Factors Associated With Cardiac Radiation Dose Reduction After Hypofractionated Radiation Therapy for Localized, Left-Sided Breast Cancer in a Large Statewide Quality Consortium

PURPOSE

Limiting cardiac radiation dose is important for minimizing long-term cardiac toxicity in patients with left-sided early-stage breast cancer.

METHODS AND MATERIALS

Prospectively collected dosimetric data were analyzed for patients undergoing moderately hypofractionated radiation therapy to the left breast within the Michigan Radiation Oncology Quality Consortium from 2016 to 2022. The mean heart dose (MHD) goal was progressively tightened from ≤2 Gy in 2016 to MHD ≤ 1.2 Gy in 2018. In 2021, a planning target volume (PTV) coverage goal was added, and the goal MHD was reduced to ≤1 Gy. Multivariate logistic regression models were developed to assess for covariates associated with meeting the MHD goals in 2016 to 2020 and the combined MHD/PTV coverage goal in 2021 to 2022.

RESULTS

In total, 4165 patients were analyzed with a median age of 64 years. Overall average cardiac metric compliance was 91.7%. Utilization of motion management increased from 41.8% in 2016 to 2020 to 46.5% in 2021 to 2022. Similarly, use of prone positioning increased from 12.2% to 22.2% in these periods. On multivariate analysis in the 2016 to 2020 cohort, treatment with motion management (odds ratio [OR], 5.20; 95% CI, 3.59-7.54; P < .0001) or prone positioning (OR, 3.21; 95% CI, 1.85-5.57; P < .0001) was associated with meeting the MHD goal, while receipt of boost (OR, 0.25; 95% CI, 0.17-0.39; P < .0001) and omission of hormone therapy (OR, 0.65; 95% CI, 0.49-0.88; P = .0047) were associated with not meeting the MHD goal. From 2021 to 2022, treatment with motion management (OR, 1.89; 95% CI, 1.12-3.21; P = .018) or prone positioning (OR, 3.71; 95% CI, 1.73-7.95; P = .0008) was associated with meeting the combined MHD/PTV goal, while larger breast volume (≥1440 cc; OR, 0.34; 95% CI, 0.13-0.91; P = .031) was associated with not meeting the combined goal.

CONCLUSIONS

In our statewide consortium, high rates of compliance with aggressive targets for limiting cardiac dose were achievable without sacrificing target coverage.

Are We Missing Acute Toxicities Associated With Hypofractionated Breast Irradiation? A Report From a Large Multicenter Cohort Study

PURPOSE

The efficacy and long-term safety of hypofractionated whole breast irradiation (HF-WBI) have been established through multiple randomized trials, yet data about acute toxicities remain more limited. Since 2013, our group has prospectively collected acute toxicity data from weekly treatment evaluations and additional assessment after completion. In 2016, we intentionally shifted the posttreatment assessment follow-up visit from 1 month to 2 weeks to evaluate for missed acute toxicity occurring in that immediate posttreatment window. Here, we report whether 2-week follow-up has resulted in increased detection of acute toxicities compared with 4-week follow-up.

METHODS AND MATERIALS

We prospectively compared acute toxicity for patients treated with HF-WBI between January 1, 2013, and August 31, 2015 (4 week follow-up cohort) to patients treated between January 1, 2016, and August 31, 2018 (2 week follow-up cohort). Analyses included a multivariable model that adjusted for other factors known to correlate with toxicity. We prospectively defined acute toxicity as maximum breast pain (moderate or severe rating) and/or occurrence of moist desquamation reported 7 days before the completion of radiation therapy (RT) until 42 days after completion.

RESULTS

A total of 2689 patients who received postlumpectomy radiation and boost were analyzed; 1862 patients in the 2-week follow-up cohort and 827 in the 4-week follow-up cohort. All acute toxicity measures assessed were statistically similar between follow-up cohorts when compared in an unadjusted fashion. Overall acute composite toxicity was 26.4% and 27.7% for patients in the 4-week follow-up and 2-week follow-up cohorts, respectively. Overall acute composite toxicity remained similar between follow-up cohorts in a multivariable, adjusted model and was significantly related to patient's age, body mass index, smoking status, and treatment technique (intensity-modulated RT vs 3-dimensional conformal radiation therapy) but not follow-up cohort.

CONCLUSIONS

An earlier posttreatment follow-up for HF-WBI patients did not reveal a significant increased incidence of acute toxicities at 2 weeks compared with 4 weeks. This study provides physicians and patients with additional data on the safety and tolerability of HF-WBI for early stage breast cancer.

Large institutional experience of early outcomes and dosimetric findings with postoperative stereotactic partial breast irradiation in breast cancer

PURPOSE

To analyze the dosimetric and toxicity outcomes of patients treated with postoperative stereotactic partial breast irradiation (S-PBI).

METHODS

We identified 799 women who underwent S-PBI at our institution between January 2016 and December 2022. The most commonly used dose-fraction and technique were 30 Gy in 5 fractions (91.7 %) and a robotic stereotactic radiation system with real-time tracking (83.7 %). The primary endpoints were dosimetric parameters and radiation-related toxicities. For comparison, a control group undergoing ultra-hypofractionated whole breast irradiation (UF-WBI, n = 468) at the same institution was selected.

RESULTS

A total of 815 breasts from 799 patients, with a median planning target volume (PTV) volume of 89.6 cm3, were treated with S-PBI. Treatment plans showed that the mean and maximum doses received by the PTV were 96.2 % and 104.8 % of the prescription dose, respectively. The volume of the ipsilateral breast that received 50 % of the prescription dose was 32.3 ± 8.9 %. The mean doses for the ipsilateral lung and heart were 2.5 ± 0.9 Gy and 0.65 ± 0.39 Gy, respectively. Acute toxicity occurred in 175 patients (21.5 %), predominantly of grade 1. Overall rate of late toxicity was 4 % with a median follow-up of 31.6 months. Compared to the UF-WBI group, the S-PBI group had comparably low acute toxicity (21.5 % vs. 25.2 %, p = 0.12) but significantly lower dosimetric parameters for all organs-at-risks (all p < 0.05).

CONCLUSION

In this large cohort, S-PBI demonstrated favorable dosimetric and toxicity profiles. Considering the reduced radiation exposure to surrounding tissues, external beam PBI with advanced techniques should at least be considered over traditional WBI-based approaches for PBI candidates.

Axillary Treatment and Chronic Breast Cancer-Related Lymphedema: Implications for Prospective Surveillance and Intervention From a Randomized Controlled Trial

PURPOSE

The PREVENT randomized trial assessed progression to chronic breast cancer-related lymphedema (cBCRL) after intervention triggered by bioimpedance spectroscopy (BIS) or tape measurement (TM). This secondary analysis identifies cBCRL risk factors on the basis of axillary treatment.

METHODS

Between June 2014 and September 2018, 881 patients received sentinel node biopsy (SNB; n = 651), SNB + regional node irradiation (RNI; n = 58), axillary lymph node dissection (ALND; n = 85), or ALND + RNI (n = 87). The primary outcome was the 3-year cBCRL rate requiring complex decongestive physiotherapy (CDP).

RESULTS

After a median follow-up of 32.8 months (IQR, 21-34.3), 69 of 881 patients (7.8%) developed cBCRL. For TM, 43 of 438 (9.8%) developed cBCRL versus 26 of 443 (5.9%) for BIS (P = .028). The 3-year actuarial risk of cBCRL was 4.4% (95% CI, 2.7 to 6.1), 4.2% (95% CI, 0 to 9.8), 25.8% (95% CI, 15.8 to 35.8), and 26% (95% CI, 15.3 to 36.7). Rural residence increased the risk in all groups. For SNB, neither RNI (SNB, 4.1% v SNB + RNI, 3.4%) nor taxane (4.4%) increased cBCRL, but risk was higher for patients with a BMI of ≥30 (6.3%). For SNB + RNI, taxane use (5.7%) or supraclavicular fossa (SCF) radiation (5.0%) increased cBCRL. For ALND patients, BMI ≥25 or chemotherapy increased cBCRL. For ALND + RNI, most patients received SCF radiation and taxanes, so no additional risk factors emerged.

CONCLUSION

The extent of axillary treatment is a significant risk factor for cBCRL. Increasing BMI, rurality, SCF radiation, and taxane chemotherapy also increase risk. These results have implications for a proposed risk-based lymphedema screening, early intervention, and treatment program.

Limitations in the Application of Clinicopathologic Factors Alone in Predicting Radiation Benefit for Women with Low-Risk DCIS after Breast Conserving Surgery: The Impact of a 7-Gene Biosignature Based on 10-Year Ipsilateral Breast Recurrence (IBR) Rates

PURPOSE/OBJECTIVE(S)

Most women diagnosed with ductal carcinoma in situ (DCIS) receive radiotherapy (RT) after breast conserving surgery (BCS); however, clinical trials show that over 70% of women with BCS alone will not have a recurrence and therefore not benefit from RT. Traditionally, clinicopathologic (CP) factors have been used to select for whom to de-escalate treatment, but prospective trials have failed to identify a low risk CP group that did not benefit from RT with respect to local control. This study assessed the re-classification of patients with low-risk CP into Risk groups defined by the 7-gene biosignature and compared to 10-yr IBR rates.

MATERIALS/METHODS

Women (n = 926) from four international DCIS cohorts treated with BCS had formalin-fixed paraffin embedded tissue samples analyzed at a CLIA lab (Laguna Hills, CA). CP low-risk patients were identified using a) RTOG-9804-like criteria [Nuclear Grade 1 or 2 & Size ≤2.5 cm & non-Palpable & Screen Detected & margin negative (no-ink on tumor)] and b) MSKCC-like criteria [low-risk score<220, determined using nomogram weighted factors (excluding: number of re-excisions and RT treatment), and using no-ink-on-tumor instead of close margin]. The 7-gene DCIS biosignature combined biomarkers with CP factors (age, size, palpability, and margin status) using an algorithm reporting a Decision Score (DS) and Residual Risk subtype (RRt). Women with low-risk CP were classified into biosignature Low Risk (DS≤2.8, no RRt) or High Risk (DS>2.8 +/- RRt) groups. 10yr in-breast event (IBR) rates with and without RT were assessed by Kaplan-Meier rates and Cox proportional hazard analyses.

RESULTS

Overall, 37% of all women were classified into the biosignature Low Risk group, while 51% and 34% were classified into CP low-risk groups (RTOG-9804-like, MSKCC-like, respectively). The biosignature Low Risk group (n = 338) had a 10-yr IBR risk of 5.6% after BCS and no significant RT benefit (absolute RT benefit = 0.8%, p = 0.70), 99% negative predictive value (NPV) for RT benefit. CP low-risk groups had 10-yr IBR rates of 12% and 8% after BCS without RT with absolute 6% (p = 0.04) and 4% (p = 0.1) IBR rate reductions with RT. The biosignature reclassified 51% and 63% of CP low-risk patients into the biosignature High Risk group. Importantly, these patients had higher IBR rates without RT (20% and 12%) and significant 13% (p = 0.005) and 8% (p = 0.01) absolute IBR rate reductions from RT. CP low-risk patients with concordant biosignature Low Risk demonstrated no significant RT benefit.

CONCLUSION

The 7-gene predictive biosignature more reliably identified patients with low 10-yr IBR rates and no significant RT benefit than the traditional CP low-risk criteria (RTOG-9804-like, MSKCC-like). Importantly, those CP low-risk patients who were re-classified as biosignature High Risk had increased 10-year IBR rates and significant RT benefit.

Comparison of Early Outcomes of Stereotactic Accelerated Partial Breast Irradiation vs. Volumetric Modulated Arc Therapy-Based FAST-FORWARD Whole Breast Irradiation for Breast Cancer

PURPOSE/OBJECTIVE(S)

Despite evidence supporting APBI from 8 published prospective randomized trials enrolling over 10,000 women, the uptake of APBI in clinical practice is surprisingly low. This is being exacerbated by a new, convenient, and safe shortened WBI schedule. Here, we report the dosimetric and early outcome analyses of the first >1000 patients treated at our institution since the first adoption of stereotactic APBI and the ultra-hypofractionated WBI regimen.

MATERIALS/METHODS

From 2016 to 2022, 801 women with breast cancers in the suitable or cautionary categories according to the ASTRO APBI consensus panel guidelines, received 30 Gy in 5 fractions (92%) either using a robotic stereotactic radiation system (83%) or stereotactic volumetric-based arc therapy (VMAT, 17%). Between 2020 and 2022, 468 women, who were not candidates for APBI and not undergoing any regional irradiation received 26 Gy in 5 fractions using VMAT to the whole breast with the addition of cardiac sparing technique in left-sided breast cancer patients. Tumor bed boosts were delivered in 99% of FF-WBI patients. We evaluated dose-volume histogram parameters for target volumes and organs-at-risk and radiation-related toxicities during RT or within 6 months after the end of RT.

RESULTS

Target volume coverage was acceptable in both groups, with mean 96% of the target volumes receiving 95% of the prescribed doses and 0 cm3 within target volumes exceeding 105% of the prescribed doses. S-APBI resulted in small, but statistically significant, reductions in the radiation dose delivered to the ipsilateral breast, contralateral breast, lungs, heart, and coronary artery compared with FF-WBI. Comparing WBI to APBI, the mean contralateral breast dose, ipsilateral lung V20 Gy, mean contralateral lung dose, and mean heart dose, were reduced by 89%, 78%, 73%, and 29%, respectively. With median follow-up periods of 32 months for s-APBI and 19 months for FF-WBI, acute toxicity was assessable in all patients. The risks of any grade acute toxicity were 21% for s-APBI and 25% for FF-WBI (p = .117). Among them, grade 2 rates were 1.3% in both groups and no severe toxicity has been reported.

CONCLUSION

We found s-APBI and VMAT-based FF WBI were associated with favorable dosimetric and acute toxicity profiles. However, considering significantly less irradiated volume in the breast, lungs, and heart, APBI with advanced available technique options should be considered over any WBI-based approach for patients at low risk for local recurrence.

Cannabis Use Patterns among Patients with Early-Stage Breast Cancer in a Large Multicenter Cohort from a State with Legalized Adult Non-Medical Cannabis

PURPOSE/OBJECTIVE(S)

Cannabis use among patients with cancer is an area of great interest given its widespread acceptance despite the lack of supporting clinical data. The absence of data limits the understanding of potential clinical benefits of cannabis and the ability of providers to deliver evidence-based recommendations for patient care. We explored cannabis use patterns in patients with early-stage breast cancer in a large multicenter cohort in a state with legalized adult non-medical cannabis.

MATERIALS/METHODS

Initial questions about cannabis use history and frequency were introduced in Michigan Radiation Oncology Quality Consortium (MROQC) breast cancer patient surveys on 2/1/2020 for female patients receiving radiation after lumpectomy for non-metastatic breast cancer. Expanded questions were introduced on 6/28/2022 to assess mode of administration, active ingredient, and reason for use. Summary statistics were generated. A multivariable model using logistic regression identified patient characteristics associated with cannabis use.

RESULTS

Among 3948 eligible patients, 2738 (69.35%) completed survey questions, and 2462/2738 (89.9%) completed the initial question on cannabis use. Among those, 364/2462 (14.8%) noted cannabis use in the last 30 days, 588 (23.9%) noted remote use (>30 days ago), 1462 (59.4%) reported never having used cannabis, 44 (1.8%) preferred not to answer cannabis use questions, and 4 (0.4%) did not provide use history. Younger age [age <50 vs 60-70, OR 2.5 (95% CI 1.65, 3.79) p<0.001)], Hispanic ethnicity [OR 2.20 (95% CI 1.06, 4.56) p = 0.03], history of smoking [OR 2.56 (95% CI 1.88, 3.48) p<0.001], current smoking [OR 4.70 (95% CI 3.22, 6.86) p<0.001)], and prior chemotherapy [OR 1.40 (95% CI 1.00, 1.96) p = 0.05] predicted recent cannabis use in a multivariable model. Of the 364 patients endorsing cannabis use in the last 30 days, 89 (24.5%), 72 (19.8%), 29 (8.0%), 66 (18.1%), 30 (8.2%), and 78 (21.4%) reported using cannabis 1-2 days, 3-5 days, 6-9 days, 10-19 days, 20-29 days, and all 30 days, respectively. The most common modes of administration among 76 individuals who responded to the expanded questionnaire to date were oral (39.4%), smoking (30.3%), and topical (10.5%). The products used contained tetrahydrocannabinol (THC; 26.3%), cannabidiol (CBD; 19.7%), balanced levels of THC and CBD (19.7%), or active ingredients that were unknown to the patient (34.2%). Patients frequently endorsed cannabis use for insomnia, anxiety, and pain.

CONCLUSION

Many patients with early-stage breast cancer are using cannabis. Younger age, Hispanic ethnicity, smoking, and chemotherapy history are predictors of cannabis use. Patients are often unaware of the active ingredients in the products that they use, suggesting an important role for patient education and a need to equip providers to advise patients in their care.

Impact of Breast Volume on Achieving a Conservative Heart and Target Coverage Metric for Patients Receiving Whole Breast Radiotherapy in a Statewide Consortium

PURPOSE/OBJECTIVE(S)

Radiation to large breast volumes (BV) has been associated with increased dose inhomogeneities, breast fibrosis, and induration. Radiation exposure to the heart during breast radiotherapy has been associated with late cardiovascular morbidity and mortality. This study, therefore, investigates the impact of BV on achieving optimal lumpectomy cavity target coverage (V95% [%] >95) while maintaining mean heart dose constraints (MHD, mean [Gy] <1) across a range of BV from patients enrolled in a statewide consortium.

MATERIALS/METHODS

A retrospective analysis was conducted for 2,506 patients receiving left-sided whole breast moderately-hypofractionated (2.5-2.8 Gy/fx) radiotherapy without nodal fields between 2018-2022. The BV was calculated for each patient from contours in the treatment planning system, and the volume distribution partitioned into quartiles. Dosimetric parameters were calculated from dose-volume histograms. The percentage of patients in which the metrics were achieved was calculated for each BV quartile for different treatment positions: all positions, supine, supine with breathing motion management, and prone.

RESULTS

The BV ranges within the quartiles (∼620 patients/quartile) were ≤720.0 cc, 720.1 to ≤1065.0 cc, 1065.1 to ≤1500.0 cc, and >1500.0 cc for quartiles Q1-Q4, respectively. Of the 2,506 patients, 76% were treated supine (of which 41.6% were treated using breathing motion management techniques), 23.5% were treated prone, and 0.5% were treated decubitus. Discrete percentages of patients able to meet the metrics are provided in the table. An increase in BV from Q1 to Q4 correlated with lower percentages of patients meeting the MHD metric, however no correlation was observed between BV and target coverage. Treating supine with breathing motion management resulted in a higher percentage of patients meeting the MHD metric (odds ratio (OR) = 1.96 relative to supine without motion management, p<0.0001), while the prone setup proved to be the superior technique across all quartiles (OR = 3.95 relative to supine, p<0.0001).

CONCLUSION

Increasing BVs resulted in lower percentages of patients receiving MHD≤1 Gy. Thus, cardiac sparing may be more difficult to achieve in patients with larger BV. Utilization of alternate treatment positions, such as supine with breathing motion management and prone, greatly improved the percentage of patients able to meet the MHD metric without sacrificing target coverage in all quartiles. Prone positioning was the technique least susceptible to BV effects in meeting the MHD≤1 Gy goal.

Factors Associated with Cardiac Radiation Dose Reduction Following Hypofractionated Radiation Therapy for Localized, Left-Sided Breast Cancer in a Large Statewide Quality Consortium

PURPOSE/OBJECTIVE(S)

Limiting radiation dose to the heart is important for minimizing the risk of long-term cardiac toxicity in patients with left-sided early-stage breast cancer.

MATERIALS/METHODS

Prospectively collected dosimetric data were analyzed for patients undergoing hypofractionated radiation therapy to the left breast for localized node-negative breast cancer within the Michigan Radiation Oncology Quality Consortium (MROQC) from 2016-2022. Goals for limiting cardiac dose were adjusted over time. From 2016-2020, the cardiac quality metric focused on total mean heart dose (MHD) from the composite whole breast and boost plans, tightening from a goal of MHD ≤2 Gy to MHD ≤1.2 Gy by 2020. In 2021-2022, the cardiac metric transitioned to a combined goal of MHD ≤1.0 Gy from the whole breast plan and ≥95% lumpectomy cavity planning target volume (PTV) receiving 95% of the prescription dose. Separate multivariate logistic regression models were developed to assess for covariates associated with meeting the MHD goal in 2016-2020 and combined MHD/PTV coverage goal in 2021-2022.

RESULTS

In total, 4,165 patients were analyzed with a median age of 64 years. Most patients (86%) had either Tis or T1 disease, and 66% received hormone therapy. Baseline demographic and disease characteristics did not change substantially between treatment periods. Use of breath-hold or motion gating increased from 42% in 2016-2020 to 46% in 2021-2022. Similarly, use of prone positioning increased from 12% to 20%. From 2016-2020, 90.9% of plans achieved the MHD goal, compared to 93.6% of plans achieving the composite MHD/PTV goal from 2021-2022. On multivariate analysis in the 2016-2020 cohort, treatment with motion management (OR 5.20, 95% CI [3.59-7.54], p<0.0001) or prone positioning (OR 3.21, 95% CI [1.85-5.57], p < 0.0001) were associated with meeting the MHD goal, while receipt of boost (OR 0.25, 95% CI [0.17-0.39], p<0.0001) and omission of hormone therapy (OR 0.65, 95% CI [0.49-0.88], p = 0.0047), were associated with not meeting the MHD goal. During the era including composite heart dose and PTV coverage goals (2021-2022), treatment with motion management (OR 1.89, 95% CI [1.12-3.21], p = 0.018) or prone positioning (OR 3.71, 95% CI [1.73-7.95], p = 0.0008) were associated with meeting the combined goal, while larger breast volume (≥1440 cc, OR 0.34, 95% CI [0.13 - 0.91], p = 0.031) and treatment at an academic center (OR 0.36, 95% CI [0.22-0.67], p = 0.0009) were associated with not meeting the combined goal.

CONCLUSION

In our statewide consortium, rates of compliance with aggressive targets for limiting cardiac dose remain high, despite tightening of these goals to include lower mean heart doses and inclusion of a concurrent PTV coverage goal. Treatment using motion management or prone positioning is associated with achieving the cardiac dose goals.

Three-Fraction Accelerated Partial Breast Irradiation (APBI) Delivered With Interstitial Brachytherapy Is Safe: First Results From the Tri-fraction Radiation Therapy Used to Minimize Patient Hospital Trips (TRIUMPH-T) Trial

PURPOSE

Shorter courses of breast radiotherapy are offered as an alternative to 4 weeks of whole-breast irradiation after lumpectomy, including brachytherapy. A prospective phase 2multi-institution clinical trial to study 3-fraction accelerated partial breast irradiation delivered by brachytherapy was conducted.

METHODS AND MATERIALS

The trial treated selected breast cancers after breast-conserving surgery with brachytherapy applicators that delivered 22.5 Gy in 3 fractions of 7.5 Gy. The planning treatment volume was 1 to 2 cm beyond the surgical cavity. Eligible women were age ≥45 years with unicentric invasive or in situ tumors ≤3 cm excised with negative margins and with positive estrogen or progesterone receptors and no metastases to axillary nodes. Strict dosimetric parameters were required to be met and follow up information was collected from the participating sites.

RESULTS

Two hundred patients were prospectively enrolled; however, a total of 185 patients who were enrolled were followed for a median of 3.63 years. Three-fraction brachytherapy was associated with low chronic toxicity. There was excellent or good cosmesis in 94% of patients. There were no grade 4 toxicities. Grade 3 fibrosis at the treatment site was present in 1.7% and 32% percent had grades 1 or 2 fibrosis at the treatment site. There was 1 rib fracture. Other late toxicities included 7.4% grade 1 hyperpigmentation, 2% grade 1 telangiectasias, 1.7% symptomatic seromas, 1.7% abscessed cavities, and 1.1% symptomatic fat necrosis. There were 2 (1.1%) ipsilateral local recurrences, 2 (1.1%) nodal recurrences and no distant recurrences. Other incidents included one contralateral breast cancer and 2 second malignancies (lung).

CONCLUSIONS

Ultra-short breast brachytherapy is feasible and has excellent toxicity and could be an alternative to standard 5-day, 10 fraction accelerated partial breast irradiation in eligible patients. Patients from this prospective trial will continue to be followed to evaluate long-term outcomes.

A Novel Biosignature Identifies Patients With DCIS With High Risk of Local Recurrence After Breast Conserving Surgery and Radiation Therapy

PURPOSE

There is an unmet need to identify women diagnosed with ductal carcinoma in situ (DCIS) with a low risk of in-breast recurrence (IBR) after breast conserving surgery (BCS), which could omit radiation therapy (RT), and also to identify those with elevated IBR risk remaining after BCS plus RT. We evaluated a novel biosignature for a residual risk subtype (RRt) to help identify patients with elevated IBR risk after BCS plus RT.

METHODS AND MATERIALS

Women with DCIS treated with BCS with or without RT at centers in the US, Australia, and Sweden (n = 926) were evaluated. Patients were classified into 3 biosignature risk groups using the decision score (DS) and the RRt category: (1) Low Risk (DS ≤2.8 without RRt), (2) Elevated Risk (DS >2.8 without RRt), and (3) Residual Risk (DS >2.8 with RRt). Total and invasive IBR rates were assessed by risk group and treatment.

RESULTS

In patients at low risk, there was no significant difference in IBR rates with or without RT (total, P = .8; invasive IBR, P = .7), and there were low overall 10-year rates (total, 5.1%; invasive, 2.7%). In patients with elevated risk, IBR rates were decreased with RT (total: hazard ratio [HR], 0.25; P < .001; invasive: HR, 0.28; P = .005); 10-year rates were 20.6% versus 4.9% (total) and 10.9% versus 3.1% (invasive). In patients with residual risk, although IBR rates decreased with RT after BCS (total: HR, 0.21; P < .001; invasive: HR, 0.29; P = .028), IBR rates remained significantly higher after RT compared with patients with elevated risk (HR, 2.5; 95% CI, 1.2-5.4; P = .018), with 10-year rates of 42.1% versus 14.7% (total) and 18.3% versus 6.5% (invasive).

CONCLUSIONS

The novel biosignature identified patients with 3 distinct risk profiles: Low Risk patients with a low recurrence risk with or without adjuvant RT, Elevated Risk patients with excellent outcomes after BCS plus RT, and Residual Risk patients with an elevated recurrence risk remaining after BCS plus RT, warranting potential intensified or alternative treatment approaches.

Bioimpedance spectroscopy for breast cancer-related lymphedema assessment: clinical practice guidelines

PURPOSE

Breast cancer-related lymphedema (BCRL) represents a significant concern for patients following breast cancer treatment, and assessment for BCRL represents a key component of survivorship efforts. Growing data has demonstrated the benefits of early detection and treatment of BCRL. Traditional diagnostic modalities are less able to detect reversible subclinical BCRL while newer techniques such as bioimpedance spectroscopy (BIS) have shown the ability to detect subclinical BCRL, allowing for early intervention and low rates of chronic BCRL with level I evidence. We present updated clinical practice guidelines for BIS utilization to assess for BCRL.

METHODS AND RESULTS

Review of the literature identified a randomized controlled trial and other published data which form the basis for the recommendations made. The final results of the PREVENT trial, with 3-year follow-up, demonstrated an absolute reduction of 11.3% and relative reduction of 59% in chronic BCRL (through utilization of compression garment therapy) with BIS as compared to tape measurement. This is in keeping with real-world data demonstrating the effectiveness of BIS in a prospective surveillance model. For optimal outcomes patients should receive an initial pre-treatment measurement and subsequently be followed at a minimum quarterly for first 3 years then biannually for years 4-5, then annually as appropriate, consistent with previous guidelines; the target for intervention has been changed from a change in L-Dex of 10 to 6.5. The lack of pre-operative measure does not preclude inclusion in the prospective surveillance model of care.

CONCLUSION

The updated clinical practice guidelines present a standardized approach for a prospective model of care using BIS for BCRL assessment and supported by evidence from a randomized controlled trial as well as real-world data.

Abstract B016: Guiding de-escalation of treatment for patients with DCIS using a predictive 7-gene biosignature: Identification of a clinically low-risk patient group

Background: NCCN treatment guidelines support de-escalation of radiotherapy (RT) for “low risk” patients with ductal carcinoma in situ (DCIS) treated with breast conserving surgery (BCS) for which improved specificity in identifying patients with low in-breast recurrence (IBR) rates who are unlikely to benefit from RT is needed. “low risk” has been defined as the absence of “high risk” clinicopathological (CP) factors, which include younger age (&lt;50 yrs) or tumors that are 2 cm or larger, palpable, or high nuclear grade. However, these CP factors have failed to identify a patient group with lower recurrence risk that do not clinically benefit from RT after BCS. Thus, the clinical utility of a Low Risk group identified by the predictive 7-gene biosignature was characterized overall and for patient subsets meeting “low risk” or “high risk” CP criteria. Methods: DCIS patients (n=926) from four international cohorts treated with BCS (negative margins) with (n=641) and without RT (n=335) were evaluated for CP criteria (age&lt;50 or grade 3, and RTOG 9804 like) and clinical outcomes. Formalin-fixed paraffin-embedded tissue samples for each patient were analyzed at a CLIA lab (PreludeDx, Laguna Hills, CA) for the predictive 7-gene biosignature with a Residual Risk subtype (RRt). The biosignature reported a decision score (DS) of 0-10 and presence/absence of the RRt subtype. A Low Risk group (DS≤2.8 without RRt) was compared with the combined Elevated Risk (DS&gt;2.8 without RRt) and Residual Risk groups (DS&gt;2.8 with RRt), where 10-yr total IBR rates were evaluated using Cox Proportional Hazards and Kaplan Meier analysis by treatment, biosignature Risk group, and CP criteria. Results: The biosignature classified 37% of women treated with BCS as Low Risk (n=338) and 63% (n=588) were classified into the combined Elevated/Residual Risk group. Among patients who did not receive RT, those in the Elevated/Residual Risk group had higher IBR rates (p&lt;.001) than those in the Low Risk group, with corresponding 10-yr IBR rates of 25.7% (95% CI: 18.8%, 34.4%) vs 5.6% (95% CI: 2.5%, 12.1%), respectively. RT did not reduce the IBR rate in the Low Risk group (p=0.71), where the 10-yr IBR rate was 4.8% (95% CI: 2.5%, 9.1%) after RT, corresponding to a number needed to treat (NNT) of ~100. However, the Elevated/Residual Risk group benefited from RT (p&lt;0.001), with a 17.7% (95% CI: 9.4%, 26%) absolute 10-year IBR rate reduction, corresponding to a NNT of 6. The biosignature reclassified 35-40% of patients with “high risk” CP criteria into the Low Risk group. IBR rates in the Low Risk group for patients with “high risk” CP were not significantly different than those with “low risk” CP criteria. Conclusion: The 7-gene biosignature was a better predictor of prognosis and RT benefit than standard CP risk stratification, identifying a low risk group with no significant benefit from RT. The 10-yr IBR rate with or without RT remained consistent in the biosignature Low Risk group independent of CP criteria, further supporting identification of a true low risk group who may forgo RT.

Citation Format: Rachel Rabinovitch, Frank A. Vicini, Chirag Shah, Julie Margenthaler, Brian Czerniecki, Pat Whitworth, Sheila Weinmann, Michael C. Leo, Fredrik Wärnberg, G. Bruce Mann, Steven C. Shivers, David Dabbs, Karuna Mittal, Troy Bremer. Guiding de-escalation of treatment for patients with DCIS using a predictive 7-gene biosignature: Identification of a clinically low-risk patient group [abstract]. In: Proceedings of the AACR Special Conference on Rethinking DCIS: An Opportunity for Prevention?; 2022 Sep 8-11; Philadelphia, PA. Philadelphia (PA): AACR; Can Prev Res 2022;15(12 Suppl_1): Abstract nr B016.

Assessing the benefit of adjuvant endocrine therapy in patients following breast-conserving surgery with or without radiation stratified by a 7-gene predictive DCIS biosignature

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Background: Breast conserving surgery (BCS) followed by radiotherapy (RT) has been the mainstay for DCIS treatment. Adjuvant endocrine therapy (ET) has often been recommended based on multiple randomized clinical trials (RCT). However, these studies have failed to identify subsets of patients who did or did not benefit from adjuvant RT/ET therapy after BCS. We evaluated the association of a 7-gene predictive DCIS biosignature (PreludeDx, Laguna Hills, CA) to assess the impact of ET on 10-yr ipsilateral breast recurrence (IBR) risk after BCS alone or with RT. Methods: DCISionRT with integrated Residual Risk subtype (RRt) reported a decision score (DS) and three risk groups, a) Low Risk (DS≤2.8), b) Elevated Risk (DS > 2.8 without RRt) and c) Residual Risk (DS > 2.8 with RRt). DCISionRT/RRt was evaluated in 926 patients from 4 cohorts who were treated with BCS alone or with RT/ET. The three risk groups were assessed for 10-yr total (invasive and in situ) IBR risk by Kaplan Meier and Cox proportional hazards survival analysis. Results: DCISionRT/RRt classified 338 (37%) women as Low Risk, 399 (43%) as Elevated Risk, and 189 (20%) as Residual Risk. Overall, patients treated with ET had a significantly lower 10-yr IBR risk in multivariable analysis independent of RT (HR = 0.55, p = 0.033). In the Low Risk group treated with BCS without RT, the average 10-yr IBR risk was 5.6% (95% CI 2.5-12.1%, n = 124) and was not significantly different with vs without ET (p = 0.33). The 10-yr IBR risk after BCS alone was 22.6% in the Elevated Risk group and 50.3% in the Residual Risk group. Compared to BCS alone, the 10-year IBR risk tended to be lower in patients prescribed ET without RT in the Elevated (11.6%, 95% CI 3.9-32%) and Residual (15.4%, 95% CI 4.1-49%) Risk groups. 10-yr IBR risk was not significantly reduced by RT within the Low Risk group (p = 0.7) but was significantly reduced to 6.3% (95% CI 3.4-12%) by RT within the Elevated Risk (HR = 0.2, p < 0.001) and to 12.5% (95% CI 6.4-23%) within the Residual Risk (HR = 0.2, p < 0.001) groups. 10-yr IBR risk was significantly higher after RT in the Residual (HR = 2.5, p = 0.013) vs. Elevated Risk groups. After BCS and RT, there was no significant reduction in 10-yr IBR risk for those treated with vs without ET in the Elevated (p = 0.22) and Residual (p = 0.87) risk groups. Conclusions: The DCISionRT/RRt biosignature demonstrated prognostic and predictive RT response in Elevated and Residual Risk patients. Consistent with prior RCT data, ET was associated with lower 10-yr IBR risk overall, and within the DCISionRT Elevated and Residual Risk groups without RT. However, neither ET nor RT were asssociated with significant risk reduction in the Low Risk group. There was no added benefit of ET in the Elevated and Residual Risk groups after BCS+RT; the Residual Risk group patients still had a high IBR risk after RT.

The impact of chemotherapy on toxicity and cosmetic outcome in patients receiving whole breast irradiation: an analysis within a state-wide quality consortium

PURPOSE

We investigated whether the use of chemotherapy prior to whole breast irradiation (WBI) using either conventional fractionation (CWBI) or hypofractionation (HWBI) is associated with increased toxicity or worse cosmetic outcome compared to WBI alone.

METHODS AND MATERIALS

We identified 6,754 patients who received WBI alone (without a third field covering the superior axillary and supraclavicular nodal regions) with data prospectively collected in a state-wide consortium. We reported rates of four toxicity outcomes: physician-reported acute moist desquamation, patient-reported acute moderate/severe breast pain, a composite acute toxicity measure (including moist desquamation and either patient-reported or physician-reported moderate/significant breast pain), and physician-reported impaired cosmetic outcome at one year following WBI. Successive multivariable models were constructed to estimate the impact of chemotherapy on these outcomes.

RESULTS

Rates of moist desquamation, patient-reported pain, composite acute toxicity, and impaired cosmetic outcome were 23%, 34%, 42%, and 10% for 2,859 patients receiving CWBI and 13%, 28%, 31%, and 11% for 3,895 patients receiving HWBI. Receipt of chemotherapy prior to CWBI was not associated with higher rates of patient-reported pain, composite acute toxicity, or impaired cosmetic outcome compared to CWBI without chemotherapy but was associated with more moist desquamation (OR=1.32 [1.07-1.63], p=0.01). Receipt of chemotherapy prior to HWBI was not associated with higher rates of any of the four toxicity outcomes compared to HWBI alone.

CONCLUSIONS

In this cohort, use of chemotherapy prior to WBI was generally well tolerated. CWBI with chemotherapy, but not to HWBI with chemotherapy, was associated with higher rates of moist desquamation. Rates of acute breast pain and impaired cosmetic outcome at one year were comparable in patients receiving chemotherapy prior to either CWBI or HWBI. These data support the use of HWBI following chemotherapy.

The Clinical Utility of DCISionRT® on Radiation Therapy Decision Making in Patients with Ductal Carcinoma In Situ Following Breast-Conserving Surgery

BACKGROUND

The role of radiation therapy (RT) following breast-conserving surgery (BCS) in ductal carcinoma in situ (DCIS) remains controversial. Trials have not identified a low-risk cohort, based on clinicopathologic features, who do not benefit from RT. A biosignature (DCISionRT®) that evaluates recurrence risk has been developed and validated. We evaluated the impact of DCISionRT on clinicians' recommendations for adjuvant RT.

METHODS

The PREDICT study is a prospective, multi-institutional, observational registry in which patients underwent DCISionRT testing. The primary endpoint was to identify the percentage of patients where testing led to a change in RT recommendations.

RESULTS

Overall, 539 women were included in this study. Pre DCISionRT testing, RT was recommended to 69% of patients; however, post-testing, a change in the RT recommendation was made for 42% of patients compared with the pre-testing recommendation; the percentage of women who were recommended RT decreased by 20%. For women initially recommended not to receive an RT pre-test, 35% had their recommendation changed to add RT following testing, while post-test, 46% of patients had their recommendation changed to omit RT after an initial recommendation for RT. When considered in conjunction with other clinicopathologic factors, the elevated DCISionRT score risk group (DS > 3) had the strongest association with an RT recommendation (odds ratio 43.4) compared with age, grade, size, margin status, and other factors.

CONCLUSIONS

DCISionRT provided information that significantly changed the recommendations to add or omit RT. Compared with traditional clinicopathologic features used to determine recommendations for or against RT, the factor most strongly associated with RT recommendations was the DCISionRT result, with other factors of importance being patient preference, tumor size, and grade.

The Risk of Subclinical Breast Cancer-Related Lymphedema by the Extent of Axillary Surgery and Regional Node Irradiation: A Randomized Controlled Trial

PURPOSE

To compare the risk of subclinical breast cancer-related lymphedema (sBCRL) using bioimpedance spectroscopy (BIS) or tape measure (TM) by the extent of axillary surgery and regional nodal irradiation (RNI).

METHODS AND MATERIALS

Patients were randomized to surveillance with TM or BIS. A BIS ≥6.5 L-Dex units or TM volume change ≥5 and <10% above presurgical baselines "triggered" sBCRL. The incidence of sBCRL by sentinel node biopsy or axillary lymph node dissection (ALND) with or without RNI was examined for 484 patients. Radiation was categorized as "limited RNI" (axilla level I/II only) or "extensive RNI" (axilla level III or supraclavicular fossa with or without level I/II).

RESULTS

At a median follow-up of 20.5 months, 109 of 498 patients (21.9%) triggered sBCRL (BIS 13.5% vs TM 25.6%; P <.001). In patients not receiving RNI, BIS triggered 12.9% of patients undergoing SNB and 25.0% undergoing ALND (P = .18). Extensive RNI significantly increased triggering with BIS versus no RNI after sentinel node biopsy (SNB; 33.3% vs 12.9%; P = .03) but not ALND (30.8% vs 25.0%; P = .69). Triggering by TM was greater than 25% for most subgroups and was inferior to BIS in discriminating the risk of sBCRL by utilization of RNI or axillary surgery.

CONCLUSIONS

The lower triggering rates with BIS and its better discrimination of the risk of sBCRL by receipt and type of RNI compared with TM support its use for posttreatment surveillance to detect sBCRL and to initiate early intervention. The risk of sBCRL increased with more extensive axillary treatment. Patients having ALND or extensive RNI require close surveillance for BCRL. Longer follow-up is required to determine rates of progression to clinical lymphedema.

Outcomes with Partial Breast Irradiation vs. Whole Breast Irradiation: a Meta-Analysis

BACKGROUND

Several randomized trials have been performed comparing partial breast irradiation (PBI) and whole breast irradiation (WBI) though controversy remains, including regarding differences by PBI technique. We performed a meta-analysis to compare results between WBI versus PBI and between PBI techniques.

METHODS

A systematic review was performed to identify modern randomized studies listed in MEDLINE from 2005 to 2020. PBI trials were divided into external beam radiation and brachytherapy techniques, with intraoperative radiation excluded. A Bayesian logistic regression model evaluated the risk of ipsilateral breast tumor recurrence (IBTR) and acute and chronic toxicities. The primary outcome was IBTR at 5 years with WBI compared with PBI.

RESULTS

A total of 9758 patients from 7 studies were included (4840-WBI, 4918-PBI). At 5 years, no statistically significant difference in the rate of IBTR was noted between PBI (1.8%, 95% HPD 0.68-3.2%) and WBI (1.7%, 95% HPD 0.92-2.4%). By PBI technique, the 5-year rate of IBTR rate for external beam was 1.7% and 2.2% for brachytherapy. Rates of grade 2 + acute toxicity were 7.1% with PBI versus 47.5% with WBI. For late toxicities, grade 2/3 rates were 0%/0% with PBI compared with 1.0%/0% with WBI.

CONCLUSIONS

IBTR rates were similar between PBI and WBI with no significant differences noted by PBI technique; PBI had reduced acute toxicities compared to WBI. Because studies did not provide toxicity data in a consistent fashion, definitive conclusions cannot be made with additional data from randomized trials needed to compare toxicity profiles between PBI techniques.

Long-term primary results of accelerated partial breast irradiation after breast-conserving surgery for early-stage breast cancer: a randomised, phase 3, equivalence trial

BACKGROUND

Whole-breast irradiation after breast-conserving surgery for patients with early-stage breast cancer decreases ipsilateral breast-tumour recurrence (IBTR), yielding comparable results to mastectomy. It is unknown whether accelerated partial breast irradiation (APBI) to only the tumour-bearing quadrant, which shortens treatment duration, is equally effective. In our trial, we investigated whether APBI provides equivalent local tumour control after lumpectomy compared with whole-breast irradiation.

METHODS

We did this randomised, phase 3, equivalence trial (NSABP B-39/RTOG 0413) in 154 clinical centres in the USA, Canada, Ireland, and Israel. Adult women (>18 years) with early-stage (0, I, or II; no evidence of distant metastases, but up to three axillary nodes could be positive) breast cancer (tumour size ≤3 cm; including all histologies and multifocal breast cancers), who had had lumpectomy with negative (ie, no detectable cancer cells) surgical margins, were randomly assigned (1:1) using a biased-coin-based minimisation algorithm to receive either whole-breast irradiation (whole-breast irradiation group) or APBI (APBI group). Whole-breast irradiation was delivered in 25 daily fractions of 50 Gy over 5 weeks, with or without a supplemental boost to the tumour bed, and APBI was delivered as 34 Gy of brachytherapy or 38·5 Gy of external bream radiation therapy in 10 fractions, over 5 treatment days within an 8-day period. Randomisation was stratified by disease stage, menopausal status, hormone-receptor status, and intention to receive chemotherapy. Patients, investigators, and statisticians could not be masked to treatment allocation. The primary outcome of invasive and non-invasive IBTR as a first recurrence was analysed in the intention-to-treat population, excluding those patients who were lost to follow-up, with an equivalency test on the basis of a 50% margin increase in the hazard ratio (90% CI for the observed HR between 0·667 and 1·5 for equivalence) and a Cox proportional hazard model. Survival was assessed by intention to treat, and sensitivity analyses were done in the per-protocol population. This trial is registered with ClinicalTrials.gov, NCT00103181.

FINDINGS

Between March 21, 2005, and April 16, 2013, 4216 women were enrolled. 2109 were assigned to the whole-breast irradiation group and 2107 were assigned to the APBI group. 70 patients from the whole-breast irradiation group and 14 from the APBI group withdrew consent or were lost to follow-up at this stage, so 2039 and 2093 patients respectively were available for survival analysis. Further, three and four patients respectively were lost to clinical follow-up (ie, survival status was assessed by phone but no physical examination was done), leaving 2036 patients in the whole-breast irradiation group and 2089 in the APBI group evaluable for the primary outcome. At a median follow-up of 10·2 years (IQR 7·5-11·5), 90 (4%) of 2089 women eligible for the primary outcome in the APBI group and 71 (3%) of 2036 women in the whole-breast irradiation group had an IBTR (HR 1·22, 90% CI 0·94-1·58). The 10-year cumulative incidence of IBTR was 4·6% (95% CI 3·7-5·7) in the APBI group versus 3·9% (3·1-5·0) in the whole-breast irradiation group. 44 (2%) of 2039 patients in the whole-breast irradiation group and 49 (2%) of 2093 patients in the APBI group died from recurring breast cancer. There were no treatment-related deaths. Second cancers and treatment-related toxicities were similar between the two groups. 2020 patients in the whole-breast irradiation group and 2089 in APBI group had available data on adverse events. The highest toxicity grade reported was: grade 1 in 845 (40%), grade 2 in 921 (44%), and grade 3 in 201 (10%) patients in the APBI group, compared with grade 1 in 626 (31%), grade 2 in 1193 (59%), and grade 3 in 143 (7%) in the whole-breast irradiation group.

INTERPRETATION

APBI did not meet the criteria for equivalence to whole-breast irradiation in controlling IBTR for breast-conserving therapy. Our trial had broad eligibility criteria, leading to a large, heterogeneous pool of patients and sufficient power to detect treatment equivalence, but was not designed to test equivalence in patient subgroups or outcomes from different APBI techniques. For patients with early-stage breast cancer, our findings support whole-breast irradiation following lumpectomy; however, with an absolute difference of less than 1% in the 10-year cumulative incidence of IBTR, APBI might be an acceptable alternative for some women.

FUNDING

National Cancer Institute, US Department of Health and Human Services.

Abstract GS4-04: Primary results of NSABP B-39/RTOG 0413 (NRG Oncology): A randomized phase III study of conventional whole breast irradiation (WBI) versus partial breast irradiation (PBI) for women with stage 0, I, or II breast cancer

Background: Conventional WBI after lumpectomy for early-stage breast cancer decreases ipsilateral breast tumor recurrence (IBTR), yielding comparable results to mastectomy. Accelerated PBI appears effective in reducing IBTR by treating only the tumor bed area. As the majority of IBTR occur at or in the vicinity of the tumor bed, we hypothesized that PBI would be as effective as WBI in controlling IBTR. The primary aim of NSABP B-39/RTOG 0413 was to determine if PBI provides equivalent local tumor control post lumpectomy compared to WBI in pts with early-stage breast cancer. The equivalency test was based on a 50% margin of increase in the hazard ratio (HR=1.5). Secondary endpoints included: overall survival (OS), recurrence-free interval (RFI), distant disease-free interval (DDFI), and toxicity.

Methods: Eligible pts had lumpectomy with histologically-free margins and 0-3 positive axillary nodes. Pts were stratified by stage, menopausal status, hormone receptor status, and intent to receive chemotherapy and then randomized to PBI or WBI. PBI was 10 fractions of 3.4-3.85 Gy, given twice daily with either brachytherapy or 3D external beam radiation. WBI was 50 Gy in 2 Gy fractions given daily with a sequential boost to the surgical cavity. Follow-up was every 6 mos for 5 yrs and then annually. All analyses were by intent-to-treat.

Results: From 3-21-05 to 4-16-13, 4216 pts were randomized: 2107 PBI; 2109 WBI. 61% were postmenopausal; 81% were hormone receptor-positive; 29% intended to receive chemotherapy. Stage distribution was: DCIS, 24%; invasive pN0, 65%; invasive pN1, 10%. As of 7-31-18, median follow-up was 10.2 yrs. There were 161 IBTRs as first events: 90 PBI v 71 WBI (HR 1.22; 90%CI 0.94-1.58). Per protocol-defined margin, to declare PBI and WBI equivalent regarding IBTR risk, the 90% CI for the observed HR had to lie entirely between 0.667 and 1.5. The percent of pts IBTR-free at 10 yrs was 95.2% PBI v 95.9% WBI. A statistically significant difference in the 10-yr RFI rate favored WBI (91.9% PBI v 93.4% WBI; HR 1.32; 95%CI 1.04-1.68; p=0.02). No statistically significant differences existed between PBI and WBI in DDFI (HR 1.31; 95%CI 0.91-1.91; p=0.15), OS (HR 1.10; 95%CI 0.90-1.35; p=0.35), or DFS (HR 1.12; 95%CI 0.98-1.29; p=0.11). Grade 3 toxicity was 9.6% PBI v 7.1% WBI, and grade 4-5 toxicity was 0.5% v 0.3%, respectively.

Discussion: PBI did not meet the criteria for equivalence to WBI in controlling IBTR based on the upper limit of the hazard ratio confidence interval. However, the absolute difference in 10-yr rate of IBTR was &lt;1% (4.8% PBI v 4.1% WBI). The risk of an RFI event was statistically significantly higher for PBI compared to WBI, but the absolute difference in 10-yr RFI rate was also small (8.1% PBI v 6.6% WBI). DDFI, OS, and DFS were not statistically different for PBI v WBI. Grade 3-5 toxicities, although low, were more common for PBI than WBI. The trial population was heterogeneous, ranging from Stage 0-2 breast cancer, and outcome by risk categories are being analyzed.

Support: U10CA180868, -180822, UG1CA189867.

Citation Format: Vicini FA, Cecchini RS, White JR, Julian TB, Arthur DW, Rabinovitch RA, Kuske RR, Parda DS, Ganz PA, Scheier MF, Winter KA, Paik S, Kuerer HM, Vallow LA, Pierce LJ, Mamounas EP, Costantino JP, Bear HD, Germaine I, Gustafson G, Grossheim L, Petersen IA, Hudes RS, Curran, Jr. WJ, Wolmark N. Primary results of NSABP B-39/RTOG 0413 (NRG Oncology): A randomized phase III study of conventional whole breast irradiation (WBI) versus partial breast irradiation (PBI) for women with stage 0, I, or II breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr GS4-04.

Abstract OT2-04-01: Phase III trial to determine if chest wall and regional nodal radiotherapy (CWRNRT) post mastectomy (Mx) or the addition of RNRT to whole breast RT post breast-conserving surgery (BCS) reduces invasive breast cancer recurrence-free interval (IBCR-FI) in patients (pts) with pathologically positive axillary (PPAx) nodes who are ypN0 after neoadjuvant chemotherapy (NC): NRG Oncology/NSABP B-51/RTOG 1304

This phase III post-NC trial evaluates if CWRNRT post-Mx or whole breast irradiation (WBI) with RNRT after BCS significantly reduces the IBCR-FI rate in pts with PPAx nodes that are pathologically negative after NC. Secondary aims are OS, LRR-FI, DR-FI, DFS-DCIS, second primary cancer, and comparison of RT effect on cosmesis in reconstructed Mx pts. Correlative science examines RT effect by tumor subtype, molecular outcome predictors for residual disease, and predictors for the degree of reduction in loco-regional recurrence.

Methods: Clinical T1-3, N1 IBC PPAx nodes (FNA or core needle biopsy) pts complete ≥8 weeks of NC (anthracycline and/or taxane). HER2+ pts receive anti-HER2 therapy. Following NC, BCS or Mx, sentinel node biopsy (≥2 nodes) and/or Ax dissection with histologically negative nodes is performed. ER/PR and HER-2neu status before NC is required. Pts may receive appropriate adjuvant systemic therapy. Radiation credentialing with a facility questionnaire/case benchmark is required. Random assignment for Mx pts is to no CWRNRT or CWRNRT and for BCS pts to WBI or WBI+RNRT.

Statistics: 1,636 pts are to be enrolled over 5 yrs (definitive analysis at 7.5 yrs). Study is powered at 80% to test that RT reduces the annual hazard rate of events for IBCR-FI by 35% for an absolute risk reduction of 4.6% (5-yr cumulative rate). Intent-to-treat analysis with 3 interim analyses (43, 86, and 129 events) and a 4th/final analysis at 172 events. Pt-reported outcomes focusing on RT effect will be provided by 736 pts before random assignment and at 3, 6, 12, and 24 mos. Accrual as of 6-21-18 is 967 (59.11%).

Contacts: Protocol: CTSU member website https://www.ctsu.org. Questions: NRG Oncology Pgh Clin Coord Dpt: 1-800-477-7227 or ccd@nsabp.org. Pt entry: OPEN at https://open.ctsu.org or the OPEN tab on CTSU member website.

NCT01872975

Support: U10 CA-2166; -180868, -180822; 189867; Elekta

Citation Format: Mamounas EP, Bandos H, White JR, Julian TB, Khan AJ, Shaitelman SF, Torres MA, Vicini FA, Ganz PA, McCloskey SA, Paik S, Gupta N, Li XA, DiCostanzo DJ, Curran WJ, Wolmark N. Phase III trial to determine if chest wall and regional nodal radiotherapy (CWRNRT) post mastectomy (Mx) or the addition of RNRT to whole breast RT post breast-conserving surgery (BCS) reduces invasive breast cancer recurrence-free interval (IBCR-FI) in patients (pts) with pathologically positive axillary (PPAx) nodes who are ypN0 after neoadjuvant chemotherapy (NC): NRG Oncology/NSABP B-51/RTOG 1304 [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr OT2-04-01.

Utilization of bioimpedance spectroscopy in the prevention of chronic breast cancer-related lymphedema

Background

This analysis was performed to assess the impact of early intervention following prospective surveillance using bioimpedance spectroscopy (BIS) to detect and manage breast cancer-related lymphedema (BCRL).

Methods

From 8/2010 to 12/2016, 206 consecutive patients were evaluated with BIS. The protocol included pre-operative assessment with L-Dex as well as post-operative assessments at regular intervals. Patients with L-Dex scores >10 from baseline were considered to have subclinical BCRL and were treated with over-the-counter (OTC) compression sleeve for 4 weeks. High-risk patients were defined as undergoing axillary lymph node dissection (ALND), receiving regional nodal irradiation (RNI), or taxane chemotherapy. Chronic BCRL was defined as the need for complex decongestive physiotherapy (CDP).

Results

Median follow-up was 25.9 months. Overall, 17% of patients had one high-risk feature, 8% two, and 7% had three. 9.8% of patients were diagnosed with subclinical BCRL with highest rates seen following ALND (23 vs. 7%, p = 0.01). Development of subclinical BCRL was associated with ALND and receipt of RNI. At last follow-up, no patients (0%) developed chronic, clinically detectable, BCRL. Subset analysis was performed of the 30 patients undergoing ALND. Median number of nodes removed was 18 and median number of positive nodes was 2. 77% received taxane chemotherapy, 62% axillary RT, and 48% had elevated BMI. Overall, 86% of patients had at least one additional high-risk feature, 70% at least two, and 23% had all three. Seven patients (23%) had abnormally elevated L-Dex scores at some point during follow-up. To date, none has required CDP.

Conclusions

The results of this study support prospective surveillance utilizing BIS initiated pre-operatively with subsequent post-operative follow-up measurements for the detection of subclinical BCRL. Intervention triggered by subclinical BCRL detection with an elevated L-Dex score was associated with no cases progressing to chronic, clinically detectable BCRL even in very high-risk patients.

Abstract 2764: Creating a review process of a digital photo database collected on NRG NSABP B39/RTOG 0413 phase III clinical trial for evaluation of cosmetic results from breast conserving therapy (BCT)

Introduction:

After local control and overall survival, acceptable cosmesis is the next most important goal of BCT. Digital photos (DP) are commonly used for assessing cosmesis on clinical trials. On NRG NSABP B39/RTOG 0413, DP at baseline, 1, and 3 years post-radiation were submitted for review by a panel of breast cancer specialists. Given no current standards for central DP review, this project seeks to develop a standard for subjective DP evaluation. The initial standardization of the photo database and reliability of the panel review is described.

Methods:

De-identified DP submitted and stored at NRG SDMC were downloaded to a secure FTP site. Cases with only 1 time point, no baseline, or photos from different patients were excluded. A minimum photo quality was set, including pre-specified criteria for contrast/light, breast/torso size, and cropping to exclude anatomy above the clavicle and below the umbilicus. DP were edited with MATLAB™ and saved in a Reformatted Digital Photo Database (RDPD). A training set was created defining 4 global cosmetic scores, and each individually assessed criteria of breast symmetry, shape, skin color, nipple, and scar appearance. A 14 case calibration set followed the training set. The process for panel review was adapted from the methods reported in the START and RAPID trials. The review panel consisted of 6 breast-specific radiation oncologists, who reviewed in groups of 3. For each session, the training set was reviewed and calibration set scored. A separate 30 case test set randomly selected from the RDPD was reviewed by 2 groups of 3. The calibration and test sets were evaluated for agreement of categorized scores (excellent/good vs. fair/poor).

Results:

There were 2064 DP from 892 patients on NRG NSABP B39/RTOG 0413 documenting the anterior view of both breasts. After exclusions, 1,717 reformatted DP were saved in the RDPD. Five 1-3 hour review sessions resulted in scoring of 777 DP (~ 155 per session). Only 2/777 (0.1%) DP were deemed poor quality and not able to be scored. There was full agreement in categorized scores for 12/14 cases (86%; kappa=0.82) across the 5 calibration sets; and 27/30 (90%; kappa=0.71) for the 2 test set reviews.

Conclusions:

Cosmesis DP prospectively collected on a large phase III clinical trial can be digitally formatted in a systematic fashion for consistent photo quality, allowing for cosmesis consensus panel review without photo quality bias. High agreement in categorized scores allowed reviews to be completed by multiple 3-person review groups. Future work will focus on creating an updated, semi-automatic analysis tool of these photos for objective evaluation of cosmesis using the same scoring guidelines that can then be compared to physician reported outcomes.

Grant Support: FUJIFILM Medical Systems/RSNA Research Resident, NCI U10CA180868, U10CA180822

Note: This abstract was not presented at the meeting.

Citation Format: Ashley Sekhon, Ruiqi Zhao, Yan Wang, Debora Grant, Kathryn A. Winter, Jennifer Moughan, Douglas W. Arthur, Stephen J. Chmura, Atif J. Khan, Simona F. Shaitelman, Aleix M. Martinez, Frank A. Vicini, Julia R. White. Creating a review process of a digital photo database collected on NRG NSABP B39/RTOG 0413 phase III clinical trial for evaluation of cosmetic results from breast conserving therapy (BCT) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2764. doi:10.1158/1538-7445.AM2017-2764

Abstract OT2-03-01: NRG oncology/NSABP B-51/RTOG 1304: A phase III superiority clinical trial designed to determine if chest wall and regional nodal radiotherapy (CWRNRT) post mastectomy (Mx) or the addition of RNRT to breast RT post breast-conserving surgery (BCS) will reduce invasive cancer events in patients (pts) with positive axillary (Ax) nodes and convert to ypN0 after neoadjuvant chemotherapy (NC)

Background:

This phase III post-NC trial evaluates if CWRNRT post Mx or whole breast irradiation (WBI) with RNRT after BCS significantly reduces the invasive breast cancer recurrence-free interval (IBC-RFI) rate in pts presenting with positive Ax nodes that are pathologically negative after NC. Secondary aims are OS, LRRFI, DRFI, DFS-DCIS, and second primary cancer, as well as comparing RT effect on cosmesis in reconstructed Mx pts.

Correlative science studies examine RT effect by tumor subtype, molecular outcome predictors for residual disease pts, and predictors for the degree of reduction in loco-regional recurrence.

Methods:

Clinical T1-3, N1 IBC pts with positive Ax nodes (FNA or core needle biopsy) complete ≥8 wks of NC (anthracycline and/or taxane). HER2-positive pts receive anti-HER2 therapy (tx). After NC, BCS or Mx is performed with a sentinel node biopsy (≥2 nodes) and/or Ax dissection with histologically negative nodes. ER/PR and HER2 neu status before NC is required. Pts receive required systemic tx. Radiation credentialing with a facility questionnaire and a case benchmark is required. Randomization for Mx pts is to no CWRNRT or CWRNRT and for BCS pts to WBI or WBI+RNRT.

Statistics:

1636 pts to be enrolled over 5 yrs with definitive analysis at 7.5 yrs. Study is powered at 80% to test that RT reduces the annual hazard rate of events for IBCR-FI by 35% for an absolute risk reduction in the 5-yr cumulative rate of 4.6%. Intent-to-treat analysis with 3 interim analyses at 43, 86, and 129 events, with a 4th/final analysis at 172 events will occur. Accrual as of 6/13/16 is 356. Pt-reported outcomes focusing on RT effect will be obtained from 736 pts before randomization and at 3, 6, 12, and 24 months.

Contacts:

Protocol: CTSU member website https://www.ctsu.org. Questions: NRG Oncology Pgh Clin Coord Dpt: 1-800-477-7227 or ccd@nsabp.org. Pt entry: OPEN at https://open.ctsu.org or the OPEN tab on CTSU member website.

Support: U10 CA-2166; -180868, -180822; -189867; Elekta.

Citation Format: Mamounas EP, Bandos H, White JR, Julian TB, Khan AJ, Shaitelman SF, Torres MA, Vicini FA, Ganz PA, McCloskey SA, Paik S, Gupta N, Li XA, DiCostanzo DJ, Curran, Jr WJ, Wolmark N. NRG oncology/NSABP B-51/RTOG 1304: A phase III superiority clinical trial designed to determine if chest wall and regional nodal radiotherapy (CWRNRT) post mastectomy (Mx) or the addition of RNRT to breast RT post breast-conserving surgery (BCS) will reduce invasive cancer events in patients (pts) with positive axillary (Ax) nodes and convert to ypN0 after neoadjuvant chemotherapy (NC) [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr OT2-03-01.

Outcomes According to Breast Cancer Subtype in Patients Treated With Accelerated Partial Breast Irradiation

BACKGROUND

The purpose of the study was to determine outcomes for patients treated with accelerated partial breast irradiation (APBI) on the basis of breast cancer subtype (BCST).

PATIENTS AND METHODS

Our single-institution, institutional review board-approved APBI database was queried for patients who had complete testing results for the estrogen (ER), progesterone (PR), and HER2/neu receptors to determine outcomes for each BCST. Women were assigned as luminal A (LA), luminal B (LB), HER2, and basal BCST using their ER, PR, and HER2/neu receptor status. Degree of ER expression supplemented the receptor-based luminal BCST assignment. Two hundred seventy-eight patients had results for all 3 receptors (LA = 164 [59%], LB = 81 [29%], HER2 = 5 [2%], basal = 28 [10%]), which were submitted for analysis (ipsilateral breast tumor recurrence [IBTR], regional nodal failure, distant metastasis [DM], disease-free survival [DFS], cause-specific survival [CSS], and overall survival [OS]).

RESULTS

Median follow-up was 5.4 years (range, 0.1-12.4 years). Basal and HER2 subtype patients had higher histologic grades (Grade 3 = 75% vs. 10% LA/LB; P < .001), larger tumors (13.0 mm basal vs. 10.7 mm LA/LB; P = .059), and were more likely to receive chemotherapy (68% vs. 15% LA/LB; P < .001). Margin and nodal status were similar among BCSTs. At 5 years, IBTR rates were similar (1.8%, 2.9%, 0%, and 4.8%) for LA, LB, HER2, and basal subtypes, respectively (P = .62). DM was only seen in LA (2.9%) and LB (1.3%) (P = .83). DFS (95%-100%), CSS (97%-100%), and OS (80%-100%) were not statistically different (P = .97, .87, .46, respectively).

CONCLUSION

Five-year local control rates after breast-conserving surgery, APBI, and appropriate systemic therapy are excellent for luminal, HER2, and basal phenotypes of early-stage breast cancer; however, further study of receptor subtype effect on risk stratification in early-stage breast cancer is needed.

The increasing role of breast cancer lymphedema screening, diagnosis, and management as part of evidence-based breast cancer survivorship

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Background: With improved outcomes across all stages, breast cancer survivorship represents an increasingly significant oncologic issue. One major facet of breast cancer survivorship is assessment and management of sequelae of treatment including breast cancer related lymphedema (BCRL) which has an incidence of 5-40% depending on locoregional and systemic treatment. BCRL represents a complication associated with physical changes as well as reduction in quality of life and continues to increase in prevalence with new diagnostics (ex. L-Dex, perometry) increasing the sensitivity for detection. Methods: Review of current evidence based guidelines from the National Comprehensive Cancer Network (NCCN), American Society of Clinical Oncology (ASCO), and the American Cancer Society. Results: Evidence based treatment guidelines for breast cancer have evolved in 2015. For the first time, the NCCN guidelines include a reference to BCRL as part of routine treatment stating “to educate, monitor, and refer for lymphedema management” represents a standard component of breast cancer treatment and survivorship and allows for the early diagnosis and treatment of BCRL. At this time, neither the ASCO Breast Cancer nor ASCO survivorship guidelines incorporate BCRL management into routine practice. At this time, BCRL management is not part of ACS survivorship protocols. Conclusions: At this time, due to increasing data on BCRL diagnosis and treatment, evidence based guidelines are beginning to incorporate BCRL education, diagnosis, and treatment into standard breast cancer management plans. With increasing focus on survivorship, prospective BCRL programs are being developed that begin evaluation prior to treatment with screening in place and early intervention to help prevent progression by using diagnostics with increased sensitivity (ex. L-Dex, perometry).

Bioimpedance spectroscopy for lymphedema assessment: Clinical practice guidelines

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Background: Breast cancer related lymphedema (BCRL) is an increasingly diagnosed complication of breast cancer treatment with incidence rates of 5% with lumpectomy alone to more than 40% with mastectomy, axillary dissection, and radiation therapy. Increasing data supports the role of early detection and treatment with one diagnostic modality being bioimpedance spectroscopy (BIS) with L-Dex measurements. Methods: A systematic review of the National Library of Medicine’s PubMed search was performed for articles applicable to BIS and BCRL. Clinical guidelines were created by the authors based on published data and consensus agreement. Results: At this time, multiple randomized and prospective trials have been performed evaluating early detection for BCRL and have demonstrated reduced rates of BCRL with such an approach. BIS with L-Dex represents a technique with published literature supporting increased sensitivity, ability to detect subclinical BCRL and standardized clinical decision points, an improvement from traditional BCRL diagnostics. BCRL surveillance programs should focus on high-risk patients including those undergoing mastectomy, axillary lymph node dissection, sentinel node biopsy with greater than 6 nodes sampled, regional nodal irradiation, and those requiring taxane based chemotherapy. Patients should undergo assessment prior to locoregional therapy and then every 3 months for the first 3 years with additional measurements made based on clinical assessment. A change in L-Dex of 10 has been utilized has a consistent trigger to initiate BCRL treatment. Conclusions: With increasing data supporting early diagnosis and treatment of BCRL, these guidelines offer clinicians a tool to help develop BCRL surveillance programs as part of routine breast cancer care.

Factors affecting survival in women with ductal carcinoma in situ (DCIS): Race and the delivery of adjuvant radiotherapy

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Background: Recent publications questioned the survival impact of adjuvant radiotherapy (A-RT) in the treatment of DCIS. These reports had in common a short follow up. We wanted to know, in a disease where long term follow up is required, the magnitude of improvement in survival and assess any correlation with race and income. Methods: Search in the Surveillance, Epidemiology and End Results database, of patients diagnosed with DCIS between 1988 and 2012, younger than 70 years old. Analyses of age, race, hormonal receptors (HR), tumor size, surgery, ART and household income. Survival analyses with Kaplan-Meier and multifactorial with Cox proportional-hazard regression. Results: 125,805 patients. Mean follow-up 7.9 years. Patients treated with A-RT resulted in a mortality by breast cancer (DBC) significantly lower (-1.10%; HR: 0.54 [IC95%:0.48-0.59]; p < 0.0001). Based on the type of surgery, mastectomy resulted on a DBC significantly higher than those treated with tumorectomy and A-RT (+1.15%; HR: 2.08 [IC95%:1.84-2.36]; p < 0.0001). Patients with HR+ presented a significantly lower DBC. Black race was the one with the lowest household income (43% < 53900$) opposite to the Asian which was the one with the highest (47% > 71520$). Black race, also presented a DBC significantly higher than the other ones. In the multifactorial analyses (see table), the only variables which presented a significantly influence in DBC were -ART (it decreases DBC) and race (black race increases DBC). Conclusions: These results show blacks, which are the ones with lowest household income, have a significantly increase in cancer mortality than the other races, and that A-RT cuts mortality rates quite drastically in women with DCIS. [Table: see text]

Practical Implications of the Publication of Consensus Guidelines by the American Society for Radiation Oncology: Accelerated Partial Breast Irradiation and the National Cancer Data Base

PURPOSE

To examine utilization trends of accelerated partial breast irradiation (APBI) in the American College of Surgeons' National Cancer Database and changes in APBI use after the 2009 publication of the American Society for Radiation Oncology (ASTRO) guidelines.

METHODS AND MATERIALS

A total of 399,705 women were identified who were diagnosed from 2004 to 2011 with nonmetastatic invasive breast cancer or ductal carcinoma in situ who were treated with breast-conserving surgery and radiation therapy to the breast. Patients were divided by the type of treatment received (whole breast irradiation or APBI) and by suitability to receive APBI as defined by the ASTRO guidelines. Logistic regression was applied to study APBI use overall and within guideline categorization, and a multivariable model was created to determine predictors of treatment with brachytherapy-based APBI based on guideline categorization.

RESULTS

For all patients, APBI use increased, from 3.8% in 2004 to 10.6% in 2011 (P<.0001). Overall rates of APBI utilization were higher among "suitable" than "cautionary"/"unsuitable" patients (14.8% vs 7.1%, P<.0001). The majority of APBI treatment was delivered using brachytherapy, for which use peaked in 2008. Starting in 2009, among "suitable" patients, utilization of APBI via brachytherapy plateaued, whereas for "cautionary"/"unsuitable" patients, treatment with brachytherapy-based APBI declined and then plateaued.

CONCLUSION

Use of APBI across all patient groups increased from 2004 through 2008. After publication of the ASTRO APBI guidelines in 2009, rates of brachytherapy-based APBI treatment plateaued among "suitable" patients and declined and then plateaued among "cautionary"/"unsuitable" patients. Our study highlights how large national databases can be used to assess national trends in radiation use in response to the publication of guidelines.

Ductal Carcinoma In Situ of the Breast: Evaluating the Role of Radiation Therapy in the Management and Attempts to Identify Low-risk Patients

Ductal carcinoma in situ of the breast has rapidly increased in incidence over the past several decades secondary to an increased use of screening mammography. Local treatment options for women diagnosed with ductal carcinoma in situ include mastectomy or breast-conserving therapy. Although several randomized trials have confirmed a >50% reduction in the risk of local recurrence with the administration of radiation therapy (RT) compared with breast-conserving surgery alone, controversy persists regarding whether or not RT is needed in selected "low-risk" patients. Over the past two decades, two prospective single-arm studies and one randomized trial have been performed and confirm that the omission of RT after surgery is associated with higher rates of local recurrence even after selecting patients with optimal clinical and pathologic features. Importantly, these trials have failed to consistently and reproducibly identify a low-risk cohort of patients (based on clinical and pathologic features) that does not benefit from RT. As a result, adjuvant RT is still advocated in the majority of patients, even in low-risk cases. Future research is moving beyond traditional clinical and pathologic risk factors and instead focusing on approaches such as multigene assays and biomarkers with the hopes of identifying truly low-risk patients who may not require RT. However, recent studies confirm that even low-risk patients identified from multigene assays have higher rates of local recurrence with local excision alone than would be expected with the addition of RT.

Abstract OT1-3-02: Will chest wall and regional nodal radiotherapy post mastectomy or the addition of regional nodal radiotherapy to breast radiotherapy post lumpectomy reduce the rate of invasive cancer events in patients with positive axillary nodes who convert to ypN0 af

Background

This phase III randomized post-neoadjuvant chemotherapy trial will evaluate if chest wall and regional nodal XRT (CWRNRT) after mastectomy or whole breast irradiation (WBI) with RNRT after breast-conserving surgery significantly reduces the rate of events for invasive breast cancer recurrence-free interval (IBCR-FI) in patients who present with histologically positive axillary nodes but become histologically negative axillary nodes after neoadjuvant chemotherapy. Secondary aims are OS, LRR-FI, DRFI, DFS-DCIS, and second primary cancer. HYPOTHESIS: Can We Use Tumor and Nodal Response to Neoadjuvant Chemotherapy in Order to Individualize the Use of L-R XRT?

Correlative science will examine the effect of RT by tumor subtype, molecular predictors of outcome for patients with residual disease, and the development of predictors of degree of reduction in loco-regional recurrence.

Methods

Eligible patients with clinical T1-3, N1 breast cancer with pathologic axillary nodal involvement (positive FNA or core needle biopsy) must complete ≥12 weeks of neoadjuvant chemotherapy (anthracycline and/or taxane-based regimen). HER2-positive patients must receive neoadjuvant trastuzumab or other anti-HER2 therapy. After neoadjuvant chemotherapy either breast-conserving surgery or mastectomy will be performed. At the time of surgery, all removed axillary nodes must be histologically free from cancer. 3 or more histologically negative sentinel nodes are acceptable to determine axillary nodal involvement. ER/PR and HER-2 neu status before neoadjuvant chemotherapy is required. All patients will receive additional required systemic therapy.

Site radiation credentialing with a facility questionnaire and case benchmarking is required. Randomization for mastectomy patients will be to no CWRNRT or CWRNRT and for breast-conserving surgery patients to WBI or WBI RNRT.

Statistical Considerations

1636 patients will be enrolled over 5 years with definitive analysis at 7.5 years. The study is powered at 80% to test the main hypothesis that RT reduces the annual hazard rate of events for IBCR-FI by 35% for an absolute risk reduction in the 5-year cumulative rate of 4.6%. Analysis will be on intent-to-treat with 3 formal interim analyses at 43, 86, and 129 events, with a 4th/final analysis at 172 events. Current accrual is 37. (as of 6-10-14)

736 enrolled patients will be evaluated with targeted patient-reported outcome instruments focusing on the effect of RT. Patient assessments will be prior to randomization and then at 3, 6, 12, and 24 months.

Contact Information

Study protocol information can be found under the protocol-specific web page on the CTSU member web site https://www.ctsu.org. For protocol-specific questions contact – NRG Oncology Pittsburgh Clinical Coordinating Department. Phone: 1-800-477-7227. Email: ccd@nsabp.org. All investigators will enroll patients by accessing OPEN at https://open.ctsu.org or from the OPEN tab on the CTSU members’ side of the web site.

Support: NCI PHS U10-CA-12027, -69651, -37377, -69974, and -2166.

Citation Format: Eleftherios P Mamounas, Hanna Bandos, Julia R White, Thomas B Julian, Atif J Khan, Simona F Shaitelman, Mylin A Torres, Susan A McCloskey, Frank A Vicini, Patricia A Ganz, Soonmyung Paik, Nilendu Gupta, Joseph P Costantino, Walter J Curran Jr, Norman Wolmark. Will chest wall and regional nodal radiotherapy post mastectomy or the addition of regional nodal radiotherapy to breast radiotherapy post lumpectomy reduce the rate of invasive cancer events in patients with positive axillary nodes who convert to ypN0 af [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr OT1-3-02.

Trends in breast cancer treatment in United States from 2000 to 2011: Consequences of 2004 National Comprehensive Cancer Network (NCCN) guidelines change

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Background: In 2004, the NCCN, changed the guidelines for the treatment of stage 1, HR+, > 70 years(y) breast cancer patients, based mainly on the CALGB/RTOG trial, which showed that in these patients, the addition of radiotherapy (RT) to surgery and tamoxifen did not improve overall survival, but significantly decreased local relapse at 5 y. Methods: Retrospective analysis about trends in breast cancer treatment in USA from years 2000 to 2011, searching the National Cancer Data Base, reviewing 458.386 cases of breast cancer stage I, HR+, with special focus in patients >70y. Chi square test was used. Results: Between years 2000-2011, in the group reviewed, mastectomy (MT) increased in women <40y (+25%) and between 40-69y (+13%), while RT decreased in both groups (-20%, -3%). In women >70y, MT decreased (-27%) progressively along these years, but radiotherapy increased until year 2003 (+3%), and begun to decrease in 2004 (-4%), with a final difference between 2003 and 2011 of -9%. In patients >70 y, chemotherapy (CH) treatments, increased progressively (+3%) from year 2000 to 2011 (p<0.001). Conclusions: Changes in NCCN breast cancer guidelines made in 2004, seem to have changed trends of breast cancer treatment in USA in patients > 70y, stage I, HR+. Since then, less aggressive “local” treatments (-4% for MT and -9% for RT) are been performed. Despite this trend for less local therapy chemotherapy utilization has increased even though the risk of systemic disease is very low. The main risk for these patients is local failure with the associated physical, psychological and family impact as well as cost of re-staging. Local RT has demonstrated a significant reduction of this risk. Today's life expectancy for a 70 y/o woman is >10y consequently local relapses and its consequences are expected. New RT techniques, such as partial breast irradiation delivered in few days are convenient and associated with very low toxicity and no mortality. Perhaps a re-look of the NCCN guidelines might be in order. [Table: see text]

Nomogram for predicting the risk of locoregional recurrence in patients treated with accelerated partial-breast irradiation

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Background: There are limited tools to guide clinicians regarding the risk of locoregional recurrence (LRR) in patients wishing to pursue APBI. The purpose of this study was to develop a nomogram taking into account clinicopathologic features to predict LRR in patients treated with APBI for early stage breast cancer. Methods: A total of 2,000 breasts (1,990 women) were treated with APBI at William Beaumont Hospital (N=551) or on the ASBrS MammoSite Registry Trial (N=1,449). Techniques included multiplanar interstitial catheters (N=98), balloon-based brachytherapy (N=1,689), and 3D conformal radiotherapy (N=213). Clinicopathologic variables were gathered prospectively. A nomogram was formulated utilizing the Cox Proportional Hazards Regression model to predict for LRR. This was validated by generating a bias-corrected index and cross-validated with a C-index. Results: Median follow-up was 5.5 years (0.9 to 18.3). Of the 2,000 cases, 435 were excluded due to missing data. Univariate analysis found that age <50, pre/perimenopausal status, close/positive margins, ER negativity, and high grade were associated with a higher frequency of LRR. These five independent covariates were used to create adjusted estimates, weighting each on a scale of 0 to 100. The total score is identified on a points scale to obtain the probability of an LRR over the study period. The model demonstrated good concordance for predicting LRR with a C-index of 0.641. Conclusions: The formulation of a practical, easy-to-use nomogram for calculating the risk of LRR in patients undergoing APBI will help guide the appropriate selection of patients for off-protocol utilization of APBI.

Utilization of breast preservation treatments in Hispanic patients with breast cancer: An analysis from the National Cancer Data Base (NCDB) from 2000 to 2011

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Background: In contrast to mastectomy, radiotherapy (RT) treatments for breast cancer (BC) patients, allows for the benefits of breast preservation therapy and brachytherapy (BT) is a very convenient and short course of RT. BT use in BC has increased since FDA approval in 2002, however, has it been used evenly among races? Methods: Trends of treatment were analyzed for BC patients stages Tis to IV using the NCDB and 2.015.671 cases were found. Specific analysis of treatment differences between Black, White and Hispanic races, and the use of BT was performed. Results: The use of surgery as the only treatment in BC patients has decreased in stages 0 to IV (-7%, -11%, -8%, -6% and -6%; p<0.0001), while the use of RT has increased in stages 0 to III (+5%, +1%, +3%, +8%; p<0.0001). The use of chemotherapy has also increased in stages 0, I, III, IV (+3%, +4%, +7%, +5%; p<0.0001), while decreased in stage II (-3%; p<0.0001). Hispanic patients, received less RT in stages I to III (-4.11%, -5.46%, -4.84%; p<0.05), while White’s in stage I and III (58.11%, 65.98%), and Black’s in stage II (52.19%) received more RT (p<0.05). In addition, Hispanic’s received significantly more mastectomy in stages I, II and IV. BT as a type of RT was used mainly in stages 0 to II. In stages III and IV its use was <0.13%. 50.836 patients stage 0-II received BT. In this group of patients, BT increased from 0.35% in 2000 to 9,76% in 2008 (p<0,0001), and from then, decreased to 8.28% in 2011 (p<0.0001). There are also significant differences between races. In White’s BT increased 11.33% in 2008 which is 1.46 more times than in Black’s and 1.79 more than Hispanic, and then decreased to 9.52% in 2011 which is 1.61 more than in Black’s, and 1.64 more than Hispanic’s. Conclusions: The use of breast preservation RT has increased significantly in stages 0 to III from year 2000 to 2011. BT use increased until year 2008, when it begun to decrease until year 2009, stabilizing in 2010 and 2011 at around 8%. There are significant differences between races in the use of RT in general, and BT in particular, being Hispanic’s the ones which significantly received less breast preservation RT treatment. This finding raises important questions.

A planning comparison of 7 irradiation options allowed in RTOG 1005 for early-stage breast cancer

This study compared the 7 treatment plan options in achieving the dose-volume criteria required by the Radiation Therapy Oncology Group (RTOG) 1005 protocol. Dosimetry plans were generated for 15 representative patients with early-stage breast cancer (ESBC) based on the protocol-required dose-volume criteria for each of the following 7 treatment options: 3D conformal radiotherapy (3DCRT), whole-breast irradiation (WBI) plus 3DCRT lumpectomy boost, 3DCRT WBI plus electron boost, 3DCRT WBI plus intensity-modulated radiation therapy (IMRT) boost, IMRT WBI plus 3DCRT boost, IMRT WBI plus electron boost, IMRT WBI plus IMRT boost, and simultaneous integrated boost (SIB) with IMRT. A variety of dose-volume parameters, including target dose conformity and uniformity and normal tissue sparing, were compared for these plans. For the patients studied, all plans met the required acceptable dose-volume criteria, with most of them meeting the ideal criteria. When averaged over patients, most dose-volume goals for all plan options can be achieved with a positive gap of at least a few tenths of standard deviations. The plans for all 7 options are generally comparable. The dose-volume goals required by the protocol can in general be easily achieved. IMRT WBI provides better whole-breast dose uniformity than 3DCRT WBI does, but it causes no significant difference for the dose conformity. All plan options are comparable for lumpectomy dose uniformity and conformity. Patient anatomy is always an important factor when whole-breast dose uniformity and conformity and lumpectomy dose conformity are considered.

Cardiac dose sparing and avoidance techniques in breast cancer radiotherapy

Breast cancer radiotherapy represents an essential component in the overall management of both early stage and locally advanced breast cancer. As the number of breast cancer survivors has increased, chronic sequelae of breast cancer radiotherapy become more important. While recently published data suggest a potential for an increase in cardiac events with radiotherapy, these studies do not consider the impact of newer radiotherapy techniques commonly utilized. Therefore, the purpose of this review is to evaluate cardiac dose sparing techniques in breast cancer radiotherapy. Current options for cardiac protection/avoidance include (1) maneuvers that displace the heart from the field such as coordinating the breathing cycle or through prone patient positioning, (2) technological advances such as intensity modulated radiation therapy (IMRT) or proton beam therapy (PBT), and (3) techniques that treat a smaller volume around the lumpectomy cavity such as accelerated partial breast irradiation (APBI), or intraoperative radiotherapy (IORT). While these techniques have shown promise dosimetrically, limited data on late cardiac events exist due to the difficulties of long-term follow up. Future studies are required to validate the efficacy of cardiac dose sparing techniques and may use surrogates for cardiac events such as biomarkers or perfusion imaging.

Shortened radiation therapy schedules for early-stage breast cancer: a review of hypofractionated whole-breast irradiation and accelerated partial breast irradiation

Breast-conserving therapy consisting of segmental mastectomy followed by whole-breast irradiation (WBI) has become widely accepted as an alternative to mastectomy as a treatment for women with early-stage breast cancer. WBI is typically delivered over the course of 5-6 weeks to the whole breast. Hypofractionated whole-breast irradiation and accelerated partial breast irradiation have developed as alternative radiation techniques for select patients with favorable early-stage breast cancer. These radiation regimens allow for greater patient convenience and the potential for decreased health care costs. We review here the scientific rationale behind delivering a shorter course of radiation therapy using these distinct treatment regimens in this setting as well as an overview of the published data and pending trials comparing these alternative treatment regimens to WBI.