[New external radiotherapy technologies for breast cancer]

Inverse radiotherapy planning in reconstructive surgery for breast cancer

BACKGROUND

Post-mastectomy radiotherapy reduces the risk of local-regional relapse and distant disease, and increases global survival in women with axillary involvement. With the new reconstruction techniques and increasing use of directed external radiotherapy, immediate reconstruction can be performed with good cosmetic results and low complication rates.

MATERIALS AND METHODS

Observational study with consecutive sampling conducted in patients undergoing reconstructive surgery for breast cancer, between 2010 and 2016, with a 12-months minimum follow-up period. A group of patients radiated after receiving an expander (RT-Expander) were compared with a control group of non-radiated patients (Non-RT), who had been treated with the same surgical technique. We compare general complications, reconstruction failure, aesthetic results and satisfaction degree with software IBM^® SPSS^® Statistics v. 21 and BREAST-Q scores.

RESULTS

Reconstruction failure was observed in 15.6% of patients in a similar proportion in both groups. External radiotherapy was not an independent significant factor influencing the occurrence of general complications, capsular contracture grade ≥3 or reconstruction failure. The Kaplan-Meyer curve showed no differences in reconstruction survival between groups. Aesthetic results were excellent-very good in 78.1% of patients. Absence of a contralateral procedure for symmetrization, occurrence of general complications, occurrence of capsular contracture grade ≥3 and reconstruction failure were significantly associated to fair-poor cosmetic results. The satisfaction degree of operated patients was similar in both groups.

CONCLUSIONS

The evolution of external radiotherapy towards more directed techniques, which modulate the dose administered to the mammary tissue and adjacent structures, allowed us to make immediate reconstruction a reality for most patients, with complication rates, cosmetic results and satisfaction degrees similar to those of non-radiated patients.

[Establishing margins from CTV to PTV in breast cancer treatment]

The benefit of postoperative radiotherapy for breast cancer both in terms of local control and overall survival is widely acknowledged. Today, technological advances in simulation imaging and positioning control enable the definition of new margins from CTV to PTV. Improvements in mathematical modeling of random and systematic errors impact the treatment plans. However, there is no universal absolute value to consistently determine the margins from CTV to PTV. It is down to each centre to assess and correct as much as possible uncertainties due to positioning and internal movements depending on techniques and methods used for the implementation of treatment and monitoring. IMRT and respiratory gating techniques for breast radiotherapy will be considered more systematically in the years to come.