Focal versus whole gland salvage brachytherapy for recurrent prostate cancer in the prostate specific membrane antigen PET era: a narrative review

BACKGROUND AND OBJECTIVE

Prostate cancer is the second most common cause of cancer in men worldwide. A significant proportion of patients will develop biochemical failure after definitive radiotherapy and an increasing number of local failures are now identifiable with prostate specific membrane antigen (PSMA) positron emission tomography and computerized tomography (PET/CT). Brachytherapy (BT) represents an excellent option for definitive local salvage treatment. Consensus guidelines for the delivery of salvage BT are heterogenous and limited. Herein, we report the results from a narrative review analyzing whole gland and partial gland BT salvage to help guide treatment recommendations.

METHODS

The PubMed and MEDLINE databases were searched in October 2022 to identify studies analyzing BT salvage in patients with recurrent prostate cancer after definitive external beam radiation therapy (EBRT). 503 initial studies met search criteria. After title and abstract screening, 25 studies met inclusion criteria and full-text review was performed. Twenty studies were included for analysis. Reports included whole gland (n=13) and partial gland or focal (n=7) salvage BT.

KEY CONTENT AND FINDINGS

The median 5-year biochemical failure free survival (BFFS) for men receiving whole gland BT salvage was 52%, which is comparable to 5-year recurrence-free survival (RFS) rates for other salvage treatment modalities (radical prostatectomy (RP) 54%, high-intensity focused ultrasound (HIFU) 53%, cryotherapy 50%). However, the median rate of severe genitourinary (GU) toxicity was lower (12%) compared to published rates for other treatment modalities (RP 21%, HIFU 23%, and cryotherapy 15%). Furthermore, patients receiving partial gland salvage BT had even lower median rates of grade 3 or higher GU toxicity (4% vs. 12%) and gastrointestinal (GI) toxicity (0% vs. 3%), with 3-year BFFS of 58%. Only two studies directly comparing BT whole versus partial gland salvage were identified with comprehensive literature search and neither provided specific comparison regarding prescription dose or dose constraints.

CONCLUSIONS

This narrative review identified only two studies that directly compared whole versus partial gland BT salvage treatment. Neither report provided a specific comparison of recommendations for dosimetric technique or normal structure dose constraints. Therefore, this review highlights a significant gap in the existing literature and provides an important framework to guide radiation treatment (RT) recommendations for both whole gland and partial gland salvage BT in patients with recurrent prostate cancer.

Prognostic impact of biologically equivalent dose in stereotactic body radiotherapy for renal cancer

Purpose /Objectives Materials/Methods

The National Cancer Database (NCDB) was queried (2004-2017) for patients with RCC who did not have surgical resection but received definitive SBRT. Kaplan-Meier analysis with log-rank test was used to evaluate overall survival (OS). Univariable (UVA) and multivariable (MVA) analysis were conducted using cox proportional hazard models to determine prognostic factors for OS.

Results

A total of 344 patients with median age 77 (IQR 70-85) were included in this study. Median BED₃ was 180 Gy (IQR 126.03-233.97). Median OS was 90 months in the highest quartile compared to 36-52 months in the lower three quartiles (p < 0.01). On UVA, the highest BED₃ quartile was a positive prognostic factor (HR 0.67, p < 0.01 CI 0.51-0.91) while age, tumor size, T-stage, metastasis, renal pelvis location, and transitional cell histology were negative factors. On MVA, the highest BED₃ quartile was remained significant (HR 0.69, p = 0.02; CI 0.49-0.95) as a positive factor, while age, metastasis were negative factors.

Conclusion

Higher BED may be associated with improved OS. Prospective investigation is needed to clearly define optimal BED for SBRT used to treat RCC.

Comparative real-world survival outcomes of muscle-invasive bladder cancer treated with bladder-only vs. whole-pelvis concurrent chemoradiation

488

Background: Elective nodal irradiation for patients with muscle-invasive bladder cancer (MIBC) undergoing trimodal therapy (TMT) is controversial. In patients with node-negative (N0) MIBC, the benefit of elective whole-pelvis concurrent chemoradiotherapy (WP-CCRT) compared to bladder-only (BO)-CCRT has not been demonstrated. Currently, the National Comprehensive Cancer Network (NCCN) guidelines do not recommend whether to include pelvic nodes in the radiation field. Using real-world data from the National Cancer Database (NCDB), we sought to compare the overall survival (OS) between BO-CCRT and WP-CCRT for MIBC. Methods: Using the 2019 NCDB Participant User File, we identified cases of MIBC diagnosed between 2017 and 2018. We selected patients with clinical T2-T4N0M0 disease receiving TMT as first-line treatment. TMT was defined as transurethral resection of bladder tumor followed by CCRT: 60–65 Gy of RT delivered to the bladder with concurrent single- or multiple-agent chemotherapy. Patients were stratified into BO-CCRT vs. WP-CCRT. Overall survival (OS) analysis was performed using Kaplan-Meier estimates and multivariable Cox proportional hazards regression analysis. The variables included in the multivariable Cox regression model were age, sex, race, comorbidity burden (as per the Charlson-Deyo comorbidity index), facility type, insurance status, median income quartile, rurality, distance from facility, and clinical T stage. Results: A total of 605 patients receiving TMT for MIBC were identified: 162 (26.8%) BO-CCRT and 443 (73.2%) WP-CCRT. The median follow-up time was 25.6 months (interquartile range [IQR]: 4.8-42.6) and 28.7 months (IQR: 3.0-51.6) for BO-CCRT and WP-CCRT, respectively. The median OS was 32.9 months (95% confidence interval [CI] 30.8 – not reached) and 48.3 months (95% CI 39.6 – not reached) for BO-CCRT and WP-CCRT, respectively. However, multivariable Cox regression analysis failed to find an association between WP-CCRT (hazard ratio [HR] 1.08, 95% CI 0.76-1.54) and improved OS, compared to BO-CCRT. Conclusions: Elective nodal-irradiation (WP-CCRT) in the setting of TMT for MIBC was not associated with a benefit in OS compared to BO-CCRT.

Leptomeningeal metastasis from neuroendocrine carcinoma of the cervix: illustrative case

BACKGROUND

Leptomeningeal carcinomatosis is a rare feature of metastasis that is characterized by thickening and increased contrast enhancement throughout the meninges of the central nervous system (CNS). Leptomeningeal disease (LMD) can occur as spread from primary CNS tumors or as a manifestation of metastasis to the CNS from primary tumor sites outside the CNS. Leptomeningeal disease is, however, rare in cervical cancer, in which metastasis occurs typically from local invasion.

OBSERVATIONS

The authors discuss the case of CNS metastasis with LMD from the rare neuroendocrine carcinoma of the cervix (NECC). Cervical cancer infrequently metastasizes to the CNS, but NECC is an aggressive variant with greater metastatic potential. Many of these patients will have previously received pelvic radiation, limiting their candidacy for craniospinal radiation for LMD treatment due to field overlap. This illustrative case documents the first known case of NECC CNS metastasis accompanied by LMD treated with intrathecal chemotherapy.

LESSONS

Reported is the first known case of NECC with CNS metastasis accompanied by LMD. The authors highlight the potentially critical role of intrathecal chemotherapy, in addition to radiotherapy, in treating leptomeningeal metastasis from cervical cancer.

A Phase 2 Trial of Enhancing Immune Checkpoint Blockade by Stereotactic Radiation and In Situ Virus Gene Therapy in Metastatic Triple-Negative Breast Cancer

PURPOSE

A Phase 2 trial of stereotactic radiotherapy and in situ cytotoxic virus therapy in patients with metastatic triple-negative breast cancer (mTNBC) followed by pembrolizumab (STOMP) was designed to evaluate dual approach of enhancing single-agent immune checkpoint blockade with adenovirus-mediated expression of herpes-simplex-virus thymidine-kinase (ADV/HSV-tk) plus valacyclovir gene therapy and stereotactic body radiotherapy (SBRT) in patients with mTNBC.

PATIENTS AND METHODS

In this single-arm, open-label Phase 2 trial, patients with mTNBC were treated with ADV/HSV-tk [5 × 1011 virus particles (vp)] intratumoral injection, followed by SBRT to the injected tumor site, then pembrolizumab (200 mg, every 3 weeks). The primary endpoint was clinical benefit rate [CBR; complete response (CR), partial response (PR), or stable disease (SD) ≥ 24 weeks per RECIST version1.1 at non-irradiated site]. Secondary endpoints included duration on treatment (DoT), overall survival (OS), and safety. Exploratory endpoints included immune response to treatment assessed by correlative tissue and blood-based biomarkers.

RESULTS

Twenty-eight patients were enrolled and treated. CBR was seen in 6 patients (21.4%), including 2 CR (7.1%), 1 PR (3.6%), and 3 SD (10.7%). Patients with clinical benefit had durable responses, with median DoT of 9.6 months and OS of 14.7 months. The median OS was 6.6 months in the total population. The combination was well tolerated. Correlative studies with Cytometry by Time of Flight (CyTOF) and imaging mass cytometry (IMC) revealed a significant increase of CD8 T cells in responders and of myeloid cells in non-responders.

CONCLUSIONS

The median OS increased by more than 2-fold in patients with clinical benefit. The therapy is a well-tolerated treatment in heavily pretreated patients with mTNBC. Early detection of increased effector and effector memory CD8 T cells and myeloids correlate with response and non-response, respectively.

Role of 21- gene recurrence score in predicting prognostic benefit of radiotherapy following breast-conserving surgery for T1N0 breast cancer

PURPOSE

The 21- gene RT-PCR recurrence score (RS) is performed in patients with hormone receptor positive, HER2 negative, node- negative breast cancer to determine which patients will likely benefit from chemotherapy following breast conserving surgery (BCS). The purpose of this study was to evaluate whether the RS can predict for patients likely to benefit from radiation therapy (RT) following BCS.

MATERIALS AND METHODS

The National Cancer Database (NCDB) was queried (2004-2017) for female patients with pT1N0 ER+ PR+ HER2- breast cancer treated with BCS who had an available RS. Patients were stratified based on their RS (low risk [LR]= 1-10, intermediate risk [IR]= 11-25, high risk [HR]= 26-100). For each RS cohort, propensity score matching (PSM) was conducted to create 1:1 matched cohorts of patients who received RT and patients who did not. Kaplan-Meier analysis evaluated overall survival (OS). Univariable (UVA) and multivariable (MVA) Cox proportional hazard analysis identified clinical and treatment factors prognostic for OS.

RESULTS

A total of 79,040 patients met the selection criteria: 18,823 in the LR cohort, 52,341 in the IR cohort, and 7,876 in the HR cohort. A total of 92% received RT: 91% in the LR cohort, 93% in the IR cohort, and 92% in the HR cohort. After PSM, the 5-year OS in the LR cohort was 95% for those who received RT and 93% for those who did not (p= 0.184). In the IR cohort, the 5-year OS was 95% for those who received RT and 93% for those who did not (p= 0.001). In the HR cohort, the 5-year OS was 95% for those who received RT and 84% for those who did not (p< 0.001). MVA demonstrated that RT was a positive prognostic factor for OS in both the IR cohort (p= 0.001) and HR cohort (p< 0.001). On MVA in the LR cohort, RT (p= 0.186) was not predictive of improved OS.

CONCLUSION

An OS benefit was observed with the use of RT in patients with IR or HR RS but not in patients with LR RS. Future prospective evaluation is warranted.

21-Gene recurrence score predictive for prognostic benefit of radiotherapy in patients age ≥ 70 with T1N0 ER/PR + HER2- breast cancer treated with breast conserving surgery and endocrine therapy

PURPOSE

Based on the results of the Cancer and Leukemia Group B (CALGB) 9343 trial, patients age ≥70 with T1N0 hormone receptor positive (ER/PR+), human epidermal growth factor receptor-2 negative (HER2-) breast cancer who are treated with breast conserving surgery (BCS) and endocrine therapy (ET) are candidates for omission of radiotherapy (RT). Because the CALGB 9343 trial did not stratify based on recurrence score (RS) test (Oncotype Dx), we conducted the present retrospective study to determine whether RS is predictive of who may benefit from RT following BCS in this cohort.

MATERIALS AND METHODS

The National Cancer Database (NCDB) was queried (2004-2017) for patients age ≥ 70 with pT1N0 ER+/PR + HER2- breast cancer treated with BCS and ET. Patients were stratified based on their RS (low risk [LR] = 1-10, intermediate risk [IR] = 11-25, high risk [HR] = 26-99). Propensity score matching (PSM) created 1:1 matched cohorts of patients who received radiotherapy and those who did not. Kaplan-Meier analysis evaluated overall survival (OS). Univariable (UVA) and multivariable (MVA) Cox proportional hazard analyses identified clinical and treatment factors prognostic for OS.

RESULTS

A total of 11,891 patients met the selection criteria: 3364 in the LR cohort, 7305 in the IR cohort, and 1222 in the HR cohort. A total of 79 % received RT: 77 % in the LR cohort, 79 % in the IR cohort, and 85 % in the HR cohort. Because PSM could not be efficiently performed in the HR cohort alone, the IR and HR cohort were merged (IRHR) for matching. After PSM, the 5-year OS in the LR cohort was 91 % for those who received RT and 89 % for those who did not (p = 0.605). In the IRHR cohort, the 5-year OS was 91 % for those who received RT and 87 % for those who did not (p = 0.003). On MVA in the LR cohort, RT (p = 0.727) was not predictive of improved OS. On MVA in the IRHR cohort, RT (p = 0.010) was a positive prognostic factor for OS.

CONCLUSION

In this older cohort of patients, there is an OS benefit with the use of RT in patients with IRHR RS but not in patients with LR RS. Pending prospective evaluation, assessment of RS in this older subset of patients is recommended with consideration of RT when RS is ≥11.

A phase II clinical trial of neoadjuvant sasanlimab and stereotactic body radiation therapy as an in situ vaccine for cisplatin-ineligible muscle invasive bladder cancer (RAD VACCINE MIBC)

TPS4611

Background: The utilization of neoadjuvant immune checkpoint inhibitor (ICI) therapy, including anti-PD1/L1 agents, prior to radical cystectomy (RC), is an emerging paradigm in muscle invasive bladder cancer (MIBC). Pathologic complete responses (pCR) have been observed in 25-40% of patients with neoadjuvant PD1/L1 inhibitor monotherapy for cisplatin-ineligible MIBC. In situ vaccination using stereotactic body radiation therapy (SBRT) may augment T-cell responses to tumor-specific antigens through immunogenic cell death. Sasanlimab (PF-06801591) is a humanized IgG monoclonal antibody that targets PD-1 selectively, for which there are both Phase 1 data and ongoing Phase 3 trials in early-stage urothelial carcinoma. There exists a strong rationale to evaluate a novel strategy of combination neoadjuvant ICI therapy with SBRT as an in situ vaccine to improve loco-regional control and decrease the risk of distant recurrence in cisplatin-ineligible patients with MIBC. Methods: This is a prospective, investigator-initiated, single-arm, single-institution, phase II trial that evaluates neoadjuvant sasanlimab in combination with SBRT as neoadjuvant therapy for patients with MIBC before RC. Eligibility requires patients to be cisplatin-ineligible (one of the following: ECOG-PS=2, creatinine clearance <60 ml/min, or comorbidities such as hearing loss or neuropathy) or those who refuse cisplatin-based chemotherapy. Sasanlimab (300 mg) will be administered subcutaneously on Day 1 of each 28-day cycle for a total of 2 cycles, in combination with SBRT to the primary tumor at a dose of 24Gy given in 3 fractions, starting on Day 1 of Cycle 2 with a 48-hour interval between fractions. The combination treatment will be assessed by using a Simon’s 2-Stage design, which the first 10 patients are enrolled as a safety lead-in to evaluate the safety and feasibility. Futility analysis will be performed after a total of 18 patients. The primary endpoint is pCR rate after neoadjuvant sasanlimab/SBRT, followed by RC. If pCR is observed in 4 or fewer patients, further enrollment of patients may be stopped with the conclusion that pT0 cannot be 40% or greater. Otherwise, an additional 15 patients will be accrued in stage II, resulting in a total of 33 patients. Secondary endpoints include adverse events, surgical complication rates, health related quality-of-life, overall survival, and recurrence free survival. Exploratory endpoints include analysis of and association with pCR of the tumor/germline genetic signatures, circulating tumor DNA, tumor PD-L1 expression, blood cytometry time-of-flight analysis to identify immune response. Enrollment opened on February 15, 2022. Clinical trial information: NCT05241340.

Abstract P3-19-15: Prognostic impact of radiation therapy in mucinous carcinoma of the breast

Purpose/Objectives Mucinous carcinoma (MC) of the breast is an uncommon variant of breast cancer which has a favorable prognosis. Current guidelines for ER/PR-positive, HER2-negative pure-MC state that endocrine therapy (ET) is only required for tumors ≥3cm and node-positive patients while chemotherapy (CTX) is not required but can be considered for node positive-patients. While radiation therapy (RT) currently remains a part of breast-conserving therapy (BCT) for this histology, the prognostic impact of RT in pure MC remains unclear. Materials/Methods The National Cancer Database (NCDB) was queried (2004-2017) for patients with non-metastatic, histologically confirmed MC who received breast-conserving surgery. Kaplan-Meier analysis was used to evaluate overall survival (OS). Univariate (UVA) and multivariate (MVA) analyses were conducted using Cox proportional hazard models to determine which clinical and treatment factors were prognostic for overall survival. Results A total of 24,837 patients with median age 70 (IQR 61-78) were included in this study. A total of 66% of carcinomas were grade 1 and 34% were grade 2. A total of 79% were pT1, 20% were pT2, and 1% were pT3-4. A total of 96% were pN0 and 4% were pN1-3. A total of 99% were ER+, 92% were PR+, and 96% were HER2-. A total of 61% received RT, 70% received ET, and 8% received CTX. The 10-year OS was 73% for those who received RT and 41% for those who did not. On UVA, RT (HR 0.31, p&lt; 0.0001; CI 0.29-0.33), ET (HR 0.52, p&lt; 0.0001; CI 0.49-0.55), CTX (HR 0.40, p&lt; 0.0001; CI 0.35-0.46), and black race (HR 0.87, p= 0.006; CI 0.79- 0.96) were positive prognostic factors for OS while older age (HR 1.10, p&lt; 0.0001; CI 1.09-1.10), CDCC comorbidity score (HR 1.93, p&lt; 0.0001; CI 1.81- 2.06), and tumor size (HR 1.01, p&lt; 0.0001; CI 1.01-1.02) were negative prognostic factors. On MVA, RT (HR 0.64, p&lt; 0.0001; CI 0.59-0.69) and ET (HR 0.85, p&lt; 0.0001; CI 0.78- 0.91) remained positive prognostic factors while older age (HR 1.08, p&lt; 0.0001; CI 1.08-1.09), CDCC comorbidity score (HR 1.61, p&lt; 0.0001; CI 1.50- 1.73), and tumor size (HR 1.02, p&lt; 0.0001; CI 1.01- 1.02) remained negative prognostic factors; chemotherapy (HR 1.19, p= 0.039; CI 1.01- 1.39) became a negative prognostic factor and black race (HR 0.99, p= 0.92; CI 0.89- 1.12) was no longer prognostic. Conclusion This is the largest study to date on mucinous carcinoma of the breast and the role of RT after breast-conserving surgery. Use of postoperative RT after lumpectomy is associated with improved OS in patients with breast MC, suggesting that post-lumpectomy RT should remain standard of care.

Citation Format: Neil Chevli, Kaidi Wang, Waqar Haque, Mary R. Schwartz, Julie Nangia, Jennifer Sasaki, Andrew M. Farach, Sandra S. Hatch, E. Brian Butler, Bin S. Teh. Prognostic impact of radiation therapy in mucinous carcinoma of the breast [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-19-15.

Time Interval to Initiation of Whole-Brain Radiation Therapy in Patients With Small Cell Lung Cancer With Brain Metastasis

Purpose

Patients with small cell lung cancer (SCLC) who have brain metastases require whole-brain radiation therapy (WBRT). When there is no emergent indication for WBRT, patients may receive systemic therapy first and WBRT afterward. In scenarios when systemic therapy is initiated first, it has not been previously investigated whether delaying WBRT is harmful.

Methods and Materials

The National Cancer Database was queried (2004-2016) for patients with SCLC with brain metastases who received 30 Gy in 10 fractions of WBRT. Patients were divided into groups based on whether they received early WBRT (3-14 days after initiation of chemotherapy) or late WBRT (15-90 days after initiation of chemotherapy). Demographic and clinicopathologic categorical variables were compared between those who had early WBRT (3-14 days) and those who had late WBRT (15-90 days). Factors predictive for late WBRT were determined. Overall survival (OS), which was defined as days from diagnosis to death, was evaluated and variables prognostic for OS were determined.

Results

A total of 1082 patients met selection criteria; 587 (54%) had early WBRT and 495 (46%) received late WBRT. Groups were similarly distributed aside from days from initiating chemotherapy to initiating WBRT (P < .001). The early WBRT group had a median of 7 days (interquartile range [IQR], 5-10 days) from initiating chemotherapy to initiating WBRT and the late WBRT group had a median of 34 days (IQR, 21-57 days). On binary logistic regression analysis, a longer time interval between diagnosis and the start of systemic therapy was predictive for later WBRT. Median OS was 8.7 months for early WBRT and 7.5 months for late WBRT (hazard ratio [HR], 1.165; P = .008). Early WBRT (P = .02), female sex (P = .045), and private insurance (P = .04) were favorable prognostic factors for OS on multivariable analysis, whereas older age (P = .006) was an unfavorable prognostic factor.

Conclusions

Patients with SCLC and brain metastases who received early WBRT were found to have a modest improvement in OS compared with patients who received late WBRT. These findings suggest that early WBRT should be offered to patients who have brain metastases, even in the absence of an indication for emergent WBRT.

DMSA-SPECT: A Novel Approach to Nephron Sparing SBRT for Renal Cell Carcinoma

PURPOSE

Stereotactic body radiation therapy (SBRT) treatment planning for renal cell carcinoma requires accurate delineation of tumor from normal tissue due to the radiosensitivity of normal renal cortical tissue. Tc-99m dimercapto succinic acid (DMSA) renal imaging is a functional imaging technique that precisely differentiates normal renal cortical tissue from tumor. There are no prior publications reporting using this imaging modality for SBRT treatment planning.

METHODS AND MATERIALS

A 59-year-old female with stage IV renal cell carcinoma progressed on systemic therapy and was dispositioned to primary cytoreduction with SBRT. She had baseline renal dysfunction and her tumor was 9 cm without clear delineation from normal tissue on conventional imaging. DMSA-single-photon emission computerized tomography (SPECT)/computed tomography (CT) was used for treatment planning.

RESULTS

DMSA-SPECT/CT precisely delineated normal renal cortical tissue from tumor. Three months after treatment, labs were stable and DMSA-SPECT/CT was unchanged. The treated lesion had markedly decreased positron emission tomography avidity.

CONCLUSIONS

DMSA-SPECT or SPECT/CT can be incorporated into radiation therapy planning for renal lesions to improve target delineation and better preserve renal function.

Stereotactic body radiation therapy and in situ oncolytic virus therapy followed by immunotherapy in metastatic non-small cell lung cancer

9115

Background: The introduction of immunotherapy has altered the treatment paradigm for metastatic non-small cell cancer (mNSCLC). Unfortunately, many patients with mNSCLC have limited or no benefit from immune checkpoint inhibitors (ICIs). A variety of approaches have been explored to augment the efficacy of ICIs. Our study’s aim was to determine whether the addition of stereotactic body radiation therapy (SBRT) and intratumoral injection of the oncolytic virus ADV/HSV-tk (adenovirus-mediated expression of herpes simplex virus thymidine kinase) to a monoclonal antibody targeting programmed cell death-1 (PD-1) would improve the ICI’s efficacy in the treatment of mNSCLC. Methods: In this single-arm, open-label phase II study, patients with mNSCLC (squamous or non-squamous) who were ICI-naive or who were previously treated with a maximum of one line of therapy that included an ICI received an intratumoral injection of ADV/HSV-tk (5 x 1011 vp) followed by SBRT (30 Gy in 5 fractions) to the same tumor. An anti-PD-1 agent (pembrolizumab 200 mg IV every 3 weeks or nivolumab 240 mg IV every 2 weeks) was then given for up to 24 months (pembrolizumab) or 12 months (nivolumab), or until disease progression or intolerable toxicity. The primary endpoint was objective response rate (ORR) as defined by the Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. A secondary endpoint was clinical benefit rate (CBR). Results: A total of 35 patients were enrolled, with 28 (80%) receiving pembrolizumab and 7 (20%) receiving nivolumab; 14 (40%) had previous ICI therapy while 21 (60%) were ICI-naive. The ORR and CBR were 28.5% and 61.9% in the ICI-naive group, and 14.2% and 64.2% in the group that previously received an ICI, respectively. Grade 3 or higher toxicity was seen in five patients (26.3%) in the ICI-naive group and in one patient (7.1%) in the previously ICI-treated group. No treatment-related deaths were observed. Conclusions: The addition of SBRT and intratumor injection of ADV/HSV-tk to anti-PD-1 therapy in mNSCLC resulted in a CBR of over 60% for both ICI-naive and previously ICI-treated patients without the use of chemotherapy. The combination was able to reinstitute sensitivity to ICIs in patients previously treated with an ICI, and also benefited some patients whose tumors did not express PD-L1. These findings should be further explored in a larger study population. Clinical trial information: NCT03004183. [Table: see text]

A phase II trial of stereotactic radiation therapy and in situ oncolytic virus therapy in metastatic triple-negative breast cancer (mTNBC) patients followed by pembrolizumab (STOMP)

1079

Background: Pembrolizumab, stereotactic body radiotherapy (SBRT), and viral vector-based gene therapy such as adenovirus-mediated expression of herpes simplex virus thymidine kinase (ADV/HSV-tk) plus ganciclovir have each shown antitumor immune activity. The combination of those modalities may represent a window of opportunity to enhance pembrolizumab efficacy in mTNBC patients. Methods: In this single-arm, open-label phase II trial, mTNBC patients were treated with in situ oncolytic ADV/HSV-tk (5 x 1011 vp) intratumoral injection, followed by SBRT to the injected tumor site, then pembrolizumab until progression or intolerable toxicity. Response was assessed in non-irradiated metastatic sites. The primary end point was clinical benefit rate (CR, PR and SD per RECIST version1.1). Secondary endpoints included duration on treatment (DoT) and safety. Immune correlative analysis with peripheral blood CYTOF (D1 baseline, D7 and D38), and tissue imaging mass cytometry (IMC) with 35 cell surface markers was performed on paired biopsies (D1 baseline and D17). Results: 28 mTNBC patients were enrolled; 18 (64.3%) had PD-L1 negative tumors. Median age was 54 years (range 34-78). Median prior lines of chemotherapy were 2 (range 0-6), with 8 (28.6%) having received >3. 3 (10.7%) had brain metastases. Clinical benefit was seen in 6 (21.43%) patients; 2 CR (7.1%),1 PR (3.57%) and 3 SD (10.7%). Patients who had clinical benefits had durable responses, with median DoT of 383 days (range 195-1195). One patient who had CR, but discontinued pembrolizumab due to Grade 3 pneumonitis, has remained disease free without any systemic therapy for 39 months. The combination was well tolerated; 9 (32.1%) patients had Grade 3- 4 AEs. Pre- and post-therapy CYTOF analysis showed significant association between immune biomarkers with clinical responses (AUC 0.75, Cohen’s Kappa 0.364). Tumor PDL1 was independently associated with response (AUC 0.70, Cohen’s Kappa 0.347); AUC for PDL1 together with immune biomarkers is 0.85. Conclusions: ADV/HSV-tk gene therapy followed by radiation therapy and then pembrolizumab is a well-tolerated promising treatment in heavily pretreated mTNBC patients. Early detection of increased effector and effector memory CD8 T cells and nonclassical monocytes correlates with response and non-response respectively. Clinical trial information: NCT03295916 .[Table: see text]

Role of 21- gene recurrence score in patients age ≥70 with T1N0 ER/PR+ HER2- breast cancer treated with breast-conserving surgery and endocrine therapy

571

Background: Based on the results of the CALGB 9343 trial, patients age ≥70 with T1N0 ER/PR+ HER2- breast cancer who are treated with breast conserving surgery (BCS) and endocrine therapy (ET) are candidates for omission of radiotherapy (RT). This trial predated the 21- gene RT-PCR recurrence score (RS) test, which is an assay now available for patients with hormone receptor positive, HER2 negative, node negative breast cancer to determine who will benefit from chemotherapy. Whether the RS can predict for patients most likely to benefit from radiation therapy (RT) following BCS has not been previously examined. The purpose of this study was to use a large database of patients age ≥70 with T1N0 ER/PR+ HER2- disease to determine if RS could predict who would benefit from RT following BCS. Methods: The National Cancer Database (NCDB) was queried (2004-2017) for female patients age ≥70 with pT1N0 ER+ PR+ HER2- breast cancer treated with BCS and ET and who had an available RS. Patients were stratified based on their RS (low risk [LR] = 1-10, intermediate risk [IR] = 11-25, high risk [HR] = 26-99). For survival analysis, propensity score matching (PSM) was conducted overall and for each group to create 1:1 matched cohorts of patients who received radiotherapy and patients who did not. Kaplan-Meier analysis with log-rank testing was used to evaluate overall survival (OS). Univariable (UVA) and multivariable (MVA) analysis were conducted using Cox proportional hazard models to determine which clinical and treatment factors were prognostic for OS. Results: A total of 13,614 patients met the selection criteria: 3,840 in the LR cohort, 8,383 in the IR cohort, and 1,391 in the HR cohort. A total of 79% received RT: 77% in the LR cohort, 79% in the IR cohort, and 85% in the HR cohort. Because PSM could not be efficiently performed in the HR cohort alone, the IR and HR cohort were merged (IRHR) for matching. After PSM, overall the 5-year OS was 90% for those who received RT and 88% for those who did not (p = 0.03). The 5-year OS in the LR cohort was 89% for those who received RT and 89% for those who did not (p = 0.517). In the IRHR cohort, the 5-year OS was 93% for those who received RT and 88% for those who did not (p = 0.004). On MVA in the overall cohort, RT (p = 0.037) was predictive of improved OS while increasing age (p < 0.001) and CDCC comorbidity score (p < 0.001) were predictive of worse OS. On MVA in the LR cohort, RT (p = 0.602) was not predictive of improved OS. However, on MVA in the IRHR cohort, RT (p = 0.004) was a positive prognostic factor for OS. Conclusions: This is the first study investigating the role of RS in this subset of patients eligible for omission of radiotherapy. There is an OS benefit with the use of RT in patients with IRHR RS, but not in patients with LR RS. Pending prospective evaluation, assessment of RS in this older subset of patients is recommended with consideration of RT when RS is ≥11.

Adaptive Radiation Therapy for Intact Thymoma: An Illustrative Report

BACKGROUND/AIM

Adaptive radiation therapy (ART) is a technique capable of reducing radiation dose to normal tissue without compromising local control. For potentially resectable thymoma, induction therapy is standard of care. Because large disease volume is common in this context, ART has been suggested to reduce toxicity from induction chemoradiation. This has not been previously illustrated in the literature.

CASE REPORT

A 38-year-old man with initially unresectable thymoma was treated with induction chemoradiation including cisplatin and etoposide. He received 45 Gy in 25 fractions and ART was utilized to shrink the radiotherapy field for the final 10 fractions.

RESULTS

Thymectomy showed Masaoka stage III disease with negative margins. He experienced no treatment-related toxicity and has no evidence of disease 8 years after diagnosis.

CONCLUSION

Induction chemoradiotherapy with ART appears to be feasible, safe, and efficacious for locally advanced intact thymoma.

Staged Stereotactic Radiosurgery Decreases Symptomatic Radionecrosis in Large Brain Metastasis

BACKGROUND

Limited brain metastasis is treated definitively with stereotactic radiosurgery when surgical resection is not indicated. Although this has historically been performed in a single fraction, multi-fraction approaches such as fraction radiosurgery (FSRS) and staged radiosurgery (SSRS) have been recently examined as alternative approaches for larger lesions to permit better tumor control without increased toxicity.

CASE REPORT

We present the case of a patient who developed symptomatic radionecrosis in two brain metastasis, 2.3 cm and 2.1 cm in size, which were treated with 18 Gy in one fraction, but no radionecrosis in a 3.3 cm lesion treated in two fractions of 15 Gy nor in two punctate lesions that were treated in one fraction of 20 Gy. Although she did not respond to steroids, she responded to bevacizumab symptomatically and on neuroimaging.

CONCLUSION

Congruent with other recent studies, our report suggests that large brain metastasis should be considered for FSRS/SSRS.

Laparoscopic Allograft Spacer Placement to Minimize Bowel Dose During Re-irradiation with Interstitial Brachytherapy

In primary or re-irradiation of gynecologic malignancies, achieving optimal dosimetry with adjacent normal tissue becomes challenging. Surgical spacers are tissue-equivalent materials placed within the patient to protect organs at risk from long-term radiation effects and are commonly used in prostate cancer. We report the use of an allograft mesh to protect adhesed bowel from high-dose radiation for definitive treatment of recurrent endometrial cancer. An 88-year-old female was diagnosed with International Federation of Gynecology and Obstetrics (FIGO) stage II endometrial cancer after she developed urinary frequency, hesitancy, and hematuria. She underwent neoadjuvant chemoradiation, followed by laparoscopic hysterectomy with bilateral salpingo-oophorectomy and adjuvant vaginal cuff brachytherapy. She developed 1.8 cm bilateral vaginal cuff recurrence and was dispositioned for interstitial brachytherapy. An allograft mesh spacer was placed laparoscopically before repeat, high dose rate brachytherapy to protect nearby structures. Dose-escalation was achieved without compromising normal tissue constraints. The patient tolerated the procedure without evidence of long-term toxicity at one year. Multidisciplinary discussion may help identify patients who would benefit from spacer placement before select dose-escalated radiation therapy. Laparoscopic allograft mesh is one of many types of surgical spacers available for such patients.

Community-based Disparities in the Treatment and Outcomes of Early-stage Non-small-cell Carcinoma

Introduction Lung cancer is the most common malignancy in men and women combined. It is also the leading cause of cancer-related deaths in the US. The objective of this study is to report the treatment and survival outcomes for early-stage non-small-cell lung carcinoma (NSCLC) when stratified by urban versus rural geography. Methods A dataset of 62,213 patients, all aged 60 years or above, with stage-1 NSCLC, who underwent treatment from 2004 to 2012 was retrieved from the Surveillance, Epidemiology, and End Results (SEER) database of the National Cancer Institute (NCI). Patients were divided into metropolitan, urban, or rural (in descending order of population density) based on their location of cancer treatment using the US Rural-Urban Continuum Code Definitions for 2003. Patient characteristics were compared using the chi-square test, and survival statistics were calculated using the Kaplan-Meier estimator. Results Rural or urban stage-1 NSCLC patients are more likely to be white, young, male, poor, and uninsured or Medicaid-dependent. They generally have squamous histology and receive radiation therapy when compared to metropolitan counterparts [probability value (p): <0.0001]. Median overall survival was shorter for rural and urban patients than metropolitan patients (41, 41, and 52 months respectively; p: <0.0001). Conclusion Tertiary care centers in metropolitan areas continue to demonstrate superior outcomes in the treatment of stage-1 NSCLC. This is presumably due to the existing disparities in patient access to care. Rural and urban stage-1 NSCLC patients (who tend to be younger, poorer, and more likely to be treated with radiation than surgery) are likely to be disproportionately impacted by changes in health policy.

Socioeconomic Factors Associated with Lack of Treatment in Early Stage Non-Small Cell Lung Cancer

With modern radiotherapy, stage I non-small cell lung cancer (S1NSCLC) cure is extended to nonsurgical candidates. Despite this, some S1NSCLC remains untreated. We aim to identify factors associated with no treatment. 62,213 S1NSCLC cases were identified (SEER: 2004-2012). Demographics were compared using Chi-squared. Multivariate analysis was performed using COX proportional HR. 11.9% of the 7373 patients lacked treatment. No insurance, Medicaid-dependence, unmarried status, advancing age, lower income, African American and Asian/Pacific Islander race, and male sex are associated with no treatment (p < .0001). No treatment portends a worse cancer-specific survival (21% vs 66% at 5Y, p < .0001) and OS (10% vs 50% at 5Y, p < .0001).

Disparities in the Treatment and Outcome of Stage I Non-Small-Cell Lung Cancer in the 21st Century

BACKGROUND

African American (AA) individuals are less likely to receive treatment and more likely to die from cancer compared with Caucasian (C) individuals. Recent advancements in surgery and radiation have improved outcomes in early stage non-small-cell lung cancer (ESNSCLC). We studied racial disparities in ESNSCLC in the past decade.

PATIENTS AND METHODS

The Surveillance, Epidemiology, and End Results database was used to retrieve data of 62,312 ESNSCLC patients age 60 years and older diagnosed between 2004 and 2012. Patients were divided into racial cohorts: C, AA, American Indian (AI), Asian/Pacific Islander (API), or unknown. Demographics characteristics, therapy, and survival were compared using χ² test, Kaplan-Meier method, and Cox multivariate analysis.

RESULTS

AA and AI individuals were less likely to receive surgery than typical ESNSCLC patients (55.9% and 57.6% vs. 66.7%; P < .0001). Two-year overall survival (OS) for C individuals was 70%, for AA 65%, AI 60%, and API 76% (P < .0001). Two-year cancer-specific survival (CSS) for C individuals was 79%, AA 76%, AI 73%, and API 84% (P < .0001). Median CSS for AI and AA individuals was less than that of typical ESNSCLC patients (49 and 80 months vs. 107 months; P < .0001). This difference disappeared in multivariate analysis, accounted by sex, age, treatment, histology, and T stage (all P < .0001).

CONCLUSION

Despite treatment advancements in the past decade, AA and AI individuals continue to have worse OS and CSS from ESNSCLC. This might be because of the association with more adverse risk factors, including older age, squamous histology, male sex, T2 stage, and tendency to forgo treatment.

Complete Local and Abscopal Responses from a Combination of Radiation and Nivolumab in Refractory Hodgkin's Lymphoma

Until recently, patients with relapsed Hodgkin's lymphoma after brentuximab vedotin (Bv) treatments had poor treatment outcomes. Checkpoint inhibitors such as nivolumab and pembrolizumab that bind to and inhibit programmed cell death protein-1 (PD-1), have demonstrated an overall response rate of 70% in Hodgkin's lymphoma patients; however, complete response is still low at 20% with median progression-free survival of 14 months. There are ongoing clinical studies to seek out synergistic combinations, with the goal of improving the complete response rates for the cure of Hodgkin's lymphoma. Although radiotherapy has a limited survival benefit in such refractory patients, several preclinical models and anecdotal clinical evidence have suggested that combining local tumor irradiation with checkpoint inhibitors can produce systemic regression of distant tumors, an abscopal effect. Most of these reported studies on the response with local conformal radiotherapy and checkpoint inhibitors in combination with the anti-cytotoxic T-lymphocyte associated antigen-4 (CTLA-4) antibody-ipilimumab are in melanoma. Here we report in our case series that the checkpoint inhibitors that block CTLA4 and B7-homolog 1 (B7-H1) or PD-1 in preclinical radiotherapy models have shown an increased the rate of tumor regression. Our case series demonstrates that combining local irradiation with anti-PD-1 checkpoint blockade treatment is feasible and synergistic in refractory Hodgkin's lymphoma. Correlative studies also suggest that the expression of programmed death-ligand 1 (PD-L1), DNA damage response and mutational tumor burden can be used as potential biomarkers for treatment response.

The utility of PET-CT after preoperative chemoradiation in predicting treatment outcomes in locally advanced esophageal cancer

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Background: In the treatment of gastroesophageal junction (GEJ) cancer, trimodality treatment with preoperative chemoradiation followed by surgery is the standard of care. However, predicting patient survival outcomes remains difficult. One possible means of predicting outcomes is comparing pre-treatment PET-CT with post-treatment PET-CT to see if a favorable response on imaging correlates with survival outcomes. Methods: We conducted a retrospective chart review of locally advanced GEJ cancer patients who underwent preoperative chemoradiotherapy followed by esophagectomy with negative margins. All patients underwent two PET-CT scans (before and after preoperative chemoradiation). We compared PET-CT imaging results and pathology results with survival outcomes. Values such as pre-treatment max SUV, post-treatment max SUV, change in max SUV, percent residual max SUV, complete response on PET-CT, and pathologic complete response were analyzed for potential impacts on recurrence rates and survival outcomes. Results: Forty patients had sufficient data to be included in our study. The median follow-up was 22.5 months. The majority of patients were male (82.5%), Caucasian (84.2%) and had adenocarcinoma histology (97.5%). Altogether, 75% of patients had stage III disease and 67.5% had locoregional nodal involvement. The majority (90%) of patients received some form of taxane and platinum based chemotherapy. Pre-treatment max SUV, post-treatment max SUV, change in max SUV, percent residual max SUV, and complete response on PET-CT were not associated with local recurrence, regional recurrence, disease-free survival, or overall survival. Pathologic complete response was associated with a decrease in the rate of distant metastasis ( P= 0.021) but not disease-free survival ( P= 0.411) or overall survival ( P= 0.878). Conclusions: Response on PET-CT after preoperative chemoradiation is not a predictive factor for recurrence, disease-free survival, or overall survival. Pathologic complete response predicted for a decrease in the rate of distant metastasis but not disease-free survival or overall survival.

Practice Patterns and Outcomes in Elderly Stage I Non-Small-cell Lung Cancer: A 2004 to 2012 SEER Analysis

BACKGROUND

We reviewed the population-based treatment patterns and outcomes for elderly patients with stage I non-small-cell lung cancer (NSCLC) treated from 2004 to 2012.

PATIENTS AND METHODS

Using the Surveillance, Epidemiology, and End Results (SEER) database, we identified biopsy-proven stage I NSCLC cases diagnosed from 2004 to 2012. The patients were divided into 5-year age subsets (60-64, 65-69, 70-74, 75-79, 80-84, 85-89, and ≥ 90 years). The demographic data, therapy, and survival were compared by year. Trends in overall survival (OS), cancer-specific survival (CSS), and practice patterns were analyzed.

RESULTS

A total of 62,213 cases were identified. The use of surgery declined sharply with age. Patients aged 60 to 64 years had a surgical rate of 81% compared with 21% for those aged ≥ 90 years (P < .0001). Radiation use increased (from 11% to 39%; P < .0001), as did the receipt of neither surgery nor radiation (from 7% to 40%; P < .0001). When analyzing the annual trends, radiation use increased, with fewer patients forgoing treatment from 2004 to 2012 (P < .0001). From 2004 to 2011, CSS at 2 years improved significantly for patients treated with radiation alone (from 48% to 72%; P < .0001) and more subtly for those receiving surgery alone (from 87% to 91%; P < .0001). The outcomes were stable for those receiving neither surgery nor radiation (38% to 45%; P = NS). Surgical outcomes declined with advancing age (P < .0001); however, the radiation outcomes did not (P = NS).

CONCLUSION

With advancing age, radiation replaces surgery as the most used treatment for early-stage NSCLC. OS and CSS have improved significantly for elderly stage I NSCLC patients treated with radiation alone during a timeline concurrent with the widespread adoption of stereotactic body radiation therapy. Dedicated prospective studies are indicated, because these findings are limited by the inherent biases of using the SEER database alone.