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

The purpose of this study is to evaluate the influence of the extent of surgery and radiation therapy (RT) on the rates and sites of local (LR) and regional recurrences (RR) in the EORTC 22922/10925 trial.

PATIENTS AND METHODS

All data were extracted from the trial's individual patients' case report forms (CRF) and analysed with a median follow-up of 15.7 years. Cumulative incidence curves were produced for LR and RR accounting for competing risks: an exploratory analysis of the effect of the extent of surgical and radiation treatments on LR rate was conducted using the Fine & Gray model accounting for competing risks and adjusted for baseline patient and disease characteristics. The significance level was set at 5%, 2-sided. Frequency tables were used to describe the spatial location of LR and RR.

RESULTS

Out of 4004 patients included in the trial, 282 (7%) patients experienced LR and 165 (4.1%) RR, respectively. Cumulative incidence rate of LR at 15 years was lower after mastectomy (3.1%) compared to BCS + RT (7.3%) (F&G: HR (Hazard Ratio) = 0.421, 95%CI = 0.282-0.628, p-value < 0.0001). LR were similar up to 3 years for both mastectomy and BCS but continued to occur at a steady rate for BCS + RT, only. The spatial location of the recurrence was related to the locoregional therapy applied and the absolute gain of RT correlated to stage of disease and extent of surgery.

CONCLUSIONS

The extent of locoregional therapies impacts significantly on LR and RR rates and spatial location.

Cosmetic Results and Side Effects of Accelerated Partial-Breast Irradiation Versus Whole-Breast Irradiation for Low-Risk Invasive Carcinoma of the Breast: The Randomized Phase III IRMA Trial

PURPOSE

The results in terms of side effects vary among the published accelerated partial-breast irradiation (APBI) studies. Here, we report the 5-year results for cosmetic outcomes and toxicity of the IRMA trial.

METHODS

We ran this randomized phase III trial in 35 centers. Women with stage I-IIA breast cancer treated with breast-conserving surgery, age ≥ 49 years, were randomly assigned 1:1 to receive either whole-breast irradiation (WBI) or external beam radiation therapy APBI (38.5 Gy/10 fraction twice daily). Patients and investigators were not masked to treatment allocation. The primary end point was ipsilateral breast tumor recurrence. We hereby present the analysis of the secondary outcomes, cosmesis, and normal tissue toxicity. All side effects were graded with the Radiation Therapy Oncology Group/European Organisation for Research and Treatment of Cancer Radiation Morbidity Scoring Schema. Analysis was performed with both intention-to-treat and as-treated approaches.

RESULTS

Between March 2007 and March 2019, 3,309 patients were randomly assigned to 1,657 WBI and 1,652 APBI; 3,225 patients comprised the intention-to-treat population (1,623 WBI and 1,602 APBI). At a median follow-up of 5.6 (interquartile range, 4.0-8.4) years, adverse cosmesis in the APBI patients was higher than that in the WBI patients at 3 years (12.7% v 9.2%; P = .009) and at 5 years (14% v 9.8%; P = .012). Late soft tissue toxicity (grade ≥ 3: 2.8% APBI v 1% WBI, P < .0001) and late bone toxicity (grade ≥ 3: 1.1% APBI v 0% WBI, P < .0001) were significantly higher in the APBI arm. There were no significant differences in late skin and lung toxicities.

CONCLUSION

External beam radiation therapy-APBI with a twice-daily IRMA schedule was associated with increased rates of late moderate soft tissue and bone toxicities, with a slight decrease in patient-reported cosmetic outcomes at 5 years when compared with WBI, although overall toxicity was in an acceptable range.

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

BACKGROUND AND PURPOSE

The multicentre EORTC 22922/10925 trial (ClinicalTrials.gov, NCT00002851) was conducted between 1996 and 2004. The trial evaluated the effect of irradiation of the internal mammary and medial supraclavicular lymph node chains (IM-MS) vs no further radiation therapy (RT) on survival and cause of death in breast cancer stage I-III patients. At 15.7 years of median follow-up, a significant reduction of breast cancer specific mortality (BCSM) and any recurrence, not translating in improved overall survival (OS), and low absolute rates of side effects were found. The aim of the current analysis was to evaluate the association of RT techniques of IM-MS lymph node irradiation with long-term outcomes.

PATIENTS AND METHODS

Three RT techniques were used for IM-MS: a standard technique using a fixed set-up combining photon/electron beams to the IM and tangential fields to the breast or chest wall vs a standard-modified technique with minor adaptation for beam settings vs a more individualised technique based on individual localisation of the IM. Techniques used were fixed per institution over the duration of the trial. We performed an exploratory and descriptive analysis of the outcomes after 15 years follow-up for the three RT techniques.

RESULTS

Between July 1996 and January 2004, 46 radiation oncology departments from 13 countries accrued 4004 patients. Median follow-up was 15.7 years. The number of patients treated by each technique was 2440 (61%) by standard vs 635 (16%) by standard-modified vs 929 (23%) patients by individualised technique. The absolute improvements of oncological outcomes in terms of disease-free survival (DFS), OS and BCSM with IM-MS RT compared to no IM-MS RT were 6.8%, 4.9% and -5.8% for the individualised technique, vs 1.6%, 2.9% and -4.3% for modified standard and -1.4%, 1.1% and -3% for standard technique, respectively. The increase in 15-year rates of side effects due to IM-MS RT, both scored longitudinally and cross-sectionally, were similar among the techniques.

CONCLUSION

Even though a straightforward comparison by technique is not possible because of variations in baseline characteristics between institutions, our findings suggest that the use of more individualised RT techniques is associated with higher rates of oncological improvements without increased risks for late side effects.

Comparing costs of standard Breast-Conserving Surgery to Oncoplastic Breast-Conserving Surgery and Mastectomy with Immediate two-stage Implant-Based Breast Reconstruction

BACKGROUND

Conventional breast-conserving surgery (C-BCS) has equal oncological outcomes and superior cosmetic and patient-reported outcomes compared to mastectomy with immediate two-stage implant-based breast reconstruction (M-IBR). Oncoplastic breast-conserving surgery (OP-BCS) is increasingly being used, as it often has better cosmetic results and it enables larger tumour resection. However, OP-BCS and M-IBR compared to C-BCS lengthens operative time and might lead to more complications and consequently to additional costs. Therefore, this study aimed to compare costs and complication rates of C-BCS, OP-BCS and M-IBR.

METHODS

This single-centre, retrospective cohort study, calculated costs for all patients who had undergone breast cancer surgery between January 2014 and December 2016. Patient-, tumour- and surgery-related data of C-BCS, OP-BCS and M-IBR patients were retrieved by medical record review. Treatment costs were calculated using hospital financial data. Differences in costs and complications were analysed.

RESULTS

A total of 220 patients were included: 74 patients in the C-BCS, 78 in the OP-BCS and 68 in the M-IBR group. From most expensive to least expensive, differences in total costs were found between C-BCS vs. OP-BCS and C-BCS vs. M-IBR (p=<0.01 and p=0.04, respectively). Costs of OP-BCS and M-IBR were comparable. Complication rates were 5.5% for C-BCS, followed by 17% for OP-BCS, and 34% for M-IBR (p<0.01).

CONCLUSION

Considering total treatment costs, OP-BCS was financially non-inferior to M-IBR, whereas complication rates were higher following M-IBR. Therefore, when considering other benefits of OP-BCS, such as higher patient-reported outcomes and similar oncological outcomes, a shift from M-IBR to BCS using oncoplastic techniques seems justified.

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

BACKGROUND

Uncertainty about the benefit/risk ratio of regional lymph node irradiation led to varying clinical protocols. We investigated long-term late side effects after internal mammary and medial supraclavicular (IM-MS) lymph node irradiation to improve shared decision-making.

METHODS

The multicentre EORTC trial (ClinicalTrials.gov, NCT00002851) randomized stage I-III breast cancer patients with involved axillary nodes and/or a medially located primary tumor. We analyzed late side effects, both longitudinally at every follow-up and cross-sectionally at 5-year intervals. All statistical tests were 2-sided.

RESULTS

Between 1996 and 2004, 46 departments from 13 countries accrued 4004 patients. Median follow-up was 15.7 years. Longitudinal follow-up data showed cumulative incidence rates at 15 years of 2.9% (95% confidence interval [CI] = 2.2%-3.8%) vs. 5.7% (95% CI = 4.7%-6.9%) (P<.001) for lung fibrosis, of 1.1% (95% CI = 0.7%-1.7%) vs. 1.9% (95% CI = 1.3%-2.6%) (P=.07) for cardiac fibrosis, and of 9.4% (95% CI = 8.0%-10.8%) vs. 11.1% (95% CI = 9.6%-12.7%) (P=.04) for any cardiac disease, when treated without or with IM-MS lymph node irradiation. There was no evidence for differences between left- and right-sided breast cancer (Wald chi-square test of treatment by breast side interaction, P=.33 and P=.35, for cardiac fibrosis and for any cardiac disease, respectively). The cumulative incidence probabilities of cross-sectionally reported side effects with a score of 2 or greater at 15 years were 0.1% (95% CI = 0.0%-0.5%) vs. 0.8% (95% CI = 0.4%-1.4%) for pulmonary (P=.02), 1.8% (95% CI = 1.1%-2.8%) vs. 2.6% (95% CI = 1.8%-3.7%) for cardiac (P=.15), and 0.0% (95% CI not evaluated) vs. 0.1% (95% CI = 0.0%-0.4%) for oesophageal (P=.16), respectively. No difference was observed in the incidence of second malignancies, contralateral breast cancer or cardiovascular deaths.

CONCLUSIONS

The incidence of late pulmonary side effects was statistically significantly higher after IM-MS lymph node irradiation, as were some of the cardiac events, without a difference between left- and right-sided treatments. Absolute rates and differences were very low, without increased non-breast cancer related mortality, even before introducing heart-sparing techniques.

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

BACKGROUND

10-year results from several studies showed improved disease-free survival and distant metastasis-free survival, reduced breast cancer-related mortality, and variable effects on overall survival with the addition of partial or comprehensive regional lymph node irradiation after surgery in patients with breast cancer. We present the scheduled 15-year analysis of the European Organisation for Research and Treatment of Cancer (EORTC) 22922/10925 trial, which aims to investigate the impact on overall survival of elective internal mammary and medial supraclavicular (IM-MS) irradiation.

METHODS

EORTC 22922/10925, a randomised, phase 3 trial done across 46 radiation oncology departments from 13 countries, included women up to 75 years of age with unilateral, histologically confirmed, stage I-III breast adenocarcinoma with involved axillary nodes or a central or medially located primary tumour. Surgery consisted of mastectomy or breast-conserving surgery and axillary staging. Patients were randomly assigned (1:1) centrally using minimisation to receive IM-MS irradiation at 50 Gy in 25 fractions (IM-MS irradiation group) or no IM-MS irradiation (control group). Stratification was done for institution, menopausal status, site of the primary tumour within the breast, type of breast and axillary surgery, and pathological T and N stage. Patients and investigators were not masked to treatment allocation. The primary endpoint was overall survival analysed according to the intention-to-treat principle. Secondary endpoints were disease-free survival, distant metastasis-free survival, breast cancer mortality, any breast cancer recurrence, and cause of death. Follow-up is ongoing for 20 years after randomisation. This study is registered with ClinicalTrials.gov, NCT00002851.

FINDINGS

Between Aug 5, 1996, and Jan 13, 2004, we enrolled 4004 patients, of whom 2002 were randomly assigned to the IM-MS irradiation group and 2002 to the no IM-MS irradiation group. At a median follow-up of 15·7 years (IQR 14·0-17·6), 554 (27·7%) patients in the IM-MS irradiation group and 569 (28·4%) patients in the control group had died. Overall survival was 73·1% (95% CI 71·0-75·2) in the IM-MS irradiation group and 70·9% (68·6-72·9) in the control group (HR 0·95 [95% CI 0·84-1·06], p=0·36). Any breast cancer recurrence (24·5% [95% CI 22·5-26·6] vs 27·1% [25·1-29·2]; HR 0·87 [95% CI 0·77-0·98], p=0·024) and breast cancer mortality (16·0% [14·3-17·7] vs 19·8% [18·0-21·7]; 0·81 [0·70-0·94], p=0·0055) were lower in the IM-MS irradiation group than in the control group. No significant differences in the IM-MS irradiation group versus the control group were seen for disease-free survival (60·8% [95% CI 58·4-63·2] vs 59·9% [57·5-62·2]; HR 0·93 [95% CI 0·84-1·03], p=0·18), or distant metastasis-free survival (70·0% [67·7-72·2] vs 68·2% [65·9-70·3]; 0·93 [0·83-1·04], p=0·18). Causes of death between groups were similar.

INTERPRETATION

The 15-year results show a significant reduction of breast cancer mortality and any breast cancer recurrence by IM-MS irradiation in stage I-III breast cancer. However, this is not converted to improved overall survival.

FUNDING

US National Cancer Institute, Ligue Nationale contre le Cancer, and KWF Kankerbestrijding.