachytherapy is an essential component in the curative treatment of many gynecological malignancies. In the past decade, advances in magnetic resonance imaging and the ability to adapt and customize treatment with hybrid interstitial applicators have led to improved clinical outcomes with decreased toxicity. Unfortunately, there has been a shift in clinical practice away from the use of brachytherapy in the United States. The decline in brachytherapy is multifactorial, but includes both a lack of exposure to clinical cases and an absence of standardized brachytherapy training for residents. In other medical specialties, a clear relationship has been established between clinical case volumes and patient outcomes, especially for procedural-based medicine. In surgical residencies, simulation-based medical education (SBME) is a required component of the program to allow for some autonomy before operating on a patient. Within radiation oncology, there is limited but growing experience with SBME for training residents and faculty in gynecological brachytherapy. This review includes single institutional, multi-institutional and national initiatives using creative strategies to teach the components of gynecological brachytherapy. These efforts have measured success in various forms; the majority serve to improve the confidence of the learners, and many have also demonstrated improved competence from the training as well. The American Brachytherapy Society launched the 300 in 10 initiative in 2020 with a plan of training 30 competent brachytherapists per year over a 10 year period and has made great strides with a formal mentorship program as well as externships available to senior residents interested in starting brachytherapy programs. Moving forward, these curricula could be expanded to provide standardized brachytherapy training for all residents. SBME could also play a role in initial certification and maintenance of certification. Given the burden of disease, it would be valuable to develop similar training for providers in low and middle income countries.

Does Prophylactic Paraortic Lymph Node Irradiation Improve Outcomes in Women With Stage IIIC1 Endometrial Carcinoma?

PURPOSE

To evaluate the impact of prophylactic paraortic lymph node (PALN) radiation therapy (RT) on clinical outcomes in patients with International Federation of Obstetrics and Gynecology 2018 stage IIIC1 endometrial cancer (EC).

METHODS AND MATERIALS

A multi-institutional retrospective study included patients with International Federation of Obstetrics and Gynecology 2018 stage IIIC1 EC lymph node assessment, status postsurgical staging, followed by adjuvant chemotherapy and RT using various sequencing regimens. Overall survival (OS) and recurrence-free survival (RFS) rates were estimated by the Kaplan-Meier method. Univariable and multivariable analysis were performed by Cox proportional hazard models for RFS/OS. In addition, propensity score matching was used to estimate the effect of the radiation field extent on survival outcomes.

RESULTS

A total of 378 patients were included, with a median follow-up of 45.8 months. Pelvic RT was delivered to 286 patients, and 92 patients received pelvic and PALN RT. The estimated OS and RFS rates at 5 years for the entire cohort were 80% and 69%, respectively. There was no difference in the 5-year OS (77% vs 87%, P = .47) and RFS rates (67% vs 70%, P = .78) between patients treated with pelvic RT and those treated with pelvic and prophylactic PALN RT, respectively. After propensity score matching, the estimated hazard ratios (HRs) of prophylactic PALN RT versus pelvic RT were 1.50 (95% confidence interval, 0.71-3.19; P = .28) for OS and 1.24 (95% confidence interval, 0.64-2.42; P = .51) for RFS, suggesting that prophylactic PALN RT does not improve survival outcomes. Distant recurrence was the most common site of first recurrence, and the extent of RT field was not associated with the site of first recurrence (P = .79).

CONCLUSIONS

Prophylactic PALN RT was not significantly associated with improved survival outcomes in stage IIIC1 EC. Distant metastasis remains the most common site of failure despite routine use of systemic chemotherapy. New therapeutic approaches are necessary to optimize the outcomes for women with stage IIIC1 EC.

Introductory patient communication training for medical physics graduate students: Pilot experience

Despite medical physics becoming a more patient‐facing part of the radiation oncology team, medical physics graduate students have no training in patient communication. An introductory patient communication training for medical physics graduate students is presented here. This training exposes participants to foundational concepts and effective communication skills through a lecture and it allows them to apply these concepts through realistic simulated patient interactions. The training was conducted virtually, and eight students participated. The impact of the training was evaluated based on changes in both confidence and competence of the participants’ patient communication skills. Participants were asked to fill out a survey to assess their confidence on communicating with patients before and after the training. They also underwent a simulated patient interaction pre‐ and postlecture. Their performance during these was evaluated by both the simulated patient actors and the participants themselves using a rubric. Each data set was paired and analyzed for significance using a Wilcoxon rank‐sum test with an alpha of 0.05. Participants reported significantly higher confidence in their feeling of preparedness to interact with patients (mean = 2.38 vs. 3.88, p = 0.008), comfort interacting independently (mean = 2.00 vs. 4.00, p = 0.002), comfort showing patients they are actively listening (mean = 3.50 vs. 4.50, p = 0.005), and confidence handling challenging patient interactions (mean = 1.88 vs. 3.38, p = 0.01), after the training. Their encounter scores, as evaluated by the simulated patient actors, significantly increased (mean = 77% vs. 91%, p = 0.022). Self‐evaluation scores increased, but not significantly (mean = 62% vs. 68%, p = 0.184). The difference between the simulated patient and self‐evaluation scores for the postinstruction encounter was statistically significant (p = 0.0014). This patient communication training for medical physics graduate students is effective at increasing both the confidence and the competence of the participants in the subject. We propose that similar trainings be incorporated into medical physics graduate training programs prior to students entering into residency.

Integrating Radiation Oncology Into Undergraduate Medical Education

Cancer is one of the most important public health problems. However, medical education has not advanced at the same rate when it comes to cancer education. Currently, the United States Medical Licensing Examination subject examinations do not cover radiation oncology, prevention, and survivorship planning in its assessment model. Incorporating medical oncology and radiation oncology training into the undergraduate medical education curriculum can have a significant benefit in training future physicians. In this paper, we review current literature and propose some ideas that can help incorporate oncology, and specifically radiation oncology, into undergraduate medical education.

Why an Increasing Number of Unmatched Residency Positions in Radiation Oncology? A Survey of Fourth-Year Medical Students

Purpose

The number of US fourth-year medical students applying to radiation oncology has decreased during the past few years. We conducted a survey of fourth-year medical students to examine factors that may be influencing the decision to pursue radiation oncology.

Methods and Materials

An anonymous online survey was sent to medical students at 9 participating US medical schools.

Results

A total of 232 medical students completed the survey. Of the 153 students who stated they were never interested in radiation oncology, 77 (50%) reported never having been exposed to the specialty as their reason for not pursuing radiation oncology. The job market was the most commonly cited factor among students who said they were once interested in but ultimately chose not to pursue radiation oncology. Conversely, the recent low pass rates for board examinations and a perception of a lack of diversity within radiation oncology had the least influence.

Conclusions

Despite discussion of potential measures to address this disquieting trend, there have been minimal formal attempts to characterize and address potential causes of a decreasing interest in radiation oncology. This study's data are consistent with previous research regarding the trend of decreased medical student interest in radiation oncology and may be used as part of ongoing introspective assessment to inform future change within radiation oncology.

Interprofessional Image Verification Workshop for Physician and Physics Residents: A Multi-Institutional Experience

PURPOSE

Verification of patient position through pretreatment setup imaging is crucial in modern radiation therapy. As treatment complexity increases and technology evolves, physicist-physician collaboration becomes imperative for safe and successful radiation delivery. Despite the importance of both, residency programs lack formal interprofessional education (IPE) activities or structured training for image verification. Here we show the impact of an interprofessional image verification workshop for residents in a multi-institutional setting.

METHODS

The workshop included a lecture by the attending physicist and physician, and hands-on image registration practice by learners (medical physics residents, MP; and radiation oncology residents, RO). All participants filled out pre- and postactivity surveys and rated their comfort from 1 to 10 in (A) selecting what type of imaging to order for a given case and (B) independently assessing the setup quality based on imaging. A paired 1-tailed t test (α = 0.05) was used to evaluate significance; Spearman rank correlation coefficient was used to assess correlation of ratings and RO postgraduate year (PGY). Surveys had free-response questions about IPE and image verification activities in residency.

RESULTS

A total of 71 residents from 7 institutions participated between 2018 and 2020. Pre- and postsurveys were completed by 50 residents (38RO, 12MP) and showed an increase in (A) from 5.5 ± 2.2 to 7.1 ± 1.6 (P < .001) and in (B) from 5.1 ± 2.3 to 6.8 ± 1.5 (P < .001), with significant increases per subgroup (A_{Δ, RO} = 1.8 ± 1.7, P < .001; B_{Δ, RO} = 1.9 ± 1.8, P <. 001; A_{Δ, MP} = 1.1 ± 1.4, P = .012; B_{Δ, MP} = 1.2 ± 1.6, P = .016). RO confidence scores moderately correlated with PGY. Survey responses indicated that image verification training is mostly unstructured, with extent of exposure varying by program and attending; most with little-to-no training. Time constraints were identified as the main barrier. IPE was noted as a useful way to incorporate different perspectives into the process.

CONCLUSIONS

Formal image verification training increases resident comfort with setup imaging review and provides opportunities for interprofessional collaboration in radiation oncology residency programs.

The Radiation Oncology Education Collaborative Study Group 2020 Spring Symposium: Is Virtual the New Reality?

PURPOSE

Because of the COVID-19 pandemic, the Radiation Oncology Education Collaborative Study Group (ROECSG) hosted its annual international symposium using a virtual format in May 2020. This report details the experience of hosting a virtual meeting and presents attendee feedback on the platform.

METHODS AND MATERIALS

The ROECSG symposium was hosted virtually on May 15, 2020. A postsymposium survey was distributed electronically to assess attendee demographics, participation, and experience. Attendee preference and experience were queried using 3-point and 5-point Likert-type scales, respectively. Symplur LLC was used to generate analytics for the conference hashtag (#ROECSG).

RESULTS

The survey was distributed to all 286 registrants, with a response rate of 67% (191 responses). Seventeen nonattendee responses were omitted from this analysis, for a total of 174 included respondents. Eighty-two attendees (47%) were present for the entire symposium. A preference for a virtual symposium was expressed by 78 respondents (45%), whereas 44 (25%) had no preference and 52 (30%) preferred an in-person meeting. A total of 150 respondents (86%) rated the symposium as "extremely" well organized. Respondents who had not attended a prior in-person ROECSG symposium were more likely to prefer the virtual format (P = .03). Seventy-eight respondents (45%) reported a preference for the virtual platform for reviewing scholarly work, and 103 (59%) reported a preference for an in-person platform for networking. On the day of the symposium, #ROECSG had 408 tweets and 432,504 impressions.

CONCLUSIONS

The 2020 ROECSG symposium was well received and can serve as a framework for future virtual meetings. Although the virtual setting may facilitate sharing research, networking aspects are more limited. Effort is needed to develop hybrid virtual and in-person meetings that meet the needs of participants in both settings. Social media is a significant avenue for dissemination and discussion of information and may be valuable in the virtual setting.

A new development in ultrasound-compatible gynecologic brachytherapy simulators

PURPOSE

Gynecologic brachytherapy is an essential component in the curative treatment of cervical cancer. With the decline in brachytherapy utilization, gynecologic brachytherapy simulators are being used to provide a mechanism to enhance proficiency-based resident training. However, most models that have been used lack procedural fidelity as they are either repurposed from OB/GYN basic models or from physics phantoms. Therefore, we set out to develop a high-fidelity, ultrasound- and CT-compatible gynecologic brachytherapy training simulator.

METHODS AND MATERIALS

Based on prior experience with gynecologic training simulators on the market, we developed a wish list for an ultrasound-compatible brachytherapy training model. A custom simulator was developed based on an existing pelvic ultrasound trainer. Features included a cervical os and endometrial canal as well as a palpable and hypoechoic cervical tumor.

RESULTS

The model took about 3 months from the initial meeting with the developer to completion. The properties of the material were equivalent to water for ultrasound, CT, and also MRI and the model did not show signs of degradation after multiple tandem insertions.

CONCLUSIONS

A high-fidelity ultrasound-compatible simulator was effectively developed and utilized to improve resident training to perform brachytherapy implants with a derivative benefit in the long term of improving survival for women with advanced gynecologic malignancies through having access to more proficient brachytherapists. Future directions include enhancing the model to allow for repetitive needle insertion and suturing for interstitial training as well as creating variations in anatomy (e.g., retroverted uterus, bulky tumors, etc.) for more advanced technical training.

Acute extraperitoneal spontaneous bladder rupture in cervical cancer patient undergoing chemoradiation: A case report and review of the literature

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Spontaneous bladder ruptures have only been reported intraperitoneally, and years after the cessation of therapy.

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Extraperitoneal bladder rupture can occur with radiation therapy in treatment of cervical cancer.

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Improved reporting of toxicity is needed to identify types of genitourinary toxicity seen with modern chemoradiation.

The standard of care for locally advanced cervical cancer is pelvic radiotherapy with sensitizing cisplatin, and intracavitary brachytherapy. This standard of care treatment paradigm has best survival outcomes, however is associated with genitourinary toxicities. Spontaneous bladder rupture (SBR) is a rare complication of chemoradiation that has only been reported in literature as an intraperitoneal rupture occurring years after the cessation of treatment. We herein present a novel case of extraperitoneal SBR in a 27-year-old female with FIGO Stage IIIC cervical cancer and no prior surgical history who was undergoing chemoradiation with sensitizing cisplatin. During her final planned brachytherapy treatment upon instilling the bladder under ultrasound guidance, an anterior midline extraperitoneal rupture was noted. She was managed conservatively for several weeks and during this time was ultimately able to complete her external beam therapy and last cycle of cisplatin. After approximately ten weeks of conservative management, imaging demonstrated complete resolution of the rupture. A review of the literature suggests this complication tends to occur as an intraperitoneal rupture years after the cessation of therapy. Late genitourinary complications and types of complications are rarely reported in clinical trials, so it is difficult to determine the true incidence of rare complications and identify patients that may be at risk.

Increasing Medical Student Engagement Through Virtual Rotations in Radiation Oncology

Corona virus disease 2019 (COVID-19) affected medical student clerkships and education around the country. A virtual medical student clerkship was created to integrate didactic education with disease specific lectures for medical students, contouring, and hands on learning with telehealth. Twelve medical students in their 3rd and 4th year were enrolled in this 2 week elective from April 27, 2020 to June 5, 2020. There was significant improvement of overall knowledge about the field of radiation oncology from pre elective to post elective (P < .001). Feedback included enjoying direct exposure to contouring, telehealth, and time with residents. Overall this 2 week rotation was successful in integrating radiation oncology virtually for medical students. This is now being expanded to multiple institutions as an educational resource and future rotations for medical students.

Image-Guided Gynecologic Brachytherapy for Cervical Cancer

The incorporation of magnetic resonance imaging in brachytherapy has resulted in an increased use of interstitial catheters in order to create a comprehensive treatment plan that covers the visualized tumor. However, the insertion with passive, image-guidance requires estimating the location of the tumor during the insertion process, rather than visualizing and inserting the catheters directly to the desired location under active tracking. In order to treat residual disease, multiparametric MR sequences can enhance the information available to the clinician. The precision availed by MR-guided brachytherapy results in substantial improvements in needle positioning, and resulting treatment plans.

The vaginal cylinder: Misunderstood, misused, or trivial? An in-depth dosimetric and multiinstitutional outcome investigation

PURPOSE

The purpose of the study was to investigate the impact on dose distribution and radiobiological metrics of common high-dose-rate vaginal brachytherapy treatment parameters and to analyze multiinstitutional data for clinically significant impact on outcomes in early-stage endometrial cancer.

METHODS AND MATERIALS

Treatment plans were created for all combinations of prescription parameters and used to quantify the dosimetric impact of each parameter and to estimate the dose delivered using common voxel-integrated radiobiological metrics. A rating system, based on risk grouping from GOG and PORTEC trials, was used to consolidate staging information into a cancer "aggressiveness" measure. Correlations between the rating, toxicity, disease recurrence, and plan parameters were investigated.

RESULTS

When prescribing to 5 mm depth, the variation caused by the diameter was very large across all dose metrics, ranging from 51% to 175% increase with the most divergence in BED_max. For surface prescription, changing the cylinder diameter from 4 cm to 2 cm caused the dose metrics of BED_min, D_min, and gBEUD (a = -3) to increase by 117%, 67%, and 52%, respectively. Prescription to 5-mm depth caused changes across all dose metrics of 260% compared with surface prescription for a 2-cm cylinder. Deeper prescription point (p = 0.005) and longer treatment length (p = 0.01) were correlated with increased stenosis rates. No correlation between recurrence and any plan parameter was found.

CONCLUSIONS

Dramatic differences in dose distributions arise by small variations of plan parameters, with large impact on rates of vaginal stenosis, but no clear relation with local recurrence. To help radiation oncologists interpret the magnitude of these effects for their patients, we created a tool that allows comparison between dose and fractionation parameters.

Co-occurring substance use disorder: The impact on treatment adherence in women with locally advanced cervical cancer

The purpose of this study was to identify the prevalence of substance use disorder and its association with adherence to treatment and survival in locally advanced cervical cancer patients treated with primary radiation therapy. This is a retrospective case series of locally advanced cervical cancer patients with substance use disorder in a single academic institution treated with radiation therapy between 2005 and 2016. Substance use disorder was identified through chart review. Those with substance use disorder were compared to those without in regards to demographics, Charlson comorbidity index, treatment details and outcomes. Of the 129 patients with locally advanced cervical cancer, 16 (12.4%) were identified as having substance use disorder. Patients with substance use disorder were younger (42.1 years vs 51.5 years, p = .013) and more likely to be smokers (81.3% vs 42.5%, p = .004). The majority of patients with substance use disorder received concurrent chemotherapy (93.8%) and brachytherapy in addition to external beam radiation therapy (81.3%). There was no significant difference in days to completion of radiation therapy between patients with and without substance use disorder. Radiation dose received, toxicities and survival were similar between groups. Among cervical cancer patients receiving treatment with radiation therapy, substance use disorder was not associated with poorer adherence, longer radiation treatment times or a difference in total dose of radiation received. Our experience demonstrates that patients with substance use disorder are able to adhere to complex, multimodal treatment plans resulting in similar cancer specific outcomes compared to patients without substance use disorder.

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Substance abuse disorder is common among locally advanced cervical cancer patients.

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Treatment adherence is similar in patients with and without substance use disorder.

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Treatment plan should not be altered based on a substance use disorder comorbidity.

Adjuvant radiation therapy for T4 non-rectal colon adenocarcinoma provides a cause-specific survival advantage: A SEER database analysis

PURPOSE

While there is no level 1 evidence supporting the use of adjuvant radiotherapy (RT) for non-rectal colon cancer in the modern chemotherapy era, there are studies that suggest a local control benefit. This treatment modality is not part of standard treatment recommendations, and we hypothesized that adjuvant RT provides a benefit in locally advanced disease. Due to the limited number who receive post-operative RT, a national database was searched to provide sufficient power.

MATERIALS AND METHODS

A retrospective analysis using the Surveillance, Epidemiology, and End Results (SEER) database was performed. Inclusion criteria were: non-rectal colon cancer, AJCC 6th or 7th edition T4 and M0, oncologic resection, and 1st cancer site. Patients were excluded for RT prior to or during surgery, or if the sequence of RT was unknown. Using a Cox proportional hazard model, the relative risk of cause-specific mortality for "RT after surgery" versus "No RT" was calculated.

RESULTS

21,789 patients were identified who met the inclusion criteria. Of these, only 1001 received adjuvant RT, and 64% were node-positive (53% RT vs. 65% no RT). When comparing RT vs. no RT, after adjusting for sex, age, N stage, and grade, we determined the relative risk of death from cancer was 0.8849 (95% CI: 0.8008-0.9779; p = 0.0165), suggesting that only 14 patients with T4 disease need receive adjuvant radiation to spare a cancer-related death.

CONCLUSIONS

Adjuvant RT is not routinely utilized for definitive treatment of T4 non-rectal colon cancer, but this analysis shows a significant cause-specific survival benefit.

The long-lasting relationship of distress on radiation oncology-specific clinical outcomes

Purpose

The diagnosis and treatment of cancer can have significant mental health ramifications. The National Comprehensive Cancer Network currently recommends using a distress screening tool to screen patients for distress and facilitate referrals to social service resources. Its association with radiation oncology–specific clinical outcomes has remained relatively unexplored.

Methods and materials

With institutional review board approval, National Comprehensive Cancer Network distress scores were collected for patients presenting to our institution for external beam radiation therapy during a 1-year period from 2015 to 2016. The association between distress scores (and associated problem list items and process-related outcomes) and radiation oncology–related outcomes, including inpatient admissions during treatment, missed treatment appointments, duration of time between consultation and treatment, and weight loss during treatment, was considered.

Results

A total of 61 patients who received either definitive (49 patients) or palliative (12 patients) treatment at our institution and completed a screening questionnaire were included in this analysis. There was a significant association between an elevated distress score (7+) and having an admission during treatment (36% vs 11%; P = .04). Among the patients treated with definitive intent, missing at least 1 appointment (71% vs 26%; P = .03) and having an admission during treatment (57% vs 10%; P = .009) were significantly associated with our institutional definition of elevated distress. We found no correlation between distress score and weight loss during treatment or a prolonged time between initial consult and treatment start.

Conclusions

High rates of distress are common for patients preparing to receive radiation therapy. These levels may affect treatment compliance and increase rates of hospital admissions. There remains equipoise in the best method to address distress in the oncology patient population. These results may raise awareness of the consequences of distress among radiation oncology patients. Specific interventions to improve distress need further study, but we suggest a more proactive approach by radiation oncologists in addressing distress.