Excision of both pretreatment marked positive nodes and sentinel nodes improves axillary staging after neoadjuvant systemic therapy in breast cancer

BACKGROUND

Marking the axilla with radioactive iodine seed and sentinel lymph node (SLN) biopsy have been proposed for axillary staging after neoadjuvant systemic therapy in clinically node-positive breast cancer. This study evaluated the identification rate and detection of residual disease with combined excision of pretreatment-positive marked lymph nodes (MLNs) together with SLNs.

METHODS

This was a multicentre retrospective analysis of patients with clinically node-positive breast cancer undergoing neoadjuvant systemic therapy and the combination procedure (with or without axillary lymph node dissection). The identification rate and detection of axillary residual disease were calculated for the combination procedure, and for MLNs and SLNs separately.

RESULTS

At least one MLN and/or SLN(s) were identified by the combination procedure in 138 of 139 patients (identification rate 99·3 per cent). The identification rate was 92·8 per cent for MLNs alone and 87·8 per cent for SLNs alone. In 88 of 139 patients (63·3 per cent) residual axillary disease was detected by the combination procedure. Residual disease was shown only in the MLN in 20 of 88 patients (23 per cent) and only in the SLN in ten of 88 (11 per cent), whereas both the MLN and SLN contained residual disease in the remainder (58 of 88, 66 per cent).

CONCLUSION

Excision of the pretreatment-positive MLN together with SLNs after neoadjuvant systemic therapy in patients with clinically node-positive disease resulted in a higher identification rate and improved detection of residual axillary disease.

Health-related quality of life of breast cancer patients after accelerated partial breast irradiation using intraoperative or external beam radiotherapy technique

PURPOSE

To compare health-related quality of life (HRQL) in elderly breast cancer patients between two types of Accelerated Partial Breast Irradiation: intraoperative radiotherapy (IORT) and external beam APBI (EB-APBI).

METHODS

Between 2011 and 2016 women ≥60 years undergoing breast conserving therapy for early stage breast cancer were included in a prospective multi-centre cohort study. Patients were treated with electron IORT (1 × 23.3 Gy) or photon EB-APBI (10 × 3.85 Gy daily). HRQL was measured by the EORTC-QLQ C30 and BR23 questionnaires before surgery and at several time points until 1 year.

RESULTS

HRQoL data was available of 204 IORT and 158 EB-APBI patients. In longitudinal analyses emotional functioning and future perspective were significantly, but not clinically relevantly, worse in IORT-treated patients, and improved significantly during follow-up in both groups. All other aspects of HRQL slightly worsened after treatment and recovered within 3 months with an improvement until 1 year. Cross-sectional analysis showed that postoperatively fatigue and role functioning were significantly worse in IORT patients compared to EB-APBI patients who were not yet irradiated, but the difference was not clinically relevant. At other timepoints there were no significant differences. Multivariable analysis at 1 year identified comorbidity and systemic therapy as risk factors for a worse global health score (GHS).

CONCLUSIONS

EB-APBI and IORT were well tolerated. Despite a temporary deterioration after treatment, all HRQL scales recovered within 3 months resulting in no clinically relevant differences until 1 year between groups nor compared to baseline levels.

Abstract GS4-01: Radiotherapy or surgery of the axilla after a positive sentinel node in breast cancer patients: 10 year follow up results of the EORTC AMAROS trial (EORTC 10981/22023)

Background: Sentinel node biopsy (SNB) is standard in assessing axillary lymph node status in patients with clinically node-negative breast cancer. The 5-year analysis of AMAROS trial showed that if locoregional treatment is advised after a tumor-positive axillary SNB, axillary radiotherapy (ART) is a reasonable alternative for an axillary lymph node dissection (ALND) with less side effects, though follow up was relatively short. Here we present the 10-year follow up data.

Methods: From February 2001 to April 2010, patients with primary breast cancer stage cT1-2N0M0 were enrolled in the EORTC phase III non-inferiority AMAROS trial by 34 European sites. Patients were randomized between ALND and ART in case of a tumor-positive SNB. The primary endpoint, axillary recurrence rate (AxR) is now assessed at 10 years in the ITT population using Fine and Gray cumulative incidence method with deaths as competing risks, as well as secondary endpoints: overall survival (OS), distant metastasis free survival (DMFS), second primaries (including cancers other than breast cancers and contralateral DCIS) and locoregional recurrences (LRR). Little extra information beyond 5 years was available concerning Quality of Life and morbidity. Data collection is still ongoing and will be presented later.

Results:Of the 4806 patients entered, 1425 patients had a tumor-positive SNB: 744 in the ALND-arm and 681 in the ART-arm, 60% with a macrometastasis. Both treatment-arms achieved a median 10-year follow-up and were comparable regarding age, tumor size, grade, tumor type and adjuvant systemic treatment. In the group who had ALND, the 5-year AxR was 0.41% (95%CI: 0.00;0.88) (4/744) and the 10-year AxR was 0.93% (95%CI:0.18;1.68) (7/744). In the group who had ART, the 5-year AxR was 1.04% (95%CI: 0.27;1.81) (7/681) and the 10-year AxR was 1.82% (95%CI: 0.74;2.94) (11/681) (HR 1.71, 95%CI: 0.67;4.39, p = 0.37). Sensitivity analysis, considering deaths and distant recurrences as competing risks, revealed consistent results. There were no significant differences between treatment arms regarding OS (ALND: 84.6% (95%CI: 81.5;87.1), ART: 81.4% (95%CI: 77.9;84.4), HR 1.17, 95%CI: 0.89;1.52, p= 0.26) and DMFS (ALND: 81.7% (95%CI: 78.5;84.4), ART: 78.2% (95%CI: 74.6;81.3), HR 1.18, 95%CI: 0.92;1.50, p=0.19). Cumulative incidence estimates of 10-year LRR are 3.59% (95%CI: 2.12;5.06) (ALND) versus 4.07% (95%CI: 2.49;5.65) (ART) (p= 0.69). More second primaries were observed after ART: 75/681 (21 contralateral breast) as compared to ALND: 57/744 (11 contralateral breast) (p = 0.035). All results are consistent in the per protocol analysis of patients with a tumor-positive SNB.

Conclusion: Axillary recurrence after 10 years in patients with a tumor-positive SNB who were treated with ART is extremely rare and not significantly different from patients who were treated with ALND. OS, DMFS and locoregional control are also comparable. Second primaries including contralateral breast cancers are more frequently encountered after ART, but the difference is still low in absolute numbers. Thus, ART is a safe treatment for breast cancer patients with a tumor-positive SNB.

Citation Format: Rutgers EJ, Donker M, Poncet C, Straver ME, Meijnen P, van de Velde CJ, Mansel RE, Blanken C, Orzalesi L, Klinkenbijl JH, van der Mijle HC, Veltkamp SC, van 't Riet M, Albregts M, Marinelli A, Rijna H, Tobon Morales R, Snoj M, Bundred N, Chauvet MP, Merkus JW, Petignat P, Schinagl DA, Coens C, Peric A, Bogaerts J, van Tienhoven G. Radiotherapy or surgery of the axilla after a positive sentinel node in breast cancer patients: 10 year follow up results of the EORTC AMAROS trial (EORTC 10981/22023) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr GS4-01.

Abstract P2-11-10: Toxicity analysis of elderly breast cancer patients using different accelerated partial breast irradiation techniques

PURPOSE We investigated the acute toxicity of Accelerated Partial Breast Irradiation using external beam (EB-APBI) and intraoperative radiotherapy (IORT) technique.

MATERIALS AND METHODS Women ≥60 years with unifocal breast tumors of ≤30 mm undergoing breast conserving therapy were eligible for this prospective multi-centre cohort study. After informed consent, patients were treated with IORT in one institute, EB-APBI was applied in other institutes. IORT was applied with electrons directly on the tumor bed following lumpectomy (21 Gy at 90% isodose). EB-APBI was delivered using 3D-conformal radiotherapy or IMRT in 10 daily fractions of 3.85 Gy. Acute toxicity was scored using the CTCAE v.3, initially by the treating physician and retrospectively by blinded researchers. The highest reported toxicity until 3 months after treatment was used. Patient reported symptoms were analysed using Visual Analogue Scales (VAS) for pain and fatigue (scale 0-10), and single items from the EORTC QLQ-C30 and Breast Cancer module questionnaires at different time points up till 3 months. P<0.01 was deemed significant.

RESULTS Between January 2011 and August 2016, 622 patients were eligible, eventually 268 patients underwent IORT and 207 underwent EB-APBI. Of those, 267 (IORT) and 206 (EB-APBI) were available for toxicity analysis. Patient characteristics are shown in table 1. Although more patients experienced >grade 2 acute toxicity in the IORT group (10.4% IORT and 4.9% EB-APBI; p=0.027), grade 3 toxicity was low and did not significantly differ between groups (3.3% IORT and 1.5% EB-APBI). No grade 4 toxicity occurred. After IORT more wound infections requiring oral antibiotics (5.2% versus 1.5%) and more seroma requiring aspiration (2.2% versus 0.5%) were observed.

Results for EORTC symptoms and VAS scores are displayed in table 2. Patients treated with EB-APBI experienced significantly less fatigue direct postoperatively (EORTC p=0.003, VAS p<0.001). After 3 months, this difference dissolved, and only pain according to the VAS scale was significantly worse in the EB-APBI group (p=0.003).

Table 1. Patient characteristics  IORT, n=267EB-APBI, n=206p-valueAge(median; range) 68; 59-9067; 59-860.683pT stagepTis7%13%0.020 pT184%74%  pT29%13% pN stagepN093%97%0.092 pN17%3% ER statusPositive93%93%0.122Systemic therapyNo59%62%0.509

Table 2. EORTC and VAS scores BaselinePostoperativeAfter EB-APBI3 months after treatment IORTEB-APBIIORTEB-APBIEB-APBIIORTEB-APBIPain771920111013Fatigue1192916241723Breast pain4425211068Swollen breast122516554Oversensitive breast33362715811Skin side effects1147835VAS pain(median)  3.03.02.02.03.0VAS fatigue(median)  4.03.04.03.04.0EORTC: Scores of “quite a bit” and “very much” were scored positive. Percentage of patients that scored positive is shown.

CONCLUSION Even though more clinically relevant toxicity is seen in IORT treatment direct postoperatively, acute toxicity in both IORT and EB-APBI treatment is acceptable. IORT patients seem to recover more rapidly regarding fatigue than EB-APBI patients. This may be explained by the fact that IORT treatment is completed in one day.

Citation Format: Jacobs DHM, Marijnen CAM, Speijer G, Straver M, Marinelli A, Merkus J, Roelofzzen EMA, Zwanenburg LAG, Fisscher U, Petoukhova AL, Mast ME, Koper P. Toxicity analysis of elderly breast cancer patients using different accelerated partial breast irradiation techniques [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 P2-11-10.

Combined PET-CT and axillary lymph node marking with radioactive iodine seeds (MARI procedure) for tailored axillary treatment in node-positive breast cancer after neoadjuvant therapy

BACKGROUND

The treatment of axillary lymph node metastases after neoadjuvant systemic therapy (NST) remains debatable and axillary lymph node dissection (ALND) is still the standard of care. Marking axillary lymph nodes with radioactive iodine seeds (MARI procedure) is accurate in restaging the axilla after NST (false-negative rate 7 per cent). Here, the potential of tailored axillary treatment, determined by combining the results of PET-CT before NST with those of the MARI procedure after NST, was analysed.

METHODS

A cohort of axillary node-positive patients was used to construct a hypothetical treatment algorithm based on a combination of PET-CT and the MARI procedure. In the algorithm, the number of fluorodeoxyglucose (FDG)-avid axillary lymph nodes (1-3 versus 4 or more) before NST and the tumour status of the MARI node (positive versus negative) after NST were used to tailor axillary treatment. All patients in the cohort underwent ALND, allowing estimation of potential overtreatment and undertreatment.

RESULTS

A total of 93 patients were included in the study. Between one and three FDG-avid axillary lymph nodes were observed in 59 patients, and four or more in 34 patients. The MARI node was tumour-negative in 32 patients and showed residual disease in 61. Treatment according to the constructed algorithm would have resulted in 74 per cent of patients avoiding an ALND, with potential undertreatment in three patients (3 per cent) and overtreatment in 16 (17 per cent).

CONCLUSION

Tailored axillary treatment after NST in node-positive patients, by combining PET-CT before NST and the MARI procedure after NST, has the potential for ALND to be avoided in 74 per cent of patients.

Characterisation of multifocal breast cancer using the 70-gene signature in clinical low-risk patients enrolled in the EORTC 10041/BIG 03-04 MINDACT trial

BACKGROUND

In multifocal breast cancer, guidelines recommend basing adjuvant systemic treatment decisions on characteristics of the largest lesion, disregarding multifocality as an independent prognosticator. We assessed the association between multifocal disease and both the 70-gene signature (70-GS), and distant metastasis-free survival (DMFS) in clinical low-risk breast cancer patients enrolled in the European Organisation for Research and Treatment of Cancer 10041/BIG 03-04 Microarray In Node-negative and 1 to 3 positive lymph node Disease may Avoid ChemoTherapy (MINDACT) trial.

PATIENTS AND METHODS

The analysed population consisted of enrolled patients in the MINDACT trial with clinical low-risk disease, defined by a modified Adjuvant! Online cut-off for the 10-year risk of recurrent disease or death. Eligibility criteria of MINDACT dictate that patients with multifocal disease could be included if the different lesions had similar pathological characteristics. The presence of multifocal disease was deducted from the case report form (CRF)-question for sum of diameter for all invasive tumour foci. Clinicopathological characteristics and gene expression of patients with unifocal and multifocal (largest lesion) disease were compared. Subsequently, the association between multifocal disease and the 70-GS was evaluated as well as the association between multifocality and 5-year DMFS.

RESULTS

The study included 3090 clinical low-risk patients with unifocal and 238 patients with multifocal disease. Apart from a higher prevalence of lobular tumours (21.8% versus 10.8%, by local pathology), we did not observe differences in baseline characteristics between multifocal and unifocal tumours. Patients with multifocal tumours were more likely to be at high genomic risk as compared to patients with unifocal tumours (22.7% versus 17.3%, odds ratio [OR] 1.45, 95% confidence interval [CI] 1.02-2.07, P = 0.038). We did not find a significant association between tumour focality and DMFS (97.1% for unifocal versus 96.9% for multifocal, hazard ratio [HR] = 1.55, 95% CI 0.68-3.46, P = 0.172), nor a signal for a potential interaction between the prognostic effect of the 70-GS and focality of the tumour regarding DMFS.

CONCLUSION

In the group of clinical low-risk MINDACT patients, multifocal tumours were more likely to have a high-risk 70-GS profile compared to unifocal tumours. We did not observe a significant interaction between multifocality and the 70-GS with respect to survival without distant metastasis in these patients.

Abstract P2-01-07: Selective elimination of axillary surgery after primary systemic treatment in clinically node-positive breast cancer patients by combining PET/CT and the MARI procedure (marking the axilla with radioactive iodine seeds)

Background The increasing use of primary systemic treatment (PST) for patients with breast cancer enables more breast conserving surgery. In addition, PST converts node-positive into node-negative disease in 20-40% of patients. However, the current guidelines still recommend axillary lymph node dissection (ALND) for clinical node-positive disease (cN+), even if it became node-negative after PST, since false-negative rates of sentinel lymph node biopsy after PST range from 5-30%. Recently, an alternative technique has been introduced to stage the axilla after PST: the MARI-procedure (sensitivity 97%; FNR 7%), in which a tumour-positive lymph node is marked with a radioactive iodine seed before the start of PST and selectively removed after PST. In the present study, we propose a new strategy for treatment of the axilla in cN+ patients by combining results of the pre-PST PET/CT with the post-PST MARI-procedure.

Material and methods All patients who received a MARI-procedure from July 2014 until May 2016 were included. Before the start of PST a PET/CT was performed for axillary staging and the detection of distant metastasis. A radioactive iodine seed was placed in a proven tumour-positive axillary lymph node (MARI-node), after which PST was given according to Dutch national guidelines. At our institute, we have implemented a protocol in which results of the pre-PST PET/CT and the post-PST MARI-procedure determine the type of axillary treatment. Patients with 1-3 positive axillary lymph nodes (ALNs) on PET/CT and a tumour-negative MARI-node receive no further axillary treatment. Patients with ≤3 positive ALNs on PET/CT and a tumour-positive MARI-node receive axillary radiotherapy, as well as patients with >3 positive ALNs on PET/CT and a tumour-negative MARI-node. An ALND is only performed in patients with >3 positive ALNs on PET/CT and a tumour-positive MARI-node.

Results In total 168 patients received a PET/CT and a MARI procedure, of whom 43% were hormone receptor positive, 28% triple negative and 29% Her2-positive. One hundred and eight patients (64%) showed ≤ 3 and 60 patients (36%) >3 suspected ALNs on PET/CT before the start of PST. The axillary pathologic complete response was 39%. In 134 patients (80%) an ALND was omitted; of these patients 94 (56%) were treated with axillary radiotherapy and 40 patients (24%) received no further axillary treatment. In 34 patients (20%) an ALND was performed (Table 1). The median number of positive additional nodes at ALND was 5 (range 0-16). During a median follow-up of 6 months there were no local recurrences.

Axillary treatmentSuspective ALNs on PET/CTOutcome MARIAxillary Treatment  NoneRadiotherapyALND + Radiotherapy≤3Negative40-- Positive-68->3Negative-26- Positive--34Total409434ALN: axillary lymph nodes; ALND: axillary lymph node dissection; MARI: Marking the Axilla with Radioactive Iodine Seeds

Conclusion Combining pre-PST axillary staging with PET/CT and post-PST staging with use of the MARI-procedure results in a reduction of 80% of axillary lymph node dissections in breast cancer patients with clinical node-positive disease.

Citation Format: van der Noordaa MEM, Straver M, van Duijnhoven FH, Groen E, Stokkel M, Vrancken Peeters M-JTFD. Selective elimination of axillary surgery after primary systemic treatment in clinically node-positive breast cancer patients by combining PET/CT and the MARI procedure (marking the axilla with radioactive iodine seeds) [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 P2-01-07.

Abstract P1-03-04: Concordance of local immunohistochemistry with TargetPrint microarray based assessment of ER, PR and Her2 and BluePrint molecular subtyping in the Symphony Triple A study

PURPOSE: A decade ago intrinsic biological breast cancer subtypes have been identified which have proven to be of clinical importance in terms of outcome and response to systemic treatment. The aim of the current study is to assess concordance between breast cancer subtypes determined by local immunohistochemistry (IHC) assessment of estrogen receptor (ER), progesterone receptor (PR) and Her2-receptor status and microarray based molecular subtyping in a subset of ER+ early stage breast cancer patients.

PATIENTS AND METHODS: In this prospective observational multicenter study information on local pathology assessment and BluePrint/TargetPrint results were obtained in ER+ Dutch early stage breast cancer patients in whom a 70-gene profile (MammaPrint) was used as they were enrolled in clinical trial based on the existence of controversy regarding the additional value of adjuvant CT. Local IHC assessment of ER, PR and Her2 status were compared with microarray based assessment (TargetPrint/BluePrint) of these characteristics. Reclassification of ER and PR overexpression was assessed by a McNemars test and by Spearman correlation. Furthermore, concordance between the clinical subtypes based on local pathology (Luminal-type: ER+/PR+/Her2-; Her2-type: Her2+ disease) and molecular subtyping was assessed.

RESULTS: Between January 2013 And December 2015 660 patients, treated in 31 hospitals, were enrolled. In 564 (85%) BluePrint and/or TargetPrint was performed in addition to the 70-GS. The majority of patients had ER+/Her2- disease and TargetPrint reclassified 1% (n = 7) of patients as ER-negative (r = 0,250, p <0,001). TargetPrint reclassified 7% (n = 40) and 2% (n = 11) of patients for PR and Her2 status respectively (table 1, r = 0,580, p <0,001 for PR

Table 1. Concordance between immunohistochemistry and TargetPrint. TargetPrint result (ER, PR and Her2 resp.)  ImmunohistochemistryPositiveNegativeOverall discordance (%)p-value*Estrogenreceptor status    Positive557 (99%)6 (1%)  Negativen.a.n.a.1%n.a.Progesterone receptor status    Positive474 (96%)18 (4%)  Negative22 (31%)49 (69%)7%0,636Her2 receptor status    Positive3 (30%)7 (70%)  Negative4 (3%)546 (97%)2%0,549Equivocal0 (0%)3 (1%)  * P-value represents results of the McNemar test.). Based on IHC 545 (98%) patients were regarded as luminal-type and the remaining 2% as Her2-type. BluePrint reclassified 2% of the clinical luminal-type patients: 4 (1%) patients were reclassified as basal-type and 3 (0%) patients as Her2-type. Of the clinical Her2-type patients 80% (n=8) was reclassified by BluePrint as molecular luminal-type.

Table 2. Concordance between clinical subtyping and molecular subtyping according to BluePrint.  BluePrint resultClinical SubtypeNo. ptsLuminalBasalHer2Luminal545539 (99%)4 (1%)3 (0%)Her2108 (80%)02 (20%)Note. Overall discordance 3%.

Conclusion: In the current study we observe a high concordance between microarray-based assessment of ER, PR and Her2 and local pathology in Dutch ER+ early stage breast cancer patients. In the small subset of ER+ patients who are considered candidates for 70 GS use and who have HER2+ tumors by IHC molecular typing of HER2 status is of additional value.

Citation Format: Kuijer A, Straver M, Elias S, Smorenburg C, Wesseling J, Linn S, Rutgers E, Siesling S, van Dalen T. Concordance of local immunohistochemistry with TargetPrint microarray based assessment of ER, PR and Her2 and BluePrint molecular subtyping in the Symphony Triple A study [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 P1-03-04.

Occupancy dynamics of wild rabbits (Oryctolagus cuniculus) in the coastal dunes of the Netherlands with imperfect detection

Context Wild rabbits are considered a key species in the coastal dunes of the Netherlands, but populations have collapsed as a result of viral diseases. Aim We studied to what extent population collapse led to local extinction and whether recolonisation of empty patches in the dunes happened. Methods We investigated occupancy dynamics using data of 245 transects where rabbits were surveyed in 1984–2009. Dynamic site-occupancy models were used to analyse the data. These models adjust for imperfect detection to avoid bias in occupancy-trend estimation. Key results The decline of the rabbit population has resulted in many local extinctions, especially in woodland and in the northern part of the coastal dunes. Most transects along grassland and mixed vegetation have recently been reoccupied. The recovery of woodland occupancy is slow, probably not because of limited dispersal capacity of rabbits, but because the quality of woodland habitats is poor. Detection probability of rabbits varied considerably over the years and among habitat types, indicating the necessity of taking detection into account. Rabbits were slightly better detected when it was cloudy, windy and rainy and when lunar phase approached new moon. Conclusion Extinction and recolonisation of habitat patches varied considerably among habitat types. Implications The current slow recolonisation hampers the recovery of rabbit populations in woodland habitats in the Dutch coastal dunes. Furthermore, monitoring rabbit occupancy should take imperfect detection into account to avoid biased results.

Abstract PD06-06: Novel Surgical Technique To Assess the Response of Metastatic Axillary Lymph Nodes to Neoadjuvant Chemotherapy in Breast Cancer Patients

Background: An important benefit of neoadjuvant chemotherapy (NAC) is the increase in breast-conserving surgery. At present the response of axillary lymph node metastases to chemotherapy is not assessed accurately, since SN biopsy either before or after NAC will not provide an accurate answer. Therefore a reliable axilla-conserving therapy is not yet a benefit. We developed a new surgical technique to evaluate the axillary nodal response by Marking of the Axillary lymph node with Radioactive Iodine seeds (= the MARI procedure)

Method: Prior to NAC, tumor positive axillary lymph nodes were marked with a Iodine-125 seed under ultrasound guidance (the MARI node). After NAC, the marked lymph node was selectively removed with the use of a gamma-detection probe. A complementary axillary lymph node dissection was performed to assess whether the pathological response in the marked node was indicative for the pathological response in the additional lymph nodes.

Results: In 44 patients who were scheduled for NAC the MARI procedure was attempted. In 42 patients the tumor-positive axillary lymph node was successfully marked with a radioactive Iodine-125 seed. Two patients appeared to have overt distant metastasis and did not undergo complete axillary dissection. Thus, in 40 patients the MARI node was selectively removed after NAC. In all these patients a complementary axillary lymph node dissection was performed. In 24 patients the MARI node contained a macrometastasis after NAC. In 4 patients only isolated tumor cells (ITC) were present in the MARI node. In 24 of these 28 patients further nodal involvement was found. More importantly: in 12 patients (=30%) no residual tumor was present in the MARI node (pathological complete response= pCR) and 10 of them also showed a pCR in the complementary axillary lymph node dissection. In one patient a macrometastasis, and in one, ITC were found in one of the additional nodes. Conclusion: In this study we present the first results of a new surgical technique to assess the response of metastatic lymph nodes in the context of NAC for breast cancer; the MARI procedure. We conclude that marking tumor-positive lymph nodes before NAC and selectively removing them after NAC is feasible. Moreover we report that this MARI node is indicative for the response to NAC in the other axillary nodes: in 30% of the treated patients an axillary pCR was found which was correctly indicated by a negative MARI node in all but one patient. Thus the MARI procedure will enable us to select patients in which axillary lymph node dissection can be avoided after NAC.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr PD06-06.

Marking the axilla with radioactive iodine seeds (MARI procedure) may reduce the need for axillary dissection after neoadjuvant chemotherapy for breast cancer

Background

An important benefit of neoadjuvant chemotherapy is the increased potential for breast-conserving surgery. At present the response of axillary lymph node metastases to chemotherapy is not easily assessed, rendering axilla-conserving treatment difficult. The aim was to assess a new surgical method for evaluating the axillary response to chemotherapy.

Methods

Before neoadjuvant chemotherapy, proven tumour-positive axillary lymph nodes were localized using ultrasound-guided insertion of iodine-125-labelled (I-125) seeds. After neoadjuvant chemotherapy, the marked lymph nodes were removed selectively with the use of a γ probe. A complete axillary lymph node clearance was carried out to determine whether the pathological response in the marked node was indicative of that in the other lymph nodes.

Results

Tumour-positive axillary lymph nodes were localized successfully with I-125 seeds in 15 patients. The marked lymph node was detected and removed selectively after neoadjuvant chemotherapy in all patients. The pathological response to chemotherapy in the marked lymph node was indicative of the overall response in other removed lymph nodes.

Conclusion

This study showed that marking and selectively removing metastatic lymph nodes after neoadjuvant chemotherapy was feasible. The tumour response in the marked lymph node may be used to tailor further axillary treatment, making axilla-conserving surgery a possibility.

The relevance of breast cancer subtypes in the outcome of neoadjuvant chemotherapy

Background

Breast cancer is increasingly considered a heterogeneous disease. The aim of this study was to assess the differences between histological and receptor-based subtypes in breast-conserving surgery and pathological complete response (pCR) after neoadjuvant chemotherapy.

Method

A consecutive series of 254 patients with operable breast cancer treated with neoadjuvant chemotherapy was analyzed. Tumors were classified according to their receptor status in estrogen receptor (ER)-positive tumors (HER2-negative), triple-negative tumors, and HER2-positive tumors. The type of surgery feasible prior to neoadjuvant chemotherapy was compared with the actual surgery performed.

Results

The overall increase in breast-conserving surgery was 37% (73 of 198). In patients with ductal and lobular carcinomas this increase was 41% (63 of 152, 95% confidence interval [95% CI] 0.34–0.49) and 20% (7 of 35, 95% CI 0.10–0.36), respectively (P = 0.02). Half of the patients with lobular carcinoma had to undergo a secondary mastectomy because of incomplete resection margins. In ER-positive, triple-negative and HER2-positive tumors, the increase in breast-conserving surgery was 39% (42 of 109, 95% CI 0.30–0.48), 24% (11 of 45, 95% CI 0.14–0.38), and 45% (20 of 44, 95% CI 0.32–0.60) (P = 0.11). The pCR rate in ductal and lobular carcinomas was 12% (23 of 195) and 2% (1 of 42), respectively (P = 0.09). In ER-positive, triple-negative and HER2-positive tumors the pCR rates were 2% (3 of 138), 28% (16 of 57), and 18% (10 of 56), respectively. Multivariate analysis showed that the receptor-based subtype was the only significant predictor of pCR (P = 0.004).

Conclusion

In lobular tumors the benefit with regard to breast-conserving surgery of neoadjuvant chemotherapy is questionable. Although in ER-positive tumors the pCR rate is low, the increase in breast-conserving surgery was remarkable in ductal ER-positive tumors.

Technical aspects of the sentinel node biopsy in the EORTC AMAROS sentinel node trial

Abstract #1006

Background: The AMAROS trial is a phase III study comparing axillary lymph node dissection (ALND) with axillary radiation therapy (ART) in patients with proven axillary metastasis by sentinel node biopsy (SNB). The main objective of the trial is to prove equivalent locoregional control and reduced morbidity for ART. The aim of this interim analysis was to analyze the technical aspects of the SNB.
 Methods: The first 2000 patients with operable unifocal invasive breast cancer (5-30 mm) and clinically negative lymph nodes enrolled in the AMAROS trial between 2001 and 2005 were analyzed. The 26 participating institutions have been site visited as part of the surgical quality assurance. SNB is performed using preoperative lymphoscintigraphy, blue dye and a gamma-ray detection probe. Patients with a negative sentinel node were not subjected to ALND or ART.
 Results: The SN identification rate was 97% (range per institute 89%- 99%), 33% (n=658) of the patients were SNB positive, 62% (n=1245) were SNB negative and 2%(n=32) had other outcomes (non-axillary, missing data). Median two sentinel nodes were removed in the SNB positive as well as the SNB negative group. In 17% (344) of the patients, non-blue and non radio-active nodes were removed during the sentinel node procedure, median 1 node. In 11 patients, these nodes were the only tumor positive nodes found. In the SNB positive group the incidence of macro-, micrometastasis and isolated tumor cells was 61% (389), 26% (164) and 13% (80), respectively. In the ALND arm, further nodal involvement was seen 47,5% , 21,4 % and 16,7%, respectively. There was no correlation between the size of metastasis and the tumor size, grade or histological subtype. Of the sentinel nodes 59% (1907/3259) were radioactive and blue, 33% (1087/3259) were only radioactive, 8 %(265/3259) were only blue. Non-visualization on lymphoscintigraphy was seen in 7.6%(152), in 78%(118) of these cases a sentinel node was found during surgery. At least one sentinel node was located in the axilla in 89%(1777), in the internal mammary chain in 5% (104) and infra/supraclavicular in 1%(15). The injection site was intra/peritumoral in 53% subcutane/intradermal over the tumor in 9% periareolair in 16%, a combination in 4%, missing data 17%. Sentinel nodes in the internal mammary chain were significantly correlated with a intratumoral injection technique.
 Conclusions: These results indicate that with a 97% detection rate in this prospective international multicenter study using the combination of radioactive tracer and blue dye, the sentinel node procedure is highly effective. Differences in injection site affect the finding of non axillary sentinel nodes.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1006.

[Neoadjuvant systemic therapy in patients with operable primary breast cancer: more benefits than breast-conserving therapy]

OBJECTIVE

To analyse the extent to which primary systemic therapy (PST) achieves the main goals in patients with operable primary breast cancer, these goals being breast-conserving therapy and pathological complete remission (pCR), and to evaluate the response.

DESIGN

Retrospective.

METHOD

In a retrospective analysis of 254 patients treated with PST in 2000-2007 in the Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, patients with inoperable disease (T4 and/or N3) were excluded. The response was mostly evaluated using contrast-enhanced MRI, whereby the chemotherapy regimen was switched if the reduction in the largest diameter of contrast washout was less than 25%. pCR was defined as no evidence of invasive cancer in the breast and axilla in the resection specimen.

RESULTS

In patients with ductal carcinoma and lobular carcinoma an increase in breast-conserving therapy was seen in 32% and 17% of patients respectively. The pCR rate was 12% and 2% respectively. Secondary mastectomy because of irradical resection was required in 3% and 50% respectively. Multivariate analysis indicated that molecular type, defined on the basis of the expression of hormone receptors and human epidermal growth factor receptor 2 (HER2), i.e. luminal (oestrogen receptor-positive), basal (hormone receptor-negative and HER2-negative) and HER2-positive tumours treated with trastuzumab was the only independent predictor of pCR; 2%, 28% and 35% respectively (p=0.004). In 43 patients the chemotherapy regimen was adjusted because the tumour did not respond sufficiently. A favourable clinical response was observed in 72% (31/43) of these patients.

CONCLUSION

The observed increase in the number of breast-conserving therapies after PST was clinically relevant. PST may be more effective when contrast-enhanced MRI is used for interim evaluation, based on which the treatment may be switched. There was a clear difference in histological and molecular types of tumour and therefore the choice of treatment may be adjusted accordingly.