No need of radiotherapy in patients with Unifocal breast cancer on MRI and favourable pathology: Lancet

The PROSPECT study published in The Lancet revealed a standard treatment protocol for early-stage breast cancer where a significant number of women can safely undergo adjuvant radiotherapy without compromising the recovery. The outcomes highlight the combination of Magnetic Resonance Imaging (MRI) and the pathology findings as a more nuanced approach to assess the local tumor burden by potentially sparing patients from unnecessary treatment and its associated side effects.

This multicentre, non-randomised study meticulously chose its participants through preoperative MRI screenings and postoperative tumor pathology assessments. The group 1 included women aged 50 and above who were diagnosed with cT1N0 non-triple-negative breast cancer and showed signs of unifocal cancer. They underwent breast-conserving surgery without the subsequent standard course of radiotherapy where their post-surgery pathology confirmed the cancer localization. The group 2 identified participants with additional cancers through MRI who received the conventional treatment regimen and included surgery and radiotherapy.

Out of the 443 patients screened with MRI between May 17, 2011 and May 6, 2019, 201 participants were placed in the radiotherapy omission group. The five-year ipsilateral invasive recurrence rate (IIRR) in this group was 1.0% where the upper limit of the 95% confidence interval at 5.4%. These figures stood in sharp contrast to the concerns surrounding radiotherapy omission that shows a viable pathway to reduce overtreatment without increasing the risk of cancer recurrence.

The study emphasizes the clinical safety of this approach and also illuminates the economic benefits. The PROSPECT pathway is estimated to save approximately AU$1980 (£953) per patient, by averting unnecessary radiotherapy and marking a significant reduction in healthcare costs. Furthermore, the approach has been related to an increase in quality-adjusted life years (QALYs) that suggests an improvement in the overall quality of life for these patients.

The only distant metastasis observed throughout the study was genetically distinct from the index cancer that underscores the precision of MRI and pathology in identifying truly localized breast cancer cases. These findings help catalyze a trend shift in how early-stage breast cancer is treated and emphasize a more personalized treatment plan that balances efficacy with the quality of life of patient.

Reference:

Mann, G. B., Skandarajah, A. R., Zdenkowski, N., Hughes, J., Park, A., Petrie, D., Saxby, K., Grimmond, S. M., Murugasu, A., Spillane, A. J., Chua, B. H., Badger, H., Braggett, H., Gebski, V., Mou, A., Collins, J. P., & Rose, A. K. (2024). Postoperative radiotherapy omission in selected patients with early breast cancer following preoperative breast MRI (PROSPECT): primary results of a prospective two-arm study. In The Lancet (Vol. 403, Issue 10423, pp. 261–270). Elsevier BV. https://doi.org/10.1016/s0140-6736(23)02476-5