One life saved by four prevented recurrences? Update of the Early Breast Cancer Trialists confirms: postoperative radiotherapy improves survival after breast conserving surgery

Improved Survival after Breast-Conserving Therapy Compared with Mastectomy in Stage I-IIA Breast Cancer

Simple Summary

The majority of patients with breast cancer are suitable for either breast-conserving therapy, consisting of breast-conserving surgery and radiation therapy, or mastectomy alone. In the present study, we compared survival outcomes in 1360 patients affected with early-stage breast cancer (stage I-IIA) according to the type of local treatment. We confirmed that patients treated with breast-conserving therapy had a lower rate of local, regional, and distant disease recurrences, and at least equivalent overall survival compared to those treated with mastectomy alone. Our results add to previous research showing a potential benefit of breast-conserving therapy when compared to mastectomy in patients suitable for both treatments at baseline.

Abstract

In the current study, we sought to compare survival outcomes after breast-conserving therapy (BCT) or mastectomy alone in patients with stage I-IIA breast cancer, whose tumors are typically suitable for both locoregional treatments. The study cohort consisted of 1360 patients with stage I-IIA (T1–2N0 or T0–1N1) breast cancer diagnosed between 2001 and 2013 and treated with either BCT (n = 1021, 75.1%) or mastectomy alone (n = 339, 24.9%). Median follow-ups for disease-free survival (DFS) and overall survival (OS) were 6.9 years (range, 0.3–15.9) and 7.5 years (range, 0.2–25.9), respectively. Fifteen (1.1%), 14 (1.0%) and 48 (3.5%) patients experienced local, regional, and distant relapse, respectively. For the whole cohort of patients, the estimated 5-year DFS and OS were 96% and 97%, respectively. After stratification based on the type of local treatment, the estimated 5-year DFS for BCT was 97%, while it was 91% (p < 0.001) for mastectomy-only treatment. Inverse probability of treatment weighting matching based on confounding confirmed that mastectomy was associated with worse DFS (HR 2.839, 95% CI 1.760–4.579, p < 0.0001), but not with OS (HR 1.455, 95% CI 0.844–2.511, p = 0.177). In our study, BCT was shown to have improved disease-specific outcomes compared to mastectomy alone, emphasizing the important role of adjuvant treatments, including postoperative radiation therapy, in patients with early-stage breast cancer at diagnosis.

Hsa-miR-375/RASD1 Signaling May Predict Local Control in Early Breast Cancer

Background: In order to characterize the various subtypes of breast cancer more precisely and improve patients selection for breast conserving therapy (BCT), molecular profiling has gained importance over the past two decades. MicroRNAs, which are small non-coding RNAs, can potentially regulate numerous downstream target molecules and thereby interfere in carcinogenesis and treatment response via multiple pathways. The aim of the current two-phase study was to investigate whether hsa-miR-375-signaling through RASD1 could predict local control (LC) in early breast cancer. Results: The patient and treatment characteristics of 81 individuals were similarly distributed between relapse (n = 27) and control groups (n = 54). In the pilot phase, the primary tumors of 28 patients were analyzed with microarray technology. Of the more than 70,000 genes on the chip, 104 potential hsa-miR-375 target molecules were found to have a lower expression level in relapse patients compared to controls (p-value < 0.2). For RASD1, a hsa-miR-375 binding site was predicted by an in silico search in five mRNA-miRNA databases and mechanistically proven in previous pre-clinical studies. Its expression levels were markedly lower in relapse patients than in controls (p-value of 0.058). In a second phase, this finding could be validated in an independent set of 53 patients using ddPCR. Patients with enhanced levels of hsa-miR-375 compared to RASD1 had a higher probability of local relapse than those with the inverse expression pattern of the two markers (log-rank test, p-value = 0.069). Conclusion: This two-phase study demonstrates that hsa-miR-375/RASD1 signaling is able to predict local control in early breast cancer patients, which—to our knowledge—is the first clinical report on a miR combined with one of its downstream target proteins predicting LC in breast cancer.

High Tangent Radiation Therapy With Field-in-Field Technique for Breast Cancer

Purpose:

We evaluated whether the field-in-field (FIF) technique improves the homogeneity of the target in high tangent radiation therapy (HTRT).

Materials and Methods:

This study included 30 patients. In total, 3 HTRT plans were created: 1 with conventional opposed fields (Conv-p), 1 with the FIF technique (FIF-p), and 1 with FIF technique using lung-blocked subfields (FIF-LB-p).

Results:

The maximum dose of the breast and planning target volume (PTV) was significantly lower for FIF-p and FIF-LB-p than Conv-p. Homogeneity index of PTV was also significantly lower for FIF-p and FIF-LB-p than Conv-p. Homogeneity index of the breast or PTV was significantly better for FIF-p than FIF-LB-p. The volumes of the breast or the PTV receiving 95% and 90% of the prescribed dose were also significantly better for FIF-p, indicating the advantages of FIF-p.

Conclusions:

The FIF technique was useful in HTRT and improved homogeneity in the target.

Hsa-miR-375 is a predictor of local control in early stage breast cancer

Background

A long-term analysis by the Early Breast Cancer Trialist Group (EBCTG) revealed a strong correlation between local control and cancer-specific mortality. MicroRNAs (miRs), short (20–25 nucleotides) non-coding RNAs, have been described as prognosticators and predictors for breast cancer in recent years. The aim of the current study was to identify miRs that can predict local control after breast conserving therapy (BCT) in early stage breast cancer.

Results

Clinical data of 46 early stage breast cancer patients with local relapse after BCT were selected from the institutional database. These patients were matched to 101 control patients showing identical clinical features but without local relapse. The study was conducted in two steps. (1) In the pilot study, 32 patients (16 relapses versus 16 controls) were screened for the most de-regulated microRNAs (= candidate microRNAs) in a panel of 1250 miRs by microarray technology. Eight miRs were found to be significantly de-regulated. (2) In the validation study, the candidate microRNAs were analyzed in an independent cohort of 115 patients (30 relapses versus 85 controls) with reverse transcription quantitative polymerase chain reaction (RT-qPCR). From these eight candidates, hsa-miR-375 could be validated. Its median fold change was 2.28 (Mann-Whitney U test, corrected p value = 0.008). In the log-rank analysis, high expression levels of hsa-miR-375 correlated with a significantly higher risk of local relapse (p = 0.003). In a multivariate analysis (forward stepwise regression) including established predictors and prognosticators, hsa-miR-375 was the only variable that was able to distinguish the statistical significance between relapse and control groups (raw p value = 0.000195 HR = 0.76, 95 % CI 0.66–0.88; corrected p value = 0.005).

Conclusions

Hsa-miR-375 predicts local control in patient with early stage breast cancer, especially in estrogen receptor α (ER-α)-positive patients. It can therefore serve as an additional molecular marker for treatment choice independently from known predictors and prognosticators. Validation in larger prospective studies is warranted.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-016-0198-1) contains supplementary material, which is available to authorized users.

Usefulness of the dual energy field-in-field technique in breast tangential radiotherapy

PURPOSE

In the field-in-field (FIF) technique in breast tangential radiotherapy, the energy of the subfield is usually the same as the energy of the main field. However, some studies have applied 10-18 MV to subfields in patients with large breasts. We compared two FIF plans in 66 breast cancer patients: in one, the energy of the subfield was the same as that of the main field (the mono energy plan); in the other, it was higher (the dual energy plan).

MATERIALS AND METHODS

The photon energy of the subfield was 6 MV in the mono energy plan and 10 MV in the dual energy plan. The percentage of the planning target volume (PTV) receiving at least 105, 100, and 95% of the prescribed dose (V105, V100, and V95, respectively) was calculated, as were the maximum and mean doses delivered to the PTV (Dmax and Dmean, respectively). Clinical target volumes (CTVs) and the thickness of the breast between the chest wall and skin surface at the level of the nipple were measured.

RESULTS

V95% was significantly higher in the dual energy plan than in the mono energy plan in patients with CTVs or breast thickness in the highest quartile. There were no significant differences in the other parameters of the two plans in these patients.

CONCLUSION

These findings demonstrate the usefulness of the dual energy FIF technique in patients with large breasts receiving breast tangential radiotherapy.

Supraclavicular and infraclavicular lymph node delineation in breast cancer patients: a proposal deriving from a comparative study

AIMS AND BACKGROUND

Current advances in radiotherapy for breast cancer require knowledge of the anatomy of irradiated areas to minimize geographic miss and spare organs at risk. This study aimed at defining a contouring approach for supraclavicular (SC) and infraclavicular (IC) nodes after mastectomy or conservative surgery in patients with breast cancer.

METHODS AND STUDY DESIGN

In 15 patients, SC and IC nodes were contoured on computed tomography slices according to Madu et al and Dijkema et al. After analyzing relapse sites, as reported by Reed et al, our approach was defined. The 3 methods were compared in all patients, quantifying differences in contours by percentage overlap (PO).

RESULTS

In our approach, SC node delineation is similar to Madu et al in the ventral and medial landmarks, but includes the lateral SC nodes described by Dijkema et al. The lateral landmarks are the scalenus anterior and medius muscle lateral border and the clavicle. Dorsal boundaries are the scalenus anterior and medius muscle ventral and lateral surfaces and the subclavian artery ventral border. In IC node delineation, major differences emerged in cranial and dorsal limits which, in our approach, are the pectoralis minor muscle upper edge and the subclavian axillary artery ventral side. Our mean and median volumes and POs were between the other 2 methods.

CONCLUSIONS

This study contributes to standardizing draining node contouring, so as to reduce variability and minimize geographic miss.

Hypofractionated radiotherapy for breast cancer acceleration of the START A treatment regime: intermediate tolerance and efficacy

Purpose

Prospective evaluation of accelerated hypofractionated radiotherapy (RT) in breast cancer patients treated with 41.6 Gy in 13 fractions plus boost delivered five times a week.

Patients and methods

Between 03/2009 and 10/2012 98 consecutive patients aged >55 years presenting with breast cancer (invasive cancer: n = 95, ductal carcinoma in situ (DCIS): n = 3) after breast conserving surgery were treated in our institution with the following schedule: 41.6 Gy in 13 fractions 4 times a week and 9 or 12 Gy boost in 3 or 4 fractions (on day 5 each week), cumulative dose: 50.6 Gy in 3.2 weeks or 53.6 Gy in 3.4 weeks, respectively depending on resection status. 56 patients had a T1 tumor, 39 a T2 tumor. N-status was as follows: N0: n = 71, N1: n = 25, N2/3: n = 2. 23 patients (24%) received chemotherapy before RT. A prospectively planned follow-up (FU) visit with objective and subjective assessment of treatment tolerance (questionnaires) was performed 0 and 8 weeks after RT completion, and one, two and four years later, respectively.

Results

Mean/median follow-up was 32/28 months (range: 12-56). After 2 years local control, loco-regional control and disease-free survival was 100%, 100%, and 98%, respectively. Overall survival was 96% at 2 years. Cosmetic outcome was very good with patients being satisfied or very satisfied in 99% (n = 86/87), 97% (n = 55/57) and 100% (n = 25/25) after one, two and four years after RT, respectively. No grade ≥ 2 pain was described in the 25 patients with a FU of at least 4 years. Fibrosis, telangiectasia and edema were found in 7-15%, 0-22% and 0-11% at one, two, and four years, respectively, and are comparable to other trials.

Conclusion

The applied hypofractionated RT regime with single doses of 3.2 Gy plus boost doses of 9-12 Gy in 3–4 fractions applied in 5 sessions a week was effective and well tolerated on intermediate term FU.

Determination of the optimal method for the field-in-field technique in breast tangential radiotherapy

Several studies have reported the usefulness of the field-in-field (FIF) technique in breast radiotherapy. However, the methods for the FIF technique used in these studies vary. These methods were classified into three categories. We simulated a radiotherapy plan with each method and analyzed the outcomes. In the first method, a pair of subfields was added to each main field: the single pair of subfields method (SSM). In the second method, three pairs of subfields were added to each main field: the multiple pairs of subfields method (MSM). In the third method, subfields were alternately added: the alternate subfields method (ASM). A total of 51 patients were enrolled in this study. The maximum dose to the planning target volume (PTV) (Dmax) and the volumes of the PTV receiving 100% of the prescription dose (V100%) were calculated. The thickness of the breast between the chest wall and skin surface was measured, and patients were divided into two groups according to the median. In the overall series, the average V100% with ASM (60.3%) was significantly higher than with SSM (52.6%) and MSM (48.7%). In the thin breast group as well, the average V100% with ASM (57.3%) and SSM (54.2%) was significantly higher than that with MSM (43.3%). In the thick breast group, the average V100% with ASM (63.4%) was significantly higher than that with SSM (51.0%) and MSM (54.4%). ASM resulted in better dose distribution, regardless of the breast size. Moreover, planning for ASM required a relatively short time. ASM was considered the most preferred method.

Partial breast re-irradiation for local recurrence of breast carcinoma: Benefit and long term side effects

INTRODUCTION AND AIMS

To evaluate the outcome after partial breast re-irradiation for in-breast tumor recurrence (IBTR) following second breast conserving surgery (BCS) as alternative to salvage mastectomy.

METHODS AND RESULTS

A survey of the literature was performed including publications between 2002 and 2012 (PubMed). Strategies comprised partial breast radiotherapy by external beam radiotherapy (EBRT), interstitial brachytherapy (BT) in low-, high- and pulse-dose rate technique, combined EBRT/BT, and intraoperative radiotherapy (IORT). Published evidence is scarce, with altogether ten articles identified, in sum reporting about 310 patients. The vast majority (82%) was treated by brachytherapy. Selection criteria for a second breast conservation attempt were comparable within all reports: all women presented with T0-2 recurrent lesions, late onset after primary treatment (70 months, mean of means) and no evidence of metastatic disease before undergoing gross tumor resection with free surgical margins. Treatment doses were in a similar range for brachytherapy (LDR 30-55 Gy, HDR 30-34 Gy; PDR 40-50 Gy), biologically comparable to the only series exclusively using EBRT (50 Gy). Follow-up times amounted 49 months (mean of the means, range 21-89). Oncologic results were similar among the different methods with local control rates ranging between 76% and 100%, and disease free and overall survival rates comparable to mastectomy series. Acute toxicity was low in all cohorts. All authors reported cosmetic outcome, scoring results from excellent to good in 60-80% of patients, mostly without using standardized evaluation schemes. Major late effects were fibrosis in re-irradiated parenchyma as a function of dose and volume, asymmetry (primarily due to double surgery), and breast pain. There were hardly any G3 and no G4 late reactions noted.

DISCUSSION AND CONCLUSION

In a highly selected group of patients with IBTR, partial breast irradiation after second BCS is a viable alternative to mastectomy, yielding high breast preservation rates without compromising oncologic safety. Whereas the evidence for brachytherapy is more solid, there is still little information about the effectiveness of PBI via EBRT or novel strategies like IORT, which therefore should preferably be investigated within trials.

Timing of radiotherapy following breast-conserving surgery: outcome of 1393 patients at a single institution

BACKGROUND

The role of postoperative radiotherapy in breast-conserving therapy is undisputed. However, optimal timing of adjuvant radiotherapy is an issue of ongoing debate. This retrospective clinical cohort study was performed to investigate the impact of a delay in surgery-radiotherapy intervals on local control and overall survival.

PATIENTS AND METHODS

Data from an unselected cohort of 1393 patients treated at a single institution over a 17-year period (1990-2006) were analyzed. Patients were assigned to two groups (CT+/CT-) according to chemotherapy status. A delay in the initiation of radiotherapy was defined as > 7 weeks (CT- group) and > 24 weeks (CT+ group).

RESULTS

The 10-year regional recurrence-free survival for the CT- and CT+ groups were 95.6 and 86.0 %, respectively. A significant increase in the median surgery-radiotherapy interval was observed over time (CT- patients: median of 5 weeks in 1990-1992 to a median of 6 weeks in 2005-2006; CT+ patients: median of 5 weeks in 1990-1992 to a median of 21 weeks in 2005-2006). There was no association between a delay in radiotherapy and an increased local recurrence rate (CT- group: p = 0.990 for intervals 0-6 weeks vs. ≥ 7 weeks; CT+ group: p = 0.644 for intervals 0-15 weeks vs. ≥ 24 weeks) or decreased overall survival (CT- group: p = 0.386 for intervals 0-6 weeks vs. ≥ 7 weeks; CT+ group: p = 0.305 for intervals 0-15 weeks vs. ≥ 24 weeks).

CONCLUSION

In the present cohort, a delay of radiotherapy was not associated with decreased local control or overall survival in the two groups (CT-/CT+). However, in the absence of randomized evidence, delays in the initiation of radiotherapy should be avoided.

Impact of respiratory motion on breast tangential radiotherapy using the field-in-field technique compared to irradiation using physical wedges

Background

This study aimed to evaluate whether the field-in-field (FIF) technique was more vulnerable to the impact of respiratory motion than irradiation using physical wedges (PWs).

Patients and methods

Ten patients with early stage breast cancer were enrolled. Computed tomography (CT) was performed during free breathing (FB). After the FB-CT data set acquisition, 2 additional CT scans were obtained during a held breath after light inhalation (IN) and light exhalation (EX). Based on the FB-CT images, 2 different treatment plans were created for the entire breast for each patient and copied to the IN-CT and EX-CT images. The amount of change in the volume of the target receiving 107%, 95%, and 90% of the prescription dose (V107%, V95%, and V90%, respectively), on the IN-plan and EX-plan compared with the FB-plan were evaluated.

Results

The V107%, V95%, and V90% were significantly larger for the IN-plan than for the FB-plan in both the FIF technique and PW technique. While the amount of change in the V107% was significantly smaller in the FIF than in the PW plan, the amount of change in the V95% and V90% was significantly larger in the FIF plan. Thus, the increase in the V107% was smaller while the increases in the V95% and V90% were larger in the FIF than in the PW plan.

Conclusions

During respiratory motion, the dose parameters stay within acceptable range irrespective of irradiation technique used although the amount of change in dose parameters was smaller with FIF technique.

Intraoperative Period and Breast Cancer: Review

Intraoperative radiation therapy in breast cancer (IORT) delivers a concentrated dose of radiation therapy to a tumor bed during surgery. IORT offers some of the following advantages with typically fewer complications like; maximum effect, sparing healthy tissues and organs, to help the patients finish treatment and get back to their normal activities. The goal of IORT is to improve local tumor control and survival rates for patients with breast cancer. IORT can both be performed with electron beams (ELIOT) and X-rays. Two main randomised trials testing intraoperative partial breast radiotherapy are TARGIT trial and the ELIOT (intraoperative radiotherapy with electrons) trial, but the techniques are fundamentally different. Whereas TARGIT delivers radiation from within the undisturbed tumour bed, for ELIOT, the mammary gland is mobilised, a prepectoral lead shield is inserted, the edges of the tumour bed are apposed, and radiation is delivered from without.

IORT with electrons as boost strategy during breast conserving therapy in limited stage breast cancer: long term results of an ISIORT pooled analysis

PURPOSE

Linac-based intraoperative radiotherapy with electrons (IOERT) was implemented to prevent local recurrences after breast conserving therapy (BCT) and was delivered as an intraoperative boost to the tumor bed prior to whole breast radiotherapy (WBI). A collaborative analysis has been performed by European ISIORT member institutions for long term evaluation of this strategy.

MATERIAL AND METHODS

Until 10/2005, 1109 unselected patients of any risk group have been identified among seven centers using identical methods, sequencing and dosage for intra- and postoperative radiotherapy. A median IOERT dose of 10 Gy was applied (90% reference isodose), preceding WBI with 50-54 Gy (single doses 1.7-2 Gy).

RESULTS

At a median follow up of 72.4 months (0.8-239), only 16 in-breast recurrences were observed, yielding a local tumor control rate of 99.2%. Relapses occurred 12.5-151 months after primary treatment. In multivariate analysis only grade 3 reached significance (p=0.031) to be predictive for local recurrence development. Taking into account patient age, annual in-breast recurrence rates amounted 0.64%, 0.34%, 0.21% and 0.16% in patients <40 years; 40-49 years; 50-59 years and ≥ 60 years, respectively.

CONCLUSION

In all risk subgroups, a 10 Gy IOERT boost prior to WBI provided outstanding local control rates, comparing favourably to all trials with similar length of follow up.