Receipt Of Postmastectomy Radiation Therapy Research Articles

Nipple-Sparing Mastectomy versus Skin-Sparing Mastectomy: Does Saving the Nipple Impact Short- and Long-Term Patient Satisfaction?

Nipple-sparing mastectomy (NSM) is an oncologically safe alternative to skin-sparing mastectomy (SSM). This study evaluated whether NSM patients were more satisfied than SSM patients in short- and long-term follow-up. Women who underwent NSM or SSM between 2009 and 2019 completed a postoperative BREAST-Q survey at least 1 year after surgery and patient characteristics were compared. Patient satisfaction at 1-5years and 6-10years after NSM and SSM were analyzed. Overall, 431 patients were included; 247 had NSM and 184 had SSM 1-10years prior to BREAST-Q survey completion. SSM patients were older, had higher body mass index (BMI), larger breast weight, and more hypertension than NSM patients, but oncologic treatments were similar between groups. BREAST-Q Psychosocial Well-Being and Sexual Well-Being scores were significantly higher in NSM patients compared with SSM patients in the 1-5years cohort; however, scores attenuated in the 6-10years cohort. Satisfaction with breasts was nearly significantly higher in NSM patients compared with SSM patients in the 1-5years cohort (p=0.056), but no different in the 6-10years cohort. Receipt of adjuvant chemotherapy, receipt of postmastectomy radiation therapy, and BMI ≥30 were independent risk factors for dissatisfaction with breasts. Women who are not candidates for NSM should be reassured that long-term qualify of life is not significantly different between SSM and NSM. Dissatisfaction with reconstructed breasts is linked with other factors (besides the nipple), which patients should be made aware of at the time of surgical decision making.

Postmastectomy Radiation Therapy for Node-Negative Breast Cancer of 5 cm or Larger Tumors: A Multicenter Retrospective Analysis (KROG 20-03).

PurposeThis study aimed to evaluate the role of postmastectomy radiation therapy (PMRT) in patients with node-negative breast cancer of 5cm or larger tumors undergoing mastectomy.Materials and MethodsMedical records of 274 patients from 18 institutions treated with mastectomy between January 2000 and December 2016 were retrospectively reviewed. Among these, 202 patients underwent PMRT, while 72 did not. Two hundred and forty-one patients (88.0%) received systemic chemotherapy, and 172 (62.8%) received hormonal therapy. Patients receiving PMRT were younger, more likely to have progesterone receptor-positive tumors, and received adjuvant chemotherapy more frequently compared with those without PMRT (p < 0.001, p=0.018, and p < 0.001, respectively). Other characteristics were not significantly different between the two groups.ResultsWith a median follow-up of 95 months (range, 1 to 249 months), there were nine locoregional recurrences, and 20 distant metastases. The 8-year locoregional recurrence-free survival rates were 98.0% with PMRT and 91.3% without PMRT (p=0.133), and the 8-year disease-free survival (DFS) rates were 91.8% with PMRT and 73.9% without PMRT (p=0.008). On multivariate analysis incorporating age, histologic grade, lymphovascular invasion, hormonal therapy, chemotherapy, and PMRT, the absence of lymphovascular invasion and the receipt of PMRT were associated with improved DFS (p=0.025 and p=0.009, respectively).ConclusionLocoregional recurrence rate was very low in node-negative breast cancer of 5 cm or larger tumors treated with mastectomy regardless of the receipt of PMRT. However, PMRT was significantly associated with improved DFS. Further investigation is needed to confirm these findings.

Impact of Post-Mastectomy Radiation Therapy (PMRT) in Women with T1-2N1M0 Breast Cancer: A Multi-Institutional Analysis

To investigate the effect of PMRT in women with pT1-2N1M0 breast cancer in the modern era. Data from 5 North American institutions were pooled to include women who underwent mastectomy without neoadjuvant therapy, with pT1-2N1M0 disease from 1995-2015. Patients were divided into discovery and validation cohorts. Missing covariate values were imputed using multiple imputation with chain equation, and combined using Rubin’s rules. Competing-risks regression was performed to identify factors associated with locoregional recurrence (LR), distant metastases (DM), and breast cancer mortality (BCM). Among 5197 patients in the discovery cohort, 639 (12%) were staged with sentinel node biopsy only, 2848 (55%) received PMRT, and 3641 (70%) received adjuvant chemotherapy (CHT). Median 11 lymph nodes (LN) were dissected. Median follow up was 9.8 years. Patients who received PMRT were significantly younger, had larger tumors, more positive LN (LN+), lymphovascular invasion (LVI), extracapsular extension (ECE), HER2+ disease, positive margins, and more frequently received CHT (all p<0.001). Despite more adverse features, the 10-year unadjusted cumulative incidence rates of LR, DM and BCM were 2.8%, 17% and 14% with PMRT and 7%, 17% and 14% without PMRT, respectively. On multivariable competing risks regression, increased LR was associated with younger age (HR 1.04, p<0.001), larger tumor size (HR 1.19, p = 0.006), grade 3 vs. 1 (HR 2.51, p = 0.002), 3 vs. 1 LN+ (HR 1.54, p = 0.02), LVI (HR 1.48, p = 0.005), and inner vs. outer tumor location (HR 1.56, p = 0.02). Decreased LR was associated with receipt of PMRT (HR 0.31, p<0.001) and CHT (HR 0.44, p<0.001). Increased DM was associated with younger age (HR 1.01, p<0.001), larger tumor size (HR 1.32, p<0.001), grade (grade 2 vs. 1 HR 2.01, p<0.001; grade 3 vs. 1 HR 3.07, p<0.001), 3 vs. 1 LN+ (HR 1.40, p<0.001), N1 vs. N1mic (HR 1.40, p = 0.01), LVI (HR 1.31, p<0.001), ER/PR negative (HR 1.28, p = 0.02), and inner vs. outer tumor location (HR 1.49, p<0.001). Decreased DM was associated with receipt of PMRT (HR 0.84, p = 0.04), CHT (HR 0.64, p<0.001), HER2+ with trastuzumab vs. HER2- (HR 0.60, p = 0.001), and later treatment era (HR 0.85, p = 0.04). Increased BCM was associated with younger age (HR 1.01, p = 0.01), larger tumor size (HR 1.33, p<0.001), grade (grade 2 vs. 1 HR 2.61, p<0.001; grade 3 vs. 1 HR 4.06, p<0.001), 3 vs. 1 LN+ (HR 1.39, p = 0.002), N1 vs. N1mic (HR 1.69, p = 0.03), LVI (HR 1.28, p = 0.002), ER/PR negative (HR 1.59, p<0.001), and inner vs. outer tumor location (HR 1.49, p<0.001). Decreased BCM was associated with CHT (HR 0.55, p<0.001) and HER2+ with trastuzumab vs. HER2- (HR 0.56, p = 0.001). Margin status and ECE were not significantly associated with any endpoints. At 10 years median follow up, PMRT for pT1-2N1 breast cancer is associated with decreased LR and DM. Nomograms will be generated and tested in a validation cohort to assist clinicians in individualizing risk estimates in contemporary practice.

A Feasibility Study of Mepitel Film for the Prevention of Breast Radiation Dermatitis in a Canadian Center

PurposeSevere radiation dermatitis (RD) is distressing and may have adverse long-term effects including fibrosis and telangiectasia. Treatment interruptions due to severe RD may increase the risk of recurrence. Two randomized trials of Mepitel film demonstrated efficacy in preventing severe RD in breast cancer, but this product has not been widely adopted in North America. We aimed to assess the feasibility and efficacy of Mepitel film for prevention of breast RD at a Canadian center. Methods and MaterialsPatients were stratified based on breast size and receipt of postmastectomy radiation therapy. The primary outcome was RD grade using the Common Terminology Criteria for Adverse Events. Secondary outcomes included moist desquamation, patient- and clinician-reported symptoms of skin toxicity, and cosmetic outcomes. ResultsThirty patients receiving external beam radiation therapy to the breast or chest wall were enrolled. Two patients (6.7%) discontinued use of the Mepitel film before completing radiation therapy. No patients developed grade 3 RD or higher. Five patients (17.9%) developed grade 2 RD: 3 (10.7%) had moist desquamation, and 2 (7.1%) had brisk erythema without moist desquamation. ConclusionsMepitel film completely prevented grade 3 RD. Rates of moist desquamation and grade 2 RD were lower with Mepitel film than in studies using aqueous cream, but unlike previous trials of Mepitel film we did not achieve complete prevention of moist desquamation. Further research is needed to confirm the efficacy of Mepitel film versus standard prophylaxis for RD and identify the patients who will benefit the most from the film.

Adjuvant Radiation Therapy for T3N0 Breast Cancer Patients Older Than 75 Years After Mastectomy: A SEER Analysis

IntroductionBreast cancer patients with tumors > 5 cm but without nodal disease who undergo mastectomy present a clinical challenge regarding the appropriate adjuvant treatment. Traditionally, postmastectomy radiation therapy (PMRT) was the standard of care. However, recent studies have suggested local failure rates without PMRT might be low enough to omit RT. This might be especially true in the elderly. Patients and MethodsWomen aged ≥ 75 years with a diagnosis of T3N0 breast cancer who had undergone mastectomy were identified from the Surveillance, Epidemiology, and End Results (SEER) 18 database. The study period was limited to 2006 to 2009 for more modern sampling. Multivariable proportional hazards modeling was used to examine the association of treatment and mortality, adjusting for demographic and clinicopathologic factors. ResultsA total of 635 patients were identified. The median follow-up period was 43 months. PMRT was given to 31.2% of the patients aged 75 to 79 years, 21.5% of those aged 80 to 84 years, and 11.7% of the patients aged ≥ 85 years (P < .001). The receipt of PMRT showed a trend toward improved overall survival on bivariable analysis (hazard ratio [HR], 0.58; P < .001) and multivariable analysis (HR, 0.78; P = .14). The 5-year overall survival was 64.2% for those who had received PMRT and 44.8% for those who had not. A nonsignificant trend was seen toward improved breast cancer-specific survival at 5 years on bivariable analysis (HR, 0.63; P = .09) but not on multivariable analysis. The interaction of age and PMRT receipt could have confounded the results. Patient age and tumor grade were significant indicators of the survival prognosis in these patients. ConclusionThe results of the present analysis of the SEER database suggest that PMRT might still be beneficial in women aged > 75 years with T3N0 disease but also supports continuing efforts to confirm whether it could be safe to omit. It is likely that efforts to subdivide this population using other factors (eg, comorbidity) will be important. The search for refined inclusion and exclusion criteria for adjuvant RT remains an important field of research both clinically and economically.

The Potential Impact of AMAROS on the Management of the Axilla in Patients with Clinical T1-2N0 Breast Cancer Undergoing Primary Total Mastectomy.

Recent trials have demonstrated that axillary observation or axillary radiation therapy (AxRT) is equivalent to axillary node dissection (ALND) for patients with one or two positive sentinel lymph nodes (SLNs). These strategies have been widely adopted for patients having breast conservation. This report demonstrates the potential impact of the AMAROS trial on axillary therapy in a retrospective cohort of mastectomy patients. Patients undergoing primary mastectomy for cT1-2N0 breast cancer who had one or two positive SLNs were identified from institutional databases (2005-2015). Locoregional management strategies were evaluated, and variables predictive of the use of postmastectomy radiation therapy (PMRT) were identified. Among 2594 mastectomies, 193 (7%) met the AMAROS eligibility criteria. The median patient age was 50years (range 22-83years). Locoregional treatment consisted of ALND + PMRT for 102 patients (53%), ALND alone for 66 patients (34%), PMRT alone for 11 patients (6%), and observation for 14 patients (7%). Overall, 59 ALND patients (35%) had additional positive nodes. In the multivariate analysis, age younger than 50years (odds ratio [OR] 3.55; 95% confidence interval [CI] 1.57-8.45), lymphovascular invasion (LVI) (OR 5.78; 95% CI 2.53-4.78), macrometastases (OR 3.99; 95% CI 1.54-10.97), and extracapsular extension (OR 11.66; 95% CI 2.55-88.34) were associated with receipt of PMRT. In this cohort of AMAROS-eligible patients, 168 (87%) underwent ALND, 102 (61%) of whom also received PMRT, suggesting that AxRT could have been used instead of ALND for a significant number of patients. Preoperative factors associated with the receipt of PMRT, such as young age and LVI, may be useful for defining a multidisciplinary decision-making framework for axillary management in this population.

Most Breast Cancer Patients with T1-2 Tumors and One to Three Positive Lymph Nodes Do Not Need Postmastectomy Radiotherapy.

Guidelines concur that postmastectomy radiation therapy (PMRT) in T1-2 tumors with one to three positive (+) lymph nodes (LNs) decreases locoregional recurrence (LRR) but advise limiting PMRT to patients at highest risk to balance against potential harms. In this study, we identify the risks of LRR after mastectomy in patients with T1-2N1 disease, treated with modern chemotherapy, and identify predictors of LRR when omitting PMRT. Patients with T1-2N1 breast cancer undergoing mastectomy between 1995 and 2006 were categorized by receipt of PMRT. The Chi square test compared the clinicopathologic features between both groups, and Kaplan-Meier and Cox regression analysis was used to determine the rates of LRR, recurrence-free survival (RFS), and overall survival (OS). Overall, 1087 patients (924 no PMRT, 163 PMRT) were included in the study, with a median follow-up of 10.8years (range 0-21). We identified 63 LRRs (56 no PMRT, 7 PMRT), and 10-year rates of LRR with and without PMRT were 4.0% and 7.0%, respectively. Patients receiving PMRT were younger (p = 0.019), had larger tumors (p = 0.0013), higher histologic grade (p = 0.029), more positive LNs (p < 0.0001), lymphovascular invasion (LVI) (p < 0.0001), extracapsular nodal extension (p < 0.0001), and macroscopic LN metastases (p < 0.0001). There was no difference in LRR, RFS, or OS between groups. On multivariate analysis, age < 40years (p < 0.0001) and LVI (p < 0.0001) were associated with LRR in those not receiving PMRT. Consistent with the guidelines, 85% of patients with T1-2N1 were spared PMRT at our center, while maintaining low LRR. Age < 40years and the presence of LVI are significantly associated with LRR in those not receiving PMRT.

Postmastectomy Radiation Therapy in Women with T1-T2 Tumors and 1 to 3 Positive Lymph Nodes: Analysis of the Breast International Group 02-98 Trial

To analyze the impact of postmastectomy radiation therapy (PMRT) for patients with T1-T2 tumors and 1 to 3 positive lymph nodes enrolled on the Breast International Group (BIG) 02-98 trial. The BIG 02-98 trial randomized patients to receive adjuvant anthracycline with or without taxane chemotherapy. Delivery of PMRT was nonrandomized and performed according to institutional preferences. The present analysis was performed on participants with T1-T2 breast cancer and 1 to 3 positive lymph nodes who had undergone mastectomy and axillary nodal dissection. The primary objective of the present study was to examine the effect of PMRT on risk of locoregional recurrence (LRR), breast cancer-specific survival, and overall survival. We identified 684 patients who met the inclusion criteria and were included in the analysis, of whom 337 (49%) had received PMRT. At 10years, LRR risk was 2.5% in the PMRT group and 6.5% in the no-PMRT group (hazard ratio 0.29, 95% confidence interval 0.12-0.73; P=.005). Lower LRR after PMRT was noted for patients randomized to receive adjuvant chemotherapy with no taxane (10-year LRR: 3.4% vs 9.1%; P=.02). No significant differences in breast cancer-specific survival (84.3% vs 83.9%) or overall survival (81.7% vs 78.3%) were observed according to receipt of PMRT. Our analysis of the BIG 02-98 trial shows excellent outcomes in women with T1-T2 tumors and 1 to 3 positive lymph nodes found in axillary dissection. Although PMRT improved LRR in this cohort, the number of events remained low at 10years. In all groups, 10-year rates of LRR were relatively low compared with historical studies. As such, the use of PMRT in women with 1 to 3 positive nodes should be tailored to individual patient risks.

Trends and variations in postmastectomy radiation therapy for breast cancer in patients with 1 to 3 positive lymph nodes: A National Cancer Data Base analysis.

High-level evidence is lacking to guide treatment decisions about postmastectomy radiation therapy (PMRT) in patients who have breast cancer with 1 to 3 positive lymph nodes who receive contemporary systemic therapies, leading to potential variations in PMRT delivery. The objective of this study was to examine nationwide trends in PMRT use in this group. The National Cancer Data Base (NCDB) was used to identify 93,372 women who had T1-T2N1 breast cancer diagnosed between 2003 and 2012. Patients who received neoadjuvant chemotherapy or radiation therapy (RT) and those who had bilateral breast cancers were excluded. Time trends were evaluated using the Cochrane-Armitage test and correlated the receipt of PMRT with various patient demographic, facility, clinicopathologic, and treatment variables using multivariable logistic regression. A second analysis was performed for patients who were diagnosed during 2010 and included radiation oncologist density as an additional covariate. P values < .0001 were considered statistically significant. Overall, 22.5% of the study population received PMRT, representing an increase from 19.1% in 2003 to 30.3% in 2012. Factors associated with greater PMRT use included younger age, lower Charlson-Deyo comorbidity scores, shorter distance to the treating facility, treatment at a comprehensive cancer program, facility location in the New England Census division, and higher density of radiation oncologists. Increased PMRT use was associated with later year of diagnosis, receipt of chemotherapy, receipt of hormone therapy, higher grade disease, larger tumor size, greater numbers of positive lymph nodes, positive margins, and absence of immediate breast reconstruction (all P < .0001). The receipt of PMRT by patients with breast cancer who have 1 to 3 positive lymph nodes has increased over time, with wide variability in practice patterns in the United States. Cancer 2018;124:482-90. © 2017 American Cancer Society.

Inflammatory Breast Cancer Outcomes in a Contemporary Series.

Evidence on the management of inflammatory breast cancer (IBC) is limited. This study investigated factors influencing IBC treatment outcomes such as event-free survival (EFS) and overall survival (OS). Data were collected from 173 patients with stage III non-IBC and 17 patients with IBC diagnosed at the Keck Medical Center and Los Angeles County and University of Southern California (LAC+USC) Medical Center. Cox proportional hazard regression evaluated associations between variables significant for EFS and OS. On multivariate analysis, negative estrogen receptor (ER)status [hazard ratio (HR)=1.88, 95% confidence interval (CI)=1.11-3.18, p<0.06) and lack of postoperative radiation treatment (HR=2.07, 95% CI=1.03-4.15, p<0.04) were significant for poorer EFS. High Scarff-Bloom-Richardson (SBR) score (HR=2.24, 95% CI=0.79-6.36, p<0.13) and lack of postoperative radiation treatment to the breast (HR=4.39, 95% CI=0.39-49.55, p<0.23) were associated with lower rates of OS. The diagnosis of IBC has a significantly worse prognosis. Receipt of post-mastectomy radiation therapy was a significant predictor of better EFS and OS.

Temporal Trends in Postmastectomy Radiation Therapy and Breast Reconstruction Associated With Changes in National Comprehensive Cancer Network Guidelines.

Evolving data on the effectiveness of postmastectomy radiation therapy (PMRT) have led to changes in National Comprehensive Cancer Network (NCCN) recommendations, counseling clinicians to "strongly consider" PMRT for patients with breast cancer with tumors 5 cm or smaller and 1 to 3 positive nodes; however, anticipation of PMRT may lead to delay or omission of reconstruction, which can have cosmetic, quality-of-life, and complication implications for patients. To determine whether revised guidelines have increased PMRT and affected receipt of breast reconstruction. We hypothesized that (1) PMRT rates would increase for women affected by the revised guidelines while remaining stable in other cohorts and (2) receipt of breast reconstruction would decrease in these women while increasing in other groups. Retrospective, population-based cohort study of Surveillance, Epidemiology, and End Results (SEER) data on women with stage I to III breast cancer undergoing mastectomy from 2000 through 2011. Our analytic sample (N = 62,442) was divided into cohorts on the basis of current NCCN radiotherapy recommendations: "radiotherapy recommended" (tumors > 5 cm or ≥ 4 positive lymph nodes), "strongly consider radiotherapy" (tumor ≤ 5 cm, 1-3 positive nodes), and "radiotherapy not recommended" (tumors ≤ 5 cm, no positive nodes). We used Joinpoint regression analysis to evaluate temporal trends in receipt of PMRT and breast reconstruction. The 3 cohorts comprised 15,999 in the "radiotherapy recommended" group, 15,006 in the "strongly consider radiotherapy" group, and 31,837 in the "radiotherapy not recommended" group. [corrected]. Rates of PMRT were unchanged in the radiotherapy recommended (29.9%) and radiotherapy not recommended (7.4%) cohorts over the study period. Receipt of PMRT for the strongly consider radiotherapy cohort was unchanged at 26.9% until 2007. At that time, a significant change in the APC was observed (P = .01) with an increase in APC from 2.1% to 9.0% (P = .02) through the end of the study period, for a final rate of 40.5%. Breast reconstruction increased across all cohorts. Despite increasing receipt of PMRT, the strongly consider radiotherapy cohort maintained a consistent increase in reconstruction (annual percentage change, 7.4%) throughout the study period. This is similar to the increase in reconstruction observed for the radiotherapy recommended (10.7%) and radiotherapy not recommended (8.4%) cohorts. Changes in NCCN guidelines have been associated with an increase in PMRT among patients with tumors 5 cm or smaller and 1 to 3 positive nodes without an associated decrease in receipt of reconstruction. This may represent increasing clinician comfort with irradiating a new breast reconstruction and may have cosmetic and quality-of-life implications for patients.

Postmastectomy radiation therapy in T3 node-negative breast cancer

BackgroundIn the absence of lymph node involvement, tumor size is arguably the most important prognostic factor for women with breast cancer. Radiation therapy use in the T3 node-negative population is controversial. We investigated the use of postmastectomy radiation therapy (PMRT) in women with T3 node-negative breast cancer. MethodsA retrospective cohort study was conducted by identifying women with T3 node-negative breast cancer from the 1988–2009 Surveillance, Epidemiology and End Results database. Our primary outcome was breast cancer-specific survival. Survival curves were generated using the Kaplan–Meier method. Cox proportional hazard ratios (HRs) and propensity score analysis were used to evaluate the impact on survival. ResultsWe identified 2874 patients with T3 node-negative breast cancer and 961 (33%) received PMRT and 1913 (67%) did not. Statistically significant differences were seen in adjuvant radiation therapy use based on patient age, marital status, tumor grade, tumor size, and receptor status (P < 0.05 for all). Overall survival was lower in the PMRT group in unadjusted analysis (crude HR, 0.718; 95% confidence interval [CI], 0.614–0.840); however, adjusted HRs demonstrated no difference in overall survival (adjusted HR, 0.898; 95% CI, 0.765–1.054). Unadjusted analysis of breast cancer-specific survival demonstrated no difference between those who received PMRT and those who did not (crude HR, 0.834; 95% CI, 0.682–1.021). Propensity score analysis demonstrated no difference in breast cancer-specific survival based on PMRT use (adjusted HR, 0.939; 95% CI, 0.762–1.157). ConclusionsAnalysis of the Surveillance, Epidemiology and End Results database suggests that receipt of PMRT is not clinically beneficial in T3 node-negative breast cancer.

The Impact of Proximity to Radiation Oncologists and General Surgeons on Receipt of Postmastectomy Radiation Therapy

Despite evidence-based guidelines recommending post-mastectomy radiation therapy (PMRT) for patients with high-risk breast cancer, significant underutilization has been reported. Clinical factors associated with PMRT receipt have been studied, however, the impact of regional health services on PMRT receipt remains unclear. The following study investigated whether reduced proximity to a radiation oncologist or surgeon serves as an additional barrier to receipt of PMRT.

Investigation on the Benefit of PMRT in Women With High Risk N0 Breast Cancer

Prior studies have shown that there are subsets of women with node-negative breast cancer with tumor-defined risk factors that portend a higher rate of locoregional recurrence (LR). These factors include lymph vascular invasion, tumor size, young age, close margins, or high tumor grade. Women who have ≥2 of these factors may benefit from post-mastectomy radiation therapy (PMRT). The general use of PMRT for women with node-negative (N0) breast cancer has been shown to be associated with decreased survival. However, providing PMRT to women at high risk of LR may result in a survival advantage. This study evaluates whether a survival benefit of PMRT can be observed in women under age 50 with high-risk N0 disease. The Surveillance, Epidemiology, and End Results database was searched for women age 20-49 diagnosed from 1990-2008 with N0 invasive breast cancer and treated with mastectomy. Multivariable proportional hazards survival analysis (MVA) assessed the association between cause specific survival (CSS) and the following factors: age, estrogen receptor (ER) or progesterone receptor (PR) expression, race, tumor size, histology, number of axillary lymph nodes removed, risk group, PMRT, and tumor grade. Risk groups were defined a priori according to number of factors associated with decreased survival on MVA as follows: high risk (tumor size >5.0cm, grade III-IV, and ER-negative and/or PR-negative, intermediate risk (1 or 2 high risk factors), and low risk (size ≤5cm, grade I-II, and ER- and PR-positive) groups. Interaction of PMRT and risk group was analyzed. A total of 7,226 patients were identified in the CSS analysis, of which 191 (2.6%) were high risk, 4,150 (57.4%) were intermediate risk, and 2,885 (40%) were low risk. Receipt of PMRT was 51.3%, 12.1%, and 7.8% in the risk groups, respectively. In the MVA, ER-negative (Hazard ratio [HR] = 1.31 [1.02-1.67] p = 0.03), PR-negative* (HR = 1.96[1.23-3.14] p = 0.005), black race (HR = 1.40 [1.10-1.78] p = 0.006) tumor size 2.1-5cm vs. ≤2cm (HR = 1.76 [1.46-2.11] p < 0.0001), tumor size >5cm vs. ≤2cm (HR = 2.00 [1.15-3.48] p = 0.01), and grade* (HR = 2.29 [1.32-3.98] p = 0.003) were associated with lower CSS (*PR-negative and grade were only associated with lower CSS after 2 years). In the interaction analysis of hazard ratios for risk, there is a lower survival for patients who had PMRT if they were intermediate risk (HR = 0.73 [0.55-0.97]). Patients in the low risk group had a trend toward lower survival with PMRT (HR = 0.59 [0.32-1.08]). Patients in the high-risk group had a trend toward improved survival with PMRT (HR = 2.13 [0.91-4.99]). Young women with N0 breast cancer who have large, high-grade tumors that do not express hormone receptors may benefit from PMRT.

P1-11-05: Investigation of Epidemiological Factors as Barriers to Indicated Radiation Therapy in Post-Mastectomy Breast Cancer Patients in South Carolina.

Abstract Purpose: Post-mastectomy radiation therapy (PMRT) has been shown to provide improved locoregional control and overall survival in intermediate and high-risk breast cancer patients1,2. To investigate the frequency of utilization and potential barriers to receipt of adjuvant PMRT in South Carolina, an analysis of the S.C. Cancer Registry (SCCR) database was undertaken. Methods: Epidemiological factors such as age, race, and geographic distance from a radiation therapy facility were analyzed as potential predictors of whether patients received the indicated radiotherapy. Post-mastectomy breast cancer patients (n=1080) recorded in the SCCR from 2006–2008 were stratified as low (Tis/T1, N0) (43%), intermediate (T1/T2, N1) (27%), or high (T3/T4, N2/N3) (30%) risk. Logistic regression models were used to predict receipt of adjuvant radiotherapy based on factors such as race, age, and geographical distance from radiation treatment facility. Results: Adjuvant PMRT was received in 4% (19/469) of low risk patients, 23% (67/288) of intermediate risk patients, and 44% (141/323) of high risk patients. In both intermediate and high risk groups, older patients were less likely to receive PMRT. The odds of receiving PMRT decreased by 3% (OR= 1.03; 95% CI: 1.01−1.05; p=0.01) and 2% (OR=1.02; 95% CI: 1.002−1.035; p=0.03) per year in the intermediate and high risk groups, respectively. Race and distance from treatment facility were not predictive of receipt of PMRT in high risk patients. Conclusion: Utilization of adjuvant PMRT in intermediate and high risk breast cancer patients in South Carolina is low, despite the evidence that it confers a survival benefit in both premenopausal and postmenopausal women. Of the patient-related factors analyzed, only age predicted lower odds of receiving radiotherapy in both the intermediate and high risk group. In high risk patients of advanced age (&amp;gt;70), breast cancer continues to be a major cause of mortality which can be improved by radiotherapy3. Future educational efforts should focus on addressing patient and physician bias against radiotherapy based on patient age. Further study is needed to identify socio-economic-, physician- and health system- related factors that maybe impacting the underutilization of PMRT in South Carolina.

Impact of evidence‐based clinical guidelines on the adoption of postmastectomy radiation in older women

Although postmastectomy radiation therapy (PMRT) improves survival for patients with high-risk breast cancer, previous literature suggested that it is underused. The impact of recent clinical guidelines on PMRT use is unknown. Accordingly, the authors used the Surveillance, Epidemiology, and End Results (SEER)-Medicare cohort to determine whether the use of PMRT has increased in response to evidence-based guidelines. In total, 38,322 women aged ≥66 years who underwent mastectomy for invasive breast cancer between 1992 and 2005 were identified. Time trends in the receipt of PMRT for low-risk (T1/T2 N0), intermediate-risk (T1/T2 N1), and high-risk (T3/T4 and/or N2/N3) patients were characterized. Multivariate logistic regression identified risk factors for PMRT omission. The receipt of PMRT by patients with high-risk breast cancer increased from 36.5% (95% confidence interval, 26%-46.9%) to 57.7% (95% confidence interval, 46.9%-68.4%) between 1996 and 1998 with the publication of landmark clinical trials. However no further increase in PMRT use was observed between 1999 and 2005 despite publication of multiple guidelines endorsing its use; during this period, only 54.8% (2729 of 4978) of high-risk patients received PMRT. Within this high-risk group, patients with smaller tumors or less advanced lymph node disease were at risk for PMRT omission. After an initial increase in PMRT use in response to clinical trials, the use of PMRT did not increase further in response to guideline publication, and nearly 50% of patients with high-risk breast cancer still do not receive PMRT. Additional research is needed to determine how clinical guidelines can be used to bridge the gap between level I evidence and clinical practice.

165: Response to Clinical Trial Information: Use of Radiation Therapy After Mastectomy between 1991-1999 in Elderly Women

Large randomized trials to assess the benefit of post-mastectomy radiation therapy (PMRT) in the setting of systemic therapy reported findings in abstract form in 1994, and published manuscripts for premenopausal women in 1997 and postmenopausal women in 1999. No systematic study has analyzed the changing patterns of PMRT use during the period of information dissemination regarding its benefit. We sought to study the receipt of PMRT in elderly women during this period, using a population-based cohort of women with breast cancer.

Radiation Therapy After Mastectomy Between 1991 and 1999 in Elderly Women: Response to Clinical Trial Information

No systematic study has analyzed the changing patterns of use of postmastectomy radiation therapy (PMRT) during the period of information dissemination regarding the benefit of radiation therapy in this setting. We sought to study the receipt of PMRT in elderly women in this period, using a population-based cohort of women with breast cancer. Using data from the linked Surveillance, Epidemiology, and End Results-Medicare database, we analyzed the use of radiation therapy between 1991 and 1999 in 19,699 women with stage I to III breast cancer who received mastectomy as definitive surgery. Multivariable logistic regression was used to investigate the association of diagnosis year and the use of PMRT, after controlling for clinical and sociodemographic factors. During the entire period studied, 2,160 (11.0%) patients treated with mastectomy received PMRT. The use of PMRT significantly increased in women diagnosed in 1996 (odds ratio [OR], 1.26; P = .04), 1997 (OR, 1.70; P < .0001), 1998 (OR, 1.57; P < .0001), and 1999 (OR, 1.77; P < .0001), relative to those diagnosed in 1991 after controlling for cancer, and sociodemographic and treatment characteristics. There were significant differences in the temporal trends of radiation use among different regions of the country (P < .0001), and between teaching versus nonteaching institutions (P = .04). The use of PMRT in elderly women increased significantly during the period of data dissemination about its efficacy; however, the trends in adoption varied among different practice settings.

Effect of distance to radiation treatment facility on use of radiation therapy after mastectomy in elderly women

We sought to study the effect of distance to the nearest radiation treatment facility on the use of postmastectomy radiation therapy (PMRT) in elderly women. Using data from the linked Surveillance, Epidemiology, and End Results-Medicare (SEER-Medicare) database, we analyzed 19,787 women with Stage I or II breast cancer who received mastectomy as definitive surgery during 1991 to 1999. Multivariable logistic regression was used to investigate the association of distance with receipt of PMRT after adjusting for clinical and sociodemographic factors. Overall 2,075 patients (10.5%) treated with mastectomy received PMRT. In addition to cancer and patient characteristics, in our primary analysis, increasing distance to the nearest radiation treatment facility was independently associated with a decreased likelihood of receiving PMRT (OR = 0.996 per additional mile, p = 0.01). Secondary analyses revealed that the decline in PMRT use appeared at distances of more than 25 miles and was statistically significant for those patients living more than 75 miles from the nearest radiation facility (odds of receiving PMRT of 0.58 [95% CI = 0.34-0.99] vs. living within 25 miles of such a facility). The effect of distance on PMRT appeared to be more pronounced with increasing patient age (>75 years). Variation in the effect of distance on radiation use between regions of the country and nodal status was also identified. Oncologists must be cognizant of the potential barrier to quality care that is posed by travel distance, especially for elderly patients; and policy makers should consider this fact in resource allocation decisions about radiation treatment centers.

Effect of distance to radiation treatment facility on use of radiation therapy after mastectomy in elderly women

6030 Background: Post-mastectomy radiation therapy (PMRT) has been shown to improve survival in patients at high risk for local or regional recurrence. However, radiation therapy necessitates daily travel to treatment centers for several weeks. We sought to study the effect of distance to the nearest radiation treatment facility on receipt of PMRT in elderly women. Methods: Using the linked Surveillance, Epidemiology, and End Results-Medicare (SEER-Medicare) database, we analyzed 19,787 women with Stage I or II breast cancer who received mastectomy as definitive surgery between 1991 and 1999. Multivariable logistic regression was used to investigate the association of travel distance with receipt of PMRT after adjusting for clinical and sociodemographic factors. Results: Overall, 2,075 (10.5%) patients treated with mastectomy received PMRT. In addition to cancer and patient characteristics, increasing distance from the nearest radiation treatment facility was independently associated with a decreased likelihood of receiving PMRT, (OR = 0.996 per additional mile, p = 0.01). The decline in PMRT use appeared at distances greater than 25 miles and was statistically significant for those patients living greater than 75 miles from the nearest radiation facility (odds of receiving PMRT of 0.58 [95% CI: 0.34–0.99] versus those living within 25 miles of such a facility). In secondary analyses, the effect of distance was only significant in women aged 75–80 years (OR = 0.992 per additional mile, p = 0.03), and those above the age of 80 (OR = 0.989, p = 0.02). When analyses were conducted separately by geographic region, the effect of distance was only significant in the Midwest (OR = 0.992, p = 0.014). The effect of distance was not significant (OR = 1.00, p = 0.87) among women with positive nodes, but was significant in women with no positive nodes (OR = 0.992, p = 0.013). Conclusions: Oncologists must be cognizant of the potential barrier to quality care that is posed by travel distance, especially for elderly patients. Mechanisms to ameliorate the effect of distance on receipt of radiation therapy by assisting individuals with transportation limitations or policies to decrease the centralization of RT services, may help to remove barriers to potentially life-saving treatment. No significant financial relationships to disclose.