Association between Tumor Volume Change on MRI with Surgical Margin Status, Pathological Response, and Local Control Following Pre-Operative Radiation Therapy for Soft Tissue Sarcoma

PURPOSE/OBJECTIVE(S)

The clinical significance of radiographic progression during pre-operative radiation therapy (RT) for soft tissue sarcoma (STS) remains unclear. We sought to evaluate associations between radiographic change on T1 post-contrast (T1c) and T2 weighted magnetic resonance imaging (MRI) with percent pathological response (PR%), positive surgical margins (+SM), and local control (LC).

MATERIALS/METHODS

We retrospectively identified patients with STS undergoing neoadjuvant RT who had both pre- and post-RT MRI prior to surgical resection. Gross tumor volumes were contoured on pre- and post-RT T1c and T2 MRI sequences and relative change in volume from baseline was calculated. Radiographic classification was defined as response (>30% reduction), progression (>30% increase), or stable (≤30% reduction or ≤30% increase). Chi squared, Fishers Exact, and Kruskal Wallis (KW) tests were used to assess differences between groups. Linear and binary logistic regression models used to assess associations between MRI response and PR% and +SM, respectively. LC was modeled with Kaplan Meier methods and log rank tests.

RESULTS

A total of 68 STS patients were identified, with a median follow up of 49 months (range 7-229). With a median age of 60.5 years (25-88) and tumor size of 10.8cm (2.7-25.7), the most common histologies were undifferentiated pleomorphic sarcoma (UPS; 32.4%) and myxoid liposarcoma (ML; 16.2%), and were primarily grade 2-3 disease (89.7%). With a median RT dose of 50 Gy in 25 fractions (44-60Gy), the median radiographic volume change was 2% (-86.4 to 953.6%) and -2.1% (-89.6 to 962.5%) for T1c and T2, respectively. Radiographic classification of response/stable/progression was 25.4%/49.2%/25.4% and 27.9%/52.5%/19.7% for T1c and T2, respectively. Histology (ML vs. UPS) and grade (1 vs. 3) were predictors for radiographic response on both T1c (72.7% vs 18.8%, p = 0.03 and 71.4% vs. 10.4%, p = 0.03) and T2 (71.5% vs. 18.2%, p = 0.02 and 71.4% vs. 14.6%, p = 0.002), respectively. With 6 +SM (8.8%), the rate of +SM for response/stable/progression was 20%/10.3%/0% in T1c (p = 0.2) and 5.9%/12.5%/0% in T2 (p = 0.5). As a continuous variable, neither relative change on T1c (p = 0.2) or T2 (p = 0.4) were associated with +SM. With an overall median PR% of 64% (0-100%), the median PR% was significantly different for response/stable/progression for both T1c (95%/42%/73%, p = 0.02) and T2 (95%/50%/87.5%, p = 0.04). Radiographic change on neither T1c (p = 0.4) or T2 (p = 0.5) were associated with PR% on a continuous basis. With a total of 4 local recurrences, there was no significant difference in LC by radiographic classification on either T1c (p = 0.65) or T2 (p = 0.85).

CONCLUSION

While radiographic response may be correlated with pathological response, radiographic progression on either T1c or T2 following neoadjuvant RT was not associated with a detriment in surgical margins or local control. These findings suggest that STS radiographic "pseudoprogression" is not associated with worse outcome.

Teaching Trainees to be Effective Mentors: A Needs-Based Assessment in Radiation Oncology

PURPOSE/OBJECTIVE(S)

Mentorship plays a critical role in the training and career development of medical trainees. Teaching-the-teacher workshops for residents translate to higher long-term job satisfaction and improved patient communication skills. Further, near-peer mentorship has been associated with increased job satisfaction and patient care experience. Resident-as-mentors can add benefit to the mentorship networks of students, particularly in resource-limited environments, while benefiting residents' own mentorship relations and career satisfaction. We hypothesized that residents would desire to be a mentor, but would lack specific skills needed for effective mentoring of students in radiation oncology.

MATERIALS/METHODS

A multi-institution, cross-sectional study was conducted among residents in the Radiation Oncology Education Collaborative Study Group (ROECSG) Graduate Medical Education working group from 06/2022-10/2022. Participants completed the Mentorship Competency Assessment (MCA), a validated 26-item questionnaire, scored on a Likert scale from 0-7 (0: most unprepared with mentorship skill, 7: most prepared with mentorship skill). The primary endpoint was the average score in individual mentorship skills among participants. Kruskal-Wallis test assessed associations between total MCA score (range 0-182) and demographics.

RESULTS

A total of 36 of 39 participants (92% response rate) responded. A majority were male (58%), from a residency size >10 (75%), and P Gy-2/3 (52%). Most had no formal training in teaching (86%) or mentorship (89%). Many believed they would be a good mentor to students on a rotation (89%), but most felt they would benefit from a formal mentorship program (92%). From the MCA, the mentorship skills residents felt most unprepared for were: coordinating effectively with other mentors (3.4/7), helping mentees acquire resources (3.6/7), negotiating a path to professional independence with mentees (3.6/7), helping mentees network effectively (3.7/7), and working with mentees to set clear expectations of the mentoring relationship (3.9/7). The mentorship skills residents felt most prepared for were: acknowledging mentees' professional contributions (5.6/7), establishing a relationship based on trust (5.6/7), active listening (5.5/7), building mentees' confidence (4.9/7), and working effectively with mentees with personal backgrounds differing from one's own (4.8/7). Higher MCA scores were associated with former training in mentorship (p = 0.0143), and a trend for former training in teaching (p = 0.0525), but was not associated with sex (p = 0.5986), residency size (p = 0.1415), or P Gy-year (p = 0.9747).

CONCLUSION

Residents are interested in mentorship training and report unpreparedness in several important skills. Future work should focus on formal training and assessment of mentoring skills for residents.

Hypofractionated Accelerated Radiation Dose-Painting (HARD) vs. Standard Radiotherapy for Unresected Soft-Tissue Sarcoma

PURPOSE/OBJECTIVE(S)

Conventionally fractionated radiotherapy (CFRT) offers modest local control (LC) for unresected soft tissue sarcoma (STS). Although STS has a low α/β (∼2 - 6) that may benefit from a hypofractionated radiotherapy regimen, it is often limited due to the toxicity risk to surrounding organs. A simultaneous integrated boost to gross disease (2.5 - 3 Gy/fraction), with lower doses to the intermediate and low risk target volume, may offer a safe isotoxic dose escalation approach. We hypothesize that this hypofractionated accelerated radiotherapy dose-painting (HARD) will improve local control compared to CFRT.

MATERIALS/METHODS

We performed a single institution retrospective analysis of patients who received external beam radiotherapy with definitive intent (≥50 Gy) for unresected STS. CFRT was defined as 1.8 - 2 Gy/fraction (Gy/fx). HARD regimens consisted of 60 - 66 Gy at 3 Gy/fx or 70 Gy at 2.5 Gy/fx to gross disease, with 1.8 - 2.4 Gy/fx to intermediate and low risk regions. All anatomical sites and histologies were included. Local control (LC) was defined from date of current diagnosis, estimated by Kaplan-Meier methods via log-rank tests or Cox regression for univariate analysis (UVA), when appropriate. Cox regression multivariate analysis (MVA) included regimen, biological effective dose (α/β 6; BED6), lesion size, age, and grade.

RESULTS

We identified 77 patients with primary and metastatic STS treated with HARD (n = 40) or CFRT (n = 37) between 1990 and 2022, with a median follow up of 24 months in surviving patients. The mean dose for CFRT and HARD are 56.8 Gy (50 - 77.4 Gy) and 64.9 Gy (60 - 70 Gy), respectively. HARD was comprised of 65% for 3 Gy/fx and 35% for 2.5 Gy/fx regimens. At the time of RT, grade 3 (69%) and extremity (39%) tumors were the most common. Tumor histology was very heterogenous across both cohorts, with undifferentiated pleomorphic sarcoma being the most common for HARD (33%) and CFRT (19%). HARD was more often utilized in stage IV patients (55% vs. 19%, p = 0.001) and had a higher mean BED6 (96 vs. 74.2 Gy, p < 0.001) than CFRT, but without differences in age (67 vs. 59 years), tumor size (8 vs. 10 cm), concurrent chemotherapy (35% vs. 30%), Karnofsky performance status (86 vs. 85), follow-up (19 vs. 28 months), and grade (all p > 0.1). On UVA, there was a LC benefit associated with higher BED6 (HR 0.94, 95% CI 0.9 - 0.98, p = 0.002) and the HARD regimen (2-year LC 95% vs. 62%, p < 0.001). On MVA, only HARD (HR 0.07, 95% CI 0.006 - 0.729, p = 0.027) was independently associated with LC.

CONCLUSION

Although the HARD regimen and higher BED6 were both associated with significant improvement in LC, only the HARD regimen independently associated with a local control benefit for unresected STS. These results suggest biologic dose-intensification exploiting the low α/β of STS with an isotoxic hypofractionated regimen may be a favorable strategy for unresectable STS. Future prospective studies are necessary to validate these findings.

TEAMRO: TEAching Mentorship in Radiation Oncology, a Multicenter Prospective Phase 2 Intervention Study on Teaching Mentorship Skills to Residents Working with Medical Students

PURPOSE/OBJECTIVE(S)

While formal curriculum on resident teaching have been associated with improved career growth and sustained positive impact on patient care, mentorship skills are rarely taught in academic medicine. We hypothesized that a formalized resident mentorship curriculum coupled with a near-peer resident-medical student mentoring program would improve resident career growth.

MATERIALS/METHODS

A multi-institutional, prospective, phase 2 intervention study, approved by each participating center's institutional review board, was conducted from 4/2022-10/2022 among interested residents in the Radiation Oncology Education Collaborative Study Group Graduate Medical Education. Intervention included: 1) a 4-week mentorship curriculum (utilizing a Six Steps approach) composed of self-guided readings, didactic lecture, and 30-minute faculty check-in, and 2) a formalized 1:1 resident-medical student mentorship program during an existing radiation oncology sub-internship with weekly meetings. Resident participants completed the Mentorship Competency Assessment (MCA), a 26-item validated survey on mentorship skills in medicine scored from 0 (most unprepared) to 7 (most prepared) before and after the intervention. The primary endpoint was average change in MCA skill from pre- to post-intervention survey, with score ranges from -7 (a decrease in 7 points) to +7 (an increase of 7 points).

RESULTS

A total of 8 residents participated and all completed pre- and post-intervention surveys. Most residents were PGY-4/5 (75%), from programs with >10 residents (68%), and did not have prior training in teaching (88%) or mentorship (88%). Residents met students on average twice weekly (range 1-3) for an average of 2 hours a week (range 1-5). After the program, most residents felt confident in being a future mentor to students (100%), their overall well-being was positively impacted (63%), and their mentorship relationships were positively impacted (50%). All 26 mentorship skills increased on MCA after intervention (average +1.3/7 per skill). Skills that showed greatest improvement were helping mentees network effectively (+2.6/7), acquire resources (+2.1/7), negotiate a path to professional independence (+2.0/7), set career goals (+1.8/7), and balance work and personal life (+1.7/7). Skills that showed least improvement were establishing a relationship based on trust (+0.4/7), identifying and accommodating different communication styles (+0.6/7), providing constructive feedback (+0.7/7), and aligning mentor-mentee expectations (+0.8/7).

CONCLUSION

The formalized mentorship program improved mentorship skills among residents, translating to increased satisfaction in residents' own mentorship relations and overall well-being. Further studies are needed to assess the sustainability of these skills, as well as impact on career growth and satisfaction.

Effects of exogenous amylolytic or fibrolytic enzymes inclusion on in vitro fermentation of lactating dairy cow diets in a dual-flow continuous-culture system

The objective of this study was to determine the effects of including exogenous amylolytic or fibrolytic enzymes in a diet for high-producing dairy cows on in vitro ruminal fermentation. Eight dual-flow continuous-culture fermentors were used in a replicated 4 × 4 Latin square. The treatments were control (CON), a xylanase and glucanase mixture (T1), an α-amylase mixture (T2), or a xylanase, glucanase, and α-amylase mixture (T3). Treatments were included at a rate of 0.008% of diet dry matter (DM) for T1 and T2 and at 0.02% for T3. All treatments replaced the equivalent amount of soybean meal in the diet compared with CON. All diets were balanced to have the same nutrient composition [30.2% neutral detergent fiber (NDF), 16.1% crude protein (CP), and 30% starch; DM basis], and fermentors were fed 106 g/d divided into 2 feedings. At each feeding, T2 was pipetted into the respective fermentor and an equivalent amount of deionized water was added to each fermentor to eliminate potential variation. Experimental periods were 10 d (7 d for adaptation and 3 d for sample collection). Composite samples of daily effluent were collected and analyzed for volatile fatty acids (VFA), NH₃-N, and lactate concentrations, degradability of DM, organic matter, NDF, CP, and starch, and flow and metabolism of N. Samples of fermentor contents were collected from each fermentor at 0, 1, 2, 4, 6, and 8 h after feeding to determine kinetics of pH, NH₃-N, lactate, and VFA concentrations over time. All data were analyzed using PROC GLIMMIX of SAS (SAS Institute Inc.), and the repeated variable of time was included for kinetics measurements. Treatment did not affect mean pH, degradability, N flow and metabolism, or the concentrations of VFA, NH₃-N, or lactate in the effluent samples. Treatment did not affect pH, acetate:propionate ratio, or the concentrations of lactate, NH₃-N, total VFA, acetate, propionate, butyrate, isobutyrate, valerate, or caproate. However, the concentration of total VFA tended to change at each time point depending upon the treatment, and T2 tended to have a greater proportion of 2-methylbutyrate and isovalerate than CON, T1, or T3. As 2-methylbutyrate and isovalerate are branched-chain VFA that are synthesized from branched-chain amino acids, T2 may have an increased fermentation of branched-chain amino acids or decreased uptake by fibrolytic microorganisms. Although we did not observe changes in N metabolism due to the enzymes, there could be changes in microbial populations that utilize branched-chain VFA. Overall, the tested enzymes did not improve in vitro ruminal fermentation in the diet of high-producing dairy cows.

Abstract P4-08-15: Locoregional recurrence in invasive breast cancer and association with tumor infiltrating leukocyte (TIL) presence

Background:

The presence of TILs has been correlated with clinical outcomes and response to therapy in breast cancer. However, evaluation of TILs in breast cancer has largely been based on pathologic examination of tumor samples. Here, we report the relationship between invasive breast cancer locoregional recurrence (LRR) and the presence of TILs estimated by transcriptomic analysis with the deconvolution algorithm CIBERSORT.

Methods:

Patients were identified from an IRB-approved prospective tissue collection protocol at one academic institution and two community hospitals. 526 primary breast tumor samples were identified and gene expression profiling was assessed with high density Affymetrix microarray chips. Proportions of 22 different TIL types in samples were inferred based on the CIBERSORT algorithm, which uses gene expression data to estimate TIL presence. TIL presence was determined by dichotomization at the level of the first quartile among all samples (&gt;Q1=TIL presence). Patient characteristics and clinical outcomes were obtained by chart review. Time to event analysis was performed using Kaplan Meier (KM) estimates and the log-rank test. Associations between patient factors, tumor factors, TIL presence, and LRR were explored with univariable (UVA) and multivariable (MVA) analyses. Factors significant on UVA (p&lt;0.10) were included on MVA. P&lt;0.05 was considered statistically significant on MVA.

Results:

526 women with invasive breast cancer and available genomic profiling were retrospectively identified for analysis. Median age at diagnosis was 58 years. 70% of tumors were Stage I-II. 69% were luminal subtypes and 17% were triple negative. 37% received mastectomy, 25% received mastectomy + radiation, and 32% received breast conserving therapy. 64% received chemotherapy, and 62% received hormonal therapy. Median follow-up was 74.4 months. There were 61 LRRs. We found significant differences in time to LRR when comparing presence vs. no presence of resting memory CD4+ T-cells (RMCD4+) (p=0.01), activated natural killer cells (ANK) (p=0.003), and neutrophils (PMNs) (p=0.03). On UVA, factors associated with LRR were patient age at diagnosis (p=0.009), pathologic T stage (p=0.045), Estrogen receptor status (p=0.03), biologic subtype (p=0.01), lymphovascular invasion (LVI) (p=0.018), positive margins (p&lt;0.0001), receipt of hormonal therapy (0.014), and presence of tumor infiltrating RMCD4+ (p=0.012), ANK (p=0.0004), and PMNs (p=0.033). On MVA, factors remaining significant were LVI (HR 2.16 CI 1.13-4.13, p=0.011), positive margins (HR 4.36 CI 1.57-12.11, p=0.018), receipt of hormonal therapy (HR 0.31 CI 0.12-0.77, p=0.042), and presence of RMCD4+ (HR 0.48 CI 0.26-0.88, p=0.017), ANK (HR 0.43 CI 0.23-0.83, p=0.012), and PMNs (HR 2.15 CI 1.02-4.53, p=0.043).

Conclusion:

In this study of 526 women with invasive breast cancer, we identified that enrichment of certain TILs is associated with LRR. These results suggest genomic-based assays of TIL presence may be useful to predict LRR in invasive breast cancer.

Citation Format: Liveringhouse CL, Grass GD, Figura NB, Mills MN, Purcell JD, Rosensweig SR, Blumencranz PW, Allen KG, Ahmed KA, Harrison LB, Torres-Roca JF, Robinson TJ, Diaz R. Locoregional recurrence in invasive breast cancer and association with tumor infiltrating leukocyte (TIL) presence [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-08-15.