No clear effect of postoperative radiotherapy on survival of breast cancer patients with 1–3 positive nodes: A population-based study
Menée dans deux régions suédoises auprès de 2 750 et 1 698 patientes atteintes d'un cancer du sein avec envahissement d'un à trois ganglions lymphatiques et traitées entre 1989 et 2006, cette étude met en évidence l'absence d'effet signicatif d'une radiothérapie post-opératoire sur la survie relative à 10 ans des patientes
Background : In published radiotherapy trials, the failure rate in the control arm among patients with 1–3 positive nodes is high compared to that seen with modern adjuvant treatments. Therefore the generalizability of the results has been questioned. The aim of the present study was to compare relative survival in breast cancer patients between two Swedish regions with screening mammography programs and adjuvant treatment guidelines similar with the exception of the indication of radiotherapy for patients with 1–3 positive nodes. Patients and methods : Between 1989 and 2006, breast cancer patients were managed very similarly in the west and southeast regions, except for indication for postoperative radiotherapy. In patients with 1–3 positive nodes, postmastectomy radiotherapy was generally given in the southeast region (89% of all cases) and generally not given in the west region (15% of all cases). For patients with 1–3 positive nodes who underwent breast-conserving surgery, patients in the west region had breast radiotherapy only, while patients in the southeast region had both breast and lymph nodes irradiated. Results : The 10-year relative survival for patients with 1–3 positive lymph nodes was 78% in the west region and 77% in the southeast region (p=0.12). Separate analyses depending on type of surgery, as well as number of examined nodes, also revealed similar relative survival. Conclusions : Loco-regional postoperative radiotherapy has well-known side effects, but in this population-based study, there was little or no influence of this type of radiotherapy on survival when 1–3 lymph nodes were involved.