Comparison of Dose Distributions With TG-43 and Collapsed Cone Convolution Algorithms Applied to Accelerated Partial Breast Irradiation Patient Plans

PURPOSE

To compare the treatment plans for accelerated partial breast irradiation calculated by the new commercially available collapsed cone convolution (CCC) and current standard TG-43-based algorithms for 50 patients treated at our institution with either a Strut-Adjusted Volume Implant (SAVI) or Contura device.

METHODS AND MATERIALS

We recalculated target coverage, volume of highly dosed normal tissue, and dose to organs at risk (ribs, skin, and lung) with each algorithm. For 1 case an artificial air pocket was added to simulate 10% nonconformance. We performed a Wilcoxon signed rank test to determine the median differences in the clinical indices V90, V95, V100, V150, V200, and highest-dosed 0.1 cm(3) and 1.0 cm(3) of rib, skin, and lung between the two algorithms.

RESULTS

The CCC algorithm calculated lower values on average for all dose-volume histogram parameters. Across the entire patient cohort, the median difference in the clinical indices calculated by the 2 algorithms was <10% for dose to organs at risk, <5% for target volume coverage (V90, V95, and V100), and <4 cm(3) for dose to normal breast tissue (V150 and V200). No discernable difference was seen in the nonconformance case.

CONCLUSIONS

We found that on average over our patient population CCC calculated (<10%) lower doses than TG-43. These results should inform clinicians as they prepare for the transition to heterogeneous dose calculation algorithms and determine whether clinical tolerance limits warrant modification.

Abstract P1-14-04: A randomized phase II neoadjuvant (NACT) study of sequential eribulin followed by FAC/FEC-regimen compared to sequential paclitaxel followed by FAC/FEC-regimen in patients (pts) with operable breast cancer not overexpressing HER-2

Background: Neoadjuvant chemotherapy (NACT) is an integral component for locally advanced and large operable breast cancer. The sequence of taxanes followed by anthracyclines has been the standard of care for almost 20 years. Eribulin (E) is a synthetic analogue of halichondrin B with distinct mechanism of action as microtubule dynamics inhibitor. The FDA approved E in 11/2010 for the treatment of patients (pts) with metastatic breast cancer who have previously received at least two chemotherapeutic regimens for the treatment of metastatic disease. Research Hypothesis: Sequential administration of eribulin followed by FAC/FEC-regimen, would have greater pathologic complete response (pCR) rate than sequential administration of paclitaxel followed by FAC/FEC-regimen as primary systemic therapy for woman with operable breast cancer.

Methods: This is a phase II, randomized, single institution, open label study. Pts were randomized 1:1 to receive E (1.4 mg/m2 d1 and d8 q 21 days x 4) or paclitaxel (P) (80 mg/m2 weekly x12). Both arms received FAC/FEC regimen x 4 doses followed by surgery. Eligible pts were women age 18 or older, Karnosfky PS 80 – 100, histologically confirmed invasive breast cancer, clinical T2-T3, N0-3, M0, HER2-negative. Baseline LVEF of &gt; 50% and normal hematology, liver and kidney laboratory function tests. Primary endpoint was pathologic complete response (pCR/RCB-0) assessed by residual cancer burden (RCB). [Symmans F, 2007]. This protocol (2012-0167) IRB of The University of Texas, MD Anderson Cancer Center.

Results: A preplanned interim analysis aimed to validate trial assumption was conducted after treatment of 54 randomized pts. Between 8/2012 to 7/2014, 54 pts were randomized and 49 were evaluable for pCR(27 P arm and 22 E arm). Tumor response by RCB is shown in the table. pCR rates were 30% and 4.5% in the P and E arm, respectively.

Table 1.ResponsePaclitaxel - FAC/FEC Arm (N=27)Eribulin - FAC/FEC Arm (N=22)RCB 0 (pCR)8 (30%)1 (4.5%)RCB I6 (22.2%)1 (4.5%)RCB II9 (33%)10 (45%)RCB III4 (14.8%)10 (45%)

53 pts were evaluable for toxicity. The combination was safe with mostly grade 1 and 2 toxicities in both arms. In the P arm grade 3 peripheral neuropathy and neutropenia was seen in 3% and 7%, respectively. In the E arm one patient died due to multiorgan failure during cycle 1. There was no other grade 3-5 toxicity. Biomarker analysis using CTCs by AdnaTest Breast were evaluated in 39 pts at baseline. 5/39 pts were positive for CTCs. 3 pts had transcripts for EpCAM, 1 for Muc-1 and another had both. 30 pts had an additional sample post therapy. 2 pts were positive for CTC at baseline as well as at follow up (FU) visit at 180 days. None of the samples showed CTC-EMT at baseline or at FU visits.

Conclusions: The interim analysis demonstrated that E arm lead to significantly lower pCR/RCB1 rate compared to P arm. Ongoing biomarker analyses include TIL, hot spot mutation analysis (HSMA) and molecular inversion probes (MIP) will be presented at the time of the meeting. Clinical trial information: NCT01593020.

Citation Format: Alvarez RH, Koenig KB, Ensor JE, Ibrahim NK, Chavez-MacGregor M, Litton JK, Schwartz Gomez JK, Cyriac A, Krishnamurty S, Caudle AS, Shaitelman SF, Whitman GJ, Booser DJ, Reuben JM, Valero V. A randomized phase II neoadjuvant (NACT) study of sequential eribulin followed by FAC/FEC-regimen compared to sequential paclitaxel followed by FAC/FEC-regimen in patients (pts) with operable breast cancer not overexpressing HER-2. [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 P1-14-04.

Abstract S3-07: Complication and economic burden of local therapy options for early breast cancer

Background: Guideline-concordant local therapy options for early breast cancer include lumpectomy plus whole breast irradiation (lump+WBI), lumpectomy plus brachytherapy (lump+brachy), mastectomy without reconstruction or radiation (mast alone), mastectomy with reconstruction without radiation (mast+recon), and, in older women, lumpectomy without radiation (lump alone). Little is known regarding the comparative complication and economic burden of these options in the general population.

Methods: We used the MarketScan database which includes younger women with private insurance and the SEER-Medicare database which includes older women with Medicare. Women were included if they had early stage disease (T1/2 N0/1 M0) diagnosed in 2000-2011, no prior cancer, and complete insurance coverage from 12 months prior through 24 months after diagnosis. A complication from local therapy was defined as a diagnosis or procedure code for any of the following within 24 months of diagnosis: wound complication, local infection, seroma/hematoma, fat necrosis, breast pain, pneumonitis, rib fracture, and implant removal. Total costs and complication-related costs within 24 months of diagnosis were calculated from a payer's perspective and are reported in 2014 dollars. Logistic regression compared complications by local therapy and generalized linear regression (log link function, gamma distribution) compared complication-related and total costs by local therapy; all models adjusted for relevant covariables.

Results: We selected 44,344 patients from the MarketScan cohort, median age of 53, and 50,562 patients from the SEER-Medicare cohort, median age of 75. For the MarketScan cohort, risk of complications varied as follows: 29% risk in patients treated with lump+WBI (referent), 44% with lump+brachy (adjusted odds ratio [AOR]=2.00;P&lt;.001), 25% with mast alone (AOR=0.85;P&lt;.001), and 54% with mast+recon (AOR=2.89;P&lt;.001). For the SEER-Medicare cohort, risk of complications varied as follows: 37% with lump+WBI (referent), 52% with lump+brachy (AOR=1.91;P&lt;.001), 37% with mast alone (AOR=0.97;P=.17), 65% with mast+recon (AOR=3.17; P&lt;.001), and 30% with lump alone (AOR=0.81; P&lt;.001). Compared to lump+WBI, mean adjusted complication-related cost was $8,085 higher per patient with mast+recon in the MarketScan cohort and $3,711 higher per patient with mast+recon in the SEER-Medicare cohort. In contrast, complication-related costs were similar (+/- $750) for all other local therapy options relative to lump+WBI in both cohorts. For total cost, mast+recon was the most expensive local therapy in the MarketScan cohort, with mean adjusted total cost of $77,321, which was $15,181 more expensive than lump+WBI. In the SEER-Medicare cohort, lump+brachy was the most expensive option ($39,534), followed by mast+recon ($35,269), lump+WBI ($32,562), mast alone ($26,401), and lump alone ($24,455).

Conclusion: Mast+recon results in the highest complication rate and complication-related cost in both younger women and older women with early breast cancer. These findings are relevant to defining which local therapies offer the highest value to patients, payers, and society, and are relevant to patients when evaluating their local therapy options.

Citation Format: Smith BD, Jiang J, Shih Y-CT, Giordano SH, Huo J, Jagsi R, Caudle AS, Hunt KK, Shaitelman SF, Buchholz TA, Shirvani SM. Complication and economic burden of local therapy options for early breast cancer. [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 S3-07.

Trends in Local Therapy Utilization and Cost for Early-Stage Breast Cancer in Older Women: Implications for Payment and Policy Reform

PURPOSE

Older women with early-stage disease constitute the most rapidly growing breast cancer demographic, yet it is not known which local therapy strategies are most favored by this population in the current era. Understanding utilization trends and cost of local therapy is important for informing the design of bundled payment models as payers migrate away from fee-for-service models. We therefore used the Surveillance, Epidemiology, and End Results Medicare database to determine patterns of care and costs for local therapy among older women with breast cancer.

METHODS AND MATERIALS

Treatment strategy and covariables were determined in 55,327 women age ≥66 with Tis-T2N0-1M0 breast cancer who underwent local therapy between 2000 and 2008. Trends in local therapy were characterized using Joinpoint. Polychotomous logistic regression determined predictors of local therapy. The median aggregate cost over the first 24 months after diagnosis was determined from Medicare claims through 2010 and reported in 2014 dollars.

RESULTS

The median age was 75. Local therapy distribution was as follows: 27,896 (50.3%) lumpectomy with external beam radiation, 18,356 (33.1%) mastectomy alone, 6159 (11.1%) lumpectomy alone, 1488 (2.7%) mastectomy with reconstruction, and 1455 (2.6%) lumpectomy with brachytherapy. Mastectomy alone declined from 39.0% in 2000 to 28.2% in 2008, and the use of breast conserving local therapies rose from 58.7% to 68.2%. Mastectomy with reconstruction was more common among the youngest, healthiest patients, whereas mastectomy alone was more common among patients living in rural low-income regions. By 2008, the costs were $36,749 for lumpectomy with brachytherapy, $35,030 for mastectomy with reconstruction, $31,388 for lumpectomy with external beam radiation, $21,993 for mastectomy alone, and $19,287 for lumpectomy alone.

CONCLUSIONS

The use of mastectomy alone in older women declined in favor of breast conserving strategies between 2000 and 2008. Using these cost estimates, price points for local therapy bundles can be constructed to incentivize the treatment strategies that confer the highest value.

Improved Axillary Evaluation Following Neoadjuvant Therapy for Patients With Node-Positive Breast Cancer Using Selective Evaluation of Clipped Nodes: Implementation of Targeted Axillary Dissection

PURPOSE

Placing clips in nodes with biopsy-confirmed metastasis before initiating neoadjuvant therapy allows for evaluation of response in breast cancer. Our goal was to determine if pathologic changes in clipped nodes reflect the status of the nodal basin and if targeted axillary dissection (TAD), which includes sentinel lymph node dissection (SLND) and selective localization and removal of clipped nodes, improves the false-negative rate (FNR) compared with SLND alone.

METHODS

A prospective study of patients with biopsy-confirmed nodal metastases with a clip placed in the sampled node was performed. After neoadjuvant therapy, patients underwent axillary surgery and the pathology of the clipped node was compared with other nodes. Patients undergoing TAD had SLND and selective removal of the clipped node using iodine-125 seed localization. The FNR was determined in patients undergoing complete axillary lymphadenectomy (ALND).

RESULTS

Of 208 patients enrolled in this study, 191 underwent ALND, with residual disease identified in 120 (63%). The clipped node revealed metastases in 115 patients, resulting in an FNR of 4.2% (95% CI, 1.4 to 9.5) for the clipped node. In patients undergoing SLND and ALND (n = 118), the FNR was 10.1% (95% CI, 4.2 to 19.8), which included seven false-negative events in 69 patients with residual disease. Adding evaluation of the clipped node reduced the FNR to 1.4% (95% CI, 0.03 to 7.3; P = .03). The clipped node was not retrieved as an SLN in 23% (31 of 134) of patients, including six with negative SLNs but metastasis in the clipped node. TAD followed by ALND was performed in 85 patients, with an FNR of 2.0% (1 of 50; 95% CI, 0.05 to 10.7).

CONCLUSION

Marking nodes with biopsy-confirmed metastatic disease allows for selective removal and improves pathologic evaluation for residual nodal disease after chemotherapy.

Contemporary Toxicity Profile of Breast Brachytherapy Versus External Beam Radiation After Lumpectomy for Breast Cancer

PURPOSE

We compared toxicities after brachytherapy versus external beam radiation therapy (EBRT) in contemporary breast cancer patients.

METHODS AND MATERIALS

Using MarketScan healthcare claims, we identified 64,112 women treated from 2003 to 2012 with lumpectomy followed by radiation (brachytherapy vs EBRT). Brachytherapy was further classified by multichannel versus single-channel applicator approach. We identified the risks and predictors of 1-year infectious and noninfectious postoperative adverse events using logistic regression and temporal trends using Cochran-Armitage tests. We estimated the 5-year Kaplan-Meier cumulative incidence of radiation-associated adverse events.

RESULTS

A total of 4522 (7.1%) patients received brachytherapy (50.2% multichannel vs 48.7% single-channel applicator). The overall risk of infectious adverse events was higher after brachytherapy than after EBRT (odds ratio [OR] = 1.21; 95% confidence interval [CI] 1.09-1.34, P<.001). However, over time, the frequency of infectious adverse events after brachytherapy decreased, from 17.3% in 2003 to 11.6% in 2012, and was stable after EBRT at 9.7%. Beyond 2007, there were no longer excess infections with brachytherapy (P=.97). The overall risk of noninfectious adverse events was higher after brachytherapy than after EBRT (OR=2.27; 95% CI 2.09-2.47, P<.0001). Over time, the frequency of noninfectious adverse events detected increased: after multichannel brachytherapy, from 9.1% in 2004 to 18.9% in 2012 (Ptrend = .64); single-channel brachytherapy, from 12.8% to 29.8% (Ptrend<.001); and EBRT, from 6.1% to 10.3% (Ptrend<.0001). The risk was significantly higher with single-channel than with multichannel brachytherapy (hazard ratio = 1.32; 95% CI 1.03-1.69, P=.03). Of noninfectious adverse events, 70.9% were seroma. Seroma significantly increased breast pain risk (P<.0001). Patients with underlying diabetes, cardiovascular disease, and treatment with chemotherapy had increased infectious and noninfectious adverse events. The 5-year incidences of fat necrosis, breast pain, and rib fracture were slightly higher after brachytherapy than after EBRT (13.7% vs 8.1%, 19.4% vs 16.0%, and 1.6% vs 1.3%, respectively), but the risks were not significantly different for multichannel versus single-channel applicators.

CONCLUSION

Toxicities after breast brachytherapy were distinct from those after EBRT. Temporal toxicity trends may reflect changing technology and evolving practitioner experience with brachytherapy.

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.

Locoregional Control According to Breast Cancer Subtype and Response to Neoadjuvant Chemotherapy in Breast Cancer Patients Undergoing Breast-conserving Therapy

BACKGROUND

Our group previously published data showing that patients could be stratified by constructed molecular subtype with respect to locoregional recurrence (LRR)-free survival after neoadjuvant chemotherapy and breast-conserving therapy (BCT). That study predated use of trastuzumab for human epidermal growth factor receptor 2 (HER2)-positive patients. The current study was undertaken to determine the impact of subtype and response to therapy in a contemporary cohort.

METHODS

Clinicopathologic data from 751 breast cancer patients who received neoadjuvant chemotherapy (with trastuzumab if HER2(+)) and BCT from 2005 to 2012 were identified. Hormone receptor (HR) and HER2 status were used to construct molecular subtypes: HR(+)/HER2(-) (n = 369), HR(+)/HER2(+) (n = 105), HR(-)/HER2(+) (n = 58), and HR(-)/HER2(-) (n = 219). Actuarial rates of LRR were determined by the Kaplan-Meier method and compared by the log-rank test. Multivariate analysis was performed to determine factors associated with LRR.

RESULTS

The pathologic complete response (pCR) rates by subtype were as follows: 16.5% (HR(+)/HER2(-)), 45.7% (HR(+)/HER2(+)), 72.4% (HR(-)/HER2(+)), and 42.0% (HR(-)/HER2(-)) (P < 0.001). Median follow-up was 4.6 years. The 5-year LRR-free survival rate for all patients was 95.4%. Five-year LRR-free survival rates by subtype were 97.2 % (HR(+)/HER2(-)), 96.1% (HR(+)/HER2(+)), 94.4% (HR(-)/HER2(+)), and 93.4% (HR(-)/HER2(-)) (P = 0.44). For patients with HR(-)/HER2(+) disease, the LRR-free survival rates were 97.4 and 86.7% for those who did and those who did not experience pCR, respectively. For patients with HR(-)/HER2(-) disease, the LRR-free survival rates were 98.6% (pCR) versus 89.9% (no pCR). On multivariate analysis, the HR(-)/HER2(-) subtype, clinical stage III disease, and failure to experience a pCR were associated with LRR.

CONCLUSIONS

Patients undergoing BCT after neoadjuvant chemotherapy have excellent rates of 5-year LRR-free survival that are affected by molecular subtype and by response to neoadjuvant chemotherapy.

The long-term risk of upper-extremity lymphedema is two-fold higher in breast cancer patients than in melanoma patients

BACKGROUND AND OBJECTIVES

We assessed the cumulative incidence, symptoms, and risk factors for upper-extremity lymphedema in breast cancer and melanoma patients undergoing sentinel lymph node biopsy or axillary lymph node dissection.

METHODS

Patients were recruited preoperatively (time 0) and assessed at 6, 12, and 18 months postoperatively. Limb volume change (LVC) was measured by perometry. Lymphedema was categorized as none, mild (LVC 5-9.9%), or moderate/severe (LVC≥10%). Symptoms were assessed with a validated lymphedema instrument. Longitudinal logistic regression analyses were conducted to identify risk factors associated with moderate/severe lymphedema.

RESULTS

Among 205 breast cancer and 144 melanoma patients, the cumulative incidence of moderate/severe lymphedema at 18 months was 36.5% and 35.0%, respectively. However, in adjusted analyses, factors associated with moderate/severe lymphedema were breast cancer (OR 2.0, P = 0.03), body mass index ≥ 30 kg/m(2) (OR 1.6, P = 0.04), greater number of lymph nodes removed (OR 1.05, P < 0.01), and longer interval since surgery (OR 2.33 at 18 months, P < 0.01).

CONCLUSIONS

Lymphedema incidence increased over time in both cohorts. However, the adjusted risk of moderate/severe lymphedema was two-fold higher in breast cancer patients. These results may be attributed to surgical treatment of the primary tumor in the breast and more frequent use of radiation.

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.

Prognosis for patients with metastatic breast cancer who achieve a no-evidence-of-disease status after systemic or local therapy

BACKGROUND

This study sought to determine outcomes for patients with metastatic breast cancer (MBC) with no evidence of disease (NED) after treatment and to identify factors predictive of outcomes once the status of NED was attained.

METHODS

This study reviewed 570 patients with MBC who were consecutively treated between January 2003 and December 2005. Ninety patients (16%) attained NED, which was defined as a complete metabolic response on positron emission tomography or sclerotic healing of bone metastases on computed tomography or magnetic resonance imaging. The median follow-up for patients attaining NED was 100 months (range, 14-134 months).

RESULTS

The 3- and 5-year overall survival (OS) rates were 44% and 24%, respectively, for the entire group and 96% and 78%, respectively, for those attaining NED. According to a landmark analysis, NED status was significantly associated with survival at 2 (P < .001; hazard ratio [HR], 0.23; 95% confidence interval [CI], 0.16-0.34) and 3 years (P < .001; HR, 0.20; 95% CI, 0.14-0.30). From the time of NED, the median survival was 102 months (range, 14-134 months) with 5-year OS and progression-free survival (PFS) rates of 77% and 40%, respectively. According to a multivariate analysis, human epidermal growth factor receptor 2 positivity was significantly associated with OS in comparison with estrogen receptor positivity (P = .02; HR, 0.44; 95% CI, 0.21-0.90), and trastuzumab use was significantly associated with PFS (P = .007; HR, 0.48; 95% CI, 0.28-0.82). Thirty-one patients (34%) with NED remained in remission at the last follow-up.

CONCLUSIONS

MBC patients who attain the status of NED have significantly prolonged survival with a durable response to therapy. Ultimately, this study provides essential outcome data for clinicians and patients living with MBC.

Role of Ultrasonography of Regional Nodal Basins in Staging Triple-Negative Breast Cancer and Implications For Local-Regional Treatment

PURPOSE

We sought to determine the rate at which regional nodal ultrasonography would increase the nodal disease stage in patients with triple-negative breast cancer (TNBC) beyond the clinical stage determined by physical examination and mammography alone, and significantly affect the treatments delivered to these patients.

METHODS AND MATERIALS

We retrospectively reviewed the charts of women with stages I to III TNBC who underwent physical examination, mammography, breast and regional nodal ultrasonography with needle biopsy of abnormal nodes, and definitive local-regional treatment at our institution between 2004 and 2011. The stages of these patients' disease with and without ultrasonography of the regional nodal basins were compared using the Pearson χ(2) test. Definitive treatments of patients whose nodal disease was upstaged on the basis of ultrasonographic findings were compared to those of patients whose disease stage remained the same.

RESULTS

A total of 572 women met the study requirements. In 111 (19.4%) of these patients, regional nodal ultrasonography with needle biopsy resulted in an increase in disease stage from the original stage by physical examination and mammography alone. Significantly higher percentages of patients whose nodal disease was upstaged by ultrasonographic findings compared to that in patients whose disease was not upstaged underwent neoadjuvant systemic therapy (91.9% and 51.2%, respectively; P<.0001), axillary lymph node dissection (99.1% and 34.5%, respectively; P<.0001), and radiation to the regional nodal basins (88.2% and 29.1%, respectively; P<.0001).

CONCLUSIONS

Regional nodal ultrasonography in TNBC frequently changes the initial clinical stage and plays an important role in treatment planning.

Abstract P3-08-01: Gamma-ray induced mutagen sensitivity and overall survival in young women with breast cancer

Background:

Hypersensitivity to radiation has been shown to be a risk factor for the development of breast cancer. We aim to determine whether the same hypersensitivity predicts for adverse clinical outcomes in patients diagnosed with carcinoma of the breast.

Methods:

465 young, female, non-Hispanic white patients diagnosed with carcinoma of the breast at our institution from 1/1997 to 12/2005 were included in this study. All cases were histologically confirmed and all blood was drawn prior to any systemic or local therapy. Patient age, body mass index (BMI), menopause status, tumor laterality, AJCC stage, ER status, nuclear grade, and receipt of chemotherapy and radiation were extracted from patient medical records. A gamma-ray-induced mutagen sensitivity assay was performed using standard published methods to evaluate individual responses to radiation. The number of simple chromatid breaks per sample was counted from 50 well-spread metaphases. Each simple chromatid break was counted as a single break and each isochromatid break, exchange figure, or interstitial deletion as two breaks. The mean value of chromatid breaks per cell (b/c) was then calculated and recorded. Cox multivariable proportional hazards model was used to estimate the hazard ratio (HR) and 95% confidence interval (CI) for the association between b/c and overall survival.

Results:

A total of 402 patients had a b/c value recorded and were included in the final analysis. The patient median age was 46 years (range 22-55). 341 patients (84.8%) had invasive cancer and 253 patients (69.9%) had ER+ disease. AJCC stage distribution was stage 0 (15.2%), stage 1 (41.5%), stage 2 (33.5%), stage 3 (9.5%) and stage 4 (0.3%). The median follow-up for all patients was 97.2 months (interquartile range, IQR 83.3-119.6 months). The median b/c was 0.5 (IQR 0.38-0.62). The 5 and 10-year survival for all patients was 92.6% and 87.5%. A statistically significant decrease in 5 and 10-year overall survival was seen in patients with b/c greater than the median value of 0.5 (96.2% vs. 89.2%, p=.007 and 90.8% vs. 84.5%, p=.046, respectively). On multivariable analysis (MVA), age at diagnosis (HR 0.95, CI 0.91-0.99, p=.017), BMI (HR 1.07, CI 1.03-1.12, p=.003), ER status (HR= 0.31, CI 0.16-0.61, p=.01), AJCC stage (HR 1.91, CI 1.2-3.0, p=.006), and b/c level (HR 5.67, CI 1.5-18.2, p=.01) all predicted for overall survival. Excluding the 61 patients with in situ disease, there remains a significant difference in survival at both 5 and 7 years (95.5% vs. 88.5%, p=.017 and 93.5% vs. 86%, p=.021). A trend for decrease survival was seen at 10 years (p=0.09). On MVA for patients with invasive disease, age at diagnosis (HR=0.95, 95% CI 0.91-0.99, p=.026), BMI (HR=1.06, 95% CI 1.01-1.11, p=.023), AJCC stage (HR=2.41, CI 1.51-3.91, p=.0003), and ER status (HR=0.25, CI 0.12-0.49, p&lt; .0001) and b/c level (HR=3.76, CI 1.39-8.06, p=.012) were associated with overall survival.

Conclusions:

In this cohort of young, female, non-Hispanic white breast cancer patients, a greater b/c level predicted for decreased overall survival. The use of a gamma-ray-induced mutagen sensitivity assay may be prognostic and help select for those at increased risk of death.

Citation Format: Michael C Stauder, Simona F Shaitelman, Pamela K Allen, Abenaa M Brewster, Banu K Arun, Wendy A Woodward, Thomas A Buchholz, Li-E Wang. Gamma-ray induced mutagen sensitivity and overall survival in young women with breast cancer [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 P3-08-01.

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.

The 21-gene recurrence score complements IBTR! Estimates in early-stage, hormone receptor-positive, HER2-normal, lymph node-negative breast cancer

Clinicians have traditionally used clinicopathological (CP) factors to determine locoregional recurrence (LR) risk of breast cancer and have generated the IBTR! nomogram to predict the risk of ipsilateral breast tumor recurrence (IBTR). The 21-gene recurrence score (RS) assay was recently correlated with LR in retrospective studies. The objective of this study was to examine the relationship between the RS and IBTR!. CP characteristics of 308 consecutive patients who underwent RS testing at our institution were examined. IBTR! was used to estimate the risk of 10-year IBTR. Descriptive statistics were used to compare the RS with the estimated IBTR!. Given a low event rate in this cohort, actual IBTR rates were not reported. Most patients had stage I/II (98%) and grade I/II (77%) disease. Median age was 54 years (range, 30–78). Median IBTR! without radiation therapy was 10% (mean, 12% [range, 4-43%]). RS was low (<18), intermediate (18–30), and high (>30) in 52% (n = 160), 40% (n = 123), and 8% (n = 25) patients. Overall, IBTR! did not correlate with RS (P = .77). We saw no correlation between RS and IBTR! in patients with less than (P = .32) or greater than (P = .48) a 10% risk of IBTR. Interestingly, Ki-67 expression correlated with both IBTR! (P = .019) and the RS (P = .002). Further study is warranted to determine if the RS can provide complementary biological information to CP factors in estimating the risk of LR. Prospective studies evaluating this association may potentially allow for individualized treatment decisions.

Recent progress in the treatment and prevention of cancer-related lymphedema

This article provides an overview of the recent developments in the diagnosis, treatment, and prevention of cancer-related lymphedema. Lymphedema incidence by tumor site is evaluated. Measurement techniques and trends in patient education and treatment are also summarized to include current trends in therapeutic and surgical treatment options as well as longer-term management. Finally, an overview of the policies related to insurance coverage and reimbursement will give the clinician an overview of important trends in the diagnosis, treatment, and management of cancer-related lymphedema.

Timing of infectious complications following breast-conserving therapy with catheter-based accelerated partial breast irradiation

BACKGROUND

Accelerated partial breast irradiation (APBI) has been used as an alternative to whole-breast irradiation as part of breast-conserving therapy. Indications and outcomes are topics of ongoing investigation. Previous publications have focused on early postoperative infections and reported low rates of delayed infection. We investigated the pattern of infection after catheter-based APBI at our institution.

METHODS

Patients who underwent single-entry catheter-based APBI were identified from an institutional prospective registry including data regarding comorbidities and outcomes. Time of infection was calculated from the date of definitive catheter insertion and classified as early (≤30 days) or delayed.

RESULTS

A total of 91 breast cancer patients were treated with APBI and enrolled in the registry from 2009 to 2011. The median follow-up was 484 days. Breast infection occurred in 13 (14.3 %), with 3 (3.3 %) occurring within 30 days of catheter placement and 10 (11.0 %) in a delayed fashion. Four patients required hospital admission, five underwent percutaneous aspiration, and one underwent incision and drainage. Eight were treated as outpatients with oral antibiotics alone.

CONCLUSIONS

Consistent with other reports, we found an overall infection rate of 14.3 % with single-entry catheter-based APBI. There were substantially fewer infections in the early postoperative period than reported elsewhere, but there were more delayed infections. The intensive follow-up in our study likely identified late infections that may not have otherwise been recognized. Vigilance for infectious complications must continue beyond the immediate treatment period in patients undergoing catheter-based APBI. These infections can range in severity but typically can be managed in an outpatient setting.

Underuse of trimodality treatment affects survival for patients with inflammatory breast cancer: an analysis of treatment and survival trends from the National Cancer Database

PURPOSE

To analyze factors that predict the use of trimodality treatment (chemotherapy, surgery, and radiation therapy [RT]) and evaluate the impact that trimodality treatment use has on survival for patients with inflammatory breast cancer (IBC).

METHODS

Using the National Cancer Data Base, patients who underwent surgical treatment of nonmetastatic IBC from 1998 to 2010 were identified. We collected demographic, tumor, and treatment data and analyzed treatment and survival trends over time. Logistic regression and Cox proportional hazard models were used to examine factors predicting treatment and survival.

RESULTS

We identified 10,197 patients who fulfilled study criteria. The use of trimodality therapy fluctuated annually (58.4% to 73.4%). Patients who were older, diagnosed earlier in the study period, lived in regions of the country outside of the Midwest, had lower incomes or public insurance, and had a higher comorbid score were significantly less likely to receive trimodality therapy (all P < .05). Five- and 10-year survival rates were highest among patients receiving trimodality treatment (55.4% and 37.3%, respectively) compared with patients who received the combination of surgery plus chemotherapy, surgery plus RT, or surgery alone. After adjusting for potential confounding variables, use of trimodality therapy remained a significant independent predictor of survival.

CONCLUSION

Underutilization of trimodality therapy negatively impacted survival for patients with IBC. The use of trimodality therapy increased marginally with time, but there remain significant factors associated with differences in use of trimodality treatment. We have identified specific barriers to care that may be targeted to improve treatment delivery and potentially improve patient outcomes.

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.

Therapeutic radiation dose delivered to the low axilla during whole breast radiation therapy in the prone position: implications for targeting the undissected axilla

PURPOSE

One interpretation of the American College of Surgeons Oncology Group Z0011 trial is that whole breast radiation therapy, known to treat a portion of the low axilla when delivered in the supine position, can treat residual microscopic disease in patients with involved axillary nodes that were not removed by axillary dissection. The purpose of this study was to quantify radiation dose delivered to the axilla for patients treated in the prone position.

METHODS AND MATERIALS

We analyzed treatment plans from 40 consecutive patients who received radiation targeting the intact breast with tangent fields in the prone position. Axillary levels were contoured using Radiation Therapy Oncology Group (RTOG) definitions and radiation dose- volume calculations were made for axillary levels, heart, and lungs. We generated revised plans for 10 patients by modifying the tangent beams to increase axillary dose and compared original with modified plans.

RESULTS

The median proportion of the axilla covered by 90% of the prescription dose was 13% of level I (range, 0%-61%), 0% of level II (range, 0%-6%), and 0% of level III (range, 0%-0%). More of the level I axilla was covered in obese compared with nonobese patients (P = .013). Level I coverage did not differ significantly by laterality (P = .740) or tumor location (P = .527). Modification of the treatment plans significantly increased level I coverage (P = .005) with all modified plans delivering 90% of the prescription dose to at least 96% of the level I axilla. The modified plans had increased lung (P = .005) and heart (P = .028) dose, which were within acceptable RTOG normal tissue constraints.

CONCLUSIONS

Most patients treated with standard whole breast tangential radiation in the prone position receive subtherapeutic dose to the level I and II axilla. Patients treated in the prone position who require therapeutic radiation dose to the low axilla need treatment field modification; this is feasible for many patients using tangent fields.

Abstract P5-14-07: Comparison of infectious complications between breast conserving therapy with catheter-based accelerated partial irradiation and whole breast irradiation

Standard treatment after breast conserving surgery (BCS) has been whole breast irradiation (WBI), however, accelerated partial breast irradiation (APBI) has recently been shown to be an alternative in a select group of patients. APBI has been associated with early postoperative as well as delayed infections. In the current study, we compared rates of infectious complications between patients treated with catheter-based APBI and WBI.

Patients were identified from a single-institution prospective registry from 2009 to 2011. Selection criteria included patients who underwent BCT with either single-entry APBI or WBI and fulfilled criteria for ABPI including ≥50 years, tumor size ≤ 3cm, pN0, and no lympho-vascular invasion. Data regarding treatment, patient comorbidities, and outcomes were obtained. Infectious complications were assessed from the date of APBI catheter insertion or from the date of surgery to start of WBI. Infectious complications were classified as early (≤ 30 days) or delayed (&gt; 30 days). Fisher's exact test was used to compare the rate of infection between APBI and WBI.

91 patients were treated with single-entry catheter-based APBI and 267 patients were treated with WBI. Median follow-up time was 76.2 weeks for APBI patients and 115 weeks for WBI patients. Re-excision was required in 20 patients (21.7%) who underwent APBI and in 51 patients (19.1%) who underwent WBI. Overall, infection occurred in 13 patients (14.1%) who underwent APBI versus 39 patients (14.6%) who underwent WBI. In the APBI group, three (3.3%) patients had infection within 30 days and 10 (10.9%) had infection more than 30 days after catheter insertion. 24 (9.0%) patients had infections within 30 days after surgery and 15 (5.6%) patients occurred more than 30 days after surgery in the WBI group. Patients began WBI within an average of 84 days after surgery. In the APBI group, 4 patients required hospital admission, 5 patients had percutaneous aspiration, and one needed incision and drainage. 8 patients were managed with outpatient oral antibiotics. In the WBI group, 5 patients required hospital admission, 13 patients had percutaneous aspiration, and 30 patients were managed with outpatient oral antibiotics. Diabetes, smoking, and BMI &gt;25 were factors commonly associated with infectious complications in both APBI and WBI but not statistically significant (P = 0.6, 0.09, 0.1. respectively).

In contrast to other studies showing that patients treated with catheter-based APBI have higher rates of infection than patients treated with WBI, our study found no statistically significant difference in infection rates between the two groups. A majority of infections following APBI or WBI can be medically managed as an outpatient basis.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-14-07.

Accelerated partial-breast irradiation using intensity-modulated proton radiotherapy: do uncertainties outweigh potential benefits?

OBJECTIVE

Passive scattering proton beam (PSPB) radiotherapy for accelerated partial-breast irradiation (APBI) provides superior dosimetry for APBI three-dimensional conformal photon radiotherapy (3DCRT). Here we examine the potential incremental benefit of intensity-modulated proton radiotherapy (IMPT) for APBI and compare its dosimetry with PSPB and 3DCRT.

METHODS

Two theoretical IMPT plans, TANGENT_PAIR and TANGENT_ENFACE, were created for 11 patients previously treated with 3DCRT APBI and were compared with PSPB and 3DCRT plans for the same CT data sets. The impact of range, motion and set-up uncertainties as well as scanned spot mismatching between fields of IMPT plans was evaluated.

RESULTS

IMPT plans for APBI were significantly better regarding breast skin sparing (p<0.005) and other normal tissue sparing than 3DCRT plans (p<0.01) with comparable target coverage (p=ns). IMPT plans were statistically better than PSPB plans regarding breast skin (p<0.002) and non-target breast (p<0.007) in higher dose regions but worse or comparable in lower dose regions. IMPT plans using TANGENT_ENFACE were superior to that using TANGENT_PAIR in terms of target coverage (p<0.003) and normal tissue sparing (p<0.05) in low-dose regions. IMPT uncertainties were demonstrated for multiple causes. Qualitative comparison of dose-volume histogram confidence intervals for IMPT suggests that numeric gains may be offset by IMPT uncertainties.

CONCLUSION

Using current clinical dosimetry, PSPB provides excellent dosimetry compared with 3DCRT with fewer uncertainties compared with IMPT.

ADVANCES IN KNOWLEDGE

As currently delivered in the clinic, PSPB planning for APBI provides as good or better dosimetry than IMPT with less uncertainty.

Accelerated partial-breast irradiation: the current state of our knowledge

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. Accelerated partial-breast irradiation (APBI) is a shorter, alternative radiation technique for select patients with favorable early-stage breast cancer. We review here the different modalities of APBI delivery and discuss the possible benefits and harms associated with these treatments.

Abstract P4-15-02: Timing of infectious complications following breast conserving therapy with catheter-based accelerated partial breast irradiation

Background: Accelerated partial breast irradiation (APBI) has been introduced as an alternative to whole breast irradiation as part of breast conserving therapy for selected patients. The long-term outcomes remain under investigation. Previous publications have emphasized early postoperative infections with APBI with less focus on delayed infection. In the current study, we evaluated patients enrolled on a prospective registry trial for infectious complications after treatment with catheter-based APBI.

Methods: Patients who underwent single-entry catheter-based APBI were identified from a single-institution prospective registry from 2009 to 2011. Data regarding treatment, patient comorbidities, complications, and outcomes were obtained from registry and retrospective chart review. Infectious complications were assessed from the date of APBI catheter insertion and were classified as early (≤30 days) or delayed (&gt;30 days). All patients were maintained on oral antibiotics while the catheter was in place.

Results: A total of 91 patients with 92 cases of primary breast cancer were enrolled on a prospective registry at a comprehensive cancer center between 2009 and 2011 and treated with single-entry catheter-based APBI. The median follow-up time was 76.2 weeks. A temporary catheter was placed at the time of initial operation in 40 cases (43.5%) and left in place a median of 6 days prior to definitive catheter insertion. There were 20 patients (21.7%) who required re-excision. Overall, breast infection occurred in 13 (14.1%) patients. Three (3.3%) patients had infection within 30 days of catheter placement and 10 (10.9%) occurred more than 30 days after catheter insertion (median 112.5 days, interquartile range 51–154). Eight patients were managed with oral antibiotics alone on an outpatient basis. The remainder required a combination of admission, intravenous antibiotics, and aspiration of abscess. One patient underwent operative drainage.

Conclusion: We found an overall infection rate of 14.1% in patients treated with catheter-based APBI. This is consistent with other reports; however, we found that the majority of infections occurred more than 30 days after definitive catheter placement. Vigilance for infectious complications must continue beyond the immediate treatment period in patients undergoing catheter-based APBI. Most infections following APBI can be managed on an outpatient basis without operative intervention.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-15-02.

Evaluation of current consensus statement recommendations for accelerated partial breast irradiation: a pooled analysis of William Beaumont Hospital and American Society of Breast Surgeon MammoSite Registry Trial Data

PURPOSE

To determine whether the American Society for Radiation Oncology (ASTRO) Consensus Statement (CS) recommendations for accelerated partial breast irradiation (APBI) are associated with significantly different outcomes in a pooled analysis from William Beaumont Hospital (WBH) and the American Society of Breast Surgeons (ASBrS) MammoSite® Registry Trial.

METHODS AND MATERIALS

APBI was used to treat 2127 cases of early-stage breast cancer (WBH, n=678; ASBrS, n=1449). Three forms of APBI were used at WBH (interstitial, n=221; balloon-based, n=255; or 3-dimensional conformal radiation therapy, n=206), whereas all Registry Trial patients received balloon-based brachytherapy. Patients were divided according to the ASTRO CS into suitable (n=661, 36.5%), cautionary (n=850, 46.9%), and unsuitable (n=302, 16.7%) categories. Tumor characteristics and clinical outcomes were analyzed according to CS group.

RESULTS

The median age was 65 years (range, 32-94 years), and the median tumor size was 10.0 mm (range, 0-45 mm). The median follow-up time was 60.6 months. The WBH cohort had more node-positive disease (6.9% vs 2.6%, P<.01) and cautionary patients (49.5% vs 41.8%, P=.06). The 5-year actuarial ipsilateral breast tumor recurrence (IBTR), regional nodal failure (RNF), and distant metastasis (DM) for the whole cohort were 2.8%, 0.6%, 1.6%. The rate of IBTR was not statistically higher between suitable (2.5%), cautionary (3.3%), or unsuitable (4.6%) patients (P=.20). The nonsignificant increase in IBTR for the cautionary and unsuitable categories was due to increased elsewhere failures and new primaries (P=.04), not tumor bed recurrence (P=.93).

CONCLUSIONS

Excellent outcomes after breast-conserving surgery and APBI were seen in our pooled analysis. The current ASTRO CS guidelines did not adequately differentiate patients at an increased risk of IBTR or tumor bed failure in this large patient cohort.

Accelerated partial breast irradiation

Whole breast irradiation (WBI) is the standard after breast conservation surgery. However, WBI in selected patients has been questioned. Accelerated partial breast irradiation (APBI) focuses treatment on the lumpectomy bed. Many modalities of delivering APBI have been developed: multicatheter interstitial brachytherapy, MammoSite balloon catheter, single insertion multicatheter devices, three-dimensional conformal external-beam radiation therapy and intraoperative techniques. Numerous studies of APBI have demonstrated excellent local control and cosmetic outcomes in early-stage breast cancer patients.

Abstract P4-10-04: Rates of Second Malignancies after Definitive Local Treatment for Ductal Carcinoma In Situ of the Breast

Background: We analyzed the risk of developing second malignancies in patients with ductal carcinoma in situ (DCIS) undergoing surgery and radiotherapy (S+RT) versus surgery alone (S).

Material and Methods: The S+RT cohort consisted of 256 women treated with breast conserving therapy at William Beaumont Hospital. The S cohort consisted of 2,788 women with DCIS in the regional SEER database treated during the same time period. A matched-pair analysis was performed in which each S+RT patient was randomly matched with 8 S patients (total of 2048 patients). Matching criteria included age +/− 2 years. The rates of second malignancies were analyzed overall and as contralateral breast versus non-breast cancers and by organ system. Results: Median follow-up was 13.7 years for the S+RT cohort and 13.3 years for the S cohort. The overall 10-/15-year rate of second malignancies among the S+RT and S cohorts were 14.2%/24.2% and 16.4%/22.6%, respectively (p=0.668). The 15-year second contralateral breast cancer rate was 14.2% in the S+RT cohort and 10.3% in the S cohort (p=0.439). The 15- year risk of a second non-breast malignancy was 14.2% for the S+RT cohort and 13.4% for the S alone cohort (p=0.660). When analyzed by organ system, the 10- and 15-year rates of second malignancies did not differ between the S+RT and the S cohorts for pulmonary, gastrointestinal, central nervous system, gynecological, genitourinary, lymphoid, sarcomatoid, head and neck, or unknown primary tumors.

Discussion: Compared with S alone, S +RT was not associated with an overall increased risk of second malignancies in women with DCIS.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-10-04.

Rates of second malignancies after definitive local treatment for ductal carcinoma in situ of the breast

PURPOSE

We analyzed the risk of second malignancies developing in patients with ductal carcinoma in situ (DCIS) undergoing surgery and radiotherapy (S+RT) vs. surgery alone.

METHODS AND MATERIALS

The S+RT cohort consisted of 256 women treated with breast-conserving therapy at William Beaumont Hospital. The surgery alone cohort consisted of 2,788 women with DCIS in the regional Surveillance, Epidemiology, and End Results database treated during the same time period. A matched-pair analysis was performed in which each S+RT patient was randomly matched with 8 surgery alone patients (total of 2,048 patients). Matching criteria included age±2 years. The rates of second malignancies were analyzed overall and as contralateral breast vs. non-breast cancers and by organ system.

RESULTS

Median follow-up was 13.7 years for the S+RT cohort and 13.3 years for the surgery alone cohort. The overall 10-/15-year rates of second malignancies among the S+RT and surgery alone cohorts were 14.2%/24.2% and 16.4%/22.6%, respectively (p=0.668). The 15-year second contralateral breast cancer rate was 14.2% in the S+RT cohort and 10.3% in the surgery alone cohort (p=0.439). The 15-year risk of a second non-breast malignancy was 14.2% for the S+RT cohort and 13.4% for the surgery alone cohort (p=0.660). When analyzed by organ system, the 10- and 15-year rates of second malignancies did not differ between the S+RT and surgery alone cohorts for pulmonary, gastrointestinal, central nervous system, gynecologic, genitourinary, lymphoid, sarcomatoid, head and neck, or unknown primary tumors.

CONCLUSIONS

Compared with surgery alone, S+RT is not associated with an overall increased risk of second malignancies in women with DCIS.

Continuous arc rotation of the couch therapy for the delivery of accelerated partial breast irradiation: a treatment planning analysis

PURPOSE

We present a novel form of arc therapy: continuous arc rotation of the couch (C-ARC) and compare its dosimetry with three-dimensional conformal radiotherapy (3D-CRT), intensity-modulated radiotherapy (IMRT), and volumetric-modulated arc therapy (VMAT) for accelerated partial breast irradiation (APBI). C-ARC, like VMAT, uses a modulated beam aperture and dose rate, but with the couch, not the gantry, rotating.

METHODS AND MATERIALS

Twelve patients previously treated with APBI using 3D-CRT were replanned with (1) C-ARC, (2) IMRT, and (3) VMAT. C-ARC plans were designed with one medial and one lateral arc through which the couch rotated while the gantry was held stationary at a tangent angle. Target dose coverage was normalized to the 3D-CRT plan. Comparative endpoints were dose to normal breast tissue, lungs, and heart and monitor units prescribed.

RESULTS

Compared with 3D-CRT, C-ARC, IMRT, and VMAT all significantly reduced the ipsilateral breast V50% by the same amount (mean, 7.8%). Only C-ARC and IMRT plans significantly reduced the contralateral breast maximum dose, the ipsilateral lung V5Gy, and the heart V5%. C-ARC used on average 40%, 30%, and 10% fewer monitor units compared with 3D-CRT, IMRT, and VMAT, respectively.

CONCLUSIONS

C-ARC provides improved dosimetry and treatment efficiency, which should reduce the risks of toxicity and secondary malignancy. Its tangent geometry avoids irradiation of critical structures that is unavoidable using the en face geometry of VMAT.