In vivodosimetry in cancer patients undergoing intraoperative radiation therapy.

In vivodosimetry (IVD) is an important tool in external beam radiotherapy (EBRT) to detect major errors by assessing differences between expected and delivered dose and to record the received dose by individual patients. Also, in intraoperative radiation therapy (IORT), IVD is highly relevant to register the delivered dose. This is especially relevant in low-risk breast cancer patients since a high dose of IORT is delivered in a single fraction. In contrast to EBRT, online treatment planning based on intraoperative imaging is only under development for IORT. Up to date, two commercial treatment planning systems proposed intraoperative ultrasound or in-room cone-beam CT for real-time IORT planning. This makes IVD even more important because of the possibility for real-time treatment adaptation. Here, we summarize recent developments and applications of IVD methods for IORT in clinical practice, highlighting important contributions and identifying specific challenges such as a treatment planning system for IORT. HDR brachytherapy as a delivery technique was not considered. We add IVD for ultrahigh dose rate (FLASH) radiotherapy that promises to improve the treatment efficacy, when compared to conventional radiotherapy by limiting the rate of toxicity while maintaining similar tumour control probabilities. To date, FLASH IORT is not yet in clinical use.

Mapping the location of local and regional recurrences according to breast cancer surgery and radiation therapy: Results from EORTC 22922/10925.

The purpose of this study is to evaluate the influence of the extent of surgery and radiation therapy (RT) on the rates and sites of local (LR) and regional recurrences (RR) in the EORTC 22922/10925 trial. PATIENTS AND METHODS: All data were extracted from the trial's individual patients' case report forms (CRF) and analysed with a median follow-up of 15.7 years. Cumulative incidence curves were produced for LR and RR accounting for competing risks: an exploratory analysis of the effect of the extent of surgical and radiation treatments on LR rate was conducted using the Fine & Gray model accounting for competing risks and adjusted for baseline patient and disease characteristics. The significance level was set at 5%, 2-sided. Frequency tables were used to describe the spatial location of LR and RR. RESULTS: Out of 4004 patients included in the trial, 282 (7%) patients experienced LR and 165 (4.1%) RR, respectively. Cumulative incidence rate of LR at 15 years was lower after mastectomy (3.1%) compared to BCS + RT (7.3%) (F&G: HR (Hazard Ratio) = 0.421, 95%CI = 0.282-0.628, p-value < 0.0001). LR were similar up to 3 years for both mastectomy and BCS but continued to occur at a steady rate for BCS + RT, only. The spatial location of the recurrence was related to the locoregional therapy applied and the absolute gain of RT correlated to stage of disease and extent of surgery. CONCLUSIONS: The extent of locoregional therapies impacts significantly on LR and RR rates and spatial location.

Trends and variation in the use of radiotherapy in non-metastatic prostate cancer: A 12-year nationwide overview from the Netherlands.

PURPOSE: This population-based study describes nationwide trends and variation in the use of primary radiotherapy for non-metastatic prostate cancer in The Netherlands in 2008-2019. METHODS: Prostate cancer patients were selected from the Netherlands Cancer Registry (N = 103,059). Treatment trends were studied over time by prognostic risk groups. Multilevel analyses were applied to identify variables associated with external beam radiotherapy (EBRT) and brachy-monotherapy versus no active treatment in low-risk disease, and EBRT versus radical prostatectomy in intermediate and high-risk disease. RESULTS: EBRT use remained stable (5-6%) in low-risk prostate cancer and increased from 21% to 32% in intermediate-risk, 37% to 45% in high-risk localized and 50% to 57% in high-risk locally advanced disease. Brachy-monotherapy decreased from 19% to 6% and from 15% to 10% in low and intermediate-risk disease, respectively, coinciding an increase of no active treatment from 55% to 73% in low-risk disease. Use of EBRT or brachy-monotherapy versus no active treatment in low-risk disease differed by region, T-stage and patient characteristics. Hospital characteristics were not associated with treatment in low-risk disease, except for availability of brachy-monotherapy in 2008-2013. Age, number of comorbidities, travel time for EBRT, prognostic risk group, and hospital characteristics were associated with EBRT versus prostatectomy in intermediate and high-risk disease. CONCLUSION: Intermediate/high-risk PCa was increasingly managed with EBRT, while brachy-monotherapy in low/intermediate-risk PCa decreased. In low-risk PCa, the no active treatment-approach increased. Variation in treatment suggests treatment decision related to patient/disease characteristics. In intermediate/high-risk disease, variation seems furthermore related to the treatment modalities available in the diagnosing hospitals.

The clinical relevance of various methods of classifying ipsilateral breast tumour recurrence as either true local recurrence or new primary.

PURPOSE: Describes the relevance of -various classification methods for ipsilateral breast tumour recurrence (IBTR) as either true recurrence (TR) or new primary (NP) on both disease-specific survival (DSS) and distant metastasis-free survival (DMFS). METHOD: Two hundred and thirty-four of 4359 women undergoing breast-conserving therapy experienced IBTR. We compared the impact of four known classification methods and two newly created classification methods. RESULTS: For three of the methods, a better DSS was observed for NP compared to TR with the hazard ratio (HR) ranging from 0.5 to 0.6. The new Twente method classification, comprising all classification criteria of three known methods, and the new Morphology method, using only morphological criteria, had the best HR and confidence interval with a HR 0.5 (95% CI 0.2-1.0) and a HR 0.5 (95% CI 0.3-1.1), respectively. For DMFS, the HR for NP compared to TR ranged from 0.6 to 0.9 for all six methods. The new Morphology method and the Twente method noted the best HR and confidence intervals with a HR 0.6 (95% CI 0.3-1.1) and a HR 0.6 (95% CI 0.4-1.2), respectively. CONCLUSION: IBTR classified as TR or NP has a prognostic value for both DSS and DMFS, but depends on the classification method used. Developing and validating a generally accepted form of classification are imperative for using TR and NP in clinical practice.

The association of internal mammary and medial supraclavicular lymph node radiation technique with clinical outcomes: Results from the EORTC 22922/10925 randomised trial.

BACKGROUND AND PURPOSE: The multicentre EORTC 22922/10925 trial (ClinicalTrials.gov, NCT00002851) was conducted between 1996 and 2004. The trial evaluated the effect of irradiation of the internal mammary and medial supraclavicular lymph node chains (IM-MS) vs no further radiation therapy (RT) on survival and cause of death in breast cancer stage I-III patients. At 15.7 years of median follow-up, a significant reduction of breast cancer specific mortality (BCSM) and any recurrence, not translating in improved overall survival (OS), and low absolute rates of side effects were found. The aim of the current analysis was to evaluate the association of RT techniques of IM-MS lymph node irradiation with long-term outcomes. PATIENTS AND METHODS: Three RT techniques were used for IM-MS: a standard technique using a fixed set-up combining photon/electron beams to the IM and tangential fields to the breast or chest wall vs a standard-modified technique with minor adaptation for beam settings vs a more individualised technique based on individual localisation of the IM. Techniques used were fixed per institution over the duration of the trial. We performed an exploratory and descriptive analysis of the outcomes after 15 years follow-up for the three RT techniques. RESULTS: Between July 1996 and January 2004, 46 radiation oncology departments from 13 countries accrued 4004 patients. Median follow-up was 15.7 years. The number of patients treated by each technique was 2440 (61%) by standard vs 635 (16%) by standard-modified vs 929 (23%) patients by individualised technique. The absolute improvements of oncological outcomes in terms of disease-free survival (DFS), OS and BCSM with IM-MS RT compared to no IM-MS RT were 6.8%, 4.9% and -5.8% for the individualised technique, vs 1.6%, 2.9% and -4.3% for modified standard and -1.4%, 1.1% and -3% for standard technique, respectively. The increase in 15-year rates of side effects due to IM-MS RT, both scored longitudinally and cross-sectionally, were similar among the techniques. CONCLUSION: Even though a straightforward comparison by technique is not possible because of variations in baseline characteristics between institutions, our findings suggest that the use of more individualised RT techniques is associated with higher rates of oncological improvements without increased risks for late side effects.

Representativeness of trial participants: linking the EORTC boost-no boost trial to the Netherlands cancer registry.

BACKGROUND AND OBJECTIVES: To evaluate the representativeness of Dutch patients participating in the European Organization for Research and Treatment of Cancer EORTC boost-no-boost trial to the target breast cancer patient population. METHODS: All female breast cancer patients diagnosed between 1989 and 1996, aged ≤70 years, treated with breast-conserving surgery and radiation therapy, were selected from the Netherlands Cancer Registry (NCR) and linked to the EORTC trial database. Baseline characteristics were compared between trial and non-trial participants, for the Dutch population and according to seven participating institutions. Kaplan-Meier curves and multivariable Cox regression were used to explore potential heterogeneity in overall survival between low, medium and high-volume institutes. RESULTS: Overall, 20,880 patients were identified from the NCR: 2,445 of 2,602 (94%) trial participants could be linked, and 18,435 were treated outside the trial. Trial participants had similar age, morphology, topography, laterality and socioeconomic status as non-trial participants, but more often stage I (62.7% vs. 56.4%) tumours and less often adjuvant treatment (22.9% vs. 26.5%). Crude 20-year survival ranged from 52.5% to 57.4%, without significant differences in multivariable analyses. CONCLUSION: This case study showed that participants in the boost-no-boost trial well represented the Dutch target population. Data linkage comes with challenges, but can close the gap between research and clinical practice.

Clinical relevance of the timing of radiotherapy after breast-conserving surgery : Results of a large, single-centre, population-based cohort study.

PURPOSE: To investigate the effect of the timing of radiation therapy after breast-conserving surgery in relation to distant metastasis-free survival and disease-specific survival. METHODS: The analysis was performed in relation to 4189 women all undergoing breast-conserving therapy (BCT). Three groups were defined with respect to lymph node status and the use of adjuvant systemic therapy (AST). Patients were categorized into time intervals: < 37 days, 37-53 days, 54-112 days and > 112 days. RESULTS: For women without lymph node metastases and with favourable characteristics aged > 55 years, an improved treatment efficacy was noted when starting radiotherapy with a time interval of < 37 days. The same was observed for women with lymph nodes metastases receiving AST aged ≤ 50 years. Finally, for women aged > 50 years with negative lymph node status but with unfavourable characteristics and receiving AST, an improved treatment efficacy was noted when starting radiotherapy after a time interval of ≥ 37 days. CONCLUSION: The results of our study further support the hypothesis that the timing of radiotherapy may have an impact on treatment efficacy and that further studies (preferably randomized trials) are indicated.

Trends and variations in the treatment of stage I-III small cell lung cancer from 2008 to 2019: A nationwide population-based study from the Netherlands.

OBJECTIVES: Recent treatment patterns for small cell lung cancer (SCLC) in the Netherlands were unknown. This nationwide population-based study describes trends and variations in the treatment of stage I-III SCLC in the Netherlands over the period 2008-2019. MATERIALS AND METHODS: Patients were selected from the population-based Netherlands Cancer Registry. Treatments were studied stratified for clinical stage. In stage II-III, factors associated with the use of concurrent (cCRT) versus sequential chemoradiation (sCRT) and accelerated versus conventionally fractionated radiotherapy in the context of cCRT were identified. RESULTS: In stage I (N = 535), 29% of the patients underwent surgery in 2008-2009 which increased to 44% in 2018-2019. Combined use of chemotherapy and radiotherapy decreased in stage I from 47% to 15%, remained constant (64%) in stage II (N = 472), and increased from 57% (2008) to 70% (2019) in stage III (N = 5,571). Use of cCRT versus sCRT in stage II-III increased over time (odds ratio (OR) 2008-2011 vs 2016-2019: 0.53 (95%-confidence interval (95%CI): 0.41-0.69)) and was strongly associated with lower age, WHO performance status 0, and diagnosis in a hospital with in-house radiotherapy. Forty-six percent of patients with stage III received cCRT in 2019. Until 2012, concurrent radiotherapy was mainly conventionally fractionated, thereafter a hyperfractionated accelerated scheme was administered more frequently (57%). Accelerated radiotherapy was strongly associated with geographic region (ORsouth vs north: 4.13 (95%CI: 3.00-5.70)), WHO performance (OR1 vs 0: 0.50 (95%CI: 0.35-0.71)), and radiotherapy facilities treating ≥ 16 vs < 16 SCLC patients annually (OR: 3.01 (95%CI: 2.38-3.79)). CONCLUSIONS: The use of surgery increased in stage I. In stages II and III, the use of cCRT versus sCRT increased over time, and since 2012 most radiotherapy in cCRT was accelerated. Treatment regimens and radiotherapy fractionation schemes varied between patient groups, regions and hospitals. Possible unwarranted treatment variation should be countered.

The impact of isolated local recurrence on long-term outcome in early-breast cancer patients after breast-conserving therapy.

PURPOSE: To analyse the prognostic impact of isolated local recurrence (ILR) on long-term outcome for early-breast cancer patients treated with breast-conserving therapy. MATERIAL AND METHODS: The data of the EORTC 22881-10882 'boost-no boost' and 22922-10925 'IM-MS' trials were used to analyse the prevalence and outcome following ILR. A multistate model described the impact of intermediate events on long-term outcomes, taking into account various prognostic factors. This model was used to predict long-term outcomes after ILR. RESULTS: Of the 8367 patients included, 726 experienced an ILR, 11.6% of them within the first 2 years and 30.0% after 10 years. Ten-year cumulative breast cancer mortality rates after ILR were 58.2% in patients with an ILR within 2 years, 31.0% for ILR between 2 and 4 years, 17.6% in patients with an ILR between 4 and 10 years, and 29.7% for ILR after year 10 (p < 0.001). The multistate model showed that when tumour-free, younger breast cancer patients had a higher probability of developing ILR compared to older patients. Shorter time to ILR was associated with a higher chance to develop distant metastases (DM), and a shorter time to development of DM were associated with an increased hazard of breast cancer-related death. The multistate model enabled prediction of long-term outcome based on individual patient covariates, length of follow-up without recurrence and timing of ILR since randomisation. CONCLUSIONS: Outcome of early-breast cancer changed not only according to baseline risk factors but also according to the presence of intermediate events, time to these events, and subsequent follow-up without any further events.

Side Effects 15 Years After Lymph Node Irradiation in Breast Cancer: Randomized EORTC Trial 22922/10925.

BACKGROUND: Uncertainty about the benefit-risk ratio of regional lymph node irradiation led to varying clinical protocols. We investigated long-term late side effects after internal mammary and medial supraclavicular (IM-MS) lymph node irradiation to improve shared decision making. METHODS: The multicenter European Organization for Research and Treatment of Cancer trial (ClinicalTrials.gov, NCT00002851) randomly assigned stage I-III breast cancer patients with involved axillary nodes and/or a medially located primary tumor. We analyzed late side effects both longitudinally at every follow-up and cross-sectionally at 5-year intervals. All statistical tests were 2-sided. RESULTS: Between 1996 and 2004, 46 departments from 13 countries accrued 4004 patients. Median follow-up was 15.7 years. Longitudinal follow-up data showed cumulative incidence rates at 15 years of 2.9% (95% confidence interval [CI] = 2.2% to 3.8%) vs 5.7% (95% CI = 4.7% to 6.9%) (P < .001) for lung fibrosis, 1.1% (95% CI = 0.7% to 1.7%) vs 1.9% (95% CI = 1.3% to 2.6%) (P = .07) for cardiac fibrosis, and 9.4% (95% CI = 8.0% to 10.8%) vs 11.1% (95% CI = 9.6% to 12.7%) (P = .04) for any cardiac disease when treated without or with IM-MS lymph node irradiation. There was no evidence for differences between left- and right-sided breast cancer (Wald χ2 test of treatment by breast side interaction, P = .33 and P = .35, for cardiac fibrosis and for any cardiac disease, respectively). The cumulative incidence probabilities of cross-sectionally reported side effects with a score of 2 or greater at 15 years were 0.1% (95% CI = 0.0% to 0.5%) vs 0.8% (95% CI = 0.4% to 1.4%) for pulmonary (P = .02), 1.8% (95% CI = 1.1% to 2.8%) vs 2.6% (95% CI = 1.8% to 3.7%) for cardiac (P = .15), and 0.0% (95% CI not evaluated) vs 0.1% (95% CI = 0.0% to 0.4%) for esophageal (P = .16), respectively. No difference was observed in the incidence of second malignancies, contralateral breast cancer, or cardiovascular deaths. CONCLUSIONS: The incidence of late pulmonary side effects was statistically significantly higher after IM-MS lymph node irradiation, as were some of the cardiac events, without a difference between left- and right-sided treatments. Absolute rates and differences were very low, without increased non-breast cancer-related mortality, even before introducing heart-sparing techniques.

Trends and variations in treatment of stage I-III non-small cell lung cancer from 2008 to 2018: A nationwide population-based study from the Netherlands.

INTRODUCTION: This Dutch population-based study describes nationwide treatment patterns and its variations for stage I-III non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: Patients diagnosed with clinical stage I-III NSCLC in the period 2008-2018 were selected from the Netherlands Cancer Registry. Treatment trends were studied over time and age groups. Use of radiotherapy versus surgery (stage I-II), and concurrent versus sequential chemoradiotherapy (stage III) were analyzed by logistic regression. RESULTS: In stage I, the rate of surgery decreased from 58 % (2008) to 40 % (2018) while radiotherapy use increased over time (from 31 % to 52 %), which mostly concerned stereotactic body radiotherapy (74 %). In stage II, 54 % of patients received surgery, and use of radiotherapy alone increased from 18 % to 25 %. The strongest factors favoring radiotherapy over surgery were WHO performance status (OR ≥ 2 vs 0: 23.39 (95% CI: 18.93-28.90)), increasing age (OR ≥ 80 vs <60 years: 14.52 (95% CI: 13.02-16.18)) and stage (OR stage II vs I: 0.61 (95% CI: 0.57-0.65)). In stage III, the combined use of chemotherapy and radiotherapy increased from 35 % (2008) to 39 % (2018). In all years, 23 % received concurrent chemoradiotherapy, 9 % sequential chemoradiotherapy, 23 % radiotherapy or chemotherapy alone, and 25 % best supportive care. The strongest factors favoring concurrent over sequential chemoradiotherapy were age (OR ≥ 80 vs <60 years: 0.14 (95% CI: 0.10-0.19)), WHO Performance status (OR ≥ 2 vs 0: 0.33 (95% CI: 0.24-0.47)) and region (OR east vs north: 0.39 (95% CI: 0.30-0.50)). CONCLUSIONS: The use of radiotherapy became more prominent over time in stage I NSCLC. Combined use of chemotherapy and radiotherapy marginally increased in stage III: only one third of patients received chemoradiotherapy, mainly concurrently. Treatment variation seen between patient groups suggests tailored treatment decision, while variation between hospitals and regions indicate differences in clinical practice.

Internal mammary and medial supraclavicular lymph node chain irradiation in stage I-III breast cancer (EORTC 22922/10925): 15-year results of a randomised, phase 3 trial.

BACKGROUND: 10-year results from several studies showed improved disease-free survival and distant metastasis-free survival, reduced breast cancer-related mortality, and variable effects on overall survival with the addition of partial or comprehensive regional lymph node irradiation after surgery in patients with breast cancer. We present the scheduled 15-year analysis of the European Organisation for Research and Treatment of Cancer (EORTC) 22922/10925 trial, which aims to investigate the impact on overall survival of elective internal mammary and medial supraclavicular (IM-MS) irradiation. METHODS: EORTC 22922/10925, a randomised, phase 3 trial done across 46 radiation oncology departments from 13 countries, included women up to 75 years of age with unilateral, histologically confirmed, stage I-III breast adenocarcinoma with involved axillary nodes or a central or medially located primary tumour. Surgery consisted of mastectomy or breast-conserving surgery and axillary staging. Patients were randomly assigned (1:1) centrally using minimisation to receive IM-MS irradiation at 50 Gy in 25 fractions (IM-MS irradiation group) or no IM-MS irradiation (control group). Stratification was done for institution, menopausal status, site of the primary tumour within the breast, type of breast and axillary surgery, and pathological T and N stage. Patients and investigators were not masked to treatment allocation. The primary endpoint was overall survival analysed according to the intention-to-treat principle. Secondary endpoints were disease-free survival, distant metastasis-free survival, breast cancer mortality, any breast cancer recurrence, and cause of death. Follow-up is ongoing for 20 years after randomisation. This study is registered with ClinicalTrials.gov, NCT00002851. FINDINGS: Between Aug 5, 1996, and Jan 13, 2004, we enrolled 4004 patients, of whom 2002 were randomly assigned to the IM-MS irradiation group and 2002 to the no IM-MS irradiation group. At a median follow-up of 15·7 years (IQR 14·0-17·6), 554 (27·7%) patients in the IM-MS irradiation group and 569 (28·4%) patients in the control group had died. Overall survival was 73·1% (95% CI 71·0-75·2) in the IM-MS irradiation group and 70·9% (68·6-72·9) in the control group (HR 0·95 [95% CI 0·84-1·06], p=0·36). Any breast cancer recurrence (24·5% [95% CI 22·5-26·6] vs 27·1% [25·1-29·2]; HR 0·87 [95% CI 0·77-0·98], p=0·024) and breast cancer mortality (16·0% [14·3-17·7] vs 19·8% [18·0-21·7]; 0·81 [0·70-0·94], p=0·0055) were lower in the IM-MS irradiation group than in the control group. No significant differences in the IM-MS irradiation group versus the control group were seen for disease-free survival (60·8% [95% CI 58·4-63·2] vs 59·9% [57·5-62·2]; HR 0·93 [95% CI 0·84-1·03], p=0·18), or distant metastasis-free survival (70·0% [67·7-72·2] vs 68·2% [65·9-70·3]; 0·93 [0·83-1·04], p=0·18). Causes of death between groups were similar. INTERPRETATION: The 15-year results show a significant reduction of breast cancer mortality and any breast cancer recurrence by IM-MS irradiation in stage I-III breast cancer. However, this is not converted to improved overall survival. FUNDING: US National Cancer Institute, Ligue Nationale contre le Cancer, and KWF Kankerbestrijding.

The Mitotic Activity Index in combination with Her2neu: a strong prognosticator in breast cancer.

PURPOSE: The aim of this study is to evaluate the prognostic value of the Mitotic Activity Index (MAI) in combination with the human epidermal growth factor receptor (Her2) for distant metastases-free survival (DMFS) and disease-specific survival (DSS) in breast cancer and compare it with the immunohistochemically (IHC) profile types. METHODS: Analyses were based on 2.923 breast-conserving breast cancer specimens with known MAI, Her2 status, and hormone receptor status, resulting in 2.678 Her2MAI combinations, MAI ≤ 12/Her2negative, MAI > 12/Her2negative, MAI > 12/Her2positive, and MAI ≤ 12/Her2positive, and 2.560 IHC profile types, luminal A, luminal B, triple negative, and non-luminal Her2positive. RESULTS: For DMFS, the MAI > 12/Her2negative combination showed a significantly worse outcome in multivariate analyses compared to the MAI ≤ 12/Her2negative combination. None of the IHC profile types showed significantly different outcomes for DMFS and DSS as compared to luminal A. We performed a separate analysis on age and lymph node status. The significance of MAI > 12/Her2negative seems to be limited to women ≤ 55 years for both DMFS and DSS. However, with respect to DSS, this seems to be limited to node negative cases. The IHC profile types for DSS, luminal B showed a significantly worse outcome for women > 55 years compared to that for luminal A, although it showed rather wide confidence interval. CONCLUSION: The MAI > 12/Her2negative combination seems to be a strong prognosticator for DMFS and DSS, particularly for women ≤ 55 years. However, none of the IHC profile types seems to be a prognosticator in breast cancer.

An actualised population-based study on the use of radiotherapy in breast cancer patients in the Netherlands.

The utilization rate of RT increased from 64.4% in 2011 to 70.3% in 2015. After BCS and mastectomy, 97.3% and 26.1% of the patients received RT, respectively. For patients undergoing BCS and mastectomy, lower age and ER + tumours were associated with higher RT utilisation rates. After mastectomy, also larger tumour sizes, lymph node involvement, grade-2 and 3 tumours and diagnosis in more recent years were associated with higher RT use.

Breast-conserving therapy in older patients with breast cancer over three decades: progress or stagnation.

BACKGROUND: The aim of this study was to analyze the distant metastases-free survival (DMFS), and disease-specific survival (DSS) after breast-conserving therapy (BCT) in older patients with breast cancer in a large, population-based, single-center cohort study with long-term follow-up. MATERIAL AND METHODS: Analyses were based on 1,425 women aged 65 years and older with breast cancer treated with BCT. Patients were divided in three age categories: 65 - 70 years, 71 - 75 years, and >75 years. The study period extended over 30 years, divided in three decades. Multivariate survival analysis was carried out using Cox regression analysis. RESULTS: The two youngest age categories showed significant improvements over time in 12-year DMFS and DSS. For women aged 65 - 70 years, this improvement was noted in stage I and stage II disease, while for women aged 71 - 75 years this was mainly in stage II tumors. Women >75 years of age did not show any improvement over time, regardless of stage. CONCLUSION: Among older Dutch women with breast cancer, outcomes with regard to DMFS and DSS after BCT differ between various age categories, showing the least gain in the very old.

Breast-conserving therapy for primary Ductal Carcinoma in Situ in The Netherlands: A multi-center study and population-based analysis.

OBJECTIVE: The aim of this study was to analyse the efficacy of breast-conserving therapy (BCT) for women with primary DCIS in a population-based setting. METHODS: Data were used from five Radiotherapy centres in The Netherlands from 2000 to 2010, all treated with BCT. Of all the cases, 59.2% received a boost of radiotherapy after their whole breast irradiation (WBI), irrespective of margin status. RESULTS: A total of 1248 cases with primary DCIS were analysed. The 10-years LRFS was 92.9%. Age ≤50 years and a positive margin were significantly related to local relapse free survival (LRFS). Having a boost had no impact on LRFS, showing a nearly equal recurrence pattern in patients with and without a boost. Separate analyses were done on patients who had received and not received a boost of radiotherapy after WBI. We noted 9.1% contra-lateral breast tumours. The 10-years disease specific survival (DSS) rate was 99.0%. CONCLUSIONS: DCIS of the breast and treated with BCT results in excellent LRFS and DSS. Primary surgical lumpectomy with negative margins followed by WBI seems to be the treatment of choice in DCIS treated with BCS with respect to IBTR.

In vivo dosimetry with MOSFETs and GAFCHROMIC films during electron IORT for Accelerated Partial Breast Irradiation.

PURPOSE: The purpose of this study was to compare the delivered dose to the expected intraoperative radiation therapy (IORT) dose with in vivo dosimetry. For IORT using electrons in accelerated partial breast irradiation, this is especially relevant since a high dose is delivered in a single fraction. METHODS: For 47 of breast cancer patients, in vivo dosimetry was performed with MOSFETs and/or GAFCHROMIC EBT2 films. A total dose of 23.33 Gy at dmax was given directly after completing the lumpectomy procedure with electron beams generated with an IORT dedicated mobile accelerator. A protection disk was used to shield the thoracic wall. RESULTS: The results of in vivo MOSFET dosimetry for 27 patients and GAFROMIC film dosimetry for 20 patients were analysed. The entry dose for the breast tissue, measured with MOSFETs, (mean value 22.3 Gy, SD 3.4%) agreed within 1.7% with the expected dose (mean value 21.9 Gy). The dose in breast tissue, measured with GAFCHROMIC films (mean value 23.50 Gy) was on average within 0.7% (SD = 3.7%, range -5.5% to 5.6%) of the prescribed dose of 23.33 Gy. CONCLUSIONS: The dose measured with MOSFETs and GAFROMIC EBT2 films agreed well with the expected dose. For both methods, the dose to the thoracic wall, lungs and heart for left sided patents was lower than 2.5 Gy even when 12 MeV was applied. The positioning time of GAFCHROMIC films is negligible and based on our results we recommend its use as a standard tool for patient quality assurance during breast cancer IORT.