Local relapse rates are falling after breast conserving surgery and systemic therapy for early breast cancer: can radiotherapy ever be safely withheld?

Postoperative radiotherapy in women with early operable breast cancer (Scottish Breast Conservation Trial): 30-year update of a randomised, controlled, phase 3 trial

BACKGROUND

Breast-conserving surgery, adjuvant systemic therapy, and radiotherapy are the standard of care for most women with early breast cancer. There are few reports of clinical outcomes beyond the first decade of follow-up of randomised trials comparing breast-conserving surgery with or without radiotherapy. We present a 30-year update of the Scottish Breast Conservation Trial.

METHODS

In this randomised, controlled, phase 3 trial across 14 hospitals in Scotland, women aged younger than 70 years with early breast cancer (tumours ≤4 cm [T1 or T2 and N0 or N1]) were included. They underwent breast-conserving surgery (1 cm margin) with axillary node sampling or clearance. Oestrogen receptor (ER)-rich patients (≥20 fmol/mg protein) received 20 mg oral tamoxifen daily for 5 years. ER-poor patients (<20 fmol/mg protein) received chemotherapy (cyclophosphamide 600 mg/m2, methotrexate 50 mg/m2, and fluorouracil 600 mg/m2 every 21 days intravenously in eight courses). Stratification was by menstrual status (within or more than 12 months from last menstrual period) and ER status (oestrogen concentration ≥20 fmol/mg protein, <20 fmol/mg protein, or unknown) and patients were randomly assigned (1:1) to high-dose (50 Gy in 20-25 fractions) local or locoregional radiotherapy versus no radiotherapy. No blinding was possible due to the nature of the treatment. We report the primary endpoint of the original trial, ipsilateral breast tumour recurrence, and the co-primary endpoint, overall survival. Clinical outcomes were compared by the log-rank test. Hazard ratios (HRs) are reported, with no radiotherapy as the reference group. Failures of the proportional hazards assumption are reported if significant. All analyses are by intention to treat.

FINDINGS

Between April 1, 1985, and Oct 2, 1991, 589 patients were enrolled and randomly assigned to the two treatment groups (293 to radiotherapy and 296 to no radiotherapy). After exclusion of four ineligible patients (two in each group), there were 291 patients in the radiotherapy group and 294 patients in the no radiotherapy group. Median follow-up was 17·5 years (IQR 8·4-27·9). Ipsilateral breast tumour recurrence was significantly lower in the radiotherapy group than in the no radiotherapy group (46 [16%] of 291 vs 107 [36%] of 294; HR 0·39 [95% CI 0·28-0·55], p<0·0001). Although there were differences in the hazard rate for ipsilateral breast tumour recurrence in the first decade after treatment (HR 0·24 [95% CI 0·15-0·38], p<0·0001), subsequent risks of ipsilateral breast tumour recurrence were similar in both groups (0·98 [0·54-1·79], p=0·95). There was no difference in overall survival between the two groups (median 18·7 years [95% CI 16·5-21·5] in the no radiotherapy group vs 19·2 years [16·9-21·3] in the radiotherapy group; HR 1·08 [95% CI 0·89-1 ·30], log-rank p=0·43).

INTERPRETATION

Our findings suggest that patients whose biology predicts a late relapse a decade or more after breast-conserving surgery for early breast cancer might gain little from adjuvant radiotherapy.

FUNDING

Breast Cancer Institute (part of Edinburgh and Lothian Health Foundation) and PFS Genomics (now part of Exact Sciences).

Locoregional Ablative Radiation Therapy for Patients With Breast Cancer Unsuitable for Surgical Resection

PURPOSE

Patients with breast cancer who are unsuitable for surgical resection are typically managed with palliative systemic therapy alone. We report outcomes of 5-fraction ablative radiation therapy for nonresected breast cancers.

METHODS AND MATERIALS

This is a retrospective analysis of an institutional registry of patients with breast cancer who were unsuitable for resection and underwent 35 to 40 Gy/5 fractions to the primary breast tumor or regional lymph nodes from 2014 to 2021. Primary outcomes were cumulative incidence of local failure and grade ≥3 toxicity (Common Terminology Criteria for Adverse Events, version 5.0).

RESULTS

We reviewed 57 patients who received 61 treatment courses (median age of 81 years; range, 38-99). Unresectable tumor (10%), patient refusal (18%), medical inoperability (35%), and metastatic disease (37%) were the causes of not having surgery. Five patients (8%) had previously undergone adjuvant locoregional radiation therapy. Fifty-four percent (n = 33/61) of treatment courses targeted the breast only, 31% (n = 19/61) both the breast and lymph nodes, and 15% (n = 9/61) the lymph nodes only. Sixty-seven percent (n = 35/52) of the courses that targeted the breast were delivered with partial breast irradiation and 33% (n = 17/52) with whole breast radiation therapy (median dose of 25 Gy in 5 fractions) ± simultaneous integrated boost to the primary tumor. Most primary tumors (65%, n = 34/52) and target lymph nodes (61%, n = 17/28) were treated with a dose of 35 Gy in 5 fractions. Most treatments (52%) were delivered with intensity modulated radiation therapy (IMRT). Radiation therapy was delivered daily (20%), every other day (18%), twice weekly (36%), or weekly (26%). The 2-year cumulative incidence of local failure was 11.4% and grade≥3 toxicity was 15.1%. The grade ≥3 toxicity was 6.5% for IMRT treatments, versus 7.7% for non-IMRT treatments targeting partial breast or lymph nodes (hazard ratio, 1.13, P = .92), versus 38.9% for non-IMRT treatments targeting the entire breast (hazard ratio, 6.91, P = .023). All grade ≥3 toxicity cases were radiation dermatitis. No cases of brachial plexopathy were observed.

CONCLUSIONS

Thirty-five to 40 Gy in 5 fractions is a safe and effective breast stereotactic body radiation therapy (SBRT) regimen and may be an attractive option for patients who are not surgical candidates. Highly conformal techniques (ie, IMRT or partial breast irradiation) were associated with a reduced risk of toxicity and should be the preferred treatment approaches.

Omission of radiation therapy post breast conserving surgery

Radiation therapy (RT) after breast conserving surgery decreases the risks of local recurrence and breast cancer mortality in the multidisciplinary management of patients with breast cancer. However, breast cancer is a heterogeneous disease, and the absolute benefit of post-operative RT in individual patients varies substantially. Clinical trials aiming to identify patients with low-risk early breast cancer in whom post-operative RT may be safely omitted, based on conventional clinical-pathologic variables alone, have not provided sufficiently tailored information on local recurrence risk assessment to guide treatment decisions. The majority of patients with early breast cancer continue to be routinely treated with RT after breast conserving surgery. This approach may represent over-treatment for a substantial proportion of the patients. The clinical impact of genomic signatures on local therapy decisions for early breast cancer has been remarkably modest due to the lack of high-level evidence supporting their clinical validity for assessment of the risk of local recurrence. Efforts to personalise breast cancer care must be supported by high level evidence to enable balanced, informed treatment decisions. These considerations underpin the importance of ongoing biomarker-directed clinical trials to generate the high-level evidence necessary for setting the future standard of care in personalised local therapy for patients with early breast cancer.

Comparison of partial-breast irradiation and intraoperative radiation to whole-breast irradiation in early-stage breast cancer patients: a Kaplan-Meier-derived patient data meta-analysis

PURPOSE

Partial breast irradiation (PBI) and intraoperative radiation (IORT) represent alternatives to whole breast irradiation (WBI) following breast conserving surgery. However, data is mixed regarding outcomes. We therefore performed a pooled analysis of Kaplan-Meier-derived patient data from randomized trials to evaluate the hypothesis that PBI and IORT have comparable long-term rates of ipsilateral breast tumor recurrence as WBI.

METHODS

In February, 2023, PubMed, EMBASE and Cochrane Central were systematically searched for randomized phase 3 trials of early-stage breast cancer patients undergoing breast-conserving surgery with PBI or IORT as compared to WBI. Time-to-event outcomes of interest included ipsilateral breast tumor recurrence (IBTR), overall survival (OS) and distant disease-free survival (DDFS). Statistical analysis was performed with R Statistical Software.

RESULTS

Eleven randomized trials comprising 15,460 patients were included; 7,675 (49.6%) patients were treated with standard or moderately hypofractionated WBI, 5,413 (35%) with PBI and 2,372 (15.3%) with IORT. Median follow-up was 9 years. PBI demonstrated comparable IBTR risk compared with WBI (HR 1.20; 95% CI 0.95-1.52; p = 0.12) with no differences in OS (HR 1.02; 95% CI 0.90-1.16; p = 0.70) or DDFS (HR 1.15; 95% CI 0.81-1.64; p = 0.43). In contrast, patients treated with IORT had a higher IBTR risk (HR 1.46; 95% CI 1.23-1.72; p < 0.01) compared with WBI with no difference in OS (HR 0.98; 95% CI 0.84-1.14; p = 0.81) or DDFS (HR 0.91; 95% CI 0.76-1.09; p = 0.31).

CONCLUSION

For patients with early-stage breast cancer following breast-conserving surgery, PBI demonstrated no difference in IBTR as compared to WBI while IORT was inferior to WBI with respect to IBTR.

Effect of high-dose radiation therapy on positive margins after breast-conserving surgery for invasive breast cancer

PURPOSE

Positive margins after breast-conserving surgery are associated with poor oncological outcomes and warrant additional surgery. This study aimed to evaluate the effectiveness of high-dose radiation therapy for positive margins by comparing local recurrence between patients with positive and negative margins.

METHODS

We retrospectively evaluated 550 patients treated with adjuvant radiation therapy after breast-conserving surgery for invasive breast cancer between 2013 and 2019. The total equivalent dose in 2 Gy fractions (EQD2) to the tumor bed ranged from 65.81 to 66.25 Gy for positive margins and 59.31-61.81 Gy for negative margins. The differences in local recurrence between the positive and negative margin groups were analyzed.

RESULTS

After a median follow-up of 58 months, the crude local recurrence rate was 7.3% in the positive margin group (n = 55) and 2.4% in the negative margin group (n = 495). Positive margins were associated with higher local recurrence without statistical significance in the entire cohort (p = 0.062). Among patients aged <60 years, those with positive margins had a significantly lower 5-year local recurrence-free survival rate than those with negative margins (89.16% vs. 97.57%, respectively; p = 0.005). In contrast, there was no significant difference in the 5-year local recurrence-free survival rate between patients with positive and negative margins among those aged ≥60 years (100.00% vs. 94.38%, respectively; p = 0.426).

CONCLUSION

In this study, positive margins were not associated with poor local control in older patients after a high-dose boosts. Further prospective studies are needed to verify our findings.

Omitting Radiotherapy after Breast-Conserving Surgery in Luminal A Breast Cancer

BACKGROUND

Adjuvant radiotherapy is prescribed after breast-conserving surgery to reduce the risk of local recurrence. However, radiotherapy is inconvenient, costly, and associated with both short-term and long-term side effects. Clinicopathologic factors alone are of limited use in the identification of women at low risk for local recurrence in whom radiotherapy can be omitted. Molecularly defined intrinsic subtypes of breast cancer can provide additional prognostic information.

METHODS

We performed a prospective cohort study involving women who were at least 55 years of age, had undergone breast-conserving surgery for T1N0 (tumor size <2 cm and node negative), grade 1 or 2, luminal A-subtype breast cancer (defined as estrogen receptor positivity of ≥1%, progesterone receptor positivity of >20%, negative human epidermal growth factor receptor 2, and Ki67 index of ≤13.25%), and had received adjuvant endocrine therapy. Patients who met the clinical eligibility criteria were registered, and Ki67 immunohistochemical analysis was performed centrally. Patients with a Ki67 index of 13.25% or less were enrolled and did not receive radiotherapy. The primary outcome was local recurrence in the ipsilateral breast. In consultation with radiation oncologists and patients with breast cancer, we determined that if the upper boundary of the two-sided 90% confidence interval for the cumulative incidence at 5 years was less than 5%, this would represent an acceptable risk of local recurrence at 5 years.

RESULTS

Of 740 registered patients, 500 eligible patients were enrolled. At 5 years after enrollment, recurrence was reported in 2.3% of the patients (90% confidence interval [CI], 1.3 to 3.8; 95% CI, 1.2 to 4.1), a result that met the prespecified boundary. Breast cancer occurred in the contralateral breast in 1.9% of the patients (90% CI, 1.1 to 3.2), and recurrence of any type was observed in 2.7% (90% CI, 1.6 to 4.1).

CONCLUSIONS

Among women who were at least 55 years of age and had T1N0, grade 1 or 2, luminal A breast cancer that were treated with breast-conserving surgery and endocrine therapy alone, the incidence of local recurrence at 5 years was low with the omission of radiotherapy. (Funded by the Canadian Cancer Society and the Canadian Breast Cancer Foundation; LUMINA ClinicalTrials.gov number, NCT01791829.).

Breast-Conserving Surgery with or without Irradiation in Early Breast Cancer

BACKGROUND

Limited level 1 evidence is available on the omission of radiotherapy after breast-conserving surgery in older women with hormone receptor-positive early breast cancer receiving adjuvant endocrine therapy.

METHODS

We performed a phase 3 randomized trial of the omission of irradiation; the trial population included women 65 years of age or older who had hormone receptor-positive, node-negative, T1 or T2 primary breast cancer (with tumors ≤3 cm in the largest dimension) treated with breast-conserving surgery with clear excision margins and adjuvant endocrine therapy. Patients were randomly assigned to receive whole-breast irradiation (40 to 50 Gy) or no irradiation. The primary end point was local breast cancer recurrence. Regional recurrence, breast cancer-specific survival, distant recurrence as the first event, and overall survival were also assessed.

RESULTS

A total of 1326 women were enrolled; 658 were randomly assigned to receive whole-breast irradiation and 668 to receive no irradiation. The median follow-up was 9.1 years. The cumulative incidence of local breast cancer recurrence within 10 years was 9.5% (95% confidence interval [CI], 6.8 to 12.3) in the no-radiotherapy group and 0.9% (95% CI, 0.1 to 1.7) in the radiotherapy group (hazard ratio, 10.4; 95% CI, 4.1 to 26.1; P<0.001). Although local recurrence was more common in the group that did not receive radiotherapy, the 10-year incidence of distant recurrence as the first event was not higher in the no-radiotherapy group than in the radiotherapy group, at 1.6% (95% CI, 0.4 to 2.8) and 3.0% (95% CI, 1.4 to 4.5), respectively. Overall survival at 10 years was almost identical in the two groups, at 80.8% (95% CI, 77.2 to 84.3) with no radiotherapy and 80.7% (95% CI, 76.9 to 84.3) with radiotherapy. The incidence of regional recurrence and breast cancer-specific survival also did not differ substantially between the two groups.

CONCLUSIONS

Omission of radiotherapy was associated with an increased incidence of local recurrence but had no detrimental effect on distant recurrence as the first event or overall survival among women 65 years of age or older with low-risk, hormone receptor-positive early breast cancer. (Funded by the Chief Scientist Office of the Scottish Government and the Breast Cancer Institute, Western General Hospital, Edinburgh; ISRCTN number, ISRCTN95889329.).

Breast cancer: an up-to-date review and future perspectives

Breast cancer is the most common cancer worldwide. The occurrence of breast cancer is associated with many risk factors, including genetic and hereditary predisposition. Breast cancers are highly heterogeneous. Treatment strategies for breast cancer vary by molecular features, including activation of human epidermal growth factor receptor 2 (HER2), hormonal receptors (estrogen receptor [ER] and progesterone receptor [PR]), gene mutations (e.g., mutations of breast cancer 1/2 [BRCA1/2] and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha [PIK3CA]) and markers of the immune microenvironment (e.g., tumor-infiltrating lymphocyte [TIL] and programmed death-ligand 1 [PD-L1]). Early-stage breast cancer is considered curable, for which local-regional therapies (surgery and radiotherapy) are the cornerstone, with systemic therapy given before or after surgery when necessary. Preoperative or neoadjuvant therapy, including targeted drugs or immune checkpoint inhibitors, has become the standard of care for most early-stage HER2-positive and triple-negative breast cancer, followed by risk-adapted post-surgical strategies. For ER-positive early breast cancer, endocrine therapy for 5-10 years is essential. Advanced breast cancer with distant metastases is currently considered incurable. Systemic therapies in this setting include endocrine therapy with targeted agents, such as CDK4/6 inhibitors and phosphoinositide 3-kinase (PI3K) inhibitors for hormone receptor-positive disease, anti-HER2 targeted therapy for HER2-positive disease, poly(ADP-ribose) polymerase inhibitors for BRCA1/2 mutation carriers and immunotherapy currently for part of triple-negative disease. Innovation technologies of precision medicine may guide individualized treatment escalation or de-escalation in the future. In this review, we summarized the latest scientific information and discussed the future perspectives on breast cancer.

Postmastectomy radiotherapy in high-risk breast cancer patients given adjuvant systemic therapy. A 30-year long-term report from the Danish breast cancer cooperative group DBCG 82bc trial

BACKGROUND

Between 1982 and 1990 the Danish Breast Cancer Cooperative Group (DBCG) conducted a randomized trial in high-risk pre- and postmenopausal (<70 years) breast cancer patients comparing mastectomy plus adjuvant systemic therapy alone versus the same treatment plus postoperative irradiation.

AIM

To present a comprehensive analysis of the complete DBCG 82bc study with a 30-year long-term follow-up of the cancer therapeutic effect and survival, together with an additional focus on the potential long-term life-threatening morbidity related to cardiac irradiation and/or the risk of secondary cancer induction.

METHODS

A total of 3083 patients with pathological stage II and stage III breast cancer were after mastectomy randomly assigned to receive adjuvant systemic therapy and postoperative irradiation to the chestwall and regional lymph nodes (1538 pts), or adjuvant systemic therapy alone (1545 pts). Pre- and menopausal patients (DBCG 82b) received 8-9 cycles of CMF with an interval of 4 weeks, whereas postmenopausal patients (DBCG 82c) received tamoxifen 30 mg daily for one year. The median follow-up time was 34 years. The primary endpoints were loco-regional recurrence (LRR) and overall mortality, and the secondary endpoints were distant metastasis, breast cancer mortality, and irradiation related late morbidity.

RESULTS

Overall the 30-year cumulative incidence of loco-regional recurrence was 9% in irradiated patients versus 37% in non-irradiated patients who received adjuvant systemic therapy alone (HR: 0.21 [95% cfl 0.18-0.26]). Distant metastasis probability at 30 years was 49% in irradiated patients compared to 60% in non-irradiated (HR: 0.77 [0.70-0.84]). Consequently, these figures resulted in a reduced breast cancer mortality: 56% vs 67% (HR: 0.75 [0.69-0.82], and overall mortality (81% vs 86% at 30 years (p < 0.0001), HR: 0.83 [0.77-0.90] in favor of irradiation. Radiotherapy did not result in any significant excess death of other courses, such as ischemic heart disease, HR: 0.82 [0.58-1.18]; nor secondary lung cancer HR: 1.44 [0.92-2.24], or other non-cancer related death HR: 1.15 [0.92-1.45].

CONCLUSION

The study definitely demonstrate that optimal long-term treatment benefit of high-risk breast cancer can only be achieved if both loco-regional and systemic tumor control are aimed for. Therefore, radiotherapy has an important role in the multidisciplinary treatment of breast cancer. The PMRT treatment did not result in excess ischemic heart damage, nor in other non-breast cancer related death.

The effectiveness of radiotherapy in preventing disease recurrence after breast cancer surgery

BACKGROUND AND OBJECTIVES

The locoregional management of breast cancer has a critical impact on prognosis. This study aimed to analyze the effectiveness of radiotherapy against the deleterious effect of positive surgical margins on disease outcomes.

METHODS

Retrospective, single-center study enrolled 721 breast cancer patients with a median follow-up of approximately 64.50 months (3.67-247.40). Analyses were performed considering the end of adjuvant therapy, except endocrine therapy. Kaplan-Meier and Cox regression were performed to obtain the predictive value of treatments.

RESULTS

The minimally adequate radiotherapy (≥45 cGy) was associated with improved outcomes in breast cancer patients compared to inadequate radiotherapy (<45 cGy/no) by controlling locoregional relapses and distant metastasis. In patients with positive surgical margins (n = 53), radiotherapy was associated with an approximate decrease of 90% in locoregional relapse risk [adjusted HR: 0.108 (0.012-0.932), p = 0.043]. Radiotherapy did not alter the adverse effect of positive surgical margins, especially in patients with a higher risk of poorly differentiated tumors (n = 146), presence of lymphovascular invasion (n = 163), and triple-negative subtype (n = 113). Notwithstanding, radiotherapy was associated with respective decreases of distant metastasis risk of 75.2% [adjusted HR: 0.248 (0.081-0.762), p = 0.015] and 67.8% [adjusted HR: 0.322 (0.101-1.029), p = 0.056] in patients with triple-negative tumors or with lymphovascular invasion.

CONCLUSION

Adequate radiotherapy is associated with better outcomes in breast cancer. Despite improving locoregional relapse-free survival, radiotherapy does not ablate positive surgical margins, a factor of poorer prognosis that prevails mainly in patients with factors of higher relapse risk.

What Is High-risk Breast Cancer With Pathologically Negative Lymph Nodes for Regional Recurrence?

PURPOSE

This study aimed to identify high-risk factors for regional recurrence in patients with breast cancer with pathologically negative lymph nodes.

METHODS AND MATERIALS

We retrospectively analyzed 3800 patients with stage pT1-pT3 breast cancer and pathologically negative lymph nodes between 2004 and 2012. All patients underwent upfront surgery with curative intent. Adjuvant systemic treatments were administered to most patients (96.7%) based on contemporary guidelines.

RESULTS

After a median follow-up of 83 months (range, 7-175 months), the estimated 10-year cumulative incidence rate of regional recurrence was 2.0%. Multivariate competing risk analysis revealed that high histologic grade, positive lymphovascular invasion, and stage pT2-3 were significant risk factors for any regional recurrence. Patients with ≥2 risk factors showed a significantly higher 10-year cumulative incidence rate of any regional recurrence than those with 1 or no risk factors (5.5% vs 1.2%; P < .001). When the number of retrieved lymph nodes was less than 10, the difference in the incidence rate of regional recurrence between patients with ≥2 risk factors and those with 1 or no risk factors was greater (6.6% vs 1.3%, respectively; P < .001). The 10-year disease-free survival was worse in patients with ≥2 risk factors than in those with 1 or no risk factors (84.7% vs 90.0%, respectively; P < .001). Patients with ≥2 risk factors also showed worse 10-year overall survival than did those with 1 or no risk factors (91.3% vs 97.0%, respectively; P < .001).

CONCLUSIONS

Overall, the cumulative incidence rate of any regional recurrence was low at 10 years. However, patients with ≥2 risk factors showed an increased risk of any regional recurrence and worse disease-free survival, particularly when the number of retrieved lymph nodes was less than 10.

Breast-Conserving Therapy in Patients with cT3 Breast Cancer with Good Response to Neoadjuvant Systemic Therapy Results in Excellent Local Control: A Comprehensive Cancer Center Experience

BACKGROUND

Many cT3 breast cancer patients are treated with mastectomy, regardless of response to neoadjuvant systemic therapy (NST). We evaluated local control of cT3 patients undergoing breast-conserving therapy (BCT) based on magnetic resonance imaging (MRI) evaluation post-NST. In addition, we analyzed predictive characteristics for positive margins after breast-conserving surgery (BCS).

METHODS

All cT3 breast cancer patients who underwent BCS after NST between 2002 and 2015 at the Netherlands Cancer Institute were included. Local recurrence-free interval (LRFI) was estimated using the Kaplan-Meier method, and predictors for positive margins were analyzed using univariable analysis and multivariable logistic regression.

RESULTS

Of 114 patients undergoing BCS post-NST, 75 had negative margins, 16 had focally positive margins, and 23 had positive margins. Of those with (focally) positive margins, 12 underwent radiotherapy, 6 underwent re-excision, and 21 underwent mastectomy. Finally, 93/114 patients were treated with BCT (82%), with an LRFI of 95.9% (95% confidence interval [CI] 91.5-100%) after a median follow-up of 7 years. Predictors for positive margins in univariable analysis were hormone receptor-positive/human epidermal growth factor receptor 2-negative (HR+/HER2-) subtype, lobular carcinoma, and non-mass enhancement (NME) on pre-NST MRI. MRI response was not correlated to positive margins. In multivariable regression, the odds of positive margins were decreased in patients with HER2-positive (HER2+; odds ratio [OR] 0.27, 95% CI 0.10-0.73; p = 0.01) and TN tumors (OR 0.17, 95% CI 0.03-0.82; p = 0.028). A trend toward positive margins was observed in patients with NME (OR 2.38, 95% CI 0.98-5.77; p = 0.055).

CONCLUSION

BCT could be performed in 82% of cT3 patients in whom BCT appeared feasible on post-NST MRI. Local control in these patients was excellent. In those patients with HR+/HER2- tumors, NME on MRI, or invasive lobular carcinoma, the risk of positive margins should be considered preoperatively.

Breast cancer

Breast cancer is still the most common cancer worldwide. But the way breast cancer is viewed has changed drastically since its molecular hallmarks were extensively characterised, now including immunohistochemical markers (eg, ER, PR, HER2 [ERBB2], and proliferation marker protein Ki-67 [MKI67]), genomic markers (eg, BRCA1, BRCA2, and PIK3CA), and immunomarkers (eg, tumour-infiltrating lymphocytes and PD-L1). New biomarker combinations are the basis for increasingly complex diagnostic algorithms. Neoadjuvant combination therapy, often including targeted agents, is a standard of care (especially in HER2-positive and triple-negative breast cancer), and the basis for de-escalation of surgery in the breast and axilla and for risk-adapted post-neoadjuvant strategies. Radiotherapy remains an important cornerstone of breast cancer therapy, but de-escalation schemes have become the standard of care. ER-positive tumours are treated with 5-10 years of endocrine therapy and chemotherapy, based on an individual risk assessment. For metastatic breast cancer, standard therapy options include targeted approaches such as CDK4 and CDK6 inhibitors, PI3K inhibitors, PARP inhibitors, and anti-PD-L1 immunotherapy, depending on tumour type and molecular profile. This range of treatment options reflects the complexity of breast cancer therapy today.

Contrast-Enhanced Mammography for Screening Women after Breast Conserving Surgery

Simple Summary

Breast cancer survivors are at risk for recurrence, and the early detection of recurrence improves survival. Therefore, imaging surveillance is performed for women who have breast-conserving surgery. The aim of our retrospective study was to compare routine mammography with contrast-enhanced mammography in the screening (asymptomatic) post-treatment setting. We confirmed that when screening women with breast conservation surgery, contrast-enhanced mammography had a higher cancer detection rate (15.4/1000) and positive predictive value of biopsies (42.9%) than full-field digital mammography (6.2/1000 and 37.5%, respectively).

Abstract

To investigate the value of contrast-enhanced mammography (CEM) compared to full-field digital mammography (FFDM) in screening breast cancer patients after breast-conserving surgery (BCS), this Health Insurance Portability and Accountability Act-compliant, institutional review board-approved retrospective, single-institution study included 971 CEM exams in 541 asymptomatic patients treated with BCS who underwent screening CEM between January 2013 and November 2018. Histopathology, or at least a one-year follow-up, was used as the standard of reference. Twenty-one of 541 patients (3.9%) were diagnosed with ipsi- or contralateral breast cancer: six (28.6%) cancers were seen with low-energy images (equivalent to FFDM), an additional nine (42.9%) cancers were detected only on iodine (contrast-enhanced) images, and six interval cancers were identified within 365 days of a negative screening CEM. Of the 10 ipsilateral cancers detected on CEM, four were detected on low-energy images (40%). Of the five contralateral cancers detected on CEM, two were detected on low-energy images (40%). Overall, the cancer detection rate (CDR) for CEM was 15.4/1000 (15/971), and the positive predictive value (PPV3) of the biopsies performed was 42.9% (15/35). For findings seen on low-energy images, with or without contrast, the CDR was 6.2/1000 (6/971), and the PPV3 of the biopsies performed was 37.5% (6/16). In the post-BCS screening setting, CEM has a higher CDR than FFDM.

Accelerated partial breast irradiation in the elderly: 8-year oncological outcomes and prognostic factors

PURPOSE

The purpose of the study is to evaluate long-term clinical outcomes and prognostic factors after accelerated partial breast irradiation (APBI) in the elderly using high-dose-rate interstitial multicatheter brachytherapy (HIBT).

METHODS AND MATERIALS

Between 2005 and 2018, 109 patients underwent APBI using HIBT (34 Gy/10f/5d or 32 Gy/8f/4d). Based on a prospective database, outcomes were retrospectively analyzed (local relapse-free survival, metastatic-free survival, specific survival (SS), and overall survival (OS)). Prognostic factors were investigated. Late toxicity and cosmetic evaluation were reported.

RESULTS

With a median followup of 97 months [7-159], median age was 81.7 years [58-89]. In accordance with the GEC-ESTRO APBI classification, 72.5%, 11.9%, and 15.6% were classified as low, intermediate, and high risk, respectively. The histological type was mainly invasive ductal carcinoma (87.1%). The median tumor size was 10 mm [range 1-35]. Eight-year local relapse-free survival, SS, and OS were 96.7% [95% confidence interval (CI) [0.923; 1]), 96.7% [95% CI [0.924; 1], and 72% [95% CI [0.616; 0.837], respectively. In univariate analysis, APBI classification was not considered as prognostic factor, whereas molecular classification was prognostic factor for OS (p < 0.0001), SS (p = 0.007), and metastatic-free survival (p = 0.009) but not for local recurrence (p = 0.586). No Grade ≥3 late toxicity was observed, whereas 61 patients (88.4%) and 8 patients (11.6%) presented Grade 1 and 2 toxicities, respectively. The cosmetic outcome was excellent/good for 96.4%.

CONCLUSIONS

Long-term followup confirms that HIBT is safe and effective for elderly early breast cancer. Our results suggest that selected elderly women presenting with high-risk breast cancer could be also considered for APBI.

Radiotherapy-Induced Fatigue in Breast Cancer Patients

Background

A large proportion of breast cancer patients who undergo adjuvant radiotherapy suffer from radiotherapy-induced fatigue. The possible causative factors of this specific side effect are diverse.

Summary

Prevalence, duration, and severity of radiotherapy-induced fatigue are dependent on the type of radiotherapy, as well as on the irradiated volume, dose scheme, on the number of radiation fields, the combination with other treatments, diurnal rhythm, smoking, and time-to-hospitalization. Recommended treatments include non-pharmacologic interventions, such as physical and psychosocial interventions. Pharmacologic therapies include treatment with methylphenidate and modafinil. In addition to its early detection with standardized instruments, adequate education to breast cancer patients about risks and predisposing factors of radiotherapy-induced fatigue is essential. Multidimensional strategies help to maintain the patients' quality of life and therefore guarantee treatment adherence and efficacy.

Key Messages

Radiotherapy-induced fatigue is an underreported, underdiagnosed, and undertreated side effect. This review provides an overview of radiotherapy-induced fatigue in breast cancer patients receiving adjuvant radiotherapy.

Fatigue following radiotherapy of low-risk early breast cancer - a randomized controlled trial of intraoperative electron radiotherapy versus standard hypofractionated whole-breast radiotherapy: the COSMOPOLITAN trial (NCT03838419)

BACKGROUND

Fatigue is one of the most common and distressing side-effects of breast cancer radiotherapy. According to current guidelines, accelerated partial breast irradiation (APBI) may be considered as an alternative treatment option for women with early-stage low-risk breast cancer. One method for APBI is single-dose intraoperative radiotherapy (IORT) applied directly to the tumor bed during breast conserving surgery (BCS). The COSMOPOLITAN trial therefore aims to analyze the intensity of fatigue following single-shot IORT with electrons (IOERT) compared to conventional hypofractionated whole breast irradiation (WBI) in low risk early breast cancer patients.

METHODS

This trial is conducted as a multicenter, prospective, randomized, two-arm phase II study comparing the intensity of fatigue in early-stage breast cancer (cT1cN0cM0, tumor size < 2,5 cm, ER pos. Her2neu neg., age > 50 years) treated either with WBI or APBI after BCS. Secondary outcomes investigated are tumor control, overall survival (OS), disease-free survival (DFS), acute and chronic toxicity, quality of life (QoL) and cosmesis. A total of 202 patients will be randomized into two arms: Patients in arm A will receive WBI (40.05 Gy, 15 fractions) after surgical resection, while patients in arm B will receive IOERT (21 Gy to the 90%-isodose) during BCS. Fatigue will be assessed 12 weeks post surgery with the help of the Functional Assessment of Chronic Illness Therapy (FACIT) Fatigue Scale.

DISCUSSION

The present trial aims to evaluate treatment response to compare single-shot intraoperative electron APBI to conventional WBI following BCS in early-stage low risk breast cancer patients. Fatigue is selected as the primary, patient-reported endpoint due its major clinical relevance.

TRIAL REGISTRATION

The study is prospectively registered on February 12th, 2019: Clinicaltrials.gov, NCT03838419. "Intraoperative Electron Radiotherapy for Low-risk Early Breast Cancer (COSMOPOLITAN)".

STUDY STATUS

Ongoing study. Start of recruitment was December 2019.

Hypofractionated breast radiotherapy for 1 week versus 3 weeks (FAST-Forward): 5-year efficacy and late normal tissue effects results from a multicentre, non-inferiority, randomised, phase 3 trial

BACKGROUND

We aimed to identify a five-fraction schedule of adjuvant radiotherapy (radiation therapy) delivered in 1 week that is non-inferior in terms of local cancer control and is as safe as an international standard 15-fraction regimen after primary surgery for early breast cancer. Here, we present 5-year results of the FAST-Forward trial.

METHODS

FAST-Forward is a multicentre, phase 3, randomised, non-inferiority trial done at 97 hospitals (47 radiotherapy centres and 50 referring hospitals) in the UK. Patients aged at least 18 years with invasive carcinoma of the breast (pT1-3, pN0-1, M0) after breast conservation surgery or mastectomy were eligible. We randomly allocated patients to either 40 Gy in 15 fractions (over 3 weeks), 27 Gy in five fractions (over 1 week), or 26 Gy in five fractions (over 1 week) to the whole breast or chest wall. Allocation was not masked because of the nature of the intervention. The primary endpoint was ipsilateral breast tumour relapse; assuming a 2% 5-year incidence for 40 Gy, non-inferiority was predefined as ≤1·6% excess for five-fraction schedules (critical hazard ratio [HR] of 1·81). Normal tissue effects were assessed by clinicians, patients, and from photographs. This trial is registered at isrctn.com, ISRCTN19906132.

FINDINGS

Between Nov 24, 2011, and June 19, 2014, we recruited and obtained consent from 4096 patients from 97 UK centres, of whom 1361 were assigned to the 40 Gy schedule, 1367 to the 27 Gy schedule, and 1368 to the 26 Gy schedule. At a median follow-up of 71·5 months (IQR 71·3 to 71·7), the primary endpoint event occurred in 79 patients (31 in the 40 Gy group, 27 in the 27 Gy group, and 21 in the 26 Gy group); HRs versus 40 Gy in 15 fractions were 0·86 (95% CI 0·51 to 1·44) for 27 Gy in five fractions and 0·67 (0·38 to 1·16) for 26 Gy in five fractions. 5-year incidence of ipsilateral breast tumour relapse after 40 Gy was 2·1% (1·4 to 3·1); estimated absolute differences versus 40 Gy in 15 fractions were -0·3% (-1·0 to 0·9) for 27 Gy in five fractions (probability of incorrectly accepting an inferior five-fraction schedule: p=0·0022 vs 40 Gy in 15 fractions) and -0·7% (-1·3 to 0·3) for 26 Gy in five fractions (p=0·00019 vs 40 Gy in 15 fractions). At 5 years, any moderate or marked clinician-assessed normal tissue effects in the breast or chest wall was reported for 98 of 986 (9·9%) 40 Gy patients, 155 (15·4%) of 1005 27 Gy patients, and 121 of 1020 (11·9%) 26 Gy patients. Across all clinician assessments from 1-5 years, odds ratios versus 40 Gy in 15 fractions were 1·55 (95% CI 1·32 to 1·83, p<0·0001) for 27 Gy in five fractions and 1·12 (0·94 to 1·34, p=0·20) for 26 Gy in five fractions. Patient and photographic assessments showed higher normal tissue effect risk for 27 Gy versus 40 Gy but not for 26 Gy versus 40 Gy.

INTERPRETATION

26 Gy in five fractions over 1 week is non-inferior to the standard of 40 Gy in 15 fractions over 3 weeks for local tumour control, and is as safe in terms of normal tissue effects up to 5 years for patients prescribed adjuvant local radiotherapy after primary surgery for early-stage breast cancer.

FUNDING

National Institute for Health Research Health Technology Assessment Programme.

Loco-regional outcomes of adjusted breast radiotherapy with conventional fractionation after breast conserving surgery: De-escalation of whole breast irradiation dose

We compared the cumulative incidence of ipsilateral breast tumor recurrence (IBTR) between 2 whole breast irradiation (WBI) dose range with conventional fractionation.We retrospectively reviewed 1122 patients who received WBI at 2 institutions between 2004 and 2012. One institution delivered WBI 41.4 to 45 Gy followed by boost 14 to 18 Gy (adjusted group), while the other delivered WBI 50 to 50.4 Gy followed by boost 10 Gy (standard group).The median follow-up period was 85 months. The 10-year cumulative incidence in all patients was 6.1% (95% confidence interval [CI]: 4.3%-8.4%) for IBTR and 3.0% (95% CI: 1.7%-4.8%) for regional recurrence. The 10-year cumulative incidence of IBTR was not significantly influenced by WBI dose (6.3% in the adjusted group vs 5.2% in the standard group, P = .136). Comparable IBTR rates between the 2 groups were observed regardless of clinical and pathological factors. The WBI dose was not significantly associated with the 10-year cumulative incidence of regional recurrence in these groups (3.5% in the adjusted group vs 0.5% in the standard group, P = .214).De-escalated WBI doses while intensifying tumor bed boost did not compromise local and regional outcomes compared to standard group.

Quantifying the Mitigating Effects of Whole-Breast Radiotherapy and Systemic Treatments on Regional Recurrence Incidence Among Breast Cancer Patients

Background

Despite the potential for residual lymph node metastases after a negative or positive sentinel lymph node biopsy (SLNB), breast cancer patients rarely experience regional recurrences (RRs). This study aimed to quantify the effects of nonsurgical treatments on RR incidence among SLNB-negative (SLNB N0) breast cancer patients.

Methods

All primary SLNB N0-staged breast cancer patients with a diagnosis between 2005 and 2008 and 5-year follow-up data on recurrences were selected from the Netherlands Cancer Registry. The cumulative incidence function (CIF) for RR was calculated as the first event at 5 years, taking into account any other first-event (local or distant recurrence, contralateral breast cancer, or death) as competing risk. Cox regression analysis was used to model the cause-specific hazard of RR developing as the first event to quantify the effect of adjuvant systemic therapy and whole-breast radiotherapy (RT) on RR incidence at 5 years.

Results

The study included 13,512 patients. Of these patients, 162 experienced an RR. The CIF of RR at 5 years was 1.3% (95% confidence interval [CI], 1.1–1.5%), whereas the CIFs for death and other events were 4.4% and 9.5%, respectively. Cox regression analysis showed hazard ratios (HRs) of 0.46 (95% CI 0.33–0.64), 0.31 (95% CI 0.18–0.55), and 0.40 (95% CI 0.24–0.67) respectively for patients treated by RT as a routine part of breast-conserving therapy (BCT), chemotherapy, and hormonal therapy.

Conclusion

RT as routine part of BCT, chemotherapy, and hormonal therapy independently exerted a mitigating effect on the risk for the development of RR. The three methods at least halved the risk.

Electronic supplementary material

The online version of this article (10.1245/s10434-020-08356-2) contains supplementary material, which is available to authorized users.

VMAT partial-breast irradiation: acute toxicity of hypofractionated schedules of 30 Gy in five daily fractions

PURPOSE

To report acute toxicities in breast cancer (BC) patients (pts) recruited in a prospective trial and treated with accelerated partial-breast irradiation (APBI) using Volumetric Modulated Arc Therapy (VMAT) delivered with a hypofractionated schedule.

METHODS

From March 2014 to June 2019, pts with early-stage BC (Stage I), who underwent breast conservative surgery (BCS), were recruited in a prospective study started at the National Cancer Institute of Milan. Pts received APBI with a hypofractionated schedule of 30 Gy in five daily fractions. Radiotherapy treatment (RT) was delivered using VMAT. Acute toxicity was assessed according to RTOG/EORTC criteria at the end of RT.

RESULTS

Between March 2014 and June 2019, 151 pts were enrolled in this study. 79 Pts had right-side and 72 had left-side breast cancer. Median age was 69 (range 43-92). All pts presented with pathological stage IA BC, molecular classification was Luminal A in 128/151 (85%) and Luminal B in 23/151 (15%) cases. Acute toxicity, assessed at the end of RT, consisted of G1 erythema in 37/151 (24. 5%) pts and skin toxicities higher than G1, did not occur. Fibrosis G1 and G2 were reported in 41/151 (27. 1%) pts and in 2/151 pts (1. 3%), respectively. Edema G1 occurred in 8/151 (5. 3%) pts and asthenia G1 occurred in 1/151 (0. 6%) pts.

CONCLUSIONS

APBI with VMAT proved to be feasible and can be a valid alternative treatment option after BCS in selected early breast cancer pts according to ASTRO guidelines. A longer follow-up is needed to assess late toxicity.

Accelerated Partial Breast Irradiation: A New Standard of Care?

Background

Breast-conserving therapy including lumpectomy and adjuvant whole breast irradiation (WBI) has become the standard therapy for early-stage breast cancer (EBC). Without WBI, the recurrence rate is significantly increased. However, when selecting patients at a low a priori risk of local recurrence only a small breast-cancer-specific mortality benefit, but no overall survival improvement, was detected for WBI. As most recurrences occur close to the lumpectomy cavity, accelerated partial breast irradiation (APBI) delivered exclusively to a limited volume of tissue around the initial lumpectomy site, has gained increased attention and is now discussed as an alternative to WBI for selected EBC patients.

Summary

Numerous techniques for APBI (interstitial brachytherapy, external beam-based APBI, intraoperative radiotherapy, MR-guided radiotherapy) allow treatment delivery in a shorter period of time, and radiation oncologists expect to further reduce side effects by using these new techniques, with improvements in cosmetics and quality of life. In this review, we aim to describe the existing evidence for the feasibility and effectiveness of different APBI techniques used in modern radiotherapy.

Key Messages

APBI has provided outcomes similar to WBI combined with potentially reduced toxicity. While appropriate patient selection persists to be crucial for acceptable recurrence rates, the precise definition of patients suitable for APBI remains a matter of discussion. As long-term data are often still lacking, special attention should be paid to late side effects and long-term outcomes. Decision-making on appropriate treatment techniques should take into account not only local control rates, but also the impact on the patient's quality of life.

In the Era After the European Organisation for Research and Treatment of Cancer 'Boost' Study, is the Additional Radiotherapy to the Breast Tumour Bed Still Beneficial for Young Women?

AIMS

The European Organisation for Research and Treatment of Cancer (EORTC) 22,881-10,882 trial showed significant benefit of a radiotherapy boost (RTB) in women ≤40 years in a pre-hormone therapy (HT) era. We determined how the use of HT and RTB changed in response to clinical guidelines and whether the benefit of routine RTB was still observed in the HT era.

MATERIALS AND METHODS

Between 1996 and 2004, a provincial database identified all women ≤40 years with breast cancer who met the inclusion criteria of the EORTC trial. In total, 411 patients were classified into three eras defined by the guidelines: era 1 (discretionary HT, discretionary RTB); era 2 (routine HT, discretionary RTB); era 3 (routine HT, routine RTB). HT use, RTB use and cumulative incidence of local recurrence were calculated and compared across eras.

RESULTS

HT use increased after the first policy change from 13% to 75% for oestrogen receptor-positive patients (P < 0.01). RTB use also increased from 33% to 76% following the second policy change (P < 0.01). At 10 years, the cumulative incidence of local recurrence was 12% in era 1, 6% in era 2 and 6% in era 3 (era 2 versus era 3, P = 0.92). For patients in the routine HT era (eras 2 and 3 combined) there was no significant difference in local recurrence between RTB and 'no RTB' patients (6% versus 7%, P = 0.81).

CONCLUSIONS

The routine use of HT and RTB increased significantly after new practice guidelines. Introduction of the HT guideline was associated with a 6% improvement in local recurrence at 10 years. No improvement in local recurrence was associated with the introduction of the RTB guideline in the HT era. The routine use of a boost in unselected young women with negative margins should be re-evaluated in the current HT era.

Evolution of radiotherapy techniques in breast conservation treatment

Radiation therapy (RT) is an important component of breast cancer treatment that reduces local recurrence and improves survival after breast conservation. Breast conservation rates have increased significantly since the late 1980s and techniques have improved with greater awareness of the impact of radiation on the heart. An overview of randomized controlled trials of breast conservation using standard whole breast irradiation, whole breast hypofractionation, accelerated partial breast irradiation (APBI) and intraoperative radiation are reviewed. Selection criteria for breast conservation and the utility of adding a boost dose to the primary tumor site are reviewed. Modern dose constraints are documented and 10 different radiation techniques from the 1980s through to modern volumetric modulated arc therapy (VMAT) are compared for a patient where the breast and internal mammary nodes are treated. A radiation boost reduces the risk of a recurrence for most, but not all patients. Short courses of RT over 3-4 weeks are generally as effective as longer courses. Short-term follow-up of trials of APBI show promise for selected good prognosis subgroups. The role of intraoperative radiation remains controversial. In the last 30 years, there have been significant advances in radiation techniques. Modern radiotherapy equipment and techniques will reduce complications and improve survival rates.

Paradigm shift in the local treatment of breast cancer: mastectomy to breast conservation surgery

There have been fundamental changes in the approach to breast cancer management over the last century but the primary objective of achieving oncological safety remains unchanged. This evolution is highlighted with a summary of the key evidences in support of the oncological safety of breast conserving surgery (BCS) in early breast cancer (EBC) management. We will also discuss the increasingly pivotal role that neoadjuvant chemotherapy (NACT) may play, in the local treatment of EBC and locally advanced breast cancer (LABC) and the long-term surgical and oncological outcomes.

Margins in breast cancer: How much is enough?

The appropriate negative margin width for women undergoing breast-conserving surgery for both ductal carcinoma in situ (DCIS) and invasive carcinoma is controversial. This review examines the available data on the margin status for invasive breast cancer and DCIS, and highlights the similarities and differences in tumor biology and standard treatments that affect the local recurrence (LR) risk and, therefore, the optimal surgical margin. Consensus guidelines support a negative margin, defined as no ink on tumor, for invasive carcinoma treated with breast-conserving therapy. Because of differences in the growth pattern and utilization of systemic therapy, a margin of 2 mm has been found to minimize the LR risk for women with DCIS undergoing lumpectomy and radiation therapy (RT). Wider negative margins do not improve local control for DCIS or invasive carcinoma when they are treated with lumpectomy and RT. Re-excision for negative margins should be individualized, and the routine practice of performing additional surgery to obtain a wider negative margin is not supported by the literature. Cancer 2018;124:1335-41. © 2018 American Cancer Society.

Can Interrogation of Tumour Characteristics Lead us to Safely Omit Adjuvant Radiotherapy in Patients with Early Breast Cancer?

Adjuvant radiotherapy after breast-conserving surgery has been an important component of the standard of care for early breast cancer. Improvements in breast cancer care have resulted in a substantial reduction in local relapse rates over recent decades. Although the proportional benefits of adjuvant radiotherapy are similar for different prognostic risk groups of patients, the absolute benefits depend on the risk of relapse and therefore vary considerably between prognostic groups. Radiotherapy is not without risk and for some patients at very low risk of relapse the risks of radiotherapy may outweigh the benefit, leading to potential overtreatment. Randomised controlled trial (RCT) evidence shows that omission of radiotherapy in low risk early breast cancer does not reduce overall survival or increase breast cancer mortality and local recurrences are salvageable. Despite this there has not been a change in practice regarding omission of radiotherapy. The reasons for this may include challenges in patient selection. Recent advances in immunohistochemistry and genomic profiling may improve risk stratification and the development of biomarkers to directed therapies. Several RCTs have quantified the benefit of radiotherapy in reducing local relapse. Where a treatment benefit is known but is considered to be so small not to be clinically relevant then alternatives to RCTs may be considered to answer the question of need. This is because we can assess risk against a fixed 'absolute' boundary rather than needing a randomised comparator. The prospective cohort study is an alternative to the RCT design to answer the question of need for radiotherapy. The feasibility of recruitment into biomarker-directed de-escalation studies will become apparent as more studies open. The challenge is to determine if we are able to accurately risk stratify patients and avoid unnecessary toxicity, thereby tailoring the need for adjuvant breast radiotherapy on an individual patient basis.

Optimal radiation dose for patients with one to three lymph node positive breast cancer following breast-conserving surgery and anthracycline plus taxane-based chemotherapy: A retrospective multicenter analysis (KROG 1418)

Background and Purpose

This study was performed to determine optimal radiation dose in pN1 breast cancer patients who received breast conserving surgery (BCS) and anthracycline plus taxane (AT)-based chemotherapy.

Materials and Methods

Retrospective chart reviews were performed in 1,147 patients who were treated between January 2006 and December 2010. The impact of radiation dose on treatment outcomes was evaluated.

Results

Median follow-up time was 66 months. The 5-year rate of disease-free survival (DFS) was 93.2%. Larger tumor size (> 20 mm), positive lymphovascular invasion, high histologic grade, and high ratio of positive nodes (> 0.1) were significantly associated with inferior DFS. By using the 4 factors related to DFS, patients were categorized into high-risk (with ≥ 3 factors) and low-risk (with < 3 factors) groups. In the high-risk group, higher radiation dose (> 60.3 Gy_EQD2) was significantly associated with better DFS than the lower dose (≤ 60.3 Gy_EQD2). However, the radiation dose did not impact DFS in the low-risk group.

Conclusions

Dosing of radiation affects the outcome of post-BCS radiotherapy in pN1 breast cancer. Doses of over 60.3 Gy_EQD2 were associated with better outcome in the high-risk patients.

Radiation therapy and early breast cancer: current controversies

Radiation therapy (RT) is an important component of breast cancer treatment. RT reduces local recurrence and breast cancer mortality after breast conservation for all patients and for node-positive patients after a mastectomy. Short courses of RT over 3-4 weeks are generally as effective as longer courses. A patient subgroup where RT can be avoided after conservative surgery has not been consistently identified. A radiation boost reduces the risk of a recurrence in the breast but may be omitted for older patients with good prognosis tumours with clear margins. Axillary recurrences can take a long time to appear, with 35% occurring after 5 years. Leaving disease untreated in regional nodes is associated with reduced survival. Not all patients require radiation after neoadjuvant chemotherapy and a subsequent mastectomy. Modern RT equipment and techniques will further improve survival rates.

Partial-breast radiotherapy after breast conservation surgery for patients with early breast cancer (UK IMPORT LOW trial): 5-year results from a multicentre, randomised, controlled, phase 3, non-inferiority trial

BACKGROUND

Local cancer relapse risk after breast conservation surgery followed by radiotherapy has fallen sharply in many countries, and is influenced by patient age and clinicopathological factors. We hypothesise that partial-breast radiotherapy restricted to the vicinity of the original tumour in women at lower than average risk of local relapse will improve the balance of beneficial versus adverse effects compared with whole-breast radiotherapy.

METHODS

IMPORT LOW is a multicentre, randomised, controlled, phase 3, non-inferiority trial done in 30 radiotherapy centres in the UK. Women aged 50 years or older who had undergone breast-conserving surgery for unifocal invasive ductal adenocarcinoma of grade 1-3, with a tumour size of 3 cm or less (pT1-2), none to three positive axillary nodes (pN0-1), and minimum microscopic margins of non-cancerous tissue of 2 mm or more, were recruited. Patients were randomly assigned (1:1:1) to receive 40 Gy whole-breast radiotherapy (control), 36 Gy whole-breast radiotherapy and 40 Gy to the partial breast (reduced-dose group), or 40 Gy to the partial breast only (partial-breast group) in 15 daily treatment fractions. Computer-generated random permuted blocks (mixed sizes of six and nine) were used to assign patients to groups, stratifying patients by radiotherapy treatment centre. Patients and clinicians were not masked to treatment allocation. Field-in-field intensity-modulated radiotherapy was delivered using standard tangential beams that were simply reduced in length for the partial-breast group. The primary endpoint was ipsilateral local relapse (80% power to exclude a 2·5% increase [non-inferiority margin] at 5 years for each experimental group; non-inferiority was shown if the upper limit of the two-sided 95% CI for the local relapse hazard ratio [HR] was less than 2·03), analysed by intention to treat. Safety analyses were done in all patients for whom data was available (ie, a modified intention-to-treat population). This study is registered in the ISRCTN registry, number ISRCTN12852634.

FINDINGS

Between May 3, 2007, and Oct 5, 2010, 2018 women were recruited. Two women withdrew consent for use of their data in the analysis. 674 patients were analysed in the whole-breast radiotherapy (control) group, 673 in the reduced-dose group, and 669 in the partial-breast group. Median follow-up was 72·2 months (IQR 61·7-83·2), and 5-year estimates of local relapse cumulative incidence were 1·1% (95% CI 0·5-2·3) of patients in the control group, 0·2% (0·02-1·2) in the reduced-dose group, and 0·5% (0·2-1·4) in the partial-breast group. Estimated 5-year absolute differences in local relapse compared with the control group were -0·73% (-0·99 to 0·22) for the reduced-dose and -0·38% (-0·84 to 0·90) for the partial-breast groups. Non-inferiority can be claimed for both reduced-dose and partial-breast radiotherapy, and was confirmed by the test against the critical HR being more than 2·03 (p=0·003 for the reduced-dose group and p=0·016 for the partial-breast group, compared with the whole-breast radiotherapy group). Photographic, patient, and clinical assessments recorded similar adverse effects after reduced-dose or partial-breast radiotherapy, including two patient domains achieving statistically significantly lower adverse effects (change in breast appearance [p=0·007 for partial-breast] and breast harder or firmer [p=0·002 for reduced-dose and p<0·0001 for partial-breast]) compared with whole-breast radiotherapy.

INTERPRETATION

We showed non-inferiority of partial-breast and reduced-dose radiotherapy compared with the standard whole-breast radiotherapy in terms of local relapse in a cohort of patients with early breast cancer, and equivalent or fewer late normal-tissue adverse effects were seen. This simple radiotherapy technique is implementable in radiotherapy centres worldwide.

FUNDING

Cancer Research UK.

Oncological safety and cosmetic outcomes in oncoplastic breast conservation surgery, a review of the best level of evidence literature

Oncoplastic breast conservation surgery (OBCS) is increasingly becoming part of routine breast cancer surgical management. OBCS may be viewed as an extension of standard breast conservation surgery for resecting tumors of larger sizes without compromising on cosmetic outcome, or as an alternative to mastectomy. High quality evidence to support the oncological safety and benefits of OBCS is lacking. This review will focus on the best available level of evidence and address key issues regarding oncological safety in OBCS, such as tumor resection margins and re-excision rates, local recurrence and patient outcome, postoperative complications and adjuvant therapy delivery, and briefly discuss cosmetic outcome in OBCS. Comparative observational studies and systematic review report no poorer outcomes compared with standard breast conservation surgery. More evidence needs to be generated to support the oncological safety and improved aesthetic outcome. Prospective data collection will significantly contribute to the generation of stronger evidence.

Locoregional Recurrence After Sentinel Lymph Node Dissection With or Without Axillary Dissection in Patients With Sentinel Lymph Node Metastases: Long-term Follow-up From the American College of Surgeons Oncology Group (Alliance) ACOSOG Z0011 Randomized Trial

BACKGROUND AND OBJECTIVE

The early results of the American College of Surgeons Oncology Group (ACOSOG) Z0011 trial demonstrated no difference in locoregional recurrence for patients with positive sentinel lymph nodes (SLNs) randomized either to axillary lymph node dissection (ALND) or sentinel lymph node dissection (SLND) alone. We now report long-term locoregional recurrence results.

METHODS

ACOSOG Z0011 prospectively examined overall survival of patients with SLN metastases undergoing breast-conserving therapy randomized to undergo ALND after SLND or no further axillary specific treatment. Locoregional recurrence was prospectively evaluated and compared between the groups.

RESULTS

Four hundred forty-six patients were randomized to SLND alone and 445 to SLND and ALND. Both groups were similar with respect to age, Bloom-Richardson score, Estrogen Receptor status, adjuvant systemic therapy, histology, and tumor size. Patients randomized to ALND had a median of 17 axillary nodes removed compared with a median of only 2 SLNs removed with SLND alone (P < 0.001). ALND, as expected, also removed more positive lymph nodes (P < 0.001). At a median follow-up of 9.25 years, there was no statistically significant difference in local recurrence-free survival (P = 0.13). The cumulative incidence of nodal recurrences at 10 years was 0.5% in the ALND arm and 1.5% in the SLND alone arm (P = 0.28). Ten-year cumulative locoregional recurrence was 6.2% with ALND and 5.3% with SLND alone (P = 0.36).

CONCLUSION

Despite the potential for residual axillary disease after SLND, SLND without ALND offers excellent regional control for selected patients with early metastatic breast cancer treated with breast-conserving therapy and adjuvant systemic therapy.

De-escalation of axillary surgery in early breast cancer

With the advent of sentinel lymph node biopsy, surgical methods for accurately staging the axilla in patients with early-stage breast cancer have become progressively less extensive, with formal axillary lymph node dissection confined to a dwindling group of patients. Although details of methods for sentinel lymph node biopsy have yet to be standardised, this technique is now widely practised and accepted as standard of care worldwide. In the past 5 years, attention has focused on minimisation of surgical morbidity by restricting further axillary surgery or considering radiotherapy in patients with a small tumour burden in their sentinel nodes. This change in approach to patients with positive sentinel lymph node biopsies has increased the complexity of axillary management, and any policy of de-escalation and avoidance of morbidity must not compromise patient outcomes. This trend for de-escalation has accompanied a shift in understanding of how any residual tumour burden can be adequately managed without surgical extirpation and reliance on effective adjuvant therapies. Indications for omission of completion axillary lymph node dissection in patients with two or fewer nodes containing macrometastases demand further clarification, together with the roles of preoperative imaging in defining axillary nodal burden, deselection of patients for sentinel lymph node biopsy, and provision of radiotherapy. Downstaging of biopsy-proven node-positive patients with neoadjuvant chemotherapy could safely permit sentinel lymph node biopsy alone when the index node has been successfully retrieved at surgery, while nodal deposits of any size continue to mandate completion axillary lymph node dissection. Developments in molecular imaging technologies and percutaneous biopsy techniques could potentially render sentinel lymph node biopsy redundant in the future.

Are there patients with T1 to T2, lymph node-negative breast cancer who are "high-risk" for locoregional disease recurrence?

BACKGROUND

Indications for postmastectomy radiotherapy (PMRT) in patients with T1 to T2, lymph node-negative (N0) breast cancer with "high-risk" features are controversial. The European Organization for Research and Treatment of Cancer (EORTC) 22922 and National Cancer Institute of Canada Clinical Trials Group MA20 trials reporting improved 10-year disease-free survival with lymph node irradiation included patients with high-risk N0 disease, but, to the authors' knowledge, benefits in patients receiving modern systemic therapy are uncertain.

METHODS

The authors retrospectively identified patients with T1 to T2N0 disease who were treated with mastectomy from January 2006 through December 2011. High-risk features included age <40 years, multifocality/multicentricity, lymphovascular invasion, medial/central tumor location, and high nuclear grade.

RESULTS

Among 672 eligible patients, only 15 received PMRT and were excluded. Of the remaining 657 patients, 187 (28%) had 1 high-risk feature and 449 patients (68%) had ≥ 2 high-risk features. A total of 36 patients with unknown tumor grade were excluded from risk analysis. Approximately 98% of patients underwent sentinel lymph node biopsy alone and 86% received adjuvant systemic therapy. At a median of 5.6 years of follow-up, the locoregional disease recurrence (LRR) rate was 4.7% (31 patients). Increasing tumor size was found to be associated with LRR (hazard ratio, 1.70; P = .006), whereas other high-risk features were not (all P > .05). Receipt of systemic therapy decreased the LRR rate (hazard ratio, 0.40; P = .03). Although crude LRR rates increased from 3.8% to 9.4% with 1 versus ≥ 4 high-risk features, the number of risk factors was not found to be significantly associated with LRR (P = .54).

CONCLUSIONS

In the current study, a low crude LRR rate (4.7%) was observed in a large unselected cohort of patients with T1 to T2N0 breast cancer with high-risk features who were treated with mastectomy and systemic therapy without PMRT. Although increasing tumor size and the omission of systemic therapy were found to be predictive, other features did not confer a higher LRR risk either independently or together, and do not by themselves mandate the use of PMRT in this patient population. Cancer 2017;123:2626-33. © 2017 American Cancer Society.

Prognostic Impact of Elective Supraclavicular Nodal Irradiation for Patients with N1 Breast Cancer after Lumpectomy and Anthracycline Plus Taxane-Based Chemotherapy (KROG 1418): A Multicenter Case-Controlled Study

Purpose

This study was conducted to evaluate the impact of supraclavicular lymph node radiotherapy (SCNRT) on N1 breast cancer patients receiving post-lumpectomy whole-breast irradiation (WBI) and anthracycline plus taxane-based (AT) chemotherapy.

Materials and Methods

We performed a case-control analysis to compare the outcomes of WBI and WBI plus SCNRT (WBI+SCNRT). Among 1,147 patients with N1 breast cancer who received post-lumpectomy radiotherapy and AT-based chemotherapy in 12 hospitals, 542 were selected after propensity score matching. Patterns of failure, disease-free survival (DFS), distant metastasis-free survival (DMFS), and treatment-related toxicity were compared between groups.

Results

A total of 41 patients (7.6%) were found to have recurrence. Supraclavicular lymph node (SCN) failure was detected in three patients, two in WBI and one in WBI+SCNRT. All SCN failures were found simultaneously with distant metastasis. There was no significant difference in patterns of failure or survival between groups. The 5-year DFS and DMFS for patients with WBI and WBI+SCNRT were 94.4% versus 92.6% (p=0.50) and 95.1% versus 94.5% (p=0.99), respectively. The rates of lymphedema and radiation pneumonitis were significantly higher in the WBI+SCNRT than in the WBI.

Conclusion

We did not find a benefit of SCNRT for N1 breast cancer patients receiving AT-based chemotherapy.

Impact of age, intrinsic subtype and local treatment on long-term local-regional recurrence and breast cancer mortality among low-risk breast cancer patients

AIM

To evaluate the long-term prognostic impact of age, local treatment and intrinsic subtypes on the risk of local-regional recurrence (LRR) and breast cancer mortality among low-risk patients.

MATERIAL AND METHODS

Cohort study with prospectively collected data, balanced five-year age groups, including 514 Danish lymph node negative breast cancer patients diagnosed between 1989 and 1998, treated with mastectomy (N = 320) or breast-conserving therapy (BCT) (N = 194) and without systemic treatment. Intrinsic subtype approximation was performed by combining information on estrogen-, progesterone-, HER2 receptor and Ki67.

RESULTS

The majority of the tumors had a luminal subtype: 70% Luminal-A (LumA), 16% Luminal-B (LumB), and 10% Luminal-HER2 + (Lum-HER2+). The distribution of intrinsic subtypes between younger (≤45 years) and older (>45 years) patients was similar. Intrinsic subtypes had no prognostic impact on the 20-year LRR risk, regardless of age. A distinct 20-year mortality pattern was observed among the younger patients: 11% of patients with LumB tumor died of breast cancer within the first five years after primary surgery, 23% of patients with Lum-HER2+ tumor died within a 5-10-year period, whereas patients with LumA tumor died with a constant low rate throughout the 20-year period. After 20 years of follow-up, patients with LumA tumor had breast cancer mortality comparable to that of patients with LumB tumor (20%) and lower than Lum-HER2+ tumor (39%). Among the older patients, no distinct mortality pattern was observed, and the 20-year breast cancer mortality was not associated with intrinsic subtypes.

CONCLUSION

Among low-risk patients, 96% of the tumors were Luminal and the distribution of intrinsic subtypes between younger (≤45 years) and older (>45 years) patients was similar. The observed higher frequency of LRR among younger low-risk BCT patients was not associated intrinsic subtype. The 20-year breast cancer mortality was non-significant for LumA tumors among the older patients, whereas among the younger patients, LumA tumors had a comparable mortality with LumB, but lower than for Lum-HER2 + tumors.

Failure pattern and survival after breast conserving therapy. Long-term results of the Danish Breast Cancer Group (DBCG) 89 TM cohort

Based on the results from the DBCG 82 trial, breast conserving therapy (BCT) has been implemented as standard in Denmark since 1989, and today constitutes more than 70% of the primary treatment. Our aim was to evaluate the implementation of BCT as a routine procedure in patients treated according to the DBCG 89 program and compare recurrence pattern and survival both overall and when separated in age groups, with the results from the randomized DBCG 82 TM trial.

MATERIAL AND METHODS

A total of 1847 patients treated between 1989 and 1999 were included in a retrospective population-based cohort study. Data from the DBCG database were completed via search through the Danish Pathology Data Bank and medical records.

RESULTS

Median follow-up time was 17 years. At 20 years the cumulative incidences of local recurrence (LR) and disease-specific mortality (DSM) were 15.3% and 25.8%, respectively. Twenty-year overall survival (OS) and recurrence-free survival were 63.7% and 43.1%, respectively. Subdivided by age groups cumulative incidences at 20 years were LR: 18.9%, 10.5% and 12.4%, and DSM: 28.9%, 18.9% and 28.4% in young (≤45 years), middle-aged (46-55 years) and older (≥56 years) women, respectively. In an adjusted analysis age maintained a significant and independent effect on both LR and DSM.

CONCLUSION

The DBCG 82 TM program was successfully implemented. The women treated with BCT in the DBCG 89 program displayed equal failure pattern and improved survival in comparison with women from the DBCG 82 TM protocol. Occurrence of first failure and mortality varied with age; demonstrated by increased risk of LR, DM and DSM in the young patients and increased risk of DM and DSM in the older patients, compared to the middle-aged patients.