T. van Dalen

Prognostic value of micrometastases in sentinel lymph nodes of patients with breast carcinoma: a cohort study

BACKGROUND The prognostic meaning and thus indication for adjuvant therapy of lymphogenic micrometastases in breast cancer patients is still under debate. PATIENTS AND METHODS From 1999 to 2007, 703 patients with (c)T(1-2)N(0) breast cancer underwent surgery including sentinel lymph node biopsy. Examination of sentinel lymph nodes consisted of hematoxylin and eosin and immunohistochemistry staining following serial sectioning of the sentinel node. Patients were divided into four groups: (p)N(0) (n=423), (p)N(1micro) (n=81), (p)N(1a) (n=130) and (p)N(>or=1b) (n=69). Median follow-up was 40 months. RESULTS At the end of follow-up, 53 patients had died and 64 had recurrent disease. Compared with (p)N(0) and following adjustment for possible confounders, including adjuvant systemic treatment, overall survival was not significantly different for (p)N(1micro) while significantly worse for (p)N(1a) and (p)N(>or=1b) {hazard ratio (HR) [95% confidence interval (CI)]: 0.59 [0.14-2.58], 4.31 [1.85-10.01], 10.66 [4.04-28.14], respectively}. Likewise, disease-free survival was not significantly different for (p)N(1micro) and worse for (p)N(1a) and (p)N(>or=1b) (HR [95% CI]: 1.43 [0.67-3.02], 2.79 [1.37-5.66], 7.13 [3.27-15.54], respectively). Distant metastases were more commonly observed in the (p)N(1micro) than in the (p)N(0) group, but still not as common as in the (p)N(1a) or (p)N(>or=1b) group (HR [95% CI]: 4.85 [1.79-13.18], 10.34 [3.82-28.00], 23.25 [7.88-68.56], respectively). CONCLUSION Although the risk of distant metastases was higher in patients in the (p)N(1micro) than in the (p)N(0) group, no statistically significant differences were observed in overall or disease-free survival between (p)N(0) and (p)N(1micro). Micrometastatic lymph node involvement in itself should not be an indication for adjuvant chemotherapy in breast cancer patients.

Population based study on sentinel node biopsy before or after neoadjuvant chemotherapy in clinically node negative breast cancer patients: Identification rate and influence on axillary treatment

The timing of the sentinel lymph node biopsy (SNB) is controversial in clinically node negative patients receiving neoadjuvant chemotherapy (NAC). We studied variation in the timing of axillary staging in breast cancer patients who received NAC and the subsequent axillary treatment in The Netherlands. Patients diagnosed with clinically node negative primary breast cancer between 1st January 2010 and 30th June 2013 who received NAC and SNB were selected from the Netherlands Cancer Registry. Data on patient and tumour characteristics, axillary staging and treatment were analysed. Two groups were defined: (1) patients with SNB before NAC (N=980) and (2) patients with SNB after NAC (N=203). Eighty-three percent of patients underwent SNB before NAC, with large regional variation (35-99%). The SN identification rate differed for SNBs conducted before and after NAC (98% versus 95%; p=0.032). A lower proportion of patients had a negative SNB when assessed before NAC compared to after (54% versus 67%; p=0.001). The proportion of patients receiving any axillary treatment was higher for those with SNB before NAC than after (45% versus 33%; p=0.006). In conclusion, variation exists in the timing of SNB in clinical practice in The Netherlands for clinically node negative breast cancer patients receiving NAC. The post-NAC SN procedure is, despite some lower SN identification rate, associated with a significantly less frequent axillary treatment and thus with less expected morbidity. The effect on recurrence rate is not yet clear. Patients in this registry will be followed prospectively for long-term outcome.

CT prediction of irresectability in esophageal carcinoma: value of additional patient positions and relation to patient outcome

Abstract.Background: To improve computed tomographic (CT) prediction of local irresectability and to correlate preoperative CT findings with patient outcome. Methods: Eighty-five patients with esophageal carcinoma underwent CT in supine, left lateral decubitus, and prone positions. CT signs that were indicative of local irresectability included (1) an angle of contact >45° with the aorta; (2) obliteration of triangular fat pad between the tumor, aorta, and spine; (3) tumor contiguous with the aorta in all three positions; and (4) indentation of the airway in all three positions. Results: All CT signs indicative for local irresectability concerning the aorta had comparable percentages of false-positive scans (75%) when correlated with surgical findings. When correlated with pathologic findings, >45° angle of contact with the aorta yielded the fewest false-positive cases (9%). Concerning the airway, additional positions changed the staging correctly in 1 of 18 cases. Median survival was 21 and 8 months, respectively, for tumors considered CT resectable or irresectable. Conclusion: Additional patient positions do not improve the CT prediction of aortic invasion. Predicted resectability correlates with a significant longer life expectancy.

Contemporary risks of local and regional recurrence and contralateral breast cancer in patients treated for primary breast cancer

INTRODUCTION Breast cancer treatment has evolved extensively over the past two decades with a shift towards less invasive local treatment and increased systemic treatment. The present study aimed to investigate the rates of local (LR) and regional (RR) recurrence and contralateral breast cancer (CBC), evaluating the influence of contributing factors. MATERIALS AND METHODS We selected all female patients operated for unilateral primary breast cancer (anyTN, M0) between 2003 and 2008 from the Netherlands Cancer Registry. The 5-year risks of developing LR, RR and CBC were estimated using Kaplan-Meier statistics. The influence of various patient, tumour and treatment characteristics was subsequently assessed in multivariable analyses. RESULTS A total of 52,626 patients were identified. The rates of LR, RR and CBC were 2.7%, 1.5% and 2.9%, respectively. The rates of LR and RR decreased significantly over time in the period 2003-2008, from 3.2% to 2.4% for LR and 1.8 to 1.3% for RR, both becoming lower than the risk of CBC of 2.8%. Multivariable analysis showed that age, tumour size, lymph node involvement, tumour histologic type, grade and hormone receptor status were significant prognosticators for LR and RR, but not for CBC. A trend towards a beneficial effect of breast conserving surgery on LR and RR was seen, while systemic therapy proved to have a protective effect on all three end-points. CONCLUSIONS In breast cancer patients treated between 2003 and 2008 locoregional recurrence rates decreased and have ended up lower than the risk of developing CBC.

Abstract S3-05: Higher 10-year overall survival after breast conserving therapy compared to mastectomy in early stage breast cancer: A population-based study with 37,207 patients

Background: Randomised controlled trials have shown that breast conserving therapy (conserving surgery with radiation therapy, BCT) has equal overall survival (OS) rates as mastectomy without radiation therapy (MAST) in early stage breast cancer. However, 10-year disease-free survival (DFS) in a population-based study was not investigated before. The aim of this study was to compare 10-year OS and DFS after BCT with MAST in Dutch women with early stage breast cancer. Methods: Data of all women diagnosed with primary invasive T1-2N0-1M0 stage breast cancer between 1 January 2000 and 31 December 2004, treated with either BCT or MAST, were selected from the Netherlands Cancer Registry. Multivariable Cox proportional hazard analysis was performed to estimate 10-year OS, stratified for T and N stage. Ten-year DFS was determined in a subgroup of patients diagnosed in 2003, of which an active follow-up was conducted registering all recurrent events within 10 years. Multiple imputation was performed to account for missing data. Results: Of in total 37,207 patients, 21,734 patients (58.4%) received BCT and 15,473 patients (41.6%) received MAST. The subcohort of 2003 consisted of 7,552 patients, with similar distributions of treatments and characteristics. In the total cohort, 10-year OS was 76.8% (99% CI: 76.1-77.5%) after BCT and 59.7 (99% CI: 58.7-60.7%) after MAST. After correction for confounding, 10-year OS was better after BCT than after MAST (HRadjusted: 0.79 [99% CI 0.75-0.83]). In the 2003 cohort, 10-year DFS was 83.6% (99% CI: 82.5-84.7%) after BCT and 81.5% (99% CI: 79.6-83.4%) after MAST. After correction for confounding, 10-year DFS was comparable for both treatments (HRadjusted 0.91 [99% CI 0.77-1.07]). All results were similar for all subgroups (Table). In the 2003 cohort, 11.0% of the patients experienced distant metastases (DM) after BCT compared to 14.7% after MAST (p Conclusion: BCT showed substantially improved OS compared to MAST. However, while DFS was similar, patients treated with BCT less often developed RR and DM. Although residual factors might explain part of the difference in recurrences, we hypothesise that radiation therapy might largely be responsible for better OS by eliminating residual tumour cells. Citation Format: van Maaren MC, de Munck L, de Bock GH, Jobsen JJ, van Dalen T, Poortmans P, Linn SC, Strobbe LJA, Siesling S. Higher 10-year overall survival after breast conserving therapy compared to mastectomy in early stage breast cancer: A population-based study with 37,207 patients. [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 S3-05.

The influence of socioeconomic status and ethnicity on adjuvant systemic treatment guideline adherence for early-stage breast cancer in the Netherlands

Background We aimed to assess whether socioeconomic status (SES) and ethnicity affect adjuvant systemic therapy (AST) guideline adherence in early breast cancer patients in a health care setting with assumed equal access to care. Methods Data from all female patients surgically treated for primary unifocal early breast cancer between January 2005 and December 2014 were retrieved from the Netherlands Cancer Registry. We assessed the association between SES, ethnicity and non-adherence to adjuvant chemotherapy (CT) or endocrine therapy (ET) guideline indications with Poisson regression models, adjusting for clinicopathological variables. Results A total of 104 201 patients were included in the current analysis. Of patients without an indication, 4% and 13% received adjuvant CT or ET (overtreatment), whereas 39% and 14% of patients with an indication did not receive CT or ET (undertreatment). Medium and low SES patients were 1.01 (95% CI 1.00-1.01) and 1.01 (95% CI 1.00-1.01) times more likely to be undertreated and 0.85 (95% CI 0.76-0.94) and 0.67 (95% CI 0.60-0.75) times more likely to be overtreated with CT compared with high SES patients [resulting in an overall relative risk of CT use of 0.94 (95% CI 0.92-0.96) and 0.85 (95% CI 0.83-0.87), respectively]. No association between SES and ET guideline adherence or ethnicity and CT/ET guideline adherence was observed. Conclusion In the Netherlands, minimal SES disparities in CT guideline adherence were observed: low SES patients are less likely be overtreated and marginally more likely to be undertreated with CT resulting in an overall decreased risk of receiving CT. No ethnical disparities in AST guideline adherence were observed.

Abstract P5-08-01: Contemporary local and regional recurrence rates in very young breast cancer patients

Introduction: Historically, young breast cancer patients proved to have a poorer prognosis regarding survival and locoregional recurrence. Over the last two decades, the survival of breast cancer patients has improved substantially, while at the same time locoregional recurrence rates decreased. The diminishing recurrence rates in the overall breast cancer population and acknowledgement of tumor biology and intrinsic subtypes in relation to age, raise the question whether the historically high locoregional recurrence risk in young women has decreased over a time where systemic treatment has evolved, particularly for the aggressive tumor types that occur frequently in young women. The aim of this study was to evaluate contemporary local and regional recurrence rates in very young breast cancer patients in relation to tumor biology in the shape of intrinsic subtypes. Methods: Women Results: A total of 1,000 patients were identified. The overall 5-year LR and RR rates were 3.5% and 3.7% respectively and a decreasing trend for both rates was observed over time. Intrinsic subtype proved to be a prognostic factor for both LR and RR (P=0.0556 and P=0.0141, respectively). Particularly HR-/HER2+ tumors were associated with high LR and RR rates. Patients with lymph node metastases at time of diagnosis had a higher RR-risk in both the total population (P=0.0349) as well as within the different intrinsic subtypes, although only significantly in the triple negative group (P=0.0401). Type of surgery did not influence the rate of LR and RR in this study. Conclusions: Overall, the LR and RR rates in very young breast cancer patients were relatively low and decreased over time. The higher recurrence rates in this population were associated with the presence of more aggressive intrinsic subtypes. We emphasize that tumor biology should guide decision-making towards optimal treatment in this specific population. Although longer follow-up is needed, especially for this very young patient population, the results of this study provide important insight in the locoregional recurrence risks for this historically high-risk population. Citation Format: Aalders KC, Postma EL, Strobbe LJ, van der Heiden-van der Loo M, Sonke GS, Boersma LJ, van Diest PJ, Siesling S, van Dalen T. Contemporary local and regional recurrence rates in very young breast cancer patients. [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 P5-08-01.

Abstract P5-08-36: Contemporary risk of local breast cancer recurrence after neo-adjuvant chemotherapy: Results of a population-based cohort study:

Introduction Neo-adjuvant chemotherapy (NAC) is increasingly used in breast cancer to enable less extensive surgery and monitor the response to systemic therapy. Little is known about local recurrence (LR) in patients who received NAC. However, this information is important when deciding on optimal local treatment in these patients, especially since NAC is increasingly being offered to patients with smaller tumors. The aim of this study is to assess the contemporary rates of local breast cancer recurrence in patients that received NAC. Methods All women treated with NAC for primary invasive breast cancer in the years 2003-2008 were selected from the Netherlands Cancer Registry. The first event within five years after NAC was included for analyses. The 5-year local (LR) recurrence rate was calculated using Kaplan Meier estimates and the prognostic value of various clinicopathological and treatment factors was evaluated. Results A total of 2,457 patients were identified of whom 43% had cT1-2, 25% cT3 and 29% cT4 tumors. Two-thirds of the patients had metastatic lymph node involvement and 85% received adjuvant radiotherapy. The overall 5-year risk of LR was 6.7% and decreased from 2003-2008. The LR-rate was lower in hormone receptor positive (HR+) than HR-negative (HR-) tumors (3.3% vs. 12.9%) and increased with larger residual tumor size (from 1.2% in ypT0 to 13.0% in ypT3 and 16.1% in ypT4 tumors). The LR-rate also increased with the ypN-stage (4.1% in ypN0, 5.7% in ypN1 and 11.3% in ypN>1 patients) and was lower following breast-conserving surgery (BCS) than after mastectomy (4.8% vs. 7.2%). Currently, we are working on the multivariate analyses, which will be available at the San Antonio Breast Cancer Symposium. Conclusions The rate of LR in patients treated with NAC has decreased over time. This will most likely be caused by enhanced imaging and radiotherapy techniques, as well as by increased insight in tumor biology resulting in improvements in both the development and application of systemic treatment modalities. Multivariate analyses will have to provide further insight into the risk of developing LR in patients treated with NAC, as well as into the prognostic value of different clinicopathological factors. Citation Format: Aalders KC, Sonke GS, van der Heiden-van der Loo M, Boersma LJ, van Diest PJ, Siesling S, van Dalen T. Contemporary risk of local breast cancer recurrence after neo-adjuvant chemotherapy: Results of a population-based cohort study. [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 P5-08-36.

Abstract P4-02-01: Only in lobular breast cancer MRI use is associated with a lower risk of positive surgical margins and a reduced number of mastectomies. A real-world analysis in The Netherlands

Background The value of magnetic resonance imaging (MRI) for patients with breast cancer remains under debate. Breast MRI may contribute to the planning of local therapy, but also bears the risk of overtreatment. We analyzed the use of MRI and its impact on surgical treatment and risk of detecting contralateral breast cancer in the Netherlands. Patients and methods All patients who underwent primary surgery for stage I-III invasive breast cancer in the years 2011-2013 were identified through the Netherlands Cancer Registry. The following data were documented: year of diagnosis, hospital type and volume, age at diagnosis, clinical T and N stage, histological type and grade, presence of multifocality in resection specimen, hormone receptor status, HER2 status and use of MRI. We analyzed whether MRI use was related to type of surgery (primary or secondary mastectomy or breast conserving surgery), surgical margin involvement, and diagnosis of synchronous contralateral breast cancer. Results MRI was performed in 10,819 (29,8%) out of 36,333 patients newly diagnosed with invasive breast cancer and treated with primary surgery in the years 2011-2013 in the Netherlands. Use of MRI did not clearly increase in this period. In the multivariate analysis, patients younger than 50 years of age compared to patients aged 70 years or older (OR 6.34, 95% CI 5.86-6.87), patients with lobular breast cancer compared to those with ductal carcinoma (OR 3.46; 95% CI 3.23-3.70) and patients with multifocal tumors compared to those without multifocality (OR 2.30, 95% CI 2.15-2.45) were more likely to undergo MRI. Hospital volume ( 150) was only marginally related to MRI use (OR 0.93; 95% CI 0.87-0.99). Patients with invasive breast cancer undergoing MRI were more likely to undergo primary mastectomy than those without MRI (OR 1.21; 95% CI 1.15-1.28), but the subgroup with invasive lobular cancer undergoing MRI were less likely to undergo primary mastectomy (OR 0.85; 95% CI 0.75-0.98). A significantly lower risk of positive surgical margins was seen in patients with lobular breast cancer and breast conserving surgery who had undergone MRI as compared to those without MRI (OR 0.58, 95% CI 0.44-0.78) and, consequently, also a lower risk of secondary mastectomy (OR 0.60, 95% CI 0.41-0.87). Risk of positive surgical margins was not reduced by MRI use in patients with invasive ductal carcinoma (OR 0.91; 95% CI 0.77-1.07). Patients who underwent MRI were almost four times more frequently diagnosed with contralateral breast cancer, compared to those in whom MRI was not performed (OR 3.60, 95% CI 3.06-4.24). Conclusion Breast MRI was significantly more often used in younger patients, patients with lobular and/or multifocal breast cancer. Interestingly, MRI use was associated with less primary and secundary mastectomies in lobular invasive breast cancer, in contrast to an increased number of primary mastectomies in patients with invasive ductal cancer. MRI was further associated with an almost fourfold higher incidence of contralateral breast cancer. Citation Format: Tjan-Heijnen VC, Lobbes MB, Vriens IJ, van Bommel AC, Nieuwenhuijzen GA, Smidt ML, Boersma LJ, van Dalen T, Smorenburg CH, Siesling S, Voogd AC. Only in lobular breast cancer MRI use is associated with a lower risk of positive surgical margins and a reduced number of mastectomies. A real-world analysis in The Netherlands. [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 P4-02-01.