Radiation-induced fibrosis in the boost area after three-dimensional conformal radiotherapy with a simultaneous integrated boost technique for early-stage breast cancer: A multivariable prediction model.

BACKGROUND AND PURPOSE: To develop a multivariable prediction model for the risk of grade⩾2 fibrosis in the boost area after breast conserving surgery (BCS) followed by three-dimensional conformal radiotherapy (RT) with a simultaneous integrated photon boost (3D-CRT-SIB), five years after RT. MATERIAL AND METHODS: This prospective cohort study included 1,030 patients treated with RT for breast cancer (stage 0-III), after BCS. Data regarding physician-rated fibrosis and dose-volume parameters were available in 546 patients. A multivariable logistic regression model for grade⩾2 fibrosis was generated. RESULTS: At 5years, grade⩾2 fibrosis was observed in 13.4% of the patients. The multivariable analysis resulted in a prediction model for grade⩾2 fibrosis in the boost area including three independent variables: patient age, breast volume receiving⩾55Gy (V55 CTV breast) and the maximum radiation dose in the breast (Dmax). CONCLUSIONS: A multivariable prediction model was developed including age, V55 CTV breast and Dmax for grade⩾2 fibrosis in the boost area after breast cancer RT using a 3D-CRT-SIB technique. This model can be used to estimate the risk of fibrosis and to optimize dose distributions aiming at reducing this risk.

The impact of age on changes in quality of life among breast cancer survivors treated with breast-conserving surgery and radiotherapy.

BACKGROUND: The purpose of the study was to determine the impact of young age on health-related quality of life (HRQoL) by comparing HRQoL of younger and older breast cancer patients, corrected for confounding, and of young patients and a general Dutch population. METHODS: The population consisted of breast cancer survivors (stage 0-III) after breast-conserving surgery and radiotherapy. Health-related quality of life was prospectively assessed using the EORTC QLQ-C30 and QLQ-BR23 questionnaires. The association between age (⩽50; 51-70; ⩾70 years) and HRQoL over time was analysed with mixed modelling. The clinical relevance of differences between/within age groups was estimated with Cohen's D and consensus-based guidelines. The HRQoL data from the young patient cohort were compared with Dutch reference data at 3 years after radiotherapy. RESULTS: A total of 1420 patients completed 3200 questionnaires. Median follow-up was 34 (range 6-70) months. Median age was 59 (range 28-85) years. Compared with older subjects, young women reported worse HRQoL in the first year after radiotherapy, but clinical relevance was limited. Three years after radiotherapy, HRQoL values in the younger group were equal to those in the reference population. Pain and fatigue after radiotherapy improved, with medium clinical relevance. CONCLUSIONS: Three years after radiotherapy for breast cancer, young age was not a risk factor for decreased HRQoL.

Impact of primary local treatment on the development of distant metastases or death through locoregional recurrence in young breast cancer patients.

In this study, we tested the hypothesis whether breast conserving therapy (BCT) compared with mastectomy is associated with a negative outcome in terms of distant metastases or death (DMD) and investigated the relation between locoregional recurrence (LRR) and DMD in young breast cancer (BC) patients. This study included a consecutive series of 536 patients ≤40 years of age at diagnosis with pathological T1N0-3M0 BC, treated between 1989 and 2005. A multistate survival model was used to evaluate the influences of local treatment and LRR on DMD, adjusted for potential prognostic factors. Patients were treated with mastectomy (N = 213) or BCT (N = 323). Median age at diagnosis was 36.3 years, with a median follow-up of 9.0 years. The 10-year actuarial cumulative incidence of DMD was 30.6 % after mastectomy and 26.3 % after BCT (P = 0.04). In total, 81 (15 %) LRRs were observed. After BCT, patients had a threefold higher risk of LRR than after mastectomy (HR 2.9; 95 % CI 1.6-5.3). Patients with LRR had a higher risk of DMD compared with patients without LRR (HR 5.5; 95 % CI 2.1-14.5). However, BCT was not negatively associated with DMD-after-LRR (HR 0.47; 95 % CI 0.2-1.1, BCT vs mastectomy). In conclusion, although LRR significantly affected DMD, the increased risk of LRR after BCT compared with mastectomy did not lead to a worse DMD outcome in BC patients ≤40 years of age.