Long-term clinical follow-up of breast cancer patients treated with photobiomodulation therapy to prevent acute radiodermatitis (Transdermis trial): Preliminary results

Introduction

In the field of oncology, clinical evidence regarding the efficacy of photobiomodulation therapy (PBMT) to prevent and manage acute radiodermatitis (ARD) is expanding considerably. During PBMT, visible and/or (near)-infrared (NIR) light is applied to the affected skin using non-ionizing light sources (i.e. laser or light-emitting diodes (LEDs)). It induces biochemical reactions in the target cells, which ultimately stimulates the wound healing process, and reduces pain and inflammation. Still, many clinicians are concerned whether the application of PBMT in cancer patients is safe. This study evaluated the disease-free survival (DFS) and overall survival (OS) of breast cancer (BC) patients treated with PBMT for ARD.

Methods

A retrospective data analysis of 120 BC patients treated with prophylactic PBMT (n=60; 2x/week, 808-905nm, 4J/cm², 0.168W/cm²) or placebo (n=60) during their radiotherapy (RT) course (25x2Gy, 8x2Gy) at the Limburg Oncology Center (Hasselt, Belgium) between April 2015 and June 2017, was performed (TRANSDERMIS trial). The follow-up of the patients included a clinical evaluation every 6 months and a blood analysis and mammography yearly in the first 5 years after the end of RT. DFS, defined as any sign of disease progression including secondary malignancy (contralateral breast or non-breast cancer), and OS were estimated.

Results

Data from 93 patients was available (PBMT n=46; placebo: n=47) for a survival analysis; 26 patients were followed up in another medical center and one patient file was not accessible. After a median follow-up of 26 months (range: 1-41), a preliminary analysis of the data by the log rank test demonstrated that DFS was not significantly different between the PBMT and placebo group (98% vs. 100%, resp., p=0.323) and OS was equal in both groups (100%). In the PBMT group, one case of contralateral BC was reported.

Conclusion

For the first time, the safety of PBMT in BC patients undergoing RT was investigated. The preliminary results of this study demonstrate no statistical correlation between the application of PBMT and locoregional recurrence, development of secondary tumors, or OS. Although, to validate these results, a follow-up of at least 5 years is recommended in a broader oncologic patient population.