A Prospective Study Assessing the Efficacy and Toxicity of Stereotactic Body Radiation Therapy for Oligometastatic Bone Metastases

Purpose

Stereotactic body radiation therapy (SBRT) is a promising treatment for oligometastatic disease in bone because of its delivery of high dose to target tissue and minimal dose to surrounding tissue. The purpose of this study is to assess the efficacy and toxicity of this treatment in patients with previously unirradiated oligometastatic bony disease.

Methods and Materials

In this prospective phase II trial, patients with oligometastatic bone disease, defined as ≤3 active sites of disease, were treated with SBRT at Brigham and Women's Hospital/Dana Farber Cancer Center and Beth Israel Deaconess Medical Center between December 2016 and May 2019. SBRT dose and fractionation regimen were not protocol mandated. Local progression-free survival, progression-free survival, prostatic specific antigen progression, and overall survival were reported. Treatment-related toxicity was also reported.

Results

A total of 98 patients and 126 lesions arising from various tumor histologies were included in this study. The median age of patients enrolled was 72.8 years (80.6% male, 19.4% female). Median follow-up was 26.7 months. The most common histology was prostate cancer (68.4%, 67/98). The most common dose prescriptions were 27/30 Gy in 3 fractions (27.0%, 34/126), 30 Gy in 5 fractions (16.7%, 21/126), or 30/35 Gy in 5 fractions (16.7%, 21/126). Multiple doses per treatment regimen reflect dose painting employing the lower dose to the clinical target volume and higher dose to the gross tumor volume. Four patients (4.1%, 4/98) experienced local progression at 1 site for each patient (3.2%, 4/126). Among the entire cohort, 2-year local progression-free survival (including death without local progression) was 84.8%, 2-year progression-free survival (including deaths as well as local, distant, and prostatic specific antigen progression) was 47.5%, and 2-year overall survival was 87.3%. Twenty-six patients (26.5%, 26/98) developed treatment-related toxicities.

Conclusions

Our study supports existing literature in showing that SBRT is effective and tolerable in patients with oligometastatic bone disease. Larger phase III trials are necessary and reasonable to determine long-term efficacy and toxicities.

Clinical Outcomes Among Patients Treated With Stereotactic Body Radiation Therapy to Femur Metastases for Oligometastatic Disease Control or Reirradiation: Results From a Large Single-Institution Experience

Purpose

There are limited data regarding outcomes after stereotactic body radiation therapy (SBRT) for femur metastases, which was an exclusion criteria for the Stereotactic Ablative Radiotherapy for the Comprehensive Treatment of Oligometastatic Cancers (SABR-COMET) trial. We aimed to characterize clinical outcomes from a large single institution experience.

Methods and Materials

Forty-eight patients with 53 lesions were consecutively treated with femur SBRT from May 2017 to June 2022. The Kaplan-Meier method and Cox proportional hazard models were used to characterize time-to-event endpoints and associations between baseline factors and clinical outcomes, respectively. Local control and locoregional control were defined as the absence of tumor progression within the radiation treatment field or within the treated femur, respectively.

Results

Most patients had Eastern Cooperative Oncology Group performance status 0 to 1 (90%), prostate (52%) or breast/lung (17%) cancer, and 1 to 3 lesions (100%), including 29 proximal and 5 distal. Fifty-seven percent of the lesions were treated with concurrent systemic therapy. Median planning target volume was 49.1 cc (range, 6.6-387 cc). Planning target volume V100 (%) was 99% (range, 90-100). Fractionation included 18 to 20 Gy/1F, 27 to 30 Gy/3F, and 28.5-40 Gy/5F. Forty-two percent had Mirels score ≥7 and most (94%) did not have extraosseous extension. Acute toxicities included grade 1 fatigue (15%), pain flare (7.5%), nausea (3.8%), and decreased blood counts (1.9%). Late toxicities included fracture (1.9%) at 1.5 years and osteonecrosis (4%) from dose of 40 Gy in 5F and 30 Gy in 5F (after prior 30 Gy/10F). One patient (2%) required fixation postradiation for progressive pain. With median follow-up 19.4 months, 1- and 2-year rates of local control were 94% and 89%, locoregional control was 83% and 67%, progression-free survival were 56% and 25%, and overall survival were 91% and 73%. Fifty percent of local regional recurrence events occurred within 5 cm of gross tumor volume.

Conclusions

Femur SBRT for oligometastatic disease control in well-selected patients was associated with good outcomes with minimal rates of acute and late toxicity. Patterns of local regional recurrence warrant consideration of larger elective volume coverage. Additional prospective study is needed.

Prospective Evaluation of the Clinical Benefits of a Novel Tattoo-less Workflow for Nonspine Bone Stereotactic Body Radiation Therapy: Integrating Surface-Guidance With Triggered Imaging Reduces Treatment Time and Eliminates the Need for Tattoos

PURPOSE

Oligometastatic disease has expanded the indications for nonspine bone stereotactic body radiation therapy (NSB SBRT). We investigated whether optical surface monitoring systems (OSMS) could enable tattoo-less setup and substitute for 2-dimensional/3-dimensional or cone beam computed tomography (CBCT)-based mid-imaging in NSB SBRT.

METHODS AND MATERIALS

OSMS was incorporated in parallel with an existing workflow using pretreatment CBCT and 2-dimensional/3-dimensional kV/kV mid-imaging beginning November 2019. The ability of OSMS to detect out-of-tolerance (>2 mm/>2°) and commanded couch shifts was analyzed. A workflow incorporating OSMS reference captures, CBCT for pretreatment verification, and OSMS/triggered imaging (TI) for intrafraction monitoring was developed for rib/sternum SBRT beginning November 2021 and all NSB SBRT beginning February 2022. Treatment time and CBCT-related radiation dose between the OSMS and the non-OSMS intrafraction monitoring group was analyzed pre- and post-OSMS/TI workflow adoption. All fractions were analyzed through statistical process control with use of an XmR chart of treatment time per quarter from February 2019 to February 2023. Special cause rules were based on Institute for Healthcare Improvement criteria.

RESULTS

From February 2019 to February 2023, 1993 NSB SBRT fractions were delivered, including 234 rib, 109 sternum, 214 ilium, and 682 multisite. Over 20 commanded shifts, OSMS could detect 2-mm shifts to within 0.4 mm 67% of the time and 0.8 mm 95% of the time. All NSB SBRT sites showed significant reductions in treatment time, including the greatest improvement in rib total treatment (21.6-13.4 minutes; P = 1.16 × 10-17) and beam time (7.9-3.2 minutes; P = 7.32 × 10-27). Significant reductions in CBCT-related radiation were also observed for several NSB sites. These process improvements were associated with OSMS adoption.

CONCLUSIONS

Adoption of a novel NSB SBRT workflow incorporating OSMS/TI for bone intrafraction motion monitoring reduced treatment time and CBCT-related radiation exposure while also allowing for more continuous intrafraction motion monitoring for NSB SBRT. OSMS/TI enabled the transition to a tattoo-less workflow.

2D and 3D multiplexed subcellular profiling of nuclear instability in human cancer

Nuclear atypia, including altered nuclear size, contour, and chromatin organization, is ubiquitous in cancer cells. Atypical primary nuclei and micronuclei can rupture during interphase; however, the frequency, causes, and consequences of nuclear rupture are unknown in most cancers. We demonstrate that nuclear envelope rupture is surprisingly common in many human cancers, particularly glioblastoma. Using highly-multiplexed 2D and super-resolution 3D-imaging of glioblastoma tissues and patient-derived xenografts and cells, we link primary nuclear rupture with reduced lamin A/C and micronuclear rupture with reduced lamin B1. Moreover, ruptured glioblastoma cells activate cGAS-STING-signaling involved in innate immunity. We observe that local patterning of cell states influences tumor spatial organization and is linked to both lamin expression and rupture frequency, with neural-progenitor-cell-like states exhibiting the lowest lamin A/C levels and greatest susceptibility to primary nuclear rupture. Our study reveals that nuclear instability is a core feature of cancer, and links nuclear integrity, cell state, and immune signaling.

Prospective Evaluation of Implementation of a Tattoo-less Workflow for Non-Spine Bone SBRT

PURPOSE/OBJECTIVE(S)

Oligometastatic disease has expanded the clinical indications for non-spine bone (NSB) SBRT. Optical surface monitoring systems (OSMS) may reduce treatment time if it represents an effective surrogate for bone intrafraction motion monitoring. We aimed to identify whether OSMS could substitute for 2D-3D mid-imaging and enable a tattoo-less set up in NSB SBRT.

MATERIALS/METHODS

Beginning 11/2019, OSMS was incorporated in parallel with an existing workflow using CBCT and mid 2D-3D kV/kV imaging for pre- and mid-imaging for NSB SBRT. The ability of OSMS to detect both observed out-of-tolerance (>2mm/>2deg) shifts and manual couch shifts was analyzed. A workflow incorporating OSMS reference captures, CBCT for pre-treatment verification and OSMS/triggered imaging (TI) for intrafraction monitoring was developed and deployed for rib/sternum SBRT beginning 11/2021 and all NSB SBRT beginning 2/2022. All NSB SBRT treatment appointments were analyzed through statistical process control (SPC) with use of an XmR chart of average set up and total treatment time per quarter from 2/2019 to 2/2023. Special cause rules were based on IHI rules and conduced with spreadsheet software.

RESULTS

From 2/2019 to 2/2023, 1962 NSB SBRT fractions were delivered, including 337 rib, 150 sternum, 197 femur, 266 ilium, 222 multi-site. Over 104 femur and 87 ilium images, there were no over tolerance intra-fraction events detected with 2D-3D or OSMS. Over 20 manual shifts, OSMS could detect 2mm shifts to within 0.4mm 67% of the time and 0.8mm 95% of time. There was no difference in treatment set up time following adoption of an OSMS/TI workflow as a replacement for 2D-3D mid-imaging. A reduction in rib SBRT delivery and multi-site treatment set-up times was significantly associated with the adoption of OSMS/TI and OSMS, respectively, as assessed based on special cause variation with 8 consecutive points below the mean.

CONCLUSION

Integration of OSMS and triggered imaging has enabled the transition to a completely tattoo-less workflow, thus sparing patients the need for permanent tattoos whilst also allowing more continuous motion monitoring and reduced radiation exposure related to unnecessary 2D-3D or CBCT mid-imaging. Treatment times were significantly reduced for patients receiving rib SBRT or multi-site NSB SBRT with this workflow.

A Prospective Study Assessing the Efficacy and Toxicity of Stereotactic Body Radiation Therapy for Oligometastatic Bone Metastases

PURPOSE/OBJECTIVE(S)

Stereotactic body radiation therapy (SBRT) is a promising treatment for oligometastatic disease in bone due to its delivery of high dose to target tissue and minimal dose to surrounding tissue. The purpose of this study is to assess efficacy and toxicity of this treatment in patients with previously unirradiated oligometastatic bony disease.

MATERIALS/METHODS

In this prospective phase II trial, patients with oligometastatic bone disease, defined as ≤3 active sites of disease, were treated with SBRT at one of two academic institutions between December 2016 and May 2019. Local progression-free survival (LPFS), progression-free survival (PFS), prostatic specific antigen (PSA) progression, and overall survival (OS) were reported. Treatment-related toxicity was also reported.

RESULTS

A total of 98 patients and 131 lesions arising from various tumor histologies were included in this study. The median age of patients enrolled in the study was 72.8 years (80.6% male, 19.4% female). Median follow-up was 26.7 months. The most common histology was prostate cancer (68.4%, 67/98). The most common dose prescriptions were 27/30 Gy in 3 fractions (26.0%, 34/131), 30 Gy in 5 fractions (19.1%, 25/131), or 30/35 Gy in 5 fractions (16.0%, 21/131). Multiple doses per treatment regimen reflect dose painting employing the lower dose to the clinical target volume (CTV) and higher dose to the gross tumor volume (GTV). Four patients (4.1%, 4/98) experienced local progression at one site for each patient (3.1%, 4/131). Among patients who progressed locally, the median time to local recurrence was 25.8 months (31.0 months among prostate cancer patients, N = 2, and 14.5 months among non-prostate cancer patients, N = 2). Among the entire cohort, 2-year LPFS (including death without local progression) was 85.0%, 2-year PFS (including deaths as well as local, distant, and PSA-based progression) was 47.0%, and 2-year OS was 87.5%. Twenty-seven patients (27.6%, 27/98) developed treatment-related toxicities, and most were Grade 1 (19.4%, 19/98) and 2 (4.1%, 4/98). Four patients (4.1%, 4/98) developed Grade 3 toxicities; there were no Grade 4 toxicities. The most common toxicity was fatigue (10.2%, 10/98). Of 68 treated spine metastases, there were four (5.9%, 4/68) vertebral fractures. Among these four patients, median time to fracture was 23.5 months (range 14.2-39.2 months).

CONCLUSION

Our study supports existing literature in showing that SBRT is effective and tolerable in patients with oligometastatic bone disease. Larger phase III trials are necessary and reasonable to determine long-term efficacy and toxicities.

Outcomes of Stereotactic Body Radiation Therapy (SBRT) for Femur Oligometastases

PURPOSE/OBJECTIVE(S)

Stereotactic body radiation therapy (SBRT) is increasingly used for oligometastatic bone disease, but there is limited data regarding the clinical outcomes of utilizing SBRT in treatment for femur metastases, which was excluded from SABR-COMET. We aimed to identify patient or treatment factors associated with clinical outcomes among patients treated with SBRT to femur metastases for oligometastatic disease control or re-irradiation.

MATERIALS/METHODS

We identified 50 patients with 56 femur lesions consecutively treated with SBRT at a single institution May 2017-June 2022. The Kaplan-Meier method was used to characterize time-to-event endpoints and Cox proportional hazards models were performed to evaluate the associations between baseline factors and clinical outcomes. Local control was defined as the absence of regional tumor progression at treated area or need for surgical fixation post radiation.

RESULTS

Most patients had ECOG 0-1 (90%), prostate (50%) or breast/lung (16%) cancer, and 1-3 lesions (100%), including 30 proximal and 5 distal. 55% of lesions received concurrent systemic therapy, including ADT (n = 18) or immunotherapy (n = 6). Median PTV volume was 54.7cc (range, 6.6 to 387cc). PTV V100(%) was 99% (range 71.5-100). Fractionation included 18-20 Gy/1F, 27-30 Gy/3F, 25-40 Gy/5F, and 50 Gy/10F. 43% of lesions had Mirel's score ≥ 7 and 91% of lesions did not have extraosseous bone extension on diagnostic CT and/or MRI. Acute toxicities included grade 1 fatigue (14.3%), pain flare (7.1%), and decreased blood counts (1.8%). Late toxicities included fracture (1.8%) at 1.5 years and 2 patients with radiation-induced osteonecrosis (3.6%) from dose of 40 Gy in 5F and 30 Gy in 5F (after prior 30 Gy/10F). One patient (n = 2%) required fixation post-radiation due to progression of disease or symptoms. With median follow up 19.4 months, 1 and 2-year rates of local control were 84% and 69%, progression-free survival were 55% and 27%, and overall survival were 91% and 74%.

CONCLUSION

There was no significant association between patient or treatment characteristics and local control outcomes. Femur SBRT for oligometastatic disease control in well-selected patients was associated with good outcomes with minimal rates of acute and late toxicity. Further prospective study is warranted.

Clinical Outcomes with Stereotactic Body Radiation Therapy for Oligometastatic Prostate Cancer: Results from a Prospective Registry Trial

PURPOSE/OBJECTIVE(S)

Metastasis-directed radiation therapy using stereotactic body radiation therapy (SBRT) in oligometastatic prostate cancer (Oligo PCa) has a demonstrated benefit for local control and biochemical recurrence free survival for men with oligorecurrent PCa; however, the impact of SBRT within other oligometastatic states and in the context of systemic therapy remains poorly characterized. In this study, we investigate prognostic factors for clinical outcomes in a prospective cohort of Oligo PCa patients treated with metastasis-directed SBRT.

MATERIALS/METHODS

Using a single-institution registry trial, we analyzed a prospective cohort of 86 patients with Oligo PCa (≤5 metastatic lesions) and treated with metastasis-directed SBRT between 2017- 2022. Patients were classified as synchronous, metachronous, or induced oligometastatic disease as per the ESTRO guidelines. We evaluated the time to radiographic progression (TTRP), defined as the time from SBRT start date to radiographic progression, as well as time to initiation of new treatment (TTNT), defined as the time from SBRT end date to initiation of new therapy (systemic or radiation therapy). Time to event (TTE) was defined as the time from SBRT start date to radiographic progression or initiation of new therapy, whichever occurred first. Patients without documented events were censored at the date of last disease assessment. Comparative analyses were performed using Kaplan-Meier and Cox proportional hazards regression methods.

RESULTS

Eighty-six men with Oligo PCa treated with SBRT were followed for a median of 16.4 months with M0 (73%), Oligo PCa (21%) or polymetastatic PCa (6%) GS > = 8 (63%) at initial diagnosis. At the time of treatment with initial SBRT, 21% had synchronous oligometastatic disease, 63% had metachronous or repeat oligorecurrence or oligoprogression, and 16% had induced oligometastatic disease. Most patients were treated to 1-3 sites (94%), which predominantly included bone (86%), and the median dose was 35 Gy/5F. Concurrent systemic therapy during SBRT was seen in 85% of patients, including (60.5% with new generation androgen receptor signaling inhibitors). Overall survival at 1-year and 2-years was 96.9% [95% CI, 88.2-99.2%] and 94.4% [95% CI, 83.2-98.2%]. Using univariable analysis, those who did not receive systemic treatment during SBRT had significantly shorter TTRP (HR 3.67, [95% CI, 1.62-8.32], p = 0.002), TTNT (HR 3.24, 95% CI [1.49-7.06], p = 0.003), and TTE (HR 3.05, [95% CI, 1.44-6.45], p = 0.004). Additionally, patients treated with SBRT for metachronous (HR 2.89, [95% CI 0.68-12.30]) and induced metastatic disease (HR 8.96, [95% CI 1.85-43.37]) had significantly shorter TTE compared to synchronous oligometastatic disease (p = 0.006).

CONCLUSION

Using a prospective registry cohort of men with Oligo PCa treated with SBRT, we identify an association of oligometastatic state and the use of concurrent systemic therapy with improved TTRP and TTNT. Further prospective studies are warranted.

Spinal Cord Delineation Based on Computed Tomography Myelogram Versus T2 Magnetic Resonance Imaging in Spinal Stereotactic Body Radiation Therapy

Purpose

Spinal cord delineation is critical to the delivery of stereotactic body radiation therapy (SBRT). Although underestimating the spinal cord can lead to irreversible myelopathy, overestimating the spinal cord may compromise the planning target volume coverage. We compare spinal cord contours based on computed tomography (CT) simulation with a myelogram to spinal cord contours based on fused axial T2 magnetic resonance imaging (MRI).

Methods and Materials

Eight patients with 9 spinal metastases treated with spinal SBRT were contoured by 8 radiation oncologists, neurosurgeons, and physicists, with spinal cord definition based on (1) fused axial T2 MRI and (2) CT-myelogram simulation images, yielding 72 sets of spinal cord contours. The spinal cord volume was contoured at the target vertebral body volume based on both images. The mixed-effect model assessed comparisons of T2 MRI- to myelogram-defined spinal cord in centroid deviations (deviations in the center point of the cord) through the vertebral body target volume, spinal cord volumes, and maximum doses (0.035 cc point) to the spinal cord applying the patient's SBRT treatment plan, in addition to in-between and within-subject variabilities.

Results

The estimate for the fixed effect from the mixed model showed that the mean difference between 72 CT volumes and 72 MRI volumes was 0.06 cc and was not statistically significant (95% confidence interval, -0.034, 0.153; P = .1832). The mixed model showed that the mean dose at 0.035 cc for CT-defined spinal cord contours was 1.24 Gy lower than that of MRI-defined spinal cord contours and was statistically significant (95% confidence interval, -2.292, -0.180; P = .0271). Also, the mixed model indicated no statistical significance for deviations in any of the axes between MRI-defined spinal cord contours and CT-defined spinal cord contours.

Conclusions

CT myelogram may not be required when MRI imaging is feasible, although uncertainty at the cord-to-treatment volume interface may result in overcontouring and hence higher estimated cord dose-maximums with axial T2 MRI-based cord definition.

Is Oligometastatic Cancer Curable?: A Survey of Oncologist Perspectives, Decision-Making, and Communication

Purpose

Oligometastatic disease (OMD) refers to a limited state of metastatic cancer, which potentially derives benefit from local treatments. Given the relative novelty of this paradigm, oncologist perspectives on OMD are not well established. We thus explored oncologist views on curability of and treatment recommendations for patients with OMD.

Methods and Materials

We developed a survey focused on oncologist views of 3 subtypes of OMD: synchronous, oligorecurrent, and oligoprogressive. Eligible participants included medical and radiation oncologists at 2 large cancer centers invited to participate between May and June 2022. Participants were presented with 3 hypothetical patient scenarios and asked about treatment recommendations, rationale, and demographic information.

Results

Of 44 respondents, over half (61.4%) agreed that synchronous OMD is curable. A smaller proportion (46.2% and 13.5%) agreed for oligorecurrence and oligoprogression, respectively. When asked whether they use the word "cure" or "curative" in discussing prognosis, 31.8% and 33.3% agreed for synchronous and oligorecurrent OMD, respectively, while 78.4% disagreed for oligoprogression. Views on curability did not significantly affect treatment recommendations. More medical oncologists recommended systemic treatment only compared with radiation oncologists for the synchronous OMD (50.0% vs 5.3%; P < .01) and oligoprogression cases (43.8% vs 10.5%; P = .02), not the oligorecurrent case. There were no significant differences in confidence in treatment recommendations by specialty.

Conclusions

In this exploratory study, we found notable divergence in oncologists' views about curability of OMD as well as variability in treatment recommendations, suggesting need for more robust research on outcomes of patients with OMD.

Abstract P2-20-09: Enhancement of anti-tumor immunity in ER+ breast cancer through dual inhibition of MCL1 and caspases

Breast cancer is one of the most commonly diagnosed cancer types and a leading cause of cancer death in women in the United States. However, it is difficult to treat with immunotherapy because of its immunological “cold” status. This underscores the importance of a novel clinical approach to increase efficacy of immunotherapy including acute upregulation of Type I Interferon (IFN) response. One strategy to enhance Type I IFN response is by release of damage-associated molecular patterns (DAMPs) from mitochondria, including mitochondrial DNA, RNA and oxidized proteins that are recognized by pattern recognition receptors (PRRs) in cytoplasm and activate downstream IFN signaling. Because many cancers including breast cancer experience increased and dysregulated mitochondrial biogenesis at baseline, they contain significantly higher levels of DAMPs compared to normal cells, but these substrates are sequestered in mitochondria and not accessible to PRRs. We set out to develop a strategy to exploit increased levels of DAMPs in cancer cell mitochondria to enhance Type I IFN response. While DAMPs are released from mitochondria upon apoptosis caused by mitochondrial outer membrane permeabilization (MOMP), Type I IFN response is still silenced due to cleavage of PRRs by activated caspases. One way to induce MOMP is by inhibition of Myeloid Cell Leukemia-1 (Mcl-1), an anti-apoptotic family protein that is frequently upregulated in breast cancer. Interestingly, breast cancer cell lines showed the highest dependency on Mcl-1 among solid cancers and inhibitors of Mcl-1 have shown efficacy in breast cancer early clinical trials. Based on our preliminary observations showing that Mcl-1 inhibition activates a robust Type I IFN response in MCF7 breast cancer cells deficient for caspase 3, we hypothesized that combining Mcl-1 inhibitors with caspase inhibitors would greatly enhance Type I IFN response in a robust and specific manner by facilitating release on DAMPs into the cytoplasm while preventing inactivation of PRRs. Strikingly, in contrast with Mcl-1 inhibitor treatment alone, combination treatment led to dramatic increase in expression levels of IFN-β and interferon-stimulated genes (ISGs) in MCF7 and ZR-75-1 ER+ breast cancer cell lines with minimal effects on cytotoxicity. In addition, T47d, a breast cancer line highly resistant to Mcl-1 inhibition due to compensation by other Bcl-2 family proteins, showed greatly enhanced Type I IFN response upon combined Mcl-1, Bcl-2 and caspase inhibition. Because reduced expression of MHC class I molecules on cell surface is one of the most important immune escape mechanisms in tumors including breast cancer, we examined whether the proposed combinatorial treatment would overcome this by enhancing expression of MHC class I. Immunofluorescence (IF) staining confirmed that the combination treatment dramatically increased total HLA-ABC protein expression on plasma membrane of ZR-75-1. Furthermore, combinatorial treatment upregulated transcription of most genes responsible for antigen presentation, a multistep process consisting of antigen peptide generation and loading of MHC class I molecules. Lastly, we sought to examine how elevated chemokine expression may impact patients with breast cancer. We examined association of cytokines highly upregulated by the combination treatment with immune cell infiltration using a TCGA dataset that included over a thousand breast cancer samples. This analysis was performed by xCell algorithm and demonstrated strong association of that cytokine expression with CD8+ T, B and DC infiltrate. Our results demonstrate that the combination of Mcl-1 and caspase inhibitors greatly enhances Type I IFN response and may improve anti-tumor immunity. We plan to further test this drug combination in immunocompetent mouse models, laying the foundation for a clinical trial assessing the combination treatment in patients with metastatic ER+ breast cancer.

Citation Format: Jae Kyo Yi, Alexander Spektor. Enhancement of anti-tumor immunity in ER+ breast cancer through dual inhibition of MCL1 and caspases. [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-20-09.

Longitudinal symptoms and temporal trends in palliative care, palliative radiotherapy, and anti-cancer treatment near end of life among patients with metastatic cancer

BACKGROUND

Early specialty palliative care (PC) integration improves oncologic outcomes. We aimed to examine longitudinal relationships between specialty PC and palliative radiotherapy (RT), temporal distribution of symptoms, and predictors of earlier specialty PC.

METHODS

We retrospectively reviewed 135 patients with metastatic cancer who received palliative RT at our institution (7/2017-2/2018) and who had died by final study follow-up (6/2021). Descriptive statistics summarized frequencies of clinical visits and symptoms over relative survival time (quartiles 1-3: first 75% of life remaining from metastatic diagnosis to death versus quartile 4: last 25% of life remaining from metastatic diagnosis to death). Logistic regression analyses revealed predictors of receiving earlier (quartiles 1-3) versus later (quartile 4) specialty PC.

RESULTS

There were 16.3%, 10.4%, 26.7%, and 46.7% of palliative RT consultations, compared to 4.7%, 7.6%, 14.0%, and 73.7% of specialty PC visits, that occurred in quartiles 1, 2, 3, and 4, respectively. On multivariable analysis, pain significantly predicted for receiving earlier specialty PC [odds ratios (OR) =15.34; 95% confidence interval (CI): 2.16-324.23; P=0.020], while patients with ≥2 prior chemotherapy regimens were less likely to have received earlier specialty PC (OR =0.16; 95% CI: 0.04-0.58; P=0.009). The most common reasons for first specialty PC visit were addressing pain (61.0%) and goals of care (19.5%). Overall, 73.3% (99/135) of patients were referred to hospice and 9.6% (13/135) received either palliative RT, chemotherapy, or surgery within 30 days of death.

CONCLUSIONS

Nearly 47% of palliative RT visits compared with 74% of specialty PC visits occurred in the last quarter of life from metastatic diagnosis to death. Multidisciplinary efforts are needed to manage longitudinal symptoms and offer goal-concordant care.

Patient and Treatment Factors Associated with Improved Local Control and Survival in Oligometastatic Bone Disease: Results from a Large Single-Institution Experience Using Stereotactic Body Radiation Therapy

PURPOSE

Limited data exists to guide optimal patient selection and treatment of bone metastases with curative intent despite the increasing application of stereotactic body radiation therapy (SBRT) for oligometastatic (OM) disease control and re-irradiation(ReRT).

METHODS

Clinical characteristics for 434 patients consecutively treated with bone SBRT at a single institution from 3/2011-6/2020 were analyzed by OM, spine, and non-spine bone using Cox regression to determine association with local control (LC), progression-free survival (PFS), and overall survival (OS), and the Kaplan-Meier method to estimate PFS and OS.

RESULTS

Most patients had prostate (39%) or breast/lung (21%) cancer and 1-3 lesions (96%), with 651 lesions (spine 63%) treated for ReRT (12%) or OMD (88%), including synchronous (10%), metachronous (28%), repeat (27%), or induced (23%) states as defined by ESTRO/EORTC criteria. Biologically effective dose (BED₁₀) ≥50 (HR 0.68, CI 0.48-0.96, p<0.03) predicted improved LC among OM lesions and planning target volume (PTV)≥150 cc (HR 1.94, CI 1.02 to 3.70, p<0.04) predicted worse LC for non-spine bone. Prostate histology, performance status (PS) 0-1, and MFI ≥2 year predicted improved PFS and OS (p<0.05). Metachronous, synchronous, or repeat OM had higher PFS and OS (p≤0.001) than induced OM. With median follow-up 25.7 months, 1 and 2-year PFS was 63% and 47% for OM and 36% and 25% for ReRT;1 and 2-yr OS was 87% and 73% for OM, 58% and 43% for ReRT. Acute toxicities included grade 1-2 pain flare (9%) and fatigue (14%). Late toxicities included fracture (1%) for OM and myelopathy (2.5%) or nerve pain (1.2%) for ReRT.

CONCLUSIONS

BED₁₀ ≥ 50 for OM and PTV<150cc for non-spine bone lesions was associated with improved LC. Prostate histology, PS 0-1, MFI≥2 years, and metachronous, synchronous, or repeat presentations per EORTC/ESTRO OM criteria predicted improved PFS and OS among OM patients treated with bone SBRT.

Regulators of tubulin polyglutamylation control nuclear shape and cilium disassembly by balancing microtubule and actin assembly

Cytoskeletal networks play an important role in regulating nuclear morphology and ciliogenesis. However, the role of microtubule (MT) post-translational modifications in nuclear shape regulation and cilium disassembly has not been explored. Here we identified a novel regulator of the tubulin polyglutamylase complex (TPGC), C11ORF49/CSTPP1, that regulates cytoskeletal organization, nuclear shape, and cilium disassembly. Mechanistically, loss of C11ORF49/CSTPP1 impacts the assembly and stability of the TPGC, which modulates long-chain polyglutamylation levels on microtubules (MTs) and thereby balances the binding of MT-associated proteins and actin nucleators. As a result, loss of TPGC leads to aberrant, enhanced assembly of MTs that penetrate the nucleus, which in turn leads to defects in nuclear shape, and disorganization of cytoplasmic actin that disrupts the YAP/TAZ pathway and cilium disassembly. Further, we showed that C11ORF49/CSTPP1-TPGC plays mechanistically distinct roles in the regulation of nuclear shape and cilium disassembly. Remarkably, disruption of C11ORF49/CSTPP1-TPGC also leads to developmental defects in vivo. Our findings point to an unanticipated nexus that links tubulin polyglutamylation with nuclear shape and ciliogenesis.

Patterns of Specialty Palliative Care Utilization Among Patients Receiving Palliative Radiation Therapy

CONTEXT

Palliative radiation therapy (RT) is frequently used to ameliorate cancer-associated symptoms and improve quality of life.

OBJECTIVES

To examine how palliative care (PC) as a specialty is integrated at the time of RT consultation for patients with advanced cancer.

METHODS

We retrospectively reviewed 162 patients with metastatic cancer who received palliative RT at our institution (7/2017-2/2018). Fisher's exact test identified differences in incidence of receiving any specialty PC. Logistic regression analyses determined predictors of receiving PC.

RESULTS

Of the 74 patients (46%) who received any specialty PC, 24 (32%) initiated PC within four weeks of RT consultation. The most common reasons for specialty PC initiation were pain (64%) and goals of care/end-of-life care management (23%). Referrals to specialty PC were made by inpatient care teams (48.6%), medical oncologists (48.6%), radiation oncologists (1.4%), and self-referring patients (1.4%). Patients with pain at RT consultation had a higher incidence of receiving specialty PC (58.7% vs. 37.4%, P = 0.0097). There was a trend toward decreased PC among patients presenting with neurological symptoms (34.8% vs. 50%, P = 0.084). On multivariable analysis, receiving specialty PC significantly differed by race (non-white vs. white, odds ratio [OR] = 6.295 [95% CI 1.951-20.313], P = 0.002), cancer type (lung vs. other histology, OR = 0.174 [95% CI 0.071-0.426], P = 0.0006), and RT consultation setting (inpatient vs. outpatient, OR = 3.453 [95% CI 1.427-8.361], P = 0.006).

CONCLUSION

Fewer than half of patients receiving palliative RT utilized specialty PC. Initiatives are needed to increase PC, especially for patients with lung cancer and neurological symptoms, and to empower radiation oncologists to refer patients to specialty PC.

A Randomized Trial of Combined PD-L1 and CTLA-4 Inhibition with Targeted Low-Dose or Hypofractionated Radiation for Patients with Metastatic Colorectal Cancer

PURPOSE

Prospective human data are lacking regarding safety, efficacy, and immunologic impacts of different radiation doses administered with combined PD-L1/CTLA-4 blockade.

PATIENTS AND METHODS

We performed a multicenter phase II study randomly assigning patients with metastatic microsatellite stable colorectal cancer to repeated low-dose fractionated radiation (LDFRT) or hypofractionated radiation (HFRT) with PD-L1/CTLA-4 inhibition. The primary endpoint was response outside the radiation field. Correlative samples were analyzed using multiplex immunofluorescence (IF), IHC, RNA/T-cell receptor (TCR) sequencing, cytometry by time-of-flight (CyTOF), and Olink.

RESULTS

Eighteen patients were evaluable for response. Median lines of prior therapy were four (range, 1-7). Sixteen patients demonstrated toxicity potentially related to treatment (84%), and 8 patients had grade 3-4 toxicity (42%). Best response was stable disease in 1 patient with out-of-field tumor shrinkage. Median overall survival was 3.8 months (90% confidence interval, 2.3-5.7 months). Correlative IF and RNA sequencing (RNA-seq) revealed increased infiltration of CD8+ and CD8+/PD-1+/Ki-67+ T cells in the radiation field after HFRT. LDFRT increased foci of micronuclei/primary nuclear rupture in two subjects. CyTOF and RNA-seq demonstrated significant declines in multiple circulating immune populations, particularly in patients receiving HFRT. TCR sequencing revealed treatment-associated changes in T-cell repertoire in the tumor and peripheral blood.

CONCLUSIONS

We demonstrate the feasibility and safety of adding LDFRT and HFRT to PD-L1/CTLA-4 blockade. Although the best response of stable disease does not support the use of concurrent PD-L1/CTLA-4 inhibition with HFRT or LDFRT in this population, biomarkers provide support that both LDFRT and HFRT impact the local immune microenvironment and systemic immunogenicity that can help guide future studies.

Evaluating the role of stereotactic body radiation therapy with respect to androgen receptor signaling inhibitors for metastatic prostate cancer

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Background: Outcomes of stereotactic body radiation therapy (SBRT) with respect to androgen receptor signaling inhibitors (ARSI) have not been characterized for metastatic prostate cancer. Our purpose is to characterize prostate specific antigen (PSA) response and progression free survival (PFS) following SBRT among men who have received ARSI in castration sensitive and resistant settings. Methods: A single institution retrospective analysis was performed for men treated with SBRT and ARSI and categorized into 4 groups: 1) oligometastatic castration-sensitive prostate cancer (omCSPC), 2) ARSI-sensitive (ARSI-s) oligometastatic castration-resistant prostate cancer (omCRPC), 3) ARSI-resistant (ARSI-r) omCRPC, and 4) polymetastatic CRPC (pmCRPC). We calculated the PSA reduction greater than 50% (PSA50) and median PFS (PSA or radiographic progression) as determined by routine care. We also used Cox regression analysis to determine factors influencing PFS for ARSI-r disease. Results: 73 men with 126 lesions were treated with SBRT and followed for a median of 14.4 months. The percentages of men who achieved a PSA50 for omCSPC, ARSI-s omCRPC, ARSI-r omCRPC and pmCRPC were 100%, 90%, 62.9%, and 16.7%, respectively. Respective median PFS values were: not reached, 17.3, 9.0, and 1.6 months. For the 35 men with ARSI-r omCRPC, incomplete ablation (defined as the presence of untreated lesions after SBRT or prior palliative external beam radiation therapy (EBRT)) (HR 3.51 [1.36, 9.06]; p = 0.01) was associated with worse PFS on multivariable analysis. For the subgroup of 22 men with ARSI-r omCRPC without prior palliative EBRT or untreated metastases, the median PFS was 13.1 months. Conclusions: SBRT may augment the efficacy of ARSI, particularly among men with ARSI-r omCRPC, provided that all lesions received ablative radiation doses. Future prospective study of SBRT for men receiving ARSI is warranted.

Characteristics and Predictors of Radiographic Local Failure in Patients With Spinal Metastases Treated With Palliative Conventional Radiation Therapy

Purpose

Although local control is an important issue for longer-term survivors of spinal metastases treated with conventional external beam radiation therapy (EBRT), the literature on radiographic local failure (LF) in these patients is sparse. To inform clinical decision-making, we evaluated rates, consequences, and predictors of radiographic LF in patients with spinal metastases managed with palliative conventional EBRT alone.

Methods and Materials

We retrospectively reviewed 296 patients with spinal metastases who received palliative EBRT at a single institution (2006-2013). Radiographic LF was defined as radiologic progression within the treatment field, with death considered a competing risk. Kaplan-Meier, cumulative incidence, and Cox regression analyses determined overall survival estimates, LF rates, and predictors of LF, respectively.

Results

There were 182 patients with follow-up computed tomography or magnetic resonance imaging; median overall survival for these patients was 7.7 months. Patients received a median of 30 Gy in 10 fractions to a median of 4 vertebral bodies. Overall, 74 of 182 patients (40.7%) experienced LF. The 6-, 12-, and 18-month LF rates were 26.5%, 33.1%, and 36.5%, respectively, while corresponding rates of death were 24.3%, 38.1%, and 45.9%. Median time to LF was 3.8 months. Of those with LF, 51.4% had new compression fractures, 39.2% were admitted for pain control, and 35.1% received reirradiation; median time from radiation therapy (RT) to each of these events was 3.0, 5.7, and 9.2 months, respectively. Independent predictors of LF included single-fraction RT (8 Gy) (hazard ratio [HR], 2.592; 95% confidence interval [CI], 1.437-4.675; P = .002), lung histology (HR, 3.568; 95% CI, 1.532-8.309; P = .003), and kidney histology (HR, 4.937; 95% CI, 1.529-15.935; P = .008).

Conclusions

Patients experienced a >30% rate of radiographic LF by 1 year after EBRT. Single-fraction RT and lung or kidney histology predicted LF. Given the high rates of LF for patients with favorable prognosis, assessing the risk of death versus LF is important for clinical decision-making.

Characteristics of Patients and Treatment Recommendations from a Multidisciplinary Spinal Tumor Program

Objective: We describe characteristics of patient and treatment recommendations from a spinal tumor board at one institution, including representation from palliative care.

Background: The impact of prospective multidisciplinary input for patients with spinal tumors is poorly understood despite their increasing complexity.

Methods: We retrospectively reviewed 622 cases sequentially discussed at a weekly spinal tumor board, and abstracted patient and treatment information from the medical record and meeting minutes.

Results: From April 2017 to February 2019, 622 cases representing 438 unique patients were discussed. The median age was 62 years (range 21–92). Most patients had spinal tumors originating from metastases (91.78%), including breast (14.3%), nonsmall cell lung cancer (13.4%), prostate (10.9%), and renal cell cancer (8.8%), and the remainder had primary central nervous system (4.3%) or benign tumors (3.9%). Sixty-five percent of patients were alive at last follow-up. Conventional external beam radiotherapy was the most common treatment recommendation (33.8%) followed by surgery (26.2%), stereotactic body radiation therapy (17.8%), imaging follow-up (16.6%), and vertebroplasty (15.9%). Palliative care was the primary treatment recommended for 4.5%, and no therapy recommended for 4.0%. Treatment recommendation involved two modalities for 29% of cases, and three in 1.3% of cases. In four cases, biopsy to confirm pathology changed management due to unexpected findings of osteomyelitis, hematopoiesis, or new diagnosis of plasmacytoma.

Conclusions: Multidisciplinary input is integral to the optimal care of spinal tumor patients. The high risk of death highlights the need to prioritize modalities that optimize quality of life in the context of a patient's individual prognosis.

Pathways for Recruiting and Retaining Women and Underrepresented Minority Clinicians and Physician Scientists Into the Radiation Oncology Workforce: A Summary of the 2019 ASTRO/NCI Diversity Symposium Session at the ASTRO Annual Meeting

Diversifying the radiation oncology workforce is an urgent and unmet need. During the American Society of Radiation Oncology (ASTRO) 2019 Annual Meeting, ASTRO's Committee on Health Equity, Diversity, and Inclusion (CHEDI) and the National Cancer Institute (NCI) collaborated on the ASTRO-NCI Diversity Symposium, entitled "Pathways for Recruiting and Retaining Women and Underrepresented Minority Clinicians and Physician Scientists Into the Radiation Oncology Workforce." Herein, we summarize the presented data and personal anecdotes with the goal of raising awareness of ongoing and future initiatives to improve recruitment and retention of underrepesented groups to radiation oncology. Common themes include the pivotal role of mentorship and standardized institutional practices – such as protected time and pay parity – as critical to achieving a more diverse and inclusive workplace.

Mechanisms generating cancer genome complexity from a single cell division error

The chromosome breakage-fusion-bridge (BFB) cycle is a mutational process that produces gene amplification and genome instability. Signatures of BFB cycles can be observed in cancer genomes alongside chromothripsis, another catastrophic mutational phenomenon. We explain this association by elucidating a mutational cascade that is triggered by a single cell division error-chromosome bridge formation-that rapidly increases genomic complexity. We show that actomyosin forces are required for initial bridge breakage. Chromothripsis accumulates, beginning with aberrant interphase replication of bridge DNA. A subsequent burst of DNA replication in the next mitosis generates extensive DNA damage. During this second cell division, broken bridge chromosomes frequently missegregate and form micronuclei, promoting additional chromothripsis. We propose that iterations of this mutational cascade generate the continuing evolution and subclonal heterogeneity characteristic of many human cancers.

Inhibition of Haspin Kinase Promotes Cell-Intrinsic and Extrinsic Antitumor Activity

Patients with melanoma resistant to RAF/MEK inhibitors (RMi) are frequently resistant to other therapies, such as immune checkpoint inhibitors (ICI), and individuals succumb to their disease. New drugs that control tumor growth and favorably modulate the immune environment are therefore needed. We report that the small-molecule CX-6258 has potent activity against both RMi-sensitive (RMS) and -resistant (RMR) melanoma cell lines. Haspin kinase (HASPIN) was identified as a target of CX-6258. HASPIN inhibition resulted in reduced proliferation, frequent formation of micronuclei, recruitment of cGAS, and activation of the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway. In murine models, CX-6258 induced a potent cGAS-dependent type-I IFN response in tumor cells, increased IFNγ-producing CD8+ T cells, and reduced Treg frequency in vivo. HASPIN was more strongly expressed in malignant compared with healthy tissue and its inhibition by CX-6258 had minimal toxicity in ex vivo-expanded human tumor-infiltrating lymphocytes (TIL), proliferating TILs, and in vitro differentiated neurons, suggesting a potential therapeutic index for anticancer therapy. Furthermore, the activity of CX-6258 was validated in several Ewing sarcoma and multiple myeloma cell lines. Thus, HASPIN inhibition may overcome drug resistance in melanoma, modulate the immune environment, and target a vulnerability in different cancer lineages. SIGNIFICANCE: HASPIN inhibition by CX-6258 is a novel and potent strategy for RAF/MEK inhibitor-resistant melanoma and potentially other tumor types. HASPIN inhibition has direct antitumor activity and induces a favorable immune microenvironment.

Ethical issues in patients referred for palliative radiation therapy

BACKGROUND

As patients with advanced cancer approach end of life, ethical issues may arise. We describe ethical issues encountered by radiation oncologists in this setting.

METHODS

A prospective, survey-based study assessed 162 consecutive consults for palliative radiation therapy (PRT) over 4 months at 3 hospitals. Consulting radiation clinicians completed a survey assessing palliative care issues encountered, based on national guidelines. Ethical issues included 5 subthemes (conflict between clinicians, caregiver-clinician conflict, internal conflict, feeling unable to do what was best for the patient, and violation of personal morals), an option for unclassified issues, and open-ended responses. Multivariate analyses (MVA) assessed potential patient-related predictors of ethical issues: gender, performance status (PS), PRT indication, physical symptoms, and presence of psychosocial, goals of care, care coordination, cultural, or spiritual issues.

RESULTS

Of 162 surveys, 140 were completed (response rate =86%). Overall, 14 (10%) surveys identified ethical issues relevant to care; 11 of 14 (78%) identified more than 1 ethical issue. Half (7; 50%) involved conflict between clinicians and clinician-caregiver conflict; 6 (43%) involved clinician distress or internal conflict; and 2 (14%) felt impeded from doing what they felt was best for the patient. Open-ended responses revealed differences in opinion between medical specialties (n=6, 43%), and conflict related to coordination of care among clinicians (n=3, 21%). On UVA, ethical issues were associated with PRT referrals for bleeding, dyspnea, or dysphagia due to visceral metastases (30%) versus CNS indications such as brain metastases or cord compression (7%) or for bony metastases (4%) P<0.001. On MVA, ethical issues were associated with PRT for visceral metastases (OR 13.0; 95% CI, 2.3-74.6; P<0.001) and presence of spiritual issues (OR 4.0; 95% CI, 1.1-14.5; P=0.04).

CONCLUSIONS

At least 1 in 10 referrals for PRT involve ethical issues. Further studies are warranted to assess the ability of radiation oncologists to manage ethical issues.

Patterns of palliative care among patients receiving palliative radiotherapy

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Background: Few studies have examined how palliative care (PC) delivered by a dedicated PC team is integrated at the time of radiotherapy (RT) consultation. We aimed to characterize patterns of PC in relation to RT, predictors of PC, and outcomes based on PC integration. Methods: We retrospectively reviewed 162 patients with metastatic cancer who received palliative RT at a single institution (7/2017-2/2018). PC integration was defined as: no PC, concurrent PC (PC initiated +/- 4 weeks within RT consult), established PC (any PC visit in the 6 months prior to RT consult), and subsequent PC (PC initiated > 4 weeks after RT consult). Logistic regression analyses determined predictors of receiving any PC. Cox proportional hazards regression identified predictors of OS. Results: Median follow-up was 7.8 months (range: 0.3-20.6). Patients (56% female; 84% white; median age: 64 years (range: 22-94)) had a median of 2 metastatic sites (range: 1-6) and 2 prior courses of palliative chemotherapy (range: 0-7). Of the 74 patients (46%) with any PC, 24 (32%) had concurrent PC, 21 (28%) had established PC, and 29 (39%) had subsequent PC. The most common reasons for PC initiation were pain (58%) and goals of care/end-of-life care management (20%). Nearly half (49%) of PC consults occurred in an inpatient setting; a minority (22%) of RT consults were inpatient. On multivariate analysis, receiving any PC significantly differed by race (non-white vs white, OR = 6.40 [95% CI 1.98-20.69], p = 0.002), cancer type (lung vs non-breast other histology, OR = 0.15 [95% CI 0.06-0.35], p < 0.001), and RT consult setting (inpatient vs outpatient, OR = 3.32 [95% CI 1.36-8.13], p = 0.009). On multivariate analysis, male sex (HR = 1.51 [95% CI 1.01-2.27], p = 0.046) and ECOG 2-4 (HR = 2.22 [95% CI 1.47-3.36], p < 0.001) predicted worse OS. Age, marital status, language, insurance type, metastatic burden, prior palliative chemotherapy, and PC integration were not independent predictors of OS. Conclusions: At our institution, dedicated PC occurred in < 50% of patients receiving palliative RT for metastatic cancer. We need initiatives to increase PC for all palliative RT patients, especially in the outpatient setting and for those with lung cancer who were less likely to receive dedicated PC.

Translational and basic science opportunities in palliative care and radiation oncology

Radiation therapy is commonly used in the metastatic setting to palliate pain, neurological deficits, bleeding and other complications of metastatic disease, allowing patients to live longer and have better quality of life. Despite the effective use of radiation and other palliative treatment modalities, many patients continue to experience poorly controlled pain and other serious sequelae of their disease, underscoring the need for additional research in this area. In this review we highlight recent developments impacting the fields of palliative care and radiation oncology and describe opportunities for research and innovation including studies of tumor microenvironment, identification of effective biomarkers of tumor response and combinatorial treatments with new systemic agents. It is our hope that progress in these fields will improve the lives of patients living with advanced malignancies.

Palliative Radiation Therapy for Vertebral Metastases and Metastatic Cord Compression in Patients Treated With Anti-PD-1 Therapy

Background: There is increasing use of immune checkpoint blockade (ICB) across multiple cancer types, including in patients at risk for vertebral metastases and cord compression. These patients are often treated with palliative radiotherapy (PRT); however, data evaluating the combination of PRT and ICB in patients with vertebral metastases is limited. Furthermore, patients with cord compression are generally excluded from prospective clinical trials. Therefore, we retrospectively evaluated outcomes following PRT and PD-1 inhibition in patients with vertebral metastases. Methods: We performed a retrospective chart review of 37 consecutive patients (total 57 lesions) treated with radiation for vertebral metastases who also received PD-1 inhibition. Patient, treatment and outcomes data were abstracted from the medical records. Results: Histologies included non-small cell lung cancer (n = 21), renal cell carcinoma (n = 9) and melanoma (n = 7). Out of 57 lesions,18 involved >1 segments of the vertebral column. There were isolated lesions in thoracic (16), lumbar (9), cervical (6), and sacral (8) vertebrae. Presenting symptoms included pain (19), numbness (10), and weakness (3). Eleven patients were asymptomatic. Radiologic cord compression was present in 12, epidural extension in 28 and compression fracture in 14. Eleven patients underwent surgical decompression prior to the onset of RT. Median radiation dose was 24 Gy (range 8-30 Gy). Stereotactic radiation was delivered in 4 patients; 33 patients received conformal RT. 21 patients received PD-1 inhibition after RT, 9 before RT and 7 with RT. Seven patients received concurrent CTLA-4 inhibitors with anti-PD-1 therapy. Treatment was in general well-tolerated. Toxicities included fatigue (6), transient pain flare (1), nausea/vomiting (1) and G1 skin changes (1). All patients reported some degree of pain relief. Numbness/weakness was improved in 6 of 13 patients with baseline symptoms (46%) and this was more likely in patients that received vertebral radiation after starting PD-1 inhibitors (71 vs. 17%, p = 0.04). Most patients (22 of 33 evaluable patients, 67%) had stability of irradiated lesions on subsequent follow up imaging performed at median of 30 days from RT, whereas 3 had a complete local response and 4 had a partial local response. Conclusions: We demonstrate that PRT administered to vertebral metastases was well-tolerated and effective in patients treated with PD-1 inhibitors. There was an encouraging rate of pain reduction and neurological improvement.

Cells Lacking the RB1 Tumor Suppressor Gene Are Hyperdependent on Aurora B Kinase for Survival

Small cell lung cancer (SCLC) accounts for 15% of lung cancers and is almost always linked to inactivating RB1 and TP53 mutations. SCLC frequently responds, albeit briefly, to chemotherapy. The canonical function of the RB1 gene product RB1 is to repress the E2F transcription factor family. RB1 also plays both E2F-dependent and E2F-independent mitotic roles. We performed a synthetic lethal CRISPR/Cas9 screen in an RB1 -/- SCLC cell line that conditionally expresses RB1 to identify dependencies that are caused by RB1 loss and discovered that RB1 -/- SCLC cell lines are hyperdependent on multiple proteins linked to chromosomal segregation, including Aurora B kinase. Moreover, we show that an Aurora B kinase inhibitor is efficacious in multiple preclinical SCLC models at concentrations that are well tolerated in mice. These results suggest that RB1 loss is a predictive biomarker for sensitivity to Aurora B kinase inhibitors in SCLC and perhaps other RB1 -/- cancers. SIGNIFICANCE: SCLC is rarely associated with actionable protooncogene mutations. We did a CRISPR/Cas9-based screen that showed that RB1 -/- SCLC are hyperdependent on AURKB, likely because both genes control mitotic fidelity, and confirmed that Aurora B kinase inhibitors are efficacious against RB1 -/- SCLC tumors in mice at nontoxic doses.See related commentary by Dick and Li, p. 169.This article is highlighted in the In This Issue feature, p. 151.

Cell Biology: When Your Own Chromosomes Act like Foreign DNA

Two recent papers report the activation of a pro-inflammatory response by cytoplasmic DNA from aberrant nuclear structures called micronuclei. The findings have implications for tumor immunity, immunotherapy biomarker discovery, and possibly the many-sided effects of senescence-associated secretory phenotype.

Characteristics of urgent palliative cancer care consultations encountered by radiation oncologists

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Background: Palliative radiation therapy(PRT)is often employed in patients with advanced cancers requiring urgent consultation given the rapidity of presentation.We report on characteristics of urgent palliative oncologic issues encountered by radiation oncologists(RO). Methods: We prospectively evaluated patterns of presentation in162 consecutive consultations for urgent PRT at 3 centers from 5/19/14 to 9/26/14.Survey of palliative care issues was completed by physicians/nurse practitioners including assessment of reasons for urgent radiation oncology consultation,disease presentation characteristics and site of RT delivery.Response rate was 86% with 140 of 162 responses received. Results: Median age of patients was 63 years(29-89)with 39% > 65, 41% from 50-65 and 20% < 50 years;56% were males and 44% females. Most were married(62%)and 30% non-Caucasians.48% had ECOG PS 0-1,whereas it was 2, 3 and 4 in 24%,9% and 3%.Primary cancer diagnoses were lung (28%),breast(13%),prostate(10%),melanoma(10%),sarcoma(7%) and other diagnoses in 32%.Pain was predominant reason for consult(57%)followed by brain metastases(29%),spinal cord/cauda compression (13%),dyspnea (10%),bleeding (8%),bone fracture(4%)and dysphagia(2%).Clinicians managed pain (69%),neurologic symptoms(51%),fatigue (49%),intestinal(21%),respiratory (19%) symptoms,bleeding (14%),insomnia (13%),nausea/vomiting(12%)and dysphagia(6%).Patients presented at all stages 79% at the time of their diagnosis of metastatic cancer,63% with an established ( > 1 month) metastatic cancer diagnosis and continuing to further cancer therapies and 17% proceeding to hospice care without further anti-cancer therapy after PRT. Conclusions: Radiation oncologists care for patients across time course of metastatic cancer diagnosis managing variety of urgent oncologic issues,most commonly metastases causing pain followed by brain metastases and cord compression.They also manage cancer-related symptoms,mostly pain,neurological symptoms and fatigue.These findings point to need for palliative care to be well integrated into radiation oncology practice including education and systems of care.

Multicenter Evaluation of the Tolerability of Combined Treatment With PD-1 and CTLA-4 Immune Checkpoint Inhibitors and Palliative Radiation Therapy

PURPOSE

To analyze immune-related adverse events (ir-AEs) in patients treated with radiation and immune checkpoint blockade.

METHODS AND MATERIALS

We retrospectively reviewed records from patients with metastatic non-small cell lung cancer, melanoma, or renal cell cancer who received at least 1 cycle of a CTLA-4 or PD-1 inhibitor and radiation. Immune-related adverse events, defined using Common Terminology Criteria for Adverse Events version 4.0, were tabulated in relation to treatment variables, and associations with sequencing and timing were assessed.

RESULTS

We identified 133 patients, of whom 28 received a CTLA-4 inhibitor alone, 88 received a PD-1 inhibitor alone, and 17 received both classes of inhibitors either sequentially (n=13) or concurrently (n=4). Fifty-six patients received radiation within 14 days of an immune checkpoint inhibitor. Forty-six patients experienced at least 1 ir-AE (34.6%). Patients receiving both CTLA-4 and PD-1 inhibitors experienced more any-grade ir-AEs as compared with either individually (71% vs 29%, P=.0008). Any-grade ir-AEs occurred in 39% of patients in whom radiation was administered within 14 days of immunotherapy, compared with 23% of other patients (P=.06) and more often in patients who received higher equivalent dose in 2-Gy fractions (EQD2) EQD2 (P=.01). However, most toxicities were mild. There were no associations between site irradiated and specific ir-AEs.

CONCLUSIONS

Our data suggest the combination of focal palliative radiation and CTLA-4 and/or PD-1 inhibitors is well tolerated, with manageable ir-AEs that did not seem to be associated with the particular site irradiated. Although conclusions are limited by the heterogeneity of patients and treatments, and future confirmatory studies are needed, this information can help guide clinical practice for patients receiving immune checkpoint therapy who require palliative radiation therapy.

Acute pain management in radiation oncology: Quality of care and the impact of an integrated palliative oncology service

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Background: Radiotherapy (RT) effectively palliates bone metastases, but relief may take weeks, frequently necessitating acute pain management (APM). NCCN Guidelines for Adult Cancer Pain (V2.2015) recommend initiation/titration of analgesics for patients with pain scale value (PSV) ≥ 4. We sought to evaluate how often symptomatic patients have analgesic regimens assessed and intervened upon at radiation oncology (RO) consult for bone metastases, and the impact of a dedicated palliative RO service on APM. Methods: We reviewed consult notes for 217 bone metastases patients treated with RT at Dana Farber Cancer Institute/Brigham & Women’s Hospital (DFCI/BWH) and University of California, San Francisco (UCSF) during June-July 2008, Jan-Feb 2010, Jan-Feb 2013, and June-July 2014, time periods before and after implementation in 2011 of a dedicated palliative RO service at DFCI/BWH. For symptomatic patients, rate of assessment of analgesic regimen was recorded. Among patients with PSV ≥ 4, rate of pain intervention was recorded. The impact of a palliative RO service on these rates was evaluated. Results: Median age was 63 and median KPS was 70. Median PSV for painful bone metastases was 5 (IQR 2-7); 51% had PSV ≥ 4. Among symptomatic patients, analgesic regimen was assessed for 44.5% (51.7% at DFCI/BWH and 28.1% at UCSF). Among patients with PSV ≥ 4, pain intervention occurred for 17.2% (20.5% for DFCI/BWH, 0% for UCSF). At DFCI/BWH, consultation by a dedicated palliative RO provider was associated with higher rate of assessment of analgesic regimen (82.4% vs 47.7%, p = 0.007). At DFCI/BWH, consultation by a palliative RO provider was associated with higher rate of pain intervention (31.2% vs 7.9%, p = 0.012). There was no difference in analgesic regimen assessment or intervention between non-dedicated palliative RO providers at DFCI/BWH and UCSF (p = 0.07 and 0.09, respectively). Conclusions: At two cancer centers, half of bone metastases patients seen for RT have PSV ≥ 4, yet a minority have analgesic assessment and intervention, indicating need for APM quality improvement in RO. An integrated palliative RO service was associated with improved assessment and management of acute pain per NCCN guidelines.