Messaggi chiave
- È stato condotto uno studio di coorte monocentrico, retrospettivo-prospettico, volto a valutare gli esiti di una strategia multimodale con radioterapia stereotassica (SBRT) su tutte le sedi di progressione associata a mantenimento del trattamento sistemico già in corso in pazienti con carcinoma mammario metastatico (mBC) e malattia oligoprogressiva (OPD) (≤5 sedi coinvolte).
- Lo studio ha incluso un totale di 129 pazienti, prevalentemente con malattia HR+/HER2- (77%), ≤2 lesioni oligoprogressive (90%) e OPD non viscerale (91%). La mediana di sopravvivenza libera da progressione post-radioterapia – l’endpoint primario dello studio – è risultata pari a 11,3 mesi (IC 95%, 9,1-13,5), con un tempo mediano al trattamento sistemico successivo di 13,6 mesi (IC 95%, 11,5-15,2). Solo 19 pazienti (15%) hanno sviluppato progressione della malattia nelle sedi di OPD sottoposte a SBRT.
- I risultati dello studio suggeriscono che un approccio con SBRT mirata alle metastasi e concomitante prosecuzione del trattamento sistemico in corso può dare esiti positivi in pazienti con mBC oligoprogressivo, soprattutto in caso di malattia HR+/HER2- e OPD non viscerale, supportando una più ampia adozione di tale strategia nella pratica clinica.
Abstract
Background
- About 15-20 % of patients with metastatic breast cancer (mBC) can experience oligoprogressive disease (OPD) in ≤5 sites of disease.
- Patients with OPD may benefit from metastasis-directed stereotactic radiotherapy (SBRT) to all sites of cancer progression while maintaining the same systemic treatment, aiming to prolong the time to next systemic treatment (NEST).
- This study aims to assess the outcomes provided by this multimodal strategy.
Methods
- Prospective-retrospective, single-center, cohort study including consecutive patients who received SBRT to all extracranial OPD sites (≤5), from January 2011 to June 2023, without changing systemic therapy, according to the multidisciplinary tumor board’s indication.
- The primary endpoint was post-radiotherapy progression-free survival (pRT-PFS).
- A sample size of 130 patients was needed to estimate a median pRT-PFS of 8 months with a 95 % confidence interval (95 %CI) ranging from 5.4 (considered clinically significant) to 10.6 months.
Results
- 129 patients were included: 99 (77 %) had hormone receptor-positive/HER2-negative (HR+/HER2-) disease, 116 (90 %) had ≤2 oligoprogressive lesions, 118 (91 %) presented with non-visceral OPD involving bones or lymph nodes.
- Patients experienced OPD after a median PFS on systemic therapy (pre-OPD PFS) of 11.3 months (95 % CI, 8.7-13.0).
- Median pRT-PFS was 11.3 months (95 % CI, 9.1-13.5) and median NEST was 13.6 months (95 % CI, 11.5-15.2).
- Only 19 (15 %) patients experienced a subsequent PD in the OPD sites treated with SBRT.
Conclusions
- Patients with oligoprogressive mBC, especially with HR+/HER2- disease and non-visceral OPD after a durable pre-OPD PFS, benefit from OPD-directed SBRT while maintaining the same systemic treatment, suggesting its broader implementation in clinical practice.