Analysis of a National Programme for Selective Internal Radiation Therapy for Colorectal Cancer Liver Metastases

AIMS

Patients with chemotherapy-refractory colorectal cancer liver metastases have limited therapeutic options. Selective internal radiation therapy (SIRT) delivers yttrium 90 microspheres as a minimally invasive procedure. This prospective, single-arm, observational, service-evaluation study was part of National Health Service England Commissioning through Evaluation.

METHODS

Patients eligible for treatment had histologically confirmed carcinoma with liver-only/liver-dominant metastases with clinical progression during or following oxaliplatin-based and irinotecan-based chemotherapy. All patients received SIRT plus standard of care. The primary outcome was overall survival; secondary outcomes included safety, progression-free survival (PFS) and liver-specific PFS (LPFS).

RESULTS

Between December 2013 and March 2017, 399 patients were treated in 10 centres with a median follow-up of 14.3 months (95% confidence interval 9.2-19.4). The median overall survival was 7.6 months (95% confidence interval 6.9-8.3). The median PFS and LPFS were 3.0 months (95% confidence interval 2.8-3.1) and 3.7 months (95% confidence interval 3.2-4.3), respectively. During the follow-up period, 143 patients experienced an adverse event and 8% of the events were grade 3.

CONCLUSION

Survival estimates from this pragmatic study show clinical outcomes attainable in the National Health Service comparable with previously published data. This study shows the value of a registry-based commissioning model to aid national commissioning decisions for highly specialist cancer treatments.

Endosymbionts Differentially Alter Exploratory Probing Behavior of a Nonpersistent Plant Virus Vector

Insect endosymbionts (hereafter, symbionts) can modify plant virus epidemiology by changing the physiology or behavior of vectors, but their role in nonpersistent virus pathosystems remains uninvestigated. Unlike propagative and circulative viruses, nonpersistent plant virus transmission occurs via transient contamination of mouthparts, making direct interaction between symbiont and virus unlikely. Nonpersistent virus transmission occurs during exploratory intracellular punctures with styletiform mouthparts when vectors assess potential host-plant quality prior to phloem feeding. Therefore, we used an electrical penetration graph (EPG) to evaluate plant probing of the cowpea aphid, Aphis craccivora Koch, an important vector of cucurbit viruses, in the presence and absence of two facultative, intracellular symbionts. We tested four isolines of A. craccivora: two isolines were from a clone from black locust (Robinia pseudoacacia L.), one infected with Arsenophonus sp. and one cured, and two derived from a clone from alfalfa (Medicago sativa L.), one infected with Hamiltonella defensa and one cured. We quantified exploratory intracellular punctures, indicated by a waveform potential drop recorded by the EPG, initiation speed and frequency within the initial 15 min on healthy and watermelon mosaic virus-infected pumpkins. Symbiont associations differentially modified exploratory intracellular puncture frequency by aphids, with H. defensa-infected aphids exhibiting depressed probing, and Arsenophonus-infected aphids an increased frequency of probing. Further, there was greater overall aphid probing on virus-infected plants, suggesting that viruses manipulate their vectors to enhance acquisition-transmission rates, independent of symbiont infection. These results suggest facultative symbionts differentially affect plant-host exploration behaviors and potentially nonpersistent virus transmission by vectors.

Interaction of preservation methods and radiation sterilization in human skin processing, with particular insight on the impact of the final water content and collagen disruption. Part I: process validation, water activity and collagen changes in tissues cryopreserved or processed using 50, 85 or 98% glycerol solutions

Current regulatory requirements demand an in-depth understanding and validation of protocols used in tissue banking. The aim of this work was to characterize the quality of split thickness skin allografts cryopreserved or manufactured using highly concentrated solutions of glycerol (50, 85 or 98%), where tissue water activity (a_w), histology and birefringence changes were chosen as parameters. Consistent a_w outcomes validated the proposed processing protocols. While no significant changes in tissue quality were observed under bright-field microscopy or in collagen birefringence, in-process findings can be harnessed to fine-tune and optimize manufacturing outcomes in particular when further radiation sterilization is considered. Furthermore, exposing the tissues to 85% glycerol seems to derive the most efficient outcomes as far as a_w and control of microbiological growth.

Delafossite and the system Cu–Fe–O

An investigation of the system Cu-Fe-O has established the existence of a phase near 3Cu2O.Fe3O4 and the non-existence of Cu2O.Fe2O3 a in the system over the range of oxygen pressures investigated.

The X-ray diffraction patterns obtained from four samples of natural delafossite have been found to be similar to that obtained from a synthetic sample of the 3Cu2O.Fe3O4 phase. It has also been shown that, when heated under equilibrium conditions in the thermobalance in air, a sample of natural delafossite and the synthetic 3Cu2O.Fe3O4 behaved similarly.

Lyme Disease Surveillance in New York State: an Assessment of Case Underreporting

Despite the mandatory nature of Lyme disease (LD) reporting in New York State (NYS), it is believed that only a fraction of the LD cases diagnosed annually are reported to public health authorities. Lack of complete LD case reporting generally stems from (i) lack of report of provider-diagnosed cases where supportive laboratory testing is not ordered or results are negative (i.e. provider underreporting) and (ii) incomplete case information (clinical laboratory reporting only with no accompanying clinical information) such that cases are considered 'suspect' and not included in national and statewide case counts (i.e. case misclassification). In an attempt to better understand LD underreporting in NYS, a two-part study was conducted in 2011 using surveillance data from three counties. Case misclassification was assessed by obtaining medical records on suspect cases and reclassifying according to the surveillance case definition. To assess provider underreporting, lists of patients for whom ICD-9-CM code 088.81 (LD) had been used were reported to NYS Department of Health (NYSDOH). These lists were matched to the NYSDOH case reporting system, and medical records were requested on patients not previously reported; cases were then classified according to the case definition. When including both provider underreporting and case misclassification, approximately 20% (range 18.4-24.6%) more LD cases were identified in the three-county study area than were originally reported through standard surveillance. The additional cases represent a minimum percentage of unreported cases; the true percentage of unreported cases is likely higher. Unreported cases were more likely to have a history of erythema migrans (EM) rash and were more likely to be young paediatric cases. Results of the study support the assertion that LD cases are underreported in NYS. Initiatives to increase reporting should highlight the importance of reporting clinically diagnosed EM and be targeted to those providers most likely to diagnose LD, specifically providers treating paediatric patients.

Abstract P2-11-07: Evaluation of lung and heart dose in patients treated with radiation for breast cancer

BACKGROUND: A recent systematic review of women receiving radiation therapy (RT) for breast cancer combined with modeled estimated risks of mortality from heart disease and lung cancer found that the mean heart dose (MHD) was 4.4 Gy (5.2 Gy for left-sided, 3.7Gy for right-sided) and the mean total lung dose (TLD) was 5.7 Gy. Estimated excess cardiac mortality ranged from 0.3-1.2% and lung cancer mortality ranged from 0.2-4.4% with modern RT. Using these data as a benchmark, we set to review the MHD and mean TLD for our patients receiving adjuvant breast RT in a modern era when RT planning includes meeting normal tissue constraints.

METHODS: We evaluated the MHD and mean TLD for patients with unilateral breast cancer treated with curative intent between January 2012 and May 2017 at our institution. Dosimetric data was complete for 793 patients. During this time period the MHD constraint was 4 Gy and lung V20 was 20% for breast only and 35% for regional nodal irradiation (RNI). RNI included the axillary, supraclavicular and internal mammary nodes.. Patients were evaluated by laterality (right vs. left), prone vs. supine position, breast only whole breast irradiation (WBI) and RNI with intact breast or chestwall post-mastectomy. The RNI group was examined by treatment technique, intensity modulated radiation therapy (IMRT) vs. 3D conformal (3DCRT). We compared differences in the MHD and mean TLD within those groups using the Student's t-test.

RESULTS: We identified 651 patients: 481 WBI only and 170 RNI. In the RNI group, 77 (45.3%) received IMRT. Of the WBI only group, 229 (47.6%) were right-sided and 313 (65.1%) were treated prone. The mean TLD for the WBI only group was significantly lower in the prone vs. supine position (0.62 Gy vs. 3.90 Gy, p<0.0001). The prone position resulted in lower MHD for both left-sided WBI (1.17 Gy vs. 1.67 Gy, p<0.0001) and right-sided WBI (0.51 Gy vs. 0.64 Gy, p=0.1067). In patients that received RNI, the mean TLD was 8.20 Gy (SD 1.03) and the MHD was 2.67 Gy (3.25 Gy for left-sided vs. 1.83 Gy for right-sided, p=0.0001). Compared to 3DCRT, IMRT increased the MHD (2.46 Gy vs. 4.23 Gy for left-sided, p<0.0001; 0.94 Gy vs. 2.85 Gy, p<0.0001 for right-sided) and mean TLD (8.50 Gy vs. 7.95 Gy, p=0.0005).

CONCLUSIONS: In the era of RT treatment planning that incorporates normal tissue constraints, very low MHD and lower TLD are achievable in prone or supine position patients receiving WBI only for breast conserving treatment. This means lower late cardiac and lung cancer mortality risks from RT. Women that receive RNI also have acceptably low MHD but high mean TLD. Node positive breast cancer patients derive a disease free survival benefit from RNI, which must be balanced against potential late risk for lung cancer, especially in smokers. More attention should be focused on identifying lung cancer risk, smoking cessation and screening efforts in node positive breast cancer patients with indications for RNI to minimize late radiation risks.

Citation Format: Healy EH, Pratt DN, DiCostanzo D, Bazan JG, White J. Evaluation of lung and heart dose in patients treated with radiation for breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-11-07.

Abstract OT2-03-04: Feasibility of assessing radiation response with MRI/CT directed preoperative accelerated partial breast irradiation in the prone position for hormone responsive early stage breast cancer

Background: Accelerated partial breast irradiation (APBI) delivers adjuvant radiation (RT) to the 1-2 cm of the breast at highest risk for recurrence surrounding the lumpectomy (L) cavity over 5-8 days and is an alternative to standard whole breast irradiation for hormone sensitive (HS) stage 1 (T1, N0) breast cancer (BC) based on 2 randomized controlled trials. External beam methods for APBI are common but have notable inherent drawbacks that include: inter-fraction inaccuracy due to patient setup based on anatomy, intra fraction error related to patient or respiratory motion, and inaccurate geometric targeting by relying on L cavity position instead of the tumor position. Postoperative RT has other limitations including delivery in the setting of disrupted blood or lymphatic supply that may be suboptimal for radio sensitivity and it eliminates observation of radiation-induced tumor response. MRI is an established tool for measuring BC extent and response from neoadjuvant systemic therapy. It's hypothesized that MRI directed pre-operative APBI using intensity modulated radiotherapy (IMRT) with image guidance (IGRT) will improve RT delivery, and that MRI features can be identified to correlate with pathologic radiation response.

Trial Design: There are 2 cohorts to this single arm prospective trial. The first cohort is for establishing and verifying patient flow and image fusion between MRI, CT and RT planning. In the second cohort eligible patients will receive preoperative APBI 38.5 Gy in 10 fractions BID with IMRT, IGRT in the prone position using MRI defined targets fused to CT treatment planning.

Eligibility: For cohort 1 it is HS Stage 1 BC that has completed CT in prone position for RT planning. Eligibility for cohort 2 requires: age > 50 yo, clinical stage 1 BC, HS, HER2 negative, intending L, clinically negative axilla verified by ultrasound, able to tolerate the prone position, and MRI with contrast.

Specific aims: To determine the reproducibility of MRI directed preoperative APBI based on meeting 3 criteria: ability to define RT targets by MRI, quality of RT plans and completion of treatment (APBI and surgery). Additional aims include assessing toxicity, cosmetic outcome, local regional cancer control and collection of tissue for correlative studies.

Statistical methods: The optimal two-stage design by Simon is used. Sample size for cohort 2 is based on the first endpoint. 19 eligible patients will be required in the first stage; if 3 or more treatments are scored unacceptable, then early stopping will be recommended. Otherwise, accrual will continue to a total accrual of 30. If > 4 of 30 treatments are scored unacceptable, the technique will be considered not reproducible, and a Phase II study will not be pursued. Under the null hypothesis of an 80% reproducibility rate, this two-stage design has an expected sample size of 24.4.

Patient accrual to cohort 1 has completed the targeted accrual of 3. Patient accrual to Cohort 2 is 5/30.

Contact information: Soyhun Mc Elroy (Sohyun.McElroy@osumc.edu) or Julia White (Julia.White@osumc.edu)

Funding source: Susan G Komen Breast Cancer Foundation Grant # GRT00035216

Citation Format: White J, McElroy S, Sekhon A, Wei L, Bazan J, Yang X, DiCostanzo D, Kuhn K, Gupta N, Knopp M. Feasibility of assessing radiation response with MRI/CT directed preoperative accelerated partial breast irradiation in the prone position for hormone responsive early stage breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT2-03-04.

Abstract OT1-02-04: SWOG S1418/NRG -BR006: A randomized, phase III trial to evaluate the efficacy and safety of MK-3475 as adjuvant therapy for triple receptor-negative breast cancer with > 1 cm residual invasive cancer or positive lymph nodes (>pN1mic) after neoadjuvant chemotherapy

Background: Patients with residual cancer after neoadjuvant chemotherapy, particularly triple negative cancers (TNBC), have poor prognosis.The SWOG S1418 / NRG BR-006 (NCT02954874) randomized, phase III trial tests the hypothesis that administration of pembrolizumab after surgery for 12 months will reduce invasive disease-free survival (IDFS) by 33% compared to observation in patients with TNBC and > 1 cm residual invasive cancer or positive lymph nodes (>pN1mic) after neoadjuvant chemotherapy.

Methods: Eligible patients ≥18 years old with triple negative breast cancer defined by ASCO/CAP guidelines and >1 cm residual invasive cancer in the breast, or any macrometastases in the lymph nodes after completion of 16-24 weeks of neoadjuvant chemotherapy. Patients may receive post-operative chemotherapy for up to 24 weeks but must be registered for screening within 35 days of completion of adjuvant chemo. Completion of radiation therapy prior to registration is allowed, but it is preferred that patients receive radiation after randomization; patients randomized to pembrolizumab will receive their XRT concomitant with pembrolizumab. Adequate organ functions: ANC > 1.5, PLT > 100, Hgb > 9, normal creatinine, Tbili < 1.5 IUNL, AST/ALT/AlkPhos < 2.5 IULN. HIV with good CD4 count is allowed. Active autoimmune disease, Hep B,C, prior immunotherapy, active immunosuppressive therapy, or live vaccines within 30 days of registration are not allowed. Five unstained slides for PDL1 staining are required for stratification. The study has a dual primary endpoint; comparison of IDFS between arms in (i) all randomized patients (1-sided a=0.01) and in PDL-1 positive patients (1-sided a=0.015). Secondary endpoints include toxicity, overall survival, distant recurrence free survival (DRFS) and quality of life measures. Patients will be randomized 1:1 with stratification for PDL1 status, T size, nodal status and adjuvant chemo (yes or no) to observation or 1 year of pembrolizumab 200mg IV q 3 weeks. The accrual goal is N=1000 patients with estimated trial duration of 8 years. Two interim analyses are planned for all randomized patients when 50% and 75% of IDFS events have occurred for early stopping for either futility or efficacy. The study was activated on 11/15/16 and 34 patients were registered as of June 9, 2017. Cancer Trials Support Unit (CTSU) sites can use “OPEN” (https://open.ctsu.org) to enroll patients to this trial.

Funding: NIH/NCI U10CA180888, U10CA180819, CA180868; and in part by Merck, Sharpe & Dohme, Corporation.

Citation Format: Pusztai L, Barlow WE, Ganz PA, Henry NL, White J, Jagsi R, Mammen JMV, Lew D, Mejia J, Karantza V, Aktan G, Sharon E, Korde L, Hortobagyi GN, Mamounas E. SWOG S1418/NRG -BR006: A randomized, phase III trial to evaluate the efficacy and safety of MK-3475 as adjuvant therapy for triple receptor-negative breast cancer with > 1 cm residual invasive cancer or positive lymph nodes (>pN1mic) after neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT1-02-04.

Abstract OT2-03-01: Multi-institution phase II trial of intraoperative electron beam radiotherapy boost at the time of breast conserving surgery with oncoplastic reconstruction in women with early-Stage breast cancer

Background: In women amenable to breast conserving therapy, lumpectomy followed by adjuvant whole breast irradiation (WBI) remains the standard of care. Randomized trials have demonstrated that the addition of a lumpectomy cavity boost significantly reduces the risk of ipsilateral breast tumor recurrences but also increases the risk of breast fibrosis. Contemporary randomized trials define the lumpectomy cavity boost volume as a 1.7 cm isometric expansion on the lumpectomy cavity as delineated on CT. However, identifying the lumpectomy cavity can be challenging, especially in women that receive adjuvant chemotherapy and in cases in which surgical clips are not present. Recently, the use of oncoplastic techniques in breast conserving surgery has increased. These techniques are used to prevent the poor cosmetic results that can occur when a large volume of breast tissue is resected. Women that undergo oncoplastic reconstruction represent especially difficult cases for lumpectomy cavity delineation. Retrospective series have evaluated the use of intraoperative electron radiotherapy (IOERT) as a boost prior to WBI in women receiving lumpectomy without oncoplastic reconstruction. In the largest series of IOERT boost prior to WBI the local control rate of this approach was >99%. Prospective data regarding IOERT boost in women undergoing oncoplastic reconstruction are limited. Advantages of this approach include direct visualization/irradiation of the tumor bed, sparing the skin of irradiation, and reducing the treatment time by ˜1 week. We hypothesize that IOERT boost followed by WBI will result in acceptably low rates of grade 3 fibrosis in women undergoing lumpectomy with oncoplastic reconstruction.

Trial Design: This is a single-arm, prospective study to evaluate the safety, toxicity and efficacy of IOERT boost at the time of breast conserving surgery in women with early-stage breast cancer undergoing oncoplastic reconstruction. Eligible women will receive 1 dose of 8 Gy to the surgical bed after lumpectomy but prior to oncoplastic reconstruction. Women will then receive adjuvant WBI of 40 Gy in 15 fractions or 50 Gy in 25 fractions.

Eligibility: Key inclusion criteria include age≥18 yo, clinically node-negative stage I/II, any breast cancer subtype.

Specific Aims: Our primary aim is to determine the rate of grade 3 breast fibrosis at 1 year. Additional aims include surgical complication rates, cosmesis, and local regional cancer control.

Statistical Methods: Safety will be evaluated by the rate of surgical complications necessitating hospital readmission or return to the operating room within 30 days of surgery+IOERT. If ≥4 events in the first 10 patients, ≥7 events in the first 20 patients, or ≥9 events in the first 30 patients are seen, the study will be halted. We hypothesize that the grade 3 fibrosis rate in our study will be ≤5%. Assuming an actual rate of 4%, an unacceptable rate of 9%, and a drop-out rate of 10%, the expected sample size is 176.

Patient Accrual: Current accrual is 0 of 176.

Contact Information: Soyhum McElroy (soyhun.mcelroy@osumc.edu) or Jose Bazan (jose.bazan2@osumc.edu)

Funding Source: Intraop Medical

Citation Format: Bazan JG, Stephens J, Terando A, Skoracki R, McElroy S, Sexton J, Gupta N, White J. Multi-institution phase II trial of intraoperative electron beam radiotherapy boost at the time of breast conserving surgery with oncoplastic reconstruction in women with early-Stage breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT2-03-01.

Abstract P4-04-07: Characterization of the effects of estrogen receptor alpha Y537S and D538G mutations on receptor function and pharmacology

The frontline therapy for estrogen receptor alpha (ERα) positive Breast Cancer (ER+BC) involves various forms of endocrine therapy, consisting of either Selective Estrogen Receptor Modulators (SERMs) or aromatase inhibitors. An emerging mechanism of ER+BC resistance to endocrine therapy, and consequently disease relapse, has been associated with a set of “hotspot” mutations in and near to helix-12 of the ERα ligand binding domain. Selective Estrogen Receptor Degraders/Down-regulators (SERDs), such as GDC-0810, AZD9496 and GDC-0927, represent a current major pharmacological strategy being applied to develop treatments for such resistant ER+BC. Here, we compare 2 of the most frequent ERα hotspot mutations (Y537S and D538G), with ERα wildtype (WT) and the ability of a set of ERα ligands (including GDC-0810, AZD9496 and GDC-0927) to bind, antagonize and degrade ERα. The concentration of each drug required to bind, antagonize or degrade ERα Y537S or ERα D538G was typically higher than that required for ERα WT. Importantly, ERα Y537S is resistant to estradiol stimulated protein degradation and 4-hydroxy-tamoxifen (a major active metabolite of tamoxifen) stabilizes ERα Y537S protein. This represents a potential mechanism of resistance of ERα Y537S ER+BC to Tamoxifen therapy.

Citation Format: Blake RA, Hartman SJ, Kleinheinz TL, White J, Daly S, Goodwin R, Zhou W, Liang J, Wang X, O'Rourke M, Metcalfe C, Friedman L. Characterization of the effects of estrogen receptor alpha Y537S and D538G mutations on receptor function and pharmacology [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-04-07.

Abstract P2-11-06: Analysis of cardiac events among node positive breast cancer (NPBC) patients treated with three-dimensional conformal radiation therapy (3D-CRT)

Background: Regional nodal irradiation (RNI) in addition to the chest wall and/or breast can maximize local regional control and improve overall survival, but has been associated with late cardiac morbidity. We examined NPBC patients treated with RNI using 3D-CT based radiation therapy (RT) to evaluate incidence and type of cardiac events.

Methods: Between 2000 and 2007, 156 NPBC patients were treated with RNI following lumpectomy or mastectomy using 3D-CRT. In all cases, treatment target and normal tissue volumes were delineated on treatment CT scans. The heart contour included the left ventricle and the atria. Prescription dose was typically 50Gy in 25 fractions (range 44-54 Gy) to the chest wall and/or breast PTVeval. 37% received a boost to the chest wall and 73% to the lumpectomy cavity. The mean prescription dose to the axilla and supraclavicular lymph nodes was 47.6 Gy (range 43.2 – 54 Gy) and 46.8 Gy to the IMN (range 35.3 – 50.4 Gy). The dose-volume cardiac data and incidence of cardiac events is reported.

Results: Median follow-up of surviving patients was 7 years (range, 0.3-10.6). Median patient age was 50 (range, 27-91), 52% were premenopausal, 76% estrogen receptor positive, and 18% were HER-2 positive. The IMN received > 40 Gy in 66%. Chemotherapy was used in 94% of patients, and it was anthracycline-based in 82.3%. At the time of RT, 12.5% smoked, 9% had diabetes, 33% with HTN, and 4.4% had a history of CAD.

Average mean heart dose for the cohort was 5.2 Gy (range, 0.2 - 25.3 Gy). Mean cardiac V25 was 5.4% (range, 0-20%), mean cardiac V45 was 1.7% (range, 0-13.3%), and mean maximum cardiac point dose was 45.4 Gy.

There was 1 (0.7% of cohort) right sided patient with cardiac events and 8 (5.1% of cohort) left experiencing cardiac events. A total of 18 cardiac diagnoses were experienced among the 9 patients: Coronary artery disease with or without myocardial infarction (4), congestive heart failure (6), cardiomyopathy (3), and arrhythmia (5).

Conclusions: The cardiac event rate among these NPBC patients treated with RNI and anthracycline-based chemotherapy was low, but more common in women with left-sided breast cancer compared to right. Additional analysis using 3DCRT volumes are important to validate these findings and better define the dose-volume parameters for cardiac toxicity.

Citation Format: Bradley JA, Sparks I, Prior P, Bergom C, Walker A, Wilson JF, Li XA, White J. Analysis of cardiac events among node positive breast cancer (NPBC) patients treated with three-dimensional conformal radiation therapy (3D-CRT) [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-11-06.

Abstract P4-15-09: Refined estimates of local recurrence risk in a clinical utility study: Integrating the DCIS score, patient age and DCIS tumor size

Background:Better tools are needed to estimate the risk of local recurrence (LR; DCIS or invasive) after breast-conserving surgery (BCS) for pts with DCIS in order to inform treatment decisions. Traditional clinico-pathologic (CP) factors, e.g., age and tumor size, provide an average LR risk derived from clinical trials and population studies. The Oncotype DX 12-gene DCIS Score assay has been validated to provide individual 10 yr LR risk estimates (Solin JNCI 2013; Rakovitch BCRT 2015). Previously we reported the impact of the DCIS Score result on radiotherapy (RT) recommendations including the pre-assay LR risk and RT recommendation and the change in RT recommendation from pre- to post-assay (Manders Ann Surg Oncol 2016).Recently a patient specific meta-analysis (MA) combined data from E5194 and Ontario DCIS Cohort (ODC) adjusting for pertinent clinico-pathologic factors to provide refined prediction estimates of LR risk after BCS alone (Rakovitch ASCO 2017). Herein we applied these risk estimates integrating DS, tumor size and patient age with adjustment for diagnosis in the year 2000 or later to refine estimates of LR in DCIS patients from the Manders et al study.

Methods: 13 U.S. sites enrolled pts with DCIS treated with BCS alone from 3/2014 to 5/2015. Pts with LCIS but no DCIS, invasive BC, or planned mastectomy were excluded. Data were prospectively collected on CP factors, physician estimates of LR risk, and DCIS Score. Refined estimates of 10-yr risk of LR are presented by DCIS Score result category (0-38; 39-54; 55-100), age group (≥50 vs <50 yr) and tumor size (≤1; >1-2.5; >2.5 cm).

Results: Of the 127 pts enrolled, median age was 60 yr,79.5% were postmenopausal. Median size was 8mm & 39% were ≤5mm. Median margin width was 3.0mm. ER and PR by IHC were positive in 89% and 78% of pts, respectively. For patients ≥50 yr with tumors ≤1 cm and low risk DS, the 10-yr LR risk ranges from 5.3-10.0%. A high DS result is associated with a higher 10-yr median predicted risk of LR in all subsets (table 1). The DCIS Score integrated with tumor size and patient age and the adjustment for diagnosis in 2000 or later provided risk estimates that are often lower than those provided by the DCIS Score alone without adjustment for diagnostic year. Using DS alone the percentage of patients with risk of LR <8% was 0%; however, incorporating patient age and tumor size with the DS and adjusting for diagnosis in 2000 or later, it increased to 30.9% of patients.

Conclusions: Integration of the DCIS Score assay, that provides individual risk estimates of LR, with patient age and DCIS tumor size and adjusting for diagnosis in 2000 or later, provides refined estimates of 10-yr LR risk after BCS alone for DCIS. This integration enhances prognostic LR risk estimates and frequently provides lower risk estimates with which to guide individualized treatment decisions.

Distribution of 10-year risk of local recurrence using DCIS Score (DS), tumor size, and age, adjusting for diagnosis in 2000 or later.  Low DS (<39)Inter DS (39-54)High DS (≥55)Tumor Size(cm)Age(Yr)NMedian (Min-Max)%NMedian (Min-Max)%NMedian (Min-Max)%≤1≥50457.0 (5.3-10)810.8 (10.2-11.8)1015.1 (12.9-18.6) <50810.3 (7.4-12.1)414.9 (14.1-15.4)0 >1-2.5≥50249.5 (7.3-12.6)914.2 (12.9-15.6)519.6 (16.5-20.4) < 50216.4 (16.1-16.7)220.4 (19.8-21.1)122.2 (22.2-22.2)>2.5≥50515.7 (14.9-23.7)0 138.4 (38.4-38.4) <500 141.2 (41.2-41.2)149.3 (49.3-49.3)

Citation Format: Manders JB, Solin LJ, Leonard CE, Mamounas EP, Lu R, Turner M, Baehner FL, White J. Refined estimates of local recurrence risk in a clinical utility study: Integrating the DCIS score, patient age and DCIS tumor size [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-15-09.

Comparison of variance estimators for meta-analysis of instrumental variable estimates

Background: Mendelian randomization studies perform instrumental variable (IV) analysis using genetic IVs. Results of individual Mendelian randomization studies can be pooled through meta-analysis. We explored how different variance estimators influence the meta-analysed IV estimate.

Methods: Two versions of the delta method (IV before or after pooling), four bootstrap estimators, a jack-knife estimator and a heteroscedasticity-consistent (HC) variance estimator were compared using simulation. Two types of meta-analyses were compared, a two-stage meta-analysis pooling results, and a one-stage meta-analysis pooling datasets.

Results: Using a two-stage meta-analysis, coverage of the point estimate using bootstrapped estimators deviated from nominal levels at weak instrument settings and/or outcome probabilities ≤ 0.10. The jack-knife estimator was the least biased resampling method, the HC estimator often failed at outcome probabilities ≤ 0.50 and overall the delta method estimators were the least biased. In the presence of between-study heterogeneity, the delta method before meta-analysis performed best. Using a one-stage meta-analysis all methods performed equally well and better than two-stage meta-analysis of greater or equal size.

Conclusions: In the presence of between-study heterogeneity, two-stage meta-analyses should preferentially use the delta method before meta-analysis. Weak instrument bias can be reduced by performing a one-stage meta-analysis.