Radiotherapy For Ductal Carcinoma Research Articles

Lumpectomy without radiation for ductal carcinoma in situ of the breast: 20-year results from the ECOG-ACRIN E5194 study

We report the 20-year rate of ipsilateral breast event (IBE) for patients with ductal carcinoma in situ (DCIS) treated with lumpectomy without radiation on a non-randomized prospective clinical trial. Patients were enrolled in cohort 1: low- or intermediate-grade DCIS, size ≤ 2.5 cm (n = 561); or cohort 2: high-grade DCIS, size ≤ 1 cm (n = 104). The Kaplan–Meier method was used to estimate time-to-event distributions. Cox proportional hazard methods were used to estimate hazard ratios (HRs) and tests for significance for event times. 561 patients were enrolled in cohort 1 and 104 in cohort 2. After central pathology review, 26% in cohort 1 were recategorized as high-grade and 26% in cohort 2 as low- or intermediate-grade. Mean DCIS size was similar at 7.5 mm in cohort 1 and 7.8 mm in cohort 2. Surgical margin was ≥3 mm in 96% of patients, and about 30% received tamoxifen. Median follow-up was 19.2 years. There were 104 IBEs, of which 54 (52%) were invasive. The IBE and invasive IBE rates increased in both cohorts up to 15 years, then plateaued. The 20-year IBE rates were 17.8% for cohort 1 and 28.7% for cohort 2 (p = 0.005), respectively. Invasive IBE occurred in 9.8% and 15.1% (p = 0.09), respectively. On multivariable analysis, IBE risk increased with size and was higher in cohort 2, but grade and margin width were not significantly associated with IBE. For patients with DCIS treated with excision without radiation, the rate of IBE increased with size and assigned cohort mostly in the first 15 years.

Patterns and Longitudinal Changes in The Practice of Breast Cancer Radiotherapy in Korea: Korean Radiation Oncology Group 22-01

To analyze contemporary practice patterns in breast cancer radiotherapy (RT) and to assess longitudinal changes therein over 5 years in Korea. A nationwide survey was conducted among board-certified radiation oncologists in Korea by the Division for Breast Cancer of the Korean Radiation Oncology Group in March 2022. The survey consisted of 44 questions related to six domains: hypofractionated (HypoFx) whole breast RT, accelerated partial breast RT (APBI), regional nodal irradiation (RNI), RT for ductal carcinoma in situ (DCIS), postmastectomy RT (PMRT), and tumor bed boost. In total, 70 radiation oncologists from 61 of 101 (60%) institutions participated in the survey. HypoFx RT was used by 62 respondents (89%), which has significantly increased from 36% in 2017. The HypoFx RT was commonly administered at 40-42.5 Gy in 15-16 fractions. APBI was used by 12 respondents (17%), which has increased from 5% in 2017. The use of RNI did not change significantly: ≥ pN2 (6%), ≥ pN1 (33%), and ≥ pN1 with pathological risk factors (61%). However, the indications for use of internal mammary lymph node (IMN) irradiation have expanded. In particular, the rates of routine treatment of IMN (11% from 6% in 2017) and treatment in cases of ≥ pN2 (27% from 14% in 2017) have doubled; however, the rate of treatment for only IMN involvement, identified on imaging, has decreased to 31% from 47% in 2017. With regard to DCIS, the use of hypoFx RT increased to 75% from 25%, and the rate of omission on of RT after breast-conserving surgery decreased to 38% from 48% in 2017. The use of hypoFx RT for PMRT also increased to 36% from 8% in 2017. The adoption of HypoFx RT after breast-conserving surgery in invasive breast cancer and DCIS has increased significantly, whereas that for PMRT has increased moderately, compared to 2017. Further studies are required to determine the optimal use of RNI.

Patterns and Longitudinal Changes in the Practice of Breast Cancer Radiotherapy in Korea: Korean Radiation Oncology Group 22-01.

We aimed to analyze contemporary practice patterns in breast cancer radiotherapy (RT) and assess longitudinal changes over five years in Korea. In 2022, a nationwide survey was conducted among board-certified radiation oncologists. The survey consisted of 44 questions related to six domains: hypofractionated (HypoFx) whole breast RT, accelerated partial breast RT (APBI), regional nodal irradiation (RNI), RT for ductal carcinoma in situ (DCIS), postmastectomy RT (PMRT), and tumor bed boost. Seventy radiation oncologists from 61 (out of 101; 60%) institutions participated in the survey. HypoFx RT was used by 62 respondents (89%), a significant increase from 36% in 2017. HypoFx RT is commonly administered at 40-42.5 Gy in 15-16 fractions. APBI was used by 12 respondents (17%), an increase from 5% in 2017. The use of RNI did not change significantly: ≥ pN2 (6%), ≥ pN1 (33%), and ≥ pN1 with pathological risk factors (61%). However, indications for internal mammary lymph node (IMN) irradiation have expanded. In particular, the rates of routine treatment of IMN (11% from 6% in 2017) and treatment in cases of ≥ pN2 (27% from 14% in 2017) have doubled; however, the rate of treatment for only IMN involvement, identified on imaging, has decreased from 47% in 2017 to 31%. For DCIS, the use of HypoFx RT increased from 25% in 2017 to 75%, and the rate of RT omissions after breast-conserving surgery (BCS) decreased from 48% in 2017 to 38%. The use of HypoFx RT for PMRT increased from 8% in 2017 to 36%. The adoption of HypoFx RT after BCS for invasive breast cancer and DCIS has increased significantly, whereas the use of HypoFx PMRT has increased moderately since 2017. However, further studies are required to determine the optimal use of RNI.

Toxicity and cosmetic outcome in hypofractionated radiation therapy for ductal carcinoma in situ after breast-conserving surgery: a preliminary report

Toxicity and cosmetic outcome in hypofractionated radiation therapy for ductal carcinoma in situ after breast-conserving surgery: a preliminary report

Long-term risk of subsequent ipsilateral lesions after surgery with or without radiotherapy for ductal carcinoma in situ of the breast

BackgroundRadiotherapy (RT) following breast-conserving surgery (BCS) for ductal carcinoma in situ (DCIS) reduces ipsilateral breast event rates in clinical trials. This study assessed the impact of DCIS treatment on a 20-year risk of ipsilateral DCIS (iDCIS) and ipsilateral invasive breast cancer (iIBC) in a population-based cohort.MethodsThe cohort comprised all women diagnosed with DCIS in the Netherlands during 1989–2004 with follow-up until 2017. Cumulative incidence of iDCIS and iIBC following BCS and BCS + RT were assessed. Associations of DCIS treatment with iDCIS and iIBC risk were estimated in multivariable Cox models.ResultsThe 20-year cumulative incidence of any ipsilateral breast event was 30.6% (95% confidence interval (CI): 28.9–32.6) after BCS compared to 18.2% (95% CI 16.3–20.3) following BCS + RT. Women treated with BCS compared to BCS + RT had higher risk of developing iDCIS and iIBC within 5 years after DCIS diagnosis (for iDCIS: hazard ratio (HR)age < 50 3.2 (95% CI 1.6–6.6); HRage ≥ 50 3.6 (95% CI 2.6–4.8) and for iIBC: HRage<50 2.1 (95% CI 1.4–3.2); HRage ≥ 50 4.3 (95% CI 3.0–6.0)). After 10 years, the risk of iDCIS and iIBC no longer differed for BCS versus BCS + RT (for iDCIS: HRage < 50 0.7 (95% CI 0.3–1.5); HRage ≥ 50 0.7 (95% CI 0.4–1.3) and for iIBC: HRage < 50 0.6 (95% CI 0.4–0.9); HRage ≥ 50 1.2 (95% CI 0.9–1.6)).ConclusionRT is associated with lower iDCIS and iIBC risk up to 10 years after BCS, but this effect wanes thereafter.

ASO Author Reflections: Omitting Radiotherapy for Ductal Carcinoma In Situ Patients with Lumpectomy: Now or in the Future?

ASO Author Reflections: Omitting Radiotherapy for Ductal Carcinoma In Situ Patients with Lumpectomy: Now or in the Future?

Local recurrence outcomes after breast conserving surgery and adjuvant radiotherapy in ductal carcinoma in situ of the breast and a comparison with ECOG E5194 study

PurposeTurkish Radiation Oncology Study Group investigated local recurrence rates and prognostic factors in patients with ductal carcinoma in situ (DCIS) of the breast treated with breast conservative surgery (BCS) followed by radiotherapy (RT) and Eastern Cooperative Oncology Group (ECOG) Study E5194 were compared with the original study. Patients and methodsTotally 252 patients were evaluated retrospectively. Prognostic factors that might influence local control (age, nuclear grade, comedo necrosis, surgical margins, tumor size, hormone receptor status) were compared. The eligibility criteria of ECOG 5194 were stratified into two groups as in the original study and were compared for local control. ResultsThe median follow-up time was 59 (21–220) months. Local recurrence was observed in 9 patients (3.6%) who had invasive carcinoma (3 patients) and DCIS (6 patients). Ten years local control rates was 91.8% respectively. We found that the risk of ipsilateral breast recurrence was significantly higher in women younger than 50 years old (p = 0.016). In addition, a statistically significant trend was found in patients with tumor larger than 1 cm and HER2 positive tumors (p = 0.051, p = 0.068 respectively). When 12-year results were compared with the ECOG 5194, adjuvant RT produced an absolute difference of 11% in low-intermediate and 20% in high grade in local control. ConclusionIn our study, the 10-year local control rate was 92% and younger than 50 years old was the most important unfavorable prognostic factor for local recurrence. There was provided 20% absolute local control with adjuvant radiotherapy which eligibility criteria of ECOG 5194 high grade group.

Systemic Effects of Radiotherapy in Ductal Carcinoma In Situ

Systemic Effects of Radiotherapy in Ductal Carcinoma In Situ

Risk of ischemic heart disease after radiotherapy for ductal carcinoma in situ

PurposeThe use of adjuvant radiotherapy (RT) in the management of ductal carcinoma in situ (DCIS) is increasing. Left-sided breast irradiation may involve exposure of the heart to ionising radiation, increasing the risk of ischemic heart disease (IHD). We examined the incidence of IHD in a population-based cohort of women with DCIS.MethodsThe Breast Cancer DataBase Sweden (BCBase) cohort includes women registered with invasive and in situ breast cancers 1992–2012 and age-matched women without a history of breast cancer. In this analysis, 6270 women with DCIS and a comparison cohort of 31,257 women were included. Through linkage with population-based registers, data on comorbidity, socioeconomic status and incidence of IHD was obtained. Hazard ratios (HR) for IHD with 95% confidence intervals (CI) were analysed.ResultsMedian follow-up time was 8.8 years. The risk of IHD was not increased for women with DCIS versus women in the comparison cohort (HR 0.93; 95% CI 0.82–1.06), after treatment with radiotherapy versus surgery alone (HR 0.77; 95% CI 0.60–0.98) or when analysing RT by laterality (HR 0.85; 95% CI 0.53–1.37 for left-sided versus right-sided RT).ConclusionsThe risk of IHD was lower for women with DCIS allocated to RT compared to non-irradiated women and to the comparison cohort, probably due to patient selection. Comparison of RT by laterality did not show any over-risk for irradiation of the left breast.

Abstract PD7-03: Cost-effectiveness analysis of intraoperative radiotherapy for ductal carcinoma in situ

Abstract Background Whole breast radiation therapy (WBRT) following lumpectomy for ductal carcinoma in situ (DCIS) is standard of care, however, the risk of local recurrence with and without radiation ranges as low as 0.9% vs. 6.7% over 7 years. Intraoperative radiotherapy (IORT) is a potential alternative with advantages of decreased toxicity to adjacent organs, convenience, and improved quality of life. While prospective trials of IORT for DCIS are ongoing, the objective of this study was to estimate the cost-effectiveness of IORT vs. WBRT vs. no radiation for DCIS. Methods We developed a Markov model using TreeAge Pro 2016 to evaluate the cost-effectiveness of WBRT, IORT, and no radiation in patients with DCIS following lumpectomy. Health states included disease free, local recurrence (ipsilateral DCIS or invasive cancer), distant recurrence or death due to breast cancer, and death due to non-breast cancer causes. A 10-year time horizon and societal perspective were used. Model input parameters were derived from the literature. Costs reflected 2016 Medicare rates. The primary endpoint was incremental cost-effectiveness ratio (ICER), defined as the difference in cost, divided by the difference in quality-adjusted life years (QALYs) of two interventions. We performed analyses of subgroups defined according to DCIS risk (histologic grade, Oncotype Dx® DCIS recurrence score, low risk per RTOG 9804 criteria) and endocrine therapy use (none, tamoxifen, aromatase inhibitor). Sensitivity analyses explored uncertainty in the model. Results IORT was the most cost-effective strategy, with an increase of 0.18 QALYs at an incremental cost of $4,728, corresponding to an ICER of $26,943/QALY when compared with no radiation therapy. WBRT resulted in an increase in 0.18 QALYs at an incremental cost of $6859, corresponding to an ICER of $39,085/QALY. For both strategies, the ICERs did not exceed the willingness to pay (WTP) threshold of $100,000. IORT remained the most cost-effective strategy across DCIS risk groups, but was more cost-effective in higher risk patients, as demonstrated by lower ICERs. In low risk DCIS defined by RTOG 9804 criteria, no radiation was most cost-effective. The ICERs for IORT and WBRT, $152,753 and $208,204/QALY, respectively, exceeded the WTP threshold. IORT remained cost-effective in the setting of endocrine therapy use. Incremental Cost-Effectiveness Ratios (ICER) for each radiation strategy for the base case and scenario analyses ICER ($/QALY) No RTIORTWBRTBase Case Analysis 26,94339,085 Scenario Analysis by DCIS Risk GroupHistologic Grade - Low 36,81152,219- High 25,64337,137 Oncotype Dx DCIS Score - Low 92,892126,398- High 32,00345,690 Low Risk DCIS 152,753208,204 Scenario Analysis by Endocrine TherapyNo Tamoxifen 23,38734,373Tamoxifen 47,81166,616 Tamoxifen 31,96146,272Aromatase Inhibitor 41,31658,674 Conclusion IORT was the most cost-effective radiation strategy for DCIS compared to WBRT and no radiation. This applied to all subgroups with the exception of low-risk DCIS defined by RTOG 9804 criteria for whom no radiation was the most cost-effective strategy. These findings provide support for ongoing studies examining the role of IORT for DCIS with high-risk features, as well as alternative treatment strategies for low-risk DCIS. Citation Format: Onishi M, Connolly EP, Wright JD, Vasan S, Gross T, Tsai W-Y, Chen L, Neugut AI, Accordino MK, Kalinsky K, Crew KD, Hershman DL. Cost-effectiveness analysis of intraoperative radiotherapy for ductal carcinoma in situ [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr PD7-03.

Patient Experiences and Clinician Views on the Role of Radiation Therapy for Ductal Carcinoma In Situ

To evaluate patient experiences with decisions regarding radiation therapy (RT) for ductal carcinoma in situ (DCIS), and to assess clinician views on the role of RT for DCIS with favorable features in the present era. A sample of women with newly diagnosed breast cancer from the population-based Georgia and Los Angeles County Surveillance, Epidemiology, and End Results (SEER) registries were sent surveys approximately 2months after undergoing breast-conserving surgery (BCS), with a 70% response rate. The analytic sample was limited to 538 respondents with unilateral DCIS. We also surveyed 761 surgeons and radiation oncologists treating breast cancer in those regions, of whom, 539 responded (71%). After BCS, 23% of patients omitted RT, with twice the rate of omission in Los Angeles County relative to Georgia (31% vs 16%; P<.001). The most common reasons for omitting RT were advice from a clinician that it was not needed (62%) and concern about side effects (24%). Cost and transportation were not reported as influential considerations. After covariate adjustment, low- and intermediate-grade disease (odds ratio [OR] 5.5, 95% confidence interval [CI] 2.5-12; and OR 3.2, 95% CI 1.7-6.1, respectively) and Los Angeles County SEER site (OR 4.3, 95% CI 2.3-8.2) were significantly associated with greater RT omission. Of the responding clinicians, 62% would discuss RT omission for a patient with DCIS with favorable features. Clinicians in Los Angeles County were more likely to discuss RT omission than were those in Georgia (67% vs 56%; P=.01). Approximately one third of clinicians would obtain the Oncotype DX DCIS score. The heterogeneity in RT omission after BCS for DCIS continues to be substantial, with systematic differences in provider opinions across the 2 regions we studied. Enhanced precision of recurrence estimates, guidance from professional organizations, and better communication are needed to improve the consistency of treatment in this controversial area.

Patterns of Fractionation and Boost Utilization in Adjuvant External Beam Radiation Therapy for Ductal Carcinoma In Situ in the United States

Patterns of Fractionation and Boost Utilization in Adjuvant External Beam Radiation Therapy for Ductal Carcinoma In Situ in the United States

Radiotherapy for ductal carcinoma in situ and risk of second non-breast cancers.

Radiotherapy for ductal carcinoma (DCIS) is increasing, but the risks and benefits of the treatment remain uncertain. We aimed to investigate the relationship between radiotherapy for DCIS and risk of second non-breast cancers in a large US cohort. We conducted a retrospective cohort study of 52,556 women in 12 U.S. population-based cancer registries diagnosed with first primary DCIS during 1992-2008 at age 25-79years. We estimated relative risks (RRs), attributable risks (AR), and excess absolute risks (EAR) of second non-breast cancers associated with radiotherapy using Poisson regression adjusted for age at year of diagnosis, grade, hormonal therapy (yes/no or unknown), and time since diagnosis. Approximately half of the women (46.3%) received radiotherapy. Radiotherapy was associated with an increased risk of all second non-breast cancers combined [RR 1.17, 95% confidence interval (CI) 1.08-1.28] and all in-field, radiation-related second cancers combined (RR 1.37, 95% CI 1.15-1.63), driven by second lung cancers (RR 1.33, 95% CI 1.10-1.60) and non-CLL leukemia (RR 1.71, 95% CI 1.02-2.86). The estimated cumulative excess risk of all second non-breast cancers was 0.8% by 15years after DCIS diagnosis. Radiotherapy was associated with an increased risk of second non-breast cancers. The specific excess of cancers at sites likely in/near the radiotherapy field suggests the findings are unlikely due exclusively to confounding, but further research into factors related to receipt of radiotherapy is needed. Our risk estimates can be used to help assess the balance of the risks and benefits of radiotherapy for DCIS and to inform clinical practice.

EP-1170: Hypofractionated radiotherapy for ductal carcinoma in situ using VMAT: acute toxicity and cosmesis

EP-1170: Hypofractionated radiotherapy for ductal carcinoma in situ using VMAT: acute toxicity and cosmesis

Abstract P1-11-03: Rates of ipsilateral breast tumor recurrence (IBTR) following breast concerving surgery (BCS) and hypofractionated radiotherapy for ductal carcinoma in situ (DCIS)

Abstract P1-11-03: Rates of ipsilateral breast tumor recurrence (IBTR) following breast concerving surgery (BCS) and hypofractionated radiotherapy for ductal carcinoma in situ (DCIS)

Selective Radiation Therapy for Ductal Carcinoma In Situ Following Breast-Conserving Surgery According to Age and Margin Width: Korean Radiation Oncology Group 11-04 and 16-02 Studies.

PurposeThe optimal indications for omitting adjuvant radiation therapy (RT) after breast-conserving surgery are still controversial in ductal carcinoma in situ (DCIS) of the breast. The purpose of this study was to validate the role of postoperative RT in DCIS patients aged ≤50 years and with tumor margin widths of <1 cm, both of which have been proven to be high-risk features for recurrence in cohorts not receiving RT.MethodsUsing two multicenter retrospective studies on DCIS, a pooled analysis was performed among patients aged ≤50 years and with margin widths <1 cm. All patients underwent breast-conserving surgery. Two hundred thirty-two patients received postoperative RT, while 54 did not. The median follow-up period was 77 months (range, 2–190 months) and 70 months (range, 5–166 months) in the patients who received RT and those who did not, respectively.ResultsThe patients who received RT had larger tumors (p<0.001), higher nuclear grade (p<0.001), closer margin width (p<0.001), and negative estrogen receptor expression (p=0.010) compared with those who did not receive RT. During the follow-up period, there were 17 ipsilateral breast tumor recurrences (IBTRs) as follows: invasive carcinoma in 10 patients and DCIS in seven. In the univariate analysis, the treatment with RT and human epidermal growth factor receptor 2 (HER2) status were significant risk factors for IBTR. The 7-year IBTR rates with and without postoperative RT were 3.6% and 13.1%, respectively (p=0.008). HER2-positive tumors had a higher IBTR rate than the HER2-negative tumors (7-year rate, 13.6% vs. 3.9%; p=0.003).ConclusionPostoperative RT following breast-conserving surgery significantly reduced the 7-year IBTR rate in the DCIS patients aged ≤50 years and with margin widths <1 cm. HER2 positivity was associated with increased IBTR in these patients.

Rates of ipsilateral breast tumour recurrence (IBTR) following breast conserving surgery (BCS) and hypofractionated radiotherapy for ductal carcinoma in situ (DCIS)

Rates of ipsilateral breast tumour recurrence (IBTR) following breast conserving surgery (BCS) and hypofractionated radiotherapy for ductal carcinoma in situ (DCIS)

EP-1156: Radiotherapy for ductal carcinoma in situ: patterns of recurrence and risk factors stratification

EP-1156: Radiotherapy for ductal carcinoma in situ: patterns of recurrence and risk factors stratification

Abstract P3-12-02: Patient prognostic score and survival benefit offered by radiotherapy for ductal carcinoma in situ

Abstract Background: In general, radiotherapy (RT) follows breast-conserving surgery (BCS) and remains the standard of care for the surgical management of both invasive carcinoma and ductal carcinoma in situ (DCIS). Although it is associated with better local control, the magnitude of survival benefit conferred by RT for DCIS has not yet been established. We sought to evaluate whether a survival benefit exists with the addition of RT for patients with DCIS and to validate a patient prognostic score to predict survival benefit. Methods: We performed a retrospective longitudinal cohort study by using the Surveillance Epidemiology and End Results database (SEER 17). Between 1988-2007, we identified 32,144 eligible patients who underwent BCS for DCIS. Using age, year of diagnosis, race, tumor size, hormone receptor status, tumor grade, marital status and SEER region, we calculated propensity score weights to balance clinicopathologic factors between patients receiving only surgery and those receiving surgery and RT. This cohort was divided into seven groups according to the previously validated patient prognostic score proposed by Smith et al. Breast cancer mortality (BCM) was assessed using a log-rank test and a multivariable Cox proportional hazards model. Results: Of 32,144 cases of DCIS, 20,329 cases (63%) were treated with RT (+RT group) and 11,815 cases (37%) were treated with surgery alone (-RT group). There were 304 breast cancer-specific deaths observed over the follow-up period (median 96 months). The weighted cumulative incidence of BCM at ten-years was 1.8% for the +RT group compared to 2.1% for the -RT group (p= 0.003). The effect of RT on survival differed by nuclear grade (p= 0.007), age (p= 0.004), and tumor size (p=0.02). We found that the survival benefit for the +RT group was significantly greater than for the –RT group in subgroups of patients with higher nuclear grade, younger age, and larger tumor size, whereas a statistical reduction of BCM with RT was not observed among patients without these prognostic factors. Moreover, the magnitude of survival benefit was significantly correlated with the patient prognostic score [p&amp;lt;0.0001, Table]. Conclusion: In this population-based cohort study, the patient prognostic score for DCIS accurately estimated the magnitude of survival benefit offered by radiotherapy after BCS, suggesting that decisions for RT could be tailored based on prognostic score and patient preference. Limitations of this study include unmeasured confounders such as a lack of information about patients' comorbidities, margin status and endocrine therapy, and further external validation is needed to confirm our results. Patient Prognostic Score and Hazard Ratio (HR) Comparing Mortality between Radiotherapy Group and non-Radiotherapy GroupPatient Prognostic ScoreNumber of patients in -RT groupNumber of patients in +RT groupWeighted HR of BCM95% CIWeighted HR of OM95% CI078213881.20.67 - 2.10.910.76 - 1.11267744801.00.70 - 1.50.880.78 - 0.992410570800.690.51 - 0.940.710.63 - 0.793304854170.730.48 - 1.10.680.58 - 0.81496517010.310.16 - 0.580.420.30 - 0.5852232480.290.09 - 0.910.430.21 - 0.9161515N.A. N.A. Abbreviation: RT, Radiotherapy; BCM, Breast Cancer Mortality; OM, Overall Mortality: N.A., not available Citation Format: Sagara Y, Freedman RA, Vaz-Luis I, Mallory MA, Wong S, Aydogan F, DeSantis S, Barry WT, Golshan M. Patient prognostic score and survival benefit offered by radiotherapy for ductal carcinoma in situ. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-12-02.

Increasing Use of Post Lumpectomy Radiation Therapy for Ductal Carcinoma In Situ of the Breast in the United States

Purpose/Objective(s): Our institution has used 3-dimensional conformal radiation therapy (3DCRT) to deliver whole breast irradiation (WBI) in the prone position since 1998 in order to address technical difficulties associated with treating large, pendulous breasts and/or large body habitus, and/or in patients with left-sided cancers to decrease radiation received by the heart. The goal of this study was to review our updated experience using prone breast WBI to determine whether the recurrence rates and survival patterns are acceptable in this set of patients. Materials/Methods: From 1998-2013, 397 women treated with breast conserving surgery underwent WBI in the prone position using 3DCRT. Patients were treated with a median of 50 Gy to the breast volume +/a boost of 10 Gy to the lumpectomy planning target volume. All patients had >12 month follow-up. Results: Median follow-up was 43.6 mo. The median age was 59 (27-91); 67% were post-menopausal. Median BMI was 32.4 (18.6-64.6). Tumors were Tis-19.8%, T1-61.5%, T2-17.2%, T3-1.5%, and 3.3% had positive axillary nodes. Eight (2%) patients were diagnosed with an ipsilateral breast tumor (5-yr recurrence rateZ1.9%). Mean time to recurrence was 57.5 mo (19-127 mo). The original tumors were DCIS (2), infiltrating lobular (3), and invasive ductal (3). Focal DCIS margin was <2mm in 3 patients. The original tumor location and location of recurrence respectively was: lower outer quadrant (LOQ)-failed in UOQ, UIQ-failed in UIQ (2), central-failed central, UOQ-failed UOQ, LOQ-failed LOQ, UOQfailed LIQ, and UOQ-failed in skin and with distant metastases. Ipsilateral disease free survival was 97.6% at 5 yr. Distant metastasis free survival was 98.4% at 5 yr. Overall survival was 95.5% at 5 yr. Conclusion: In patients with large pendulous breasts, increased BMI and/ or left-sided tumors, delivering WBI in the prone position using 3DCRT results in recurrence rates and failure patterns similar to those anticipated using supine WBI. This series adds to the growing literature demonstrating prone WBI provides local control rates comparable to supine WBI with minimal toxicity to organs at risk. Author Disclosure: H. Saeed: None. H. Cheng: None. T.R. Kelly: None. J.A. Bovi: None. J.R. White: None. C. Bergom: None. A.D. Currey: None. J. Wilson: None.