Phase II Trial of Definitive Therapy for Osseous Oligometastases in Breast Cancer

PURPOSE/OBJECTIVE(S)

Phase II data for consolidative local therapy for oligometastatic disease demonstrated improved outcomes for various malignancies. However, a randomized phase II study of oligometastatic breast cancer patients testing predominantly ablative dose radiotherapy (RT) did not demonstrate progression-free survival (PFS) benefit. We conducted a single-arm phase II trial evaluating local therapy as part of the multidisciplinary management of breast cancer patients with limited bone metastases.

MATERIALS/METHODS

Patients with synchronous (n = 15) and metachronous (n = 15) oligometastatic breast cancer involving ≤3 osseous sites were enrolled from July 2009 to April 2016 and treated to a total of 44 bone metastases. The trial closed early due to slow accrual. Following ≤9 months of systemic therapy, local therapy entailed surgery (n = 3) or RT delivered via conventional fractionation (≥60 Gy, n = 36) or stereotactic technique (27 Gy/3 fractions for spine mets, n = 6). When indicated, RT to the primary was delivered concurrently (n = 15). The primary endpoint was to determine PFS. Secondary endpoints were overall survival (OS), local control (LC) and toxicity. Outcomes were evaluated with Kaplan-Meier and univariate Cox proportional hazards analyses.

RESULTS

Of the 30 patients included in the trial, 23 (77%) had ER+ or PR+/HER2- disease, 4 (13%) had Her2+ disease, and 3 (10%) were triple negative. Median age was 53, and 20 patients (67%) presented with 1 distant metastasis. A total of 21 patients (70%) experienced disease progression at a median 20.5 months (IQR: 8.2-41.2), including 5 local failures among 44 treated bone metastases (11%). At a median follow-up of 76.7 mon (IQR: 45.4-108.8), the median PFS was 37.8 mon, with 2- and 5-year rates (95% CI) of 60% (45-80%) and 32% (19-55%), respectively. The 2- and 5-year OS rates were 93% (85-100%) and 64% (48-85%), respectively, and the 2- and 5-year LC rates were 91% (80-100%) and 71% (51-98%). For patients who achieved LC, median PFS was 47.7 months (IQR 12.2-73.0). Twenty-one patients (70%) received cytotoxic chemotherapy with or without endocrine therapy for newly diagnosed oligometastatic disease. Nine patients (30%) were still alive with no evidence of disease (NED) at a median 96.9 mon (range: 47.7-158.6). PFS was worse among triple negative patients (p = 0.03), with no difference based on synchronous vs non-synchronous presentation (p = 0.10), receipt of cytotoxic chemotherapy prior to definitive therapy (p = 0.08) or Her2+ status (p = 0.21). There were no Grade ≥3 adverse events.

CONCLUSION

Definitive, predominantly conventionally fractionated local therapy was associated with long-term NED status for 30% of patients with oligometastatic breast cancer involving osseous sites, with minimal treatment-associated toxicity. Developing randomized trials for breast cancer subsets may warrant consideration of standard fractionation regimen data and the need for strategies to identify patients who may benefit from definitive local therapy.

Abstract P2-11-12: Prospective comparison of late toxicity and cosmetic outcome after accelerated partial breast irradiation with conformal external beam radiotherapy or single-entry multi-lumen intracavitary brachytherapy

Purpose/Objective(s):

To prospectively compare late toxicity after accelerated partial breast irradiation (APBI) with 3D-conformal external beam radiotherapy (3D-CRT) or single-entry multi-lumen intracavitary brachytherapy.

Patients/Methods:

Two hundred eighty-one patients with pTis or pT2N0 (≤3.0 cm) breast cancer treated with segmental mastectomy were prospectively enrolled on a multi-institution observational protocol from 12/2008 – 8/2014. Patients were enrolled and treated at primary, satellite, and affiliated academic institutions. APBI was delivered using 3D-CRT or with a Contura®, MammoSite®, or SAVI® brachytherapy catheter. 3D-CRT patients were treated to 34.0 Gy (7%) or 38.5 Gy (93%) at 3.4-3.85 Gy/fx BID and brachytherapy patients were treated to 34.0 Gy at 3.4 Gy/fx BID. Per protocol, patients were clinically evaluated at 2, 6, 12, 18, and 24 months and then annually. At each clinical evaluation the radiation oncologist scored cosmetic outcome (excellent/good/fair/poor according to the Harvard Cosmesis Scale), toxicity (seroma/infection/fat necrosis/pain/telangiectasia/radiation dermatitis/hyperpigmentation/hypopigmentation/fibrosis/induration/edema/other according to CTCAE v3.0) and recurrence status.

Results:

The median age was 61 years. Of 281 patients, 211 (75%) had invasive breast cancer and 70 (25%) had in situ disease. Among patients with invasive disease, 90% were HR+/HER2-, and among patients with in situ disease, 83% were HR+. APBI was delivered with 3D-CRT in 29 (10%) patients and with single-entry multi-lumen intracavitary brachytherapy in 252 (90%) patients. Among the brachytherapy patients, APBI was delivered with the SAVI®, Contura®, and MammoSite® devices in 176 (70%), 56 (22%), and 20 (8%) patients, respectively. With a median follow-up of 49 months, rates of Grade 1 (G1) and Grade 2-3 (G2-3) toxicity are:

 3D-CRTBrachytherapy   G1G2-3G1G2-3G1G2-3 N (%)N (%)N (%)N (%)  Fibrosis13 (46%)1 (4%)176 (72%)6 (2%)p=0.008p=0.54Fat Necrosis0 (0%)0 (0%)0 (0%)4 (2%)p=1.00p=1.00Telangiectasia6 (21%)1 (4%)44 (18%)5 (2%)p=0.61p=0.48Seroma2 (7%)1 (4%)135 (55%)12 (5%)p<0.0001p=1.00

Mean skin dose of the maximally-irradiated 0.1 cc (D0.1cc) of skin was significantly higher in patients who developed telangiectasia (103.4% ± 16.1% compared to 96.5% ± 18.6% of prescription dose, p=0.007) and fibrosis (100.1% ± 15.5% compared to 92.8% ± 23.0% of prescription dose, p=0.02). Crude rates of fair or poor cosmetic outcome at 2-4 and 4-6 years were 6.9% and 14.8%, respectively, for 3D-CRT and 14.8% and 21.3%, respectively, for brachytherapy (p>0.05 at both timepoints). Five-year recurrence-free survival was 96.3% with 3D-CRT and 96.1% for brachytherapy (p>0.05).

Conclusion:

APBI with single-entry multi-lumen intracavitary brachytherapy is associated with increased rates of grade 1 fibrosis and seroma than APBI with 3D-CRT. Higher mean skin D0.1cc is associated with increased risk of telangiectasia and fibrosis. Despite increased low-grade fibrosis, there is no significant difference in radiation oncologist-reported fair or poor cosmetic outcome out to six years, or rate of five-year ipsilateral breast recurrence.

Citation Format: Stecklein SR, Babiera GV, Bedrosian I, Shaitelman SF, Ballo MT, Tereffe W, Arzu IY, Perkins GH, Strom EA, Reed VK, Dvorak T, Smith BD, Woodward WA, Hoffman KE, Schlembach PJ, Chronowski GM, Shah SJ, Kirsner SM, Nelson CL, Guerra W, Dibaj SS, Bloom ES. Prospective comparison of late toxicity and cosmetic outcome after accelerated partial breast irradiation with conformal external beam radiotherapy or single-entry multi-lumen intracavitary brachytherapy [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-11-12.

Abstract P5-14-08: Prospective phase II study of concurrent capecitabine and radiation demonstrates futility in triple negative chemo-resistant breast cancer

Background: Capecitabine is an established radiosensitizer in rectal and other cancers. We conducted a prospective single arm phase II study to examine the response rate of gross chemo-refractory breast cancer treated with concurrent capecitabine and radiotherapy.

Methods: Patients who had inoperable or marginally operable gross disease in the breast and/or lymph node(s) after chemotherapy or gross disease on the chest wall or in the regional lymphatics after mastectomy were eligible. Patients 1-9 received capecitabine 825 mg/m2 BID daily beginning on the first day of radiotherapy. Excess grade 3 toxicity (%) was observed; the protocol was amended and subsequent patients received drug only on radiation treatment days. Radiation dose was at the discretion of the treating physician (50Gy-72 Gy, with no more than 2.5 Gy/fraction). Response was assessed by a single physician using paired radiation planning CTs (pretreatment and on-treatment after 45 Gy). Clinical correlation to all other available imaging was also made. Kaplan-Meier curves were used to estimate overall survival (OS) and local recurrence-free survival (LRFS). Circulating tumor cells (CTCs) in blood were examined in consenting patients.

Results: The trial was stopped early after an unplanned interim analysis prompted by slow accrual suggested futility independent of response. From 2009-2012, 32 patients were accrued; 26 completed protocol specific treatment (17 post-mastectomy radiation with gross nodes, 4 pre-op, 5 aggressive palliation) and are included in this analysis. Median follow up was 7.3 months (interquartile range 6.7 – 17.4). Nineteen patients (73%) had a partial or complete response. Fourteen patients (53.9%) experienced at least one grade 3 non-dermatitis toxicity including 7/9 treated with continuous dosing. Four inoperable patients were treated with pre-op radiation therapy and 3 converted to operable. None achieved a pCR or near pCR. One-year actuarial OS was 52%. There was no difference in OS comparing among PMRT vs. preoperative or palliative RT (P = 0.90). One-year actuarial local recurrence free survival among PMRT patients was 38%. Ten patients had triple negative (TN) receptor status. There was no difference in radiation response by receptor status (P = 0.56); however, treatment was deemed subjectively futile (i.e., converted to operable but death secondary to new widespread M1 disease immediately post-op) in 9 of the 10 patients with TN disease versus 6 of the 16 patients with non-TN disease (P = 0.014). Median OS and 1-yr actuarial OS, among non-TN vs. TN patients were not reached vs. 6.1 months and 77% vs. 10% (P < 0.001), respectively. Eight/fifteen patients tested were positive for CTCs. CTCs did not correlate to receptor status, futility of RT or OS.

Conclusions: Capecitabine can be safely administered as a daily concurrent chemoradiation regimen with weekend holidays. However, in this small, prospective and selected cohort, concurrent chemoradiation with capecitabine was futile among patients with TN breast cancer. Alternative strategies are urgently needed in TN patients.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-14-08.

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 (> 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 >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.

Abstract P3-10-07: Lymph node status and survival in inflammatory breast cancer

Objectives: Positive lymph node status in breast cancer is known to be associated with poor outcomes when compared with node-negative disease, but the effect of lymph node status on outcomes in inflammatory breast cancer (IBC) has not been evaluated. This study was designed to investigate the association between lymph-node status and overall survival (OS) in individuals with inflammatory breast cancer using prospective data from the Surveillance, Epidemiology, and End Results (SEER) database.

Methods: We identified 750 patients in the April 2012 edition of the SEER 17 registry who had non-metastatic IBC diagnosed from 1973–2008. Patients were included only if they met a stringent definition of IBC (ICD-O-2 morphology code 8503) and their pathologic nodal status was known. Patients who did not receive mastectomy as part of their local therapy were excluded, to minimize the likelihood of inadvertently including patients with metastatic disease at or shortly after diagnosis. A total of 711 patients were deemed evaluable for analysis (145 node-negative, 566 node-positive). Survival analysis was performed using the Kaplan–Meier method. Cox proportional hazard regression was performed to evaluate univariate and multivariate associations between treatment and OS. Information regarding receipt of systemic therapy and human epidermal growth factor receptor 2 (HER2) status was not available in this version of the SEER database.

Results: Positive lymph node status was associated with a significant decrease in OS (p = 0.01) when compared with node negative status. In lymph node-positive patients, ER or PR positivity was associated with better OS than ER or PR negativity (adjusted HR 0.56 (p = 0.005) for ER+ vs. ER−, and adjusted HR 0.55 (p = 0.009) for PR+vs. PR−). In patients with positive lymph nodes, the combination of surgery and radiation therapy improved overall survival when compared with surgery alone (adjusted HR 0.56, p = 0.003). In node-negative patients, the combination of surgery and radiation therapy was not clearly superior to surgery alone, possibly due to the rarity of node-negative IBC (adjusted HR 0.53, 95% CI 0.23–1.19, p = 0.13).

Conclusions: Our findings provide a better understanding of the characteristics of inflammatory breast cancer, and creates the opportunity for future studies to evaluate the prognostic significance and treatment implications of lymph node status in inflammatory breast cancer. Our study is limited by lack of knowledge of use of systemic therapy, the HER2 status for each patient, and information regarding locoregional recurrence. However, institutions participating in the SEER registry are likely to follow guidelines set forth by the National Comprehensive Cancer Network, recommending induction chemotherapy followed by surgery followed by radiation for IBC. Nearly 80% of the IBC patients included in this study had nodal metastasis, reflecting the inherently aggressive biology of this disease. Further studies are required to characterize the biology of IBC and guide the optimal treatment of this disease.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-10-07.

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.

Abstract P4-11-15: Outcomes for Breast Cancer Patients with Isolated Metastasis or Recurrence to the Contralateral Nodal Basins

Background: Aggressive treatment of isolated breast cancer metastasis to either bone or lung has been reported to achieve long term survival. For the first time, we analyzed outcomes for patients (pts) with isolated metastasis to the contralateral (contra) supraclavicular (SCV) and/or axillary nodal basins.

Material and Methods: Pts treated with definitive or palliative radiation to the contra nodal basin(s) at M.D. Anderson were analyzed from the period of 2005-2010. They were divided into two groups: pts initially diagnosed with contra SCV and/or axilla as the only site of metastasis (designated Primary), and pts with recurrence in the contra SCV and/or axilla, without other distant metastasis (designated Recurrent).

Results: Of 34 potential pts with contra lymph node metastasis, 13 had isolated disease and were analyzed. In the Primary group (N=8, T4d N1- 3c M1), median survival was 25 mos, and 2-yr actuarial overall survivalwas 62.5%. All received neoadjuvant anthracycline and/or taxane-based chemotherapy followed by ipsilateral (ipsi) modified radical mastectomy and ipsi axillary lymph node dissection (ALND). The contra lymphatics were treated with ALND followed by radiation (N=5, 56-60 Gy) or with radiation alone (N=3, 45-66 Gy). Radiation fields included ipsi chest wall as well as ipsi and involved contra lymphatics. The contra chest wall or breast was radiated in 3 of the 8 pts. Two pts had estrogen receptor (ER) positive disease, and all had Her2-neu negative disease. Both ER+ pts are alive with no evidence of disease (NED; 1 had contra ALND; survival 25 and 51 mos). All 6 ER-pts died with disease (WD; 4 had contra ALND; survival 10 to 32 mos). One pt had an in-field recurrence in the contra nodal basin (51 Gy post ALND). No contra chest wall/breast recurrences were seen. All ER-pts developed additional distant metastasis, most within 4 mos of starting adjuvant radiation.

Regarding the Recurrent group (N=5), median survival was 25 mos after recurrence. Two ER+ pts received initial anti-estrogen therapy; all ER-pts initially received a taxane-based chemotherapy. The contra chest wall or breast was radiated in addition to the involved contra lymphatics in 3 of the 5 pts. Two pts had adjuvant radiation treatment with definitive intent to the contra lymphatics after ALND (50-50.4 Gy), with 1 alive/NED (66 mos from recurrence, no radiation to the contra breast) and 1 dead/WD (25 mos from recurrence). Radiation intent was palliation in 3 pts (none received ALND) with 1 alive/WD (60 Gy, 64 mos from recurrence) and 2 dead/WD (53.8 and 45 Gy, 6 and 18 mos from recurrence, respectively). In-field recurrence in the contra nodal basin occurred in 1 pt (50.4 Gy). Pts who died had progressive disease or additional distant metastasis within 3 mos of starting radiation.

Discussion: In this uncommon clinical scenario, locoregional control of the contra lymphatics was achieved with radiation alone or with surgery followed by radiation for a select group of pts; control was achieved without radiating the contra chest wall/breast. Only ER+ pts were rendered NED. Most ER-pts quickly developed other distant metastasis, highlighting the need for more effective systemic therapy.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-11-15.

Abstract P1-17-02: Outcome after Locoregional Recurrence in Patients with Inflammatory Breast Cancer

Purpose: High rates of locoregional recurrence (LRR) have been reported in spite of comprehensive tri-modality therapy for patients with inflammatory breast cancer (IBC). The aim of this study was to examine the prognosis of patients who have experienced LRR after treated primary IBC. Methods:

We retrospectively reviewed information for 124 IBC patients who experienced a LRR seen in our institution from 1990-2008. 63 patients had simultaneous distant disease (DM) +/−3 months of LRR (simLRR),

5 patients had LRR &gt; 3 months subsequent to DM, while 56 patients had isolated LRR &gt;3 months prior to DM (isLRR). Overall survival (OS) was calculated from date of recurrence using the Kaplan-Meier method. Results:

Median time to LRR from diagnosis was 13 months (interquartile range 8-21 months). Median survival after LRR was 15 months. 2-yr OS was 46%. Regarding the primary tumors, 23% were estrogen receptor positive (ER+), 33% were HER2-neu positive (H2N+), 81% had lymph vascular space invasion (LVSI), and 83% were grade 3. Comparing isLRR and simLRR cohorts, median survival was 18 months vs. 10 months and 2 yr-OS was 66% vs. 28%, respectively. ER+ and H2N+ primary status predicted for longer 2 yr OS among patients with simLRR but not among isLRR patients. (simLRR, ER+ 57% vs. ER-19% p = 0.02, H2N+ 45% vs. H2N-17% p = 0.01; IsLRR ER+ vs. ER-92% vs. 55% p = 0.15, H2N+ 86% vs. H2N-57% p = 0.11). LVSI was not prognostic in either group and Grade 3 primary trended towards worse outcome among isLRR cohort only, Grade 2 83% vs. Grade 3 64% P = 0.08. Molecular subtyping using ER and H2N status to group tumors demonstrates basal subtype in the primary tumor compared to H2N, luminal B and luminal A is associated with significantly worse 2 yr OS after isLRR (43% vs. 88%, 82%, and 83%, P = 0.04) and simLRR (13% vs. 34%, 80%, 32% P = 0.005) respectively. Conclusions:

Forty-five% of LRR occurred as isolated first events. LRRs generally occur within 2 years after primary IBC treatment and are associated with poor outcomes even as first events. Basal subtype predicts for worse overall survival regardless of distant disease.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-17-02.

Clinical Data Do Not Support the Hypothesis That Irradiation Promotes Biologically Aggressive Local Recurrences through Stromal Activation

Objective: Recent data in select pre-clinical models suggest that radiation can activate normal stroma to promote tumor metastases and aggressiveness. We hypothesized that if these were occurring clinically, there would be a lower survival after locoregional recurrence (LRR) in patients after post-mastectomy radiation therapy (PMRT) compared to mastectomy (Mx) alone. This study used two independent datasets to compare survival after LRR in women treated with versus without PMRT.Methods: Data from 229 of 1,505 patients who experienced LRR after treatment on sequential non-randomized institutional prospective trials at the MD Anderson Cancer Center (MDA) and 66 of 318 patients enrolled in the British Columbia (BC) PMRT randomized trial who experienced LRR were analyzed. All patients underwent Mx and level I/II axillary dissection. In both data sets analysis was based on treatment received. Patients from MDA received doxorubicin based chemotherapy +/- PMRT, with 45 LRR after PMRT and 184 LRR after Mx alone). Patients treated on the BC trial received CMF chemotherapy +/- PMRT, with LRR in 14/160 after PMRT versus 52/158 after Mx alone. Survival was calculated from time of LRR to death using Kaplan-Meier and log rank statistics.Results:MDA Data: Median follow up of living patients was 192 months. Analyzing data from all patients with LRR regardless of distant metastasis (DM), patients with LRR after PMRT were younger (47 vs. 51 y, p = 0.033) and had shorter time to first LRR (40mo vs. 51 mo, p = 0.018). 5-yr/10-yr OS were 31%/16% without PMRT and 20%/7% after PMRT (p = 0.008). However, PMRT-treated patients had increased risk factors for DM (advanced T and N stage) and more PMRT-treated patients developed DM prior to LRR (58% vs. 36% p = 0.009). Analyzing only patients without DM there was no difference in OS between groups (p = 0.67), and a separate analysis of all patients who developed metastatic disease (N = 385 no PMRT, 233 after PMRT) revealed no difference in 5 or 10-yr OS after DR (15%/4% without PMRT vs. 13%/6% after PMRT, p = 0.5).BC Data: Median follow up of living patients was 235 months. The distributions of age, T stage, N stage, grade, LVI, ER status, excised nodes and nodal ratio were similar between patients with LRR after Mx alone vs. Mx plus PMRT. (all p &gt; 0.05). The mean time to first LRR was 39 mo in patients treated with Mx alone and 57 mo in patients treated with PMRT, p= 0.27). The rate of DM was similar in patients with LRR after Mx with vs without PMRT (93% vs. 96%, p=0.60). Distant relapse free survival after LRR was similar in Mx alone vs. PMRT-treated patients (log rank p=0.75). Overall survival was also similar in the two groups (5-yr/10-yr OS 21%/8% without PMRT vs. 23%/12% with PMRT, log rank p=0.93).Conclusions: Decades of randomized data have demonstrated that PMRT reduces LRR and improves overall survival. In the non-randomized dataset, removing the competing risk of DM which is higher in patients selected for PMRT by studying patients with isolated LRR, we find no difference in survival after LRR in the PMRT setting. Analysis of the randomized PMRT trial dataset confirmed the finding of similar survival among women with LRR irrespective of PMRT use.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 4101.

Local-regional recurrence with and without radiation after neoadjuvant chemotherapy and mastectomy for T3N0 breast cancer patients

Abstract #74

Purpose: The goal of this study was to compare the local-regional recurrence (LRR) risk in patients with clinical T3N0 breast cancer who were treated with neoadjuvant chemotherapy (NeoChemo) and mastectomy (Mastx) according to the use of adjuvant radiation (RT).&#x2028; Methods: Clinicopathologic data from 164 patients with clinical T3N0 breast cancer who received NeoChemo and Mastx from 1985 to 2004 were retrospectively reviewed. In this cohort, 121 (74%) patients received adjuvant radiation (RT) while 43 (26%) patients did not. The median number of axillary lymph nodes (LN) dissected was 15. After NeoChemo, 54% of patients (n=89) had no pathologically involved lymph nodes at the time of surgery (ypLN-) while 46% (n=75) had at least 1 lymph node pathologically positive (ypLN+). Actuarial rates were calculated using Kaplan-Meier analysis and compared using log-rank test. Cox proportional hazards models were fit to determine the association of RT with the risk of LRR after adjustment for other patient and disease characteristics.&#x2028; Results: At a median follow-up of 77 months, 17 of the 164 patients had a LRR. For all patients, the 5-year local-regional control rates (5-yr LRC) were 90%. The 5-yr LRC for those who received RT (n=121) was 95% and for those who did not received RT (n=43) was 76% (p = 0.002), with a higher proportion of the patients who received RT having pathologically involved LN (+RT 53% vs –RT 23%, p=0.002).&#x2028; Among the entire cohort, the 5-yr LRC was 85% for patients with ypLN+ disease and 94% for patients with ypLN- disease (p=0.093). In patients with ypLN+, the 5-yr LRC with no RT (n=11) was 47% and with RT (n=64) was 92% (p&lt;0.001). In patients with ypLN-, the 5-yr LRC with no RT (n=32) was 86% and with RT (n=57) was 98% (p=0.063). Patients who had tumors with high nuclear grade had worse 5-yr LRC (Grade low 100%, intermediate 97%, high 81%, p=0.023). The presence of lymphovascular invasion, close/positive margin, or estrogen receptor status did not statistically correlate with LRC. In a Cox regression model, patients with tumor exhibiting high nuclear grade (Hazard Ratio (HR) 5.0, 95% Confidence Interval (CI) 1.6-15.4), ypLN+ (HR 6.6, 95% CI 2.0-22.1) and no adjuvant RT (HR 7.6, 95% CI 2.4-24.0) had increased risk of LRR.&#x2028; Conclusions: Post mastectomy adjuvant RT appears to improve LRC in clinical T3N0 breast cancer patients treated with neoadjuvant chemotherapy and mastectomy.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 74.