A Retrospective Analysis of Toxicity and Efficacy for 2 Hypofractionated Irradiation Schedules Versus a Conventional One for Post-Mastectomy Adjuvant Radiotherapy in Breast Cancer

Efficacy and safety analysis of hypofractionated and conventional fractionated radiotherapy in postoperative breast cancer patients

OBJECTIVES

In this meta-analysis, we conducted a comparative analysis of the safety and efficacy of hypofractionated and conventional fractionated radiotherapy in individuals who had undergone surgery for breast cancer.

METHODS

This study involved a systematic and independent review of relevant research articles published in reputable databases such as PubMed, Embase, Cochrane Library, and Web of Science. Two investigators conducted the review, which included studies published up to January 3, 2023. The quality of the eligible studies was evaluated and data were extracted using Review Manager software 5.4 (RevMan 5.4) to calculate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

The analysis comprised 35 studies and encompassed a collective sample of 18,246 individuals diagnosed with breast cancer. We did not find a statistically significant disparity in efficacy between conventional fractionated (CF) radiotherapy and hypofractionated (HF) radiotherapy regarding local recurrence (LR; OR = 0.91, 95% CI: 0.76-1.09, P = 0.30), disease-free survival (DFS; OR = 1.20, 95% CI: 1.01-1.42, P = 0.03), and overall survival (OS; OR = 1.08, 95% CI: 0.93-1.26, P = 0.28). Concerning safety, there was no significant difference between the HF and CF regimens in terms of breast pain, breast atrophy, lymphedema, pneumonia, pulmonary fibrosis, telangiectasia, and cardiotoxicity. However, the HF regimen resulted in lower skin toxicity (OR = 0.43, 95% CI: 0.33-0.55, P < 0.01) and improved patient fatigue outcomes (OR = 0.73, 95% CI: 0.60 - 0.88, P < 0.01).

CONCLUSIONS

Although there is no substantial difference in LR, DFS, OS, or many other side effects between the HF and CF regimens, the HF regimen reduces skin toxicity and relieves patient fatigue. If these two issues need to be addressed in clinical situations, the HF regimen may be a superior alternative to conventional radiotherapy in postoperative breast cancer patients.

Long-term treatment results of conventional and hypofractionation radiotherapy in postmastectomy cancer breast patients: A retrospective study from rural cancer center of Maharashtra, India

AIM

This study aims to evaluate the long-term treatment outcome of conventional and hypofractionation radiotherapy in postmastectomy cancer breast patients.

MATERIAL AND METHODS

A total of 140 postmastectomy breast cancer patients were included in this retrospective study, who were treated from 2012 to 2014 with chemotherapy and various fractionation radiotherapy schedules. Radiotherapy treatment records for study group-I received radiotherapy 4256 cGy in 16 fractions over 3½ weeks, group-II patients received 4005 cGy in 15 fractions over 3 weeks, and conventional radiotherapy group-III received 5000 cGy in 25 fractions over 5 weeks.

RESULTS

The median follow-up of patients from all groups was 60 months (range 9 to 111 months). There were 39 cases with disease failure, 13 (26%) in group I (42.56 Gy), 16 (40%) in group II (40.05 Gy), and 10 (20%) in group III (50 Gy). There were 4 locoregional recurrences (LRRs), two isolated, and 11 distant failures in group I, 3 LRRs (1 isolated LRR) and 15 distant failures in group II, and only one LRR and 9 distant failures in group III. The disease-free survival (DFS) were 74%, 60%, and 80%, respectively, in groups I, II, and III (P =0.044).

CONCLUSION

The long-term results of this study show that hypofractionation radiotherapy in postmastectomy cases is well tolerated and acute and late side effects are also comparable to conventional fractionation. In our study, locoregional and distant failure seems slightly higher with hypofractionation schedules than in other studies, highlighting the need for more studies with long-term follow-up in postmastectomy patients.

Significance of Hypofractionated Radiotherapy in Postoperative Irradiation for Breast Cancer: An Asian Multi-institutional Prospective Study

AIMS

There is a need for the adequate distribution of healthcare resources in Southeast Asia. Many countries in the region have more patients with advanced breast cancer who are eligible for postmastectomy radiotherapy (PMRT). Therefore, it is critical that hypofractionated PMRT is effective in most of these patients. This study investigated the significance of postoperative hypofractionated radiotherapy in patients with breast cancer, including advanced breast cancer, in these countries.

MATERIALS AND METHODS

Eighteen facilities in 10 Asian countries participated in this prospective, interventional, single-arm study. The study included two independent regimens: hypofractionated whole-breast irradiation (WBI) for patients who had undergone breast-conserving surgery and hypofractionated PMRT for patients who had undergone total mastectomy at a dose of 43.2 Gy in 16 fractions. In the hypofractionated WBI group, patients with high-grade factors received additional 8.1 Gy boost irradiation sessions for the tumour bed in three fractions.

RESULTS

Between February 2013 and October 2019, 227 and 222 patients were enrolled in the hypofractionated WBI and hypofractionated PMRT groups, respectively. The median follow-up periods in the hypofractionated WBI and hypofractionated PMRT groups were 61 and 60 months, respectively. The 5-year locoregional control rates were 98.9% (95% confidence interval 97.4-100.0) and 96.3% (95% confidence interval 93.2-99.4) in the hypofractionated WBI and hypofractionated PMRT groups, respectively. Regarding adverse events, grade 3 acute dermatitis was observed in 2.2% and 4.9% of patients in the hypofractionated WBI and hypofractionated PMRT groups, respectively. However, no other adverse events were observed.

CONCLUSION

Although further follow-up is required, hypofractionated radiotherapy regimens for postoperative patients with breast cancer in East and Southeast Asian countries are effective and safe. In particular, the proven efficacy of hypofractionated PMRT indicates that more patients with advanced breast cancer can receive appropriate care in these countries. Hypofractionated WBI and hypofractionated PMRT are reasonable approaches that can contain cancer care costs in these countries. Long-term observation is required to validate our findings.

Outcomes and toxicity following post-operative hypofractionated radiotherapy to the regional nodes and the breast or the chest wall in locally advanced breast cancer

OBJECTIVES

We aimed to analyze the impact of a 3-week schedule of HypoFractionated (HF) radiotherapy (RT) after axillary dissection and breast surgery, in terms of safety and efficacy in patients with locally advanced breast cancer (BC).

METHODS

Eligible patients were females with Stage IIA - IIIC BC who underwent axillary dissection and breast surgery, either quadrantectomy or mastectomy. HF RT was delivered in 15 or 16 fractions for a total dose of 40.05 Gy or 42.56 Gy, respectively, to the clavicular nodal region along with the whole breast (HF WBRT) or the chest wall (HF PMRT), according to the type of surgery. Locoregional recurrence (LRR), distant metastases-free survival (DMFS), overall survival (OS) and acute and late treatment-related toxicities were estimated.

RESULTS

57 patients with a median age of 60 years (32-85) were retrospectively analyzed. 34 (60%) of patients underwent breast conservative surgery in the form of quadrantectomy and 23 (40%) were offered radical mastectomy. All patients underwent hypofractionated regional nodal irradiation (HF RNI). 34 (60%) of them underwent HF WBRT, while 23 (40%) received HF PMRT.At a median follow-up of 80 months (30-113), the 7-year LRR-free survival was 93% (95% CI, 74%-95%). The same features for DMFS and OS were 76% (95% CI, 52%-78%) and 67% (95% CI, 50%-80%), respectively. Only one (2%) patient experienced G3 acute skin toxicity. No grade ≥2 late toxicity was observed.

CONCLUSION

Our study shows that HF RNI with HF RT to the whole breast or the chest wall after breast surgery is safe and effective in patients with locally advanced BC. Longer follow-up is needed to strengthen further analyses on late toxicity and clinical outcomes.

ADVANCES IN KNOWLEDGE

This paper adds to the evidence that post-operative RNI with WBRT or PMRT can be safely and effectively delivered with 3-week HF regimen. Locally advanced BC patients can be offered HF RT to the regional nodes and the breast or the chest wall regardless the type of surgery.

Ten-year outcomes of hypofractionated postmastectomy radiation therapy of 26 Gy in 6 fractions

PURPOSE

To investigate the efficacy and long-term side effects of hypofractionated postmastectomy radiation therapy (HFRT-PM) of 26 Gy in 6 fractions over 5 weeks.

MATERIALS & METHODS

We retrospectively reviewed characteristics and outcomes of patients with stage I-III breast cancer treated with HFRT-PM between 2000-2009. Treatment provided four fractions of 4 Gy (day (d)1, d3, d15, d17) then two fractions of 5 Gy (d29, d31) over 5 weeks. The treatment techniques were applied by using 3D conformal radiotherapy of chest wall with regional nodal volume if required.

RESULTS

454 patients were identified, with a median follow-up of 10.6 years (range 0.5-22.9). Regional nodal irradiation was made in 84.1 % of patients. At 10 years, the cumulative incidence of locoregional relapse was 15.1 %. In multivariate analysis, regional lymph nodes involvement (≥ 4 nodes) was associated with worse locoregional control (HR 1.68; [95% CI 1.06-2.67], p = 0.03) and overall survival (HR 2.16; [95% CI 1.59-2.95], p < 0.001). The toxicities were acceptable. The incidence of cardiac disorders (3.3 %), and symptomatic lung fibrosis (1.5 %) was low during follow-up. At 10 years, the cumulative rate of arm lymphedema was 9.5 % and considered severe in 20 patients (4.4 %).

CONCLUSION

The long-term results of this study show that HFRT-PM of 26 Gy in 6 fractions over 5 weeks seems safes but locoregional recurrence seems slightly higher than those observed in the literature, highlighting that long-term follow-up is needed and the need of randomized trials for hypofractionated radiotherapy therapy in postmastectomy situation.

Hypofractionated radiotherapy in ten fractions for postmastectomy patients: a phase II study compared with another hypofractionation schedule with sixteen fractions

Background

The purpose of this phase II study was to evaluate the feasibility of hypofractionated radiotherapy (HFRT) with a dose of 36.5 Gy in 10 fractions in postmastectomy patients.

Methods

From March 2014 to December 2015, 85 patients with locally advanced breast cancer were eligible to participate in this study with a schedule of 36.5 Gy in 10 fractions. Intensity-modulated radiation therapy (IMRT) was delivered to the chest wall with or without the supraclavicular region. The primary endpoint was radiation-related toxicities. The secondary endpoints were locoregional failure-free survival (LRFFS), disease-free survival (DFS) and overall survival (OS). And the outcomes were compared with our retrospective study of 72 patients with 42.5 Gy in 16 fractions.

Results

The median follow-up was 69.0 (range 66.5-71.5) months in the 36.5 Gy group and 93.0 (range 91.9-94.1) months in the 42.5 Gy group, respectively. Radiation-related toxicities were mainly grade 1, although a few patients had grade 2 plexopathy (1.2%) and acute skin toxicity (1.2%) in the 36.5 Gy group, and grade 2 acute skin toxicity (5.6%) and lymphedema (4.2%) in the 42.5 Gy group. There were no significant differences between the groups in acute and late toxicities. For all the patients, the 5-year LRFFS, DFS and OS were 97.7 and 100.0%, 93.1 and 90.3%, 98.8 and 97.2%, respectively, without significant differences between the groups.

Conclusion

Postmastectomy HFRT with a schedule of 36.5 Gy in 10 fractions was feasible, with mild toxicities and excellent 5-year clinical outcome.

Trial registration

Trial registration number: ChiCTR-ONRC-14004391.

Date of registration: 9/3/2014.

A radiobiological comparison of hypo-fractionation versus conventional fractionation for breast cancer 3D-conformal radiation therapy

Background

The present research was aimed to compare the toxicity and effectiveness of conventional fractionated radiotherapy versus hypo-fractionated radiotherapy in breast cancer utilizing a radiobiological model.

Materials and methods

Thirty-five left-sided breast cancer patients without involvement of the supraclavicular and axillary lymph nodes (with the nodal stage of N0) that had been treated with conventional or hypo-fractionated were incorporated in this study. A radiobiological model was performed to foretell normal tissue complication probability (NTCP) and tumor control probability (TCP).

Results

The data represented that TCP values for conventional and hypo-fractionated regimens were 99.16 ± 0.09 and 95.96 ± 0.48, respectively (p = 0.00). Moreover, the NTCP values of the lung for conventional and hypo-fractionated treatment were 0.024 versus 0.13 (p = 0.035), respectively. Also, NTCP values of the heart were equal to zero for both regimens.

Conclusion

In summary, hypo-fractionated regimens had comparable efficacy to conventional fraction radiation therapy in the case of dosimetry parameters for patients who had left breast cancer. But, utilizing the radiobiological model, conventional fractionated regimens presented better results compared to hypo-fractionated regimens.

Hypofractionated Postmastectomy Radiation Therapy

Purpose

To provide an overview of the major randomized trials that support the use of hypofractionated post-mastectomy radiation therapy for locally advanced breast cancer patients.

Methods and Materials

PubMed was systematically reviewed for publications reporting use of of hypofractionated radiation therapy in patients requiring post-mastectomy radiation.

Results

Standard fractionation, which is typically delivered over 5 to 7 weeks, is considered the standard of care in setting of post-mastectomy radiation therapy (PMRT). Modern data has helped to establish hypofractionated whole breast irradiation, which consists of a 3- to 4-week regimen, as a new standard of care for early-stage breast cancer. Hypofractionated whole breast irradiation has also laid the groundwork for the exploration of a hypofractionated approach in the setting of hypofractionated post-mastectomy radiation therapy.

Conclusions

While standard fractionation remains the most commonly utilized regimen for PMRT, recently published trials support the safety and efficacy of a hypofractionated approach. Ongoing trials are further investigating the use of hypofractionated PMRT.

Comparing hypofractionated to conventional fractionated radiotherapy in postmastectomy breast cancer: a meta-analysis and systematic review

Purpose

To compare the efficacy and toxicity of hypofractionated radiotherapy versus conventional fractionated radiotherapy in postmastectomy breast cancer using meta-analysis.

Methods

The PubMed, EMbase, Cochrane Library, Google Scholar, Wan Fang and CNKI databases were searched to identify controlled clinical trials comparing hypofractionated radiotherapy versus conventional fractionated radiotherapy in postmastectomy breast cancer. Overall survival (OS) was the primary endpoint, and disease-free survival (DFS), locoregional recurrence (LRR), distant metastasis (DM), acute skin toxicity, acute lung toxicity, late skin toxicity, lymphedema,, shoulder restriction, and late cardiac related toxicity were the secondary endpoints.

Results

Twenty-five controlled clinical trials involving 3871 postmastectomy breast cancer patients were included in this meta-analysis according to the selection criteria. The meta-analysis revealed that there were no significant differences in OS (OR = 1.08, 95% CI = 0.87~1.33, P = 0.49), DFS (OR = 1.13, 95% CI = 0.91~1.40, P = 0.28), LRR (OR = 1.01, 95% CI = 0.76~1.33, P = 0.96), DM (OR = 1.16, 95% CI = 0.85~1.58, P = 0.34), acute skin toxicity (OR = 0.94, 95% CI = 0.67~1.32, P = 0.72), acute lung toxicity (OR = 0.94, 95% CI = 0.74~1.20, P = 0.62), late skin toxicity (OR = 0.98, 95% CI = 0.75~1.27, P = 0.88), lymphedema (OR = 0.99, 95% CI = 0.77~1.28, P = 0.94), shoulder restriction (OR = 0.75, 95% CI = 0.43~1.31, P = 0.31), or late cardiac related toxicity (OR = 1.17, 95% CI = 0.82~1.65, P = 0.39) between the two groups.

Conclusions

The results of this study show that compared to conventional fractionated radiotherapy, hypofractionated radiotherapy is not significantly different with respect to efficacy or toxicity in postmastectomy breast cancer. Additional large randomized clinical trials are needed to further confirm this conclusion.

Comparison of Treatment Outcome between Hypofractionated Radiotherapy and Conventional Radiotherapy in Postmastectomy Breast Cancer

Objective:

The aim of this study was to compare Conventional fractionated radiotherapy (CFRT) and Hypofractionated radiotherapy (HFRT) in terms of treatment outcomes, such as in 5-year loco-regional recurrence free survival, disease free survival, overall survival, and distant metastatic free survival rates as well as toxicity.

Materials and Methods:

We retrospectively analyzed the data obtained from 462 breast cancer patients who received complete adjuvant radiotherapy treatment between January 2012 and December 2014. One hundred twenty eight patients received CFRT 2 Gy daily fractions at a total dose of 48-60 Gy (group 1), while 334 patients received HFRT 2.65-2.67 Gy daily for 15-19 fractions at a total dose of 39.7-47.8 Gy 9 (grup 2). Treatment outcome such as 5-year loco-regional recurrence free survival, disease free survival, overall survival, and distant metastatic free survival rates as well as toxicity were measured and compared between two groups.

Results:

Median follow-up was 65.7 months (ranging from 45.1 to 95.2 months). Five-year loco-regional recurrence free survival rate was 96.1% in both CFRT and HFRT groups (p=0.993). Five-year disease-free survival rate of CFRT group was higher (68.8%), but this difference was not significant (HFRT =63.5%) (p=0.396). These were complied with 5-year overall survival rate (71.9% and 64.7%, p=0.385). Five-year distant metastatic free survival rate was 85.9% in CFRT group and 79.6% in HFRT group (p=0.169). No difference was observed between two groups in terms of toxicities, including changes in chest wall appearance, skin fib rosis, brachial plexopathy, arm edema, pulmonary fibrosis, and cardiovascular events.

Conclusion:

The treatment outcomes of hypofractionated radiotherapy in the postmastectomy breast cancer patients is comparable to the outcomes of conventional treatment at the Chonburi Cancer Hospital as previously reported from other studies, and HFRT can be implemented in resource-limited settings.

Conventional versus hypofractionated postmastectomy radiotherapy: a report on long-term outcomes and late toxicity

Objective

We evaluated the long-term outcomes and late toxicity of conventional fractionated (CF) and hypofractionated (HF) postmastectomy radiotherapy (PMRT) in terms of locoregional recurrence-free survival (LRRFS), disease-free survival (DFS), overall survival (OS), and late toxicity.

Methods

A cohort of 1640 of breast cancer patients receiving PMRT between January 2004 and December 2014 were enrolled. Nine hundred eighty patients were treated with HF-PMRT: 2.65 Gy/fraction to a total of 42.4–53 Gy and 660 patients were treated with CF-PMRT: 2 Gy/fraction to a total of 50–60 Gy.

Results

The median follow-up time was 71.8 months (range 41.5–115.9 months). No significant difference was found in the rates of 5-year LRRFS, DFS, and OS of HF-PMRT vs CF-PMRT; 96% vs. 94% (p = 0.373), 70% vs. 72% (p = 0.849), and 73% vs. 74% (p = 0.463), respectively. We identified a cohort of 937 eligible breast cancer patients who could receive late toxicities assessment. With a median follow-up time of this patient cohort of 106.3 months (range 76–134 months), there was a significant higher incidence of grade 2 or more late skin (4% vs 1%) and subcutaneous (7% vs 2%) toxicity in patients treated with HF-PMRT vs CF-PMRT. Patients who received additional radiation boost were significantly higher in the HF-PMRT group. Grade 2 or more late RTOG/EORTC lung toxicity was significant lesser in HF-PMRT vs CF-PMRT (9% vs 16%). Grade 1 brachial plexopathy was also significant lesser in HF-PMRT vs CF-PMRT (2% vs 8%). Heart toxicity and lymphedema were similar in both groups.

Conclusions

HF-PMRT is feasible to deliver with comparable long-term efficacy to CF-PMRT. HF-PMRT had higher grade 2 or more skin and subcutaneous toxicity but less lung and brachial plexus toxicity.

Hypofractionated versus conventional fractionated postmastectomy radiotherapy for patients with high-risk breast cancer: a randomised, non-inferiority, open-label, phase 3 trial

BACKGROUND

To our knowledge, no randomised study has compared postmastectomy hypofractionated radiotherapy with conventional fractionated radiotherapy in patients with breast cancer. This study aimed to determine whether a 3-week schedule of postmastectomy hypofractionated radiotherapy is as efficacious and safe as a 5-week schedule of conventional fractionated radiotherapy.

METHODS

This randomised, non-inferiority, open-label, phase 3 study was done in a single academic hospital in China. Patients aged 18-75 years who had undergone mastectomy and had at least four positive axillary lymph nodes or primary tumour stage T3-4 disease were eligible to participate. Patients were randomly assigned (1:1) according to a computer-generated central randomisation schedule, without stratification, to receive chest wall and nodal irradiation at a dose of 50 Gy in 25 fractions over 5 weeks (conventional fractionated radiotherapy) or 43·5 Gy in 15 fractions over 3 weeks (hypofractionated radiotherapy). The modified intention-to-treat population (including all eligible patients who underwent randomisation but excluding those who were considered ineligible or withdrew consent after randomisation) was used in primary and safety analyses. The primary endpoint was 5-year locoregional recurrence, and a 5% margin was used to establish non-inferiority (equivalent to a hazard ratio <1·883). This trial is registered at ClinicalTrials.gov, number NCT00793962.

FINDINGS

Between June 12, 2008, and June 16, 2016, 820 patients were enrolled and randomly assigned to the conventional fractionated radiotherapy group (n=414) or hypofractionated radiotherapy group (n=406). 409 participants in the conventional fractionated radiotherapy group and 401 participants in the hypofractionated radiotherapy group were included in the modified intention-to-treat analyses. At a median follow-up of 58·5 months (IQR 39·2-81·8), 60 (7%) patients had developed locoregional recurrence (31 patients in the hypofractionated radiotherapy group and 29 in the conventional fractionated radiotherapy group); the 5-year cumulative incidence of locoregional recurrence was 8·3% (90% CI 5·8-10·7) in the hypofractionated radiotherapy group and 8·1% (90% CI 5·4-10·6) in the conventional fractionated radiotherapy group (absolute difference 0·2%, 90% CI -3·0 to 2·6; hazard ratio 1·10, 90% CI 0·72 to 1·69; p<0·0001 for non-inferiority). There were no significant differences between the groups in acute and late toxicities, except that fewer patients in the hypofractionated radiotherapy group had grade 3 acute skin toxicity than in the conventional fractionated radiotherapy group (14 [3%] of 401 patients vs 32 [8%] of 409 patients; p<0·0001).

INTERPRETATION

Postmastectomy hypofractionated radiotherapy was non-inferior to and had similar toxicities to conventional fractionated radiotherapy in patients with high-risk breast cancer. Hypofractionated radiotherapy could provide more convenient treatment and allow providers to treat more patients.

FUNDING

National Key Projects of Research and Development of China; the Chinese Academy of Medical Science Innovation Fund for Medical Sciences; and Beijing Marathon of Hope, Cancer Foundation of China.

A feasibility study of spatiotemporally integrated radiotherapy using the LQ model

This paper investigates the feasibility of spatiotemporally modulated radiotherapy (STMRT)-integrated model with explicit constraints on the tumor dose heterogeneity. In particular, we demonstrate the effect of the tumor dose heterogeneity on the tumor biologically effective dose (BED) achievable and optimal fractionation. We propose an STMRT model that simultaneously optimizes the dose distributions and fractionation schedule for each individual case with the maximum and minimum constraints on the tumor BED to explicitly control the level of tumor dose heterogeneity. Sixteen thoracic phantom cases were planned using (1) STMRT and (2) standard fractionation (60 Gy in 30 fractions fixed) IMRT. Constraints on the organs-at-risk (OAR) BED were identical for both plans. BEDs were calculated using the [Formula: see text] ratio of 10 Gy for the tumor and 3 Gy for all OARs. The maximum tumor BED for STMRT plans was constrained to be less than 100%-150% of the maximum tumor BED resulted from the standard fractionation plans. The mean tumor BED from STMRT plans was up to 110.7%, 128.3%, 135.0% and 148.0% of that from the standard fractionation plans when the maximum tumor BED was constrained to be less than 100%, 120%, 130% and 150% of the maximum BED achieved using the standard plans. The optimal number of fractions varied widely for different phantom geometries for the same radiobiological parameter values. The increase in the tumor BED and the range of optimal fractionation was larger with a larger tumor dose heterogeneity allowed. The results have shown the feasibility of personalizing fractionation schedule using an STMRT integrated model to deliver a maximum feasible BED to the tumor for a fixed OAR BED. The potential increase in the tumor BED was positively correlated to the tumor dose heterogeneity allowed.

Possible benefits from post-mastectomy radiotherapy in node-negative breast cancer patients: a multicenter analysis in Korea (KROG 14-22)

PURPOSE

This study was performed to identify a subset of patients who may benefit from post-mastectomy radiotherapy (PMRT) among node-negative breast cancer patients.

MATERIALS AND METHODS

We retrospectively reviewed 1,828 patients with pT1-2N0 breast cancer, treated with mastectomy without PMRT from 2005 to 2010 at 10 institutions. Univariate and multivariate analyses for locoregional recurrence (LRR) and any first recurrence (AFR) were performed according to clinicopathologic factors and biologic subtypes.

RESULTS

During a median follow-up period of 5.9 years (range: 0.7-10.4 years), 98 patients developed AFR (39 isolated LRR, 13 LRR with synchronous distant metastasis, and 46 isolated distant metastasis), and 52 patients developed LRR. The 7-year LRR and AFR rates were 3.8% and 6.7%, respectively. Multivariate analysis revealed that age of ≤ 40 years (p<0.001) and T2 stage (p=0.013) were independent risk factors for LRR. The 7-year LRR rates were 2.5% with no risk factors, 4.5% with one risk factor, and 12.4% with two risk factors. Multivariate analysis for AFR revealed that age of ≤ 40 years (p<0.001), T2 stage (p<0.001), and triple-negative biological subtype (p=0.045) were independent risk factors for AFR. The 7-year AFR rates were 3.9% with no risk factors, 8.4% with one risk factor, and 15.7% with two to three risk factors.

CONCLUSIONS

Mastectomy without PMRT is a sufficient local treatment for pT1-2N0M0 breast cancer. Nevertheless, PMRT might be considered for patients with two or three risk factors, among those of young age, with T2 tumors, and with the triple-negative biological subtype based on LRR and AFR.