In a select population of patients with low-volume metastases, there has been increasing interest in metastases-directed therapy (MDT). The theory behind such treatment is that their treatment may allow for delay to systemic therapy or even drug holidays. At this time, depending on location and nature of the oligometastatic sites, focal treatment techniques include surgery (metastatectomy), radiofrequency ablation (RFA) or stereotactic radiotherapy (SRT). Some predictive factors include longer disease-free intervals (>12 months), complete resection, solitary site of metastases,
The authors herein describe their single-institution experience with MDT. All patients had to have had clear cell RCC, have undergone focal ablative intervention, and were grouped into 3 groups:
1) Oligometastatic (1 or 2 sites, less than 5 metastases)
2) Partial responders (to systemic therapy)
3) Dissociated response (to systemic therapy)
Seventy-one patients with 78 focal treatments (23 RFA, 47 metastasectomy and 8 SRT) were reviewed. Patients were 68% male, primarily Fuhrman Grade 3-4 (81%), pT3/4 (60%), and had metachronous tumors (80%).
For 44 patients, the disease was oligometastatic, (1 or 2 sites, up to 5 metastases). Of the remaining 44, 15 patients had a partial response to systemic treatment before MDT and 12 patients had a dissociated response to systemic treatment. 56% had metastatectomy, 29% RFA, 6% metastasectomy + RFA, 1% metastatectomtt + SRT, and 10% SRT.
Progression post MDT occurred in 53 (74.6 %) of patients. Median PFS was 14 months (95 CI 8-16 months) and median OS was 77 months (95 % CI, 41 months-not reach). This is a significant drug-free time frame post-MDT treatment. Local control was achieved in 83.3 % and the complication rate was 36.3 % due to local treatments; no deaths related to treatment were noted.
The authors noted, somewhat anecdotally, that a diagnosis of metachronous metastases and a disease-free interval of at least one year (from diagnosis to first metastases) seemed to be associated with better outcomes.
This data is consistent with prior studies in this space. There is obviously the significant limitations of a retrospective single-institution series – huge selection bias, no control arm. However, in clinical practice, if patients are selected well, we agree that MDT has an important role in mRCC management.
Speaker: Laura Salabert
Co-Authors: Marine Gross-Goupil, Thibaud Haaser, Jean-Christophe Bernhard, Jean Palussière, Alain Ravaud
Institution(s): Bordeaux University Hospital, Bordeaux, France; Centre Hospitalier-Universitaire Saint Andre, Bordeaux, France; Bordeaux University Hospital, Pessac, France; University Hospital Bordeaux, Bordeaux, France; Institut Bergonié, Bordeaux, France
Written by: Thenappan Chandrasekar, MD, Clinical Fellow, University of Toronto, Twitter: @tchandra_uromd at the 2018 American Society of Clinical Oncology Genitourinary (ASCO GU) Cancers Symposium, February 8-10, 2018 - San Francisco, CA