Abstract P5-22-21: Radioactive seed and targeted axillary dissection: A feasibility study

Targeted axillary dissection (TAD) with a radioactive seed is a new and promising technique to evaluate the axillary status in post-neoadjuvant chemotherapy (NACT) node-positive breast cancer patients. This study aims to evaluate the feasibility of TAD with a radioactive seed in a Canadian setting.

We conducted a retrospective observational study of a prospectively gathered database of patients having undergone TAD with a radioactive seed implanted in a proven metastatic axillary node, between 2015 and 2017 in our institution. An iodine-125 radioactive seed was implanted under ultrasound guidance by trained radiologists. Patients then underwent standard sentinel lymph node biopsy (SLNB) using technicium-99 and blue dye, as well as selective removal of the node containing the radioactive seed. Data was gathered from electronic medical records and chart review.

Nine patients with a median age of 54 underwent TAD for unilateral breast cancer post-NACT between 2015 and 2017, three of which were "triple-negative". A median of 3 lymph nodes were removed, including that which contained the radioactive seed. Postoperative pathological evaluation showed 4 patients with positive nodes and 5 pathologic complete responses in the axilla. In all patients, the seed had been accurately positioned in a positive node (no false negatives). The seed also located a positive retropectoral node that would otherwise have been missed using standard dual tracer SLNB. No complications due to the use of the radioactive seed were encountered. All implanted seeds were identified and retrieved within the pathology specimen.

In our experience, TAD with a radioactive seed combined to dual tracer SLNB is an accurate and safe method of evaluating the axillary lymph node status in post-NACT node positive breast cancer patients. Further studies with larger cohorts are warranted to ensure continued feasibility and reproducibility of our positive results.

Citation Format: Boulva K, Rodriguez-Qizilbash S, Guilarte L, Lazizi S, Robidoux A, Younan R, Patocskai E. Radioactive seed and targeted axillary dissection: A feasibility study [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 P5-22-21.

Breast magnetic resonance imaging: are those who need it getting it?

BACKGROUND

Indications for breast magnetic resonance imaging (mri), a very sensitive but less-specific tool for breast investigation, remain controversial, and accessibility is limited. The purposes of our study were to determine the proportion of breast mri exams performed for various clinical indications, to assess the wait times for breast mri, and to create a list of evidence-based indications for breast mri.

METHODS

The indications for breast mri exams performed in September 2013 at our academic centre were audited. A multidisciplinary meeting held in May 2014 established a list of evidence-based indications for breast mri, after which, in September 2014 and 2015, breast mri exams were re-audited for clinical indications, and pending requests were calculated.

RESULTS

In September 2013, surveillance of women with a prior diagnosis of breast cancer represented 21% of breast mri exams (24 of 113), with preoperative staging representing 18% of exams (20 of 113) and high-risk screening representing 12% (13 of 113). Of pending mri requests, 230 were within the recommended delay period, and 457 exceeded the recommended delay. After elaboration of evidence-based guidelines, repeat audits in September 2014 and September 2015 showed that mri performed for women with a prior breast cancer diagnosis represented 23% (33 of 141) and 7% (10 of 143) of exams respectively, with preoperative staging having declined to 9% (13 of 141) and 11% (16 of 143) of exams, and high-risk screening having increased to 36% (51 of 141) and 46% (66 of 143) of exams. Overall, wait times were improved for all breast mri indications.

CONCLUSIONS

Through multidisciplinary discussion, we actualized a list of breast mri indications, prioritized requests more adequately, and improved wait times.

Abstract P3-14-13: Total mastectomy and immediate breast reconstruction for breast cancer: A ten-year Canadian single institution experience

Fear of high local recurrence rate associated with immediate breast reconstruction (IBR) following total mastectomy for breast cancer might be a contributing factor to the low rate of immediate reconstruction performed in Quebec. The aim of this study was to demonstrate the oncological safety of total mastectomy with immediate breast reconstruction.

A retrospective chart review of all patients who underwent total mastectomy with immediate breast reconstruction at the University of Montreal Hospital Center between 2006 and 2015 was performed.

375 patients (420 cases) met the inclusion criteria. The mean age was 51.5 years (25-77). The median follow-up was 45.6 months (0.4-115.2). Clinical cancer staging was done according to the American Joint Committee on Cancer (AJCC) criteria. 349 cases (83.1%) were classified as Stage < cIIb and 71 cases (16.9%) as ≥ cIIb. 73 patients (19.5%) received neoadjuvant chemotherapy, 113 (30.1%) received adjuvant chemotherapy and 91 (21.7%) received postoperative radiotherapy. Only 4 patients (3.5%) had a significant delay in receiving adjuvant chemotherapy and 4 patients (4.4%) had a delay in initiation of radiotherapy. In total, there were 12 (2.6%) local recurrences and 29 (7.7%) distant recurrences.

The results of this study demonstrate a low rate of local recurrence that is comparable to the current litterature. Total mastectomy in association with immediate breast reconstruction is therefore an oncologically safe approach for the treatment of breast cancer and should be more widely adopted by medical centers throughout Quebec.

Citation Format: Younan RJ, Al Khaldi M, Maalouf C, Guez M, Boulva K, robidoux A, Nassif E, Poljicak M, BouMerhi J, Bernier C, Patocskai E. Total mastectomy and immediate breast reconstruction for breast cancer: A ten-year Canadian single institution experience [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-14-13.

Preoperative intensity modulated radiation therapy for retroperitoneal sarcoma

The use of intensity modulated radiation therapy (IMRT) has allowed for the administration of high doses to retroperitoneal sarcomas (RSTS) while limiting toxicity to adjacent organs. The purpose of our study is to assess the outcome and toxicities of patients with RSTS treated with neo-adjuvant external beam radiation (EBRT) therapy using IMRT. This is a retrospective study of 21 patients treated with preoperative IMRT for primary or recurrent RSTS between 2005 and 2011. Overall survival (OS) and local recurrence free survival (LRFS) were computed using the Kaplan-Meier method (log-rank test). Acute and chronic toxicities were assessed using the CTCAE v. 3 criteria. The actuarial 2 and 3-year OS was 66% for both and the 5-year OS was 51%. As for LRFS it was 57% at 2 and 3-year and 51% for the 5-year LRFS. Factors predictive for local control were microscopically negative margins (p = 0.022), a median tumor diameter <15 cm (p = 0.007) and pathology of liposarcoma (p = 0.021). Furthermore, patients treated for recurrent disease fared worse (p = 0.04) in local control than patients treated for primary disease. As for OS, patients treated for Grade 1 histology had a better outcome (p 5 0.05). EBRT was generally well tolerated. Acute gastrointestinal (GI) Grade 1 or 2 toxicities occurred in 33% of patients and one patient had unexplained post-radiation Grade 2 fever that resolved after tumor resection. As for chronic toxicities 24% of our patients presented Grade 1 GI toxicity and one patient presented Grade 3 small bowel stenosis not clearly due to radiation toxicity. Despite the location and volume of the tumors treated, preoperative IMRT was very well tolerated in our patients with retroperitoneal sarcoma. Unfortunately local recurrences remain common and dose escalation is to be considered.

Sentinel node biopsy after neoadjuvant therapy: Relevance of sentinel node micrometastases, isolated tumor cells, and value of immunohistochemistry

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Background: Sentinel node biopsy (SNB) is used in breast cancer patients that present with clinically negative nodes. In this setting, most guidelines do not support the use of immunohistochemistry (IHC) and recommend against completion node dissection (CND) when only isolated tumor cells (pN0(i+)) or micrometasases (pN1mi) are identified. When SNB is used after neoadjuvant therapy (NAT), the relevance of ypN0(i+) and ypN1mi sentinel nodes (SNs) and the value of IHC are not well established. The goals of this study are to determine if CND should be recommended in the presence of ypN0(i+) or ypN1mi SNs and if IHC should be used to evaluate SNs after NAT. Methods: From March 2009 to December 2012, 152 women with biopsy proven node positive breast cancer were accrued to the multicentric prospective SN FNAC trial. After NAT, SNB was followed by a CND in all participants. SNs were cut in serial slices no thicker than 2 mm. Hematoxylin and eosin stains (H and E) were done on all slices, and if negative, IHC was used. The size of the largest SN metastasis and the primary method of identification (H and E or IHC) were recorded. ypN0(i+), ypN1mi and ypN1 SNs were considered as positive. Pathology was centrally reviewed. Results: 145 women were eligible for the trial. Axillary pathologic complete response rate = 34% (49/145). SNB success rate = 88% (127/145). False negative rate = 8.4% (7/83). If ypN0(i+) SNs are classified as node negative, the false negative rate is increased to 13.3% (11/83). For patients with ypN0(i+) (n=7), ypN1mi (n=8) and ypN1 (n=61) SNs, the rates of non-SN involvement are 57%, 38% and 56% respectively (p=NS). 40% (27/68) of positive SNBs are primarily detected by IHC. This is increased to 64% (9/14) for the identification of SN metastases ≤ 2mm. Conclusions: After NAT, particularly when presenting with biopsy proven node positive breast cancer, patients with ypN0(i+) and ypN1mi SNs have a significant rate of non-SN involvement. In the absence of evidence to show that a CND can be safely avoided, efforts should be made to identify even minimal amounts of disease when SNBs are done following NAT. IHC is useful to increase the detection of small SN metastases in this setting. Clinical trial information: NCT00909441.

Sentinel node biopsy following neoadjuvant chemotherapy in biopsy proven node positive breast cancer: The SN FNAC study

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Background: A significant and increasing proportion of patients (>30%) with biopsy proven node positive breast cancer will obtain a pathological complete response (pCR) in the axilla after neoadjuvant chemotherapy (NAC). If sentinel node biopsy (SNB) can accurately identify these patients, they could potentially avoid the morbidity of an axillary node dissection. The primary aim of this study is to evaluate the identification rate (IR), false negative rate (FNR) and accuracy of SNB in this setting. The accuracy of post NAC axillary ultrasound and clinical examination are evaluated as secondary endpoints. Methods: Patients with biopsy proven node positive breast cancer (T0-3, N1-2, M0) treated with NAC were eligible to participate in this multi-centre prospective trial. Following NAC, axillary ultrasound and clinical examination results were obtained. At time of surgery, all participants underwent both a SNB and a completion node dissection. A SNB IR greater than 90% and a FNR of less than 10% were pre-determined as being optimal. Results: From September 2009 to December 2012, 153 patients were accrued to the study. 7 patients were not eligible and 5 patients had not yet undergone surgery at the time of analysis. Axillary pCR rate = 34.0% (48/141). SNB IR = 87.2% (123/141), 95% CI [81.7%-92.7%] and FNR = 9.9% (8/81), 95% CI [3.4%-16.4%]. If only one sentinel node was removed, FNR = 19.0%(4/21); if there were 2 or more sentinel nodes, FNR = 6.6% (4/61) (p < 0.0001). Accuracy of SNB, axillary ultrasound and clinical examination were 93.5%, 63.2%, and 45.5% respectively. Conclusions: SNB following NAC in biopsy proven node positive breast cancer is associated with a suboptimal IR. FNR (less than 10%) and accuracy of SNB in this study are comparable to that of patients that present with clinically negative nodes. The FNR decreases when more than one sentinel node is identified. However, in an era where regional nodal radiation is increasingly used, the relevance of leaving residual disease in the undissected axilla after NAC is unknown and remains to be investigated. Clinical trial information: NCT00909441.

Preoperative intensity modulated radiation therapy for retroperitoneal sarcoma

322

Background: The use of intensity modulated radiation therapy (IMRT) has allowed for the administration high doses to retroperitoneal sarcomas (RSTS) while limiting toxicity to adjacent organs. The purpose of our study is to assess the outcome and toxicities of patients with RSTS treated with neoadjuvant external beam radiation (EBRT) therapy using IMRT. Methods: This is a retrospective study of 21patients treated with preoperative IMRT for primary or recurrent RSTS between 2005 and 2011. Overall survival (OS) and local recurrence free survival (LRFS) were computed using the Kaplan-Meier method (log-rank test). Acute and chronic toxicities were assessed according to the CTCAE v. 3 criteria. Results: The actuarial 3 and 5-year OS and LRFS was 66% and 51%, 57% and 41% respectively. Factors predictive for LRFS were microscopically negative margins (p=0.022), a median tumor diameter < 15 cm (p=0.007) and a pathology of liposarcoma (p=0.021); however, patients treated for recurrent disease fared worse (p=0.04). As for OS, grade 1 histology was a predictive factor for better outcome (p=0.05). EBRT was generally well tolerated. Acute gastrointestinal grade 1 or 2 toxicity occurred in 33% of patients and one patient had unexplained post-radiation grade 2 fever that resolved after tumor resection. As for chronic toxicities 24% of our patients presented grade 1 gastrointestinal toxicity and one patient presented grade 3 small bowel stenosis not clearly due to radiation toxicity. Conclusions: Despite the location and volume of the tumors treated, preoperative IMRT was very well tolerated in our patients with retroperitoneal sarcoma. Unfortunately local recurrences remain common and dose escalation is to be considered.

The contribution of founder mutations to early-onset breast cancer in French-Canadian women

In an ethnically-homogeneous population, it is valuable to identify founder mutations in cancer-predisposing genes. Founder mutations have been found in four breast-cancer-predisposing genes in French-Canadian breast cancer families. The frequencies of the mutant alleles have been measured neither in a large series of unselected breast cancer patients from Quebec, nor in healthy controls. These estimates are necessary to measure their contribution to the hereditary burden of breast cancer in Quebec and to help develop genetic screening policies which are appropriate for the province. We studied 564 French-Canadian women with early-onset invasive breast cancer who were treated at a single Montreal hospital. Patients had been diagnosed at age 50 or less, and were ascertained between 2004 and 2008. We screened all 564 patients for nine founder mutations: four in BRCA1, three in BRCA2 and one each in PALB2 and CHEK2. We also studied 6433 DNA samples from newborn infants from the Quebec City area to estimate the frequency of the nine variant alleles in the French-Canadian population. We identified a mutation in 36 of the 564 breast cancer cases (6.4%) and in 35 of 6443 controls (0.5%). In the breast cancer patients, the majority of mutations were in BRCA2 (54%). However, in the general population (newborn infants), the majority of mutations were in CHEK2 (54%). The odds ratio for breast cancer to age 50, given a BRCA1 mutation, was 10.1 (95% CI: 3.7-28) and given a BRCA2 mutation was 29.5 (95% CI: 12.9-67). The odds ratio for breast cancer to age 50, given a CHEK2 mutation, was 3.6 (95% CI: 1.4-9.1). One-half of the women with a mutation had a first- or second-degree relative diagnosed with breast or ovarian cancer. Thus, it can be concluded that a predisposing mutation in BRCA1, BRCA2, CHEK2 or PALB2 is present in approximately 6% of French-Canadian women with early-onset breast cancer. It is reasonable to offer screening for founder mutations to all French-Canadian women with breast cancer before age 50. The frequency of these mutations in the general population (0.5%) is too low to advocate population-based screening.

The Contribution of Founder Mutations to Early-Onset Breast Cancer in French-Canadian Women

Background: In an ethnically-homogeneous population, it is valuable to identify founder mutations in cancer-predisposing genes. Founder mutations have been found in four breast cancer predisposing genes in French-Canadian breast cancer families. The frequencies of the mutant alleles have not been measured in a large series of unselected breast cancer patients from Quebec, nor in healthy controls. These estimates are necessary to measure their contribution to the hereditary burden of breast cancer in Quebec and to help develop genetic screening policies which are appropriate for the province.Methods: We studied 564 French-Canadian women with early-onset invasive breast cancer who were treated at a single Montreal hospital. Patients had been diagnosed at age 50 or less, and were ascertained between 2004 and 2008. We screened all 564 patients for nine founder mutations; four in BRCA1, three in BRCA2 and one each in PALB2 and CHEK2. We also studied 6433 DNA samples from newborn infants from the Quebec City area to estimate the frequency of the nine variant alleles in the French-Canadian population.Results: We identified a mutation in 36 of the 564 breast cancer cases (6.4%) and in 35 of 6443 controls (0.5%). In the breast cancer patients, the majority of mutations were in BRCA2 (54%). However, in the general population (newborn infants), the majority of mutations were in CHEK2 (54%). The odds ratio for breast cancer to age 50, given a BRCA1 mutation was 10.1 (95% CI: 3.7 to 28) and given a BRCA2 mutation was 29.5 (95% CI: 12.9 – 67). The odds ratio for breast cancer to age 50, given a CHEK2 mutation was 3.6 (95% CI: 1.4 – 9.1). One-half of the women with a mutation had a first or second-degree relative diagnosed with breast or ovarian cancer.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 902.

Epirubicin plus cyclophosphamide followed by docetaxel plus trastuzumab and bevacizumab as neoadjuvant therapy for HER2-positive locally advanced breast cancer (LABC) or as adjuvant therapy for HER2-positive pathologic stage III breast cancer (PS3BC): A phase II trial of the NSABP Foundation Research Group

580

Background: A previous phase II study evaluating the combination of trastuzumab (tras) and bevacizumab (bev) as first-line therapy in HER2 + MBC showed a response rate of 54%. The purpose of this trial is to determine the cardiac safety profile of these agents with docetaxel (T) following epirubicin plus cyclophosphamide (EC) in women with LABC and PS3BC and the activity in those with LABC. Methods: Since June 2007, 75 women with HER-2 + LABC or PS3BC have begun epirubicin 90 mg/m2 IV plus cyclophosphamide 600 mg/m2 IV q3wks x 4 followed by docetaxel 100 mg/m2 IV q3wks x 4. Targeted therapy: Cohort A (neoadjuvant), bev 15 mg/kg IV with Cycle 4 of EC, continued with the first 3 cycles of T. Standard weekly tras with 4 cycles of T. Postop, bev 15 mg/kg IV and tras 6 mg/kg IV q3wks to complete 1 yr of targeted therapy. Cohort B (adjuvant), bev 15 mg/kg q3wks for 4 cycles and weekly tras with T. After chemotherapy, bev and tras q3wks to complete 1 yr of therapy. Primary endpoints were the rate of cardiac events in both cohorts and pCR rate in breast/axillary lymph nodes in Cohort A. Results: Median age was 50 yrs. In Cohort A, 28 (53%) patients (pts) were stage IIIA, 20 (38%) stage IIIB, and 5 (9%) stage IIIC. 13 (25%) had inflammatory BC. A pCR occurred in 19 of the first 36 pts (53%). Toxicity information on the first 73 pts in both cohorts showed that grade 2 LVEF dysfunction has developed in 5 pts and grade 3 LVEF dysfunction in 2, 1 with NYHA Class II and 1 with Class III symptoms. The latter met criteria for a cardiac event. Conclusions: The regimen is active with an acceptable preliminary rate of cardiac toxicity. Updated results will be presented. This trial is conducted with the support of Genentech.

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