Oligometastatic prostatic cancer recurrence: role of salvage lymph node dissection (sLND) and radiation therapy-stereotactic body radiation therapy (RT-SBRT)

The impact of locoregional treatments for metastatic castration resistant prostate cancer on disease progression: real life experience from a multicenter cohort

BACKGROUND

Available data on medical treatment of metastatic castration resistant prostate cancer (mCRPC) support the use of more than one therapy line to delay chemotherapy. We evaluate in a longitudinal real life multicenter cohort, the oncological outcome of mCRPC patients treated with Abiraterone Acetate (AA) and Enzalutamide (EZ) in a chemo-naïve setting, who received locoregional treatments for subsequent development of oligorecurrent disease.

METHODS

We prospectively collected data on chemo-naïve mCRPC patients, who received either AA or EZ as first or second line treatment between Oct-2012 and Nov-2020 at 5 centers. High-volume disease at mCRPC onset was defined as bulky positive nodes (≥5 cm) or more than 6 bone metastases. Survival probabilities were computed at 12, 24, 48 and 60 months after treatment start. The impact of loco-regional treatments on progression free survival (PFS) were assessed with the Kaplan-Meier method and the log-rank test was applied.

RESULTS

Overall, 117 chemo-naive mCRPC patients received a first line therapy. Fifty-seven (48.7%) patients received AA and 60 (51.3%) received EZ. Eight (6.7%) patients underwent salvage chemotherapy after first line failure. Overall, 28 patients shifted to a second line therapy. Two-yr progression-free, cancer-specific and overall survival probabilities were 65.5%, 82.2% and 78.4% respectively. Since diagnosis of mCRPC, oligo progression occurred in 25 patients who received stereotactic radiation therapy (23/25, 92%) focused on metastasis (4 nodal sites and 19 bones) or salvage lymph node dissection (2/25, 8%). At Kaplan-Meier analysis, patients with low volume disease displayed higher PFS probabilities (log rank p = 0.009) and in this subgroup of patients loco-regional treatments had a significant impact on PFS (p = 0.048), while it was negligible in the whole cohort and in patients with high volume disease (p = 0.6 and p = 0.75).

CONCLUSIONS

Low-volume mCRPC patients are exposed to improved PFS and seem to benefit from locoregional treatments.

Stereotactic radiotherapy of nodal oligometastases from prostate cancer: a prisma-compliant systematic review

Androgen deprivation therapy (ADT) is the standard treatment of metastatic prostate cancer (PCa). However, metastases-directed therapies can delay the initiation or switch of systemic treatments and allow local control (LC) and prolonged progression-free survival (PFS), particularly in patients with lymph nodes (LN) oligometastases. We performed a systematic review on stereotactic body radiotherapy (SBRT) in this setting. Papers reporting LC and/or PFS were selected. Data on ADT-free survival, overall survival, and toxicity were also collected from the selected studies. Fifteen studies were eligible (414 patients), 14 of them were retrospective analyses. A high heterogeneity was observed in terms of patient selection and treatment. In one study SBRT was delivered as a single 20 Gy fraction, while in the others the median total dose ranged between 24 and 40 Gy delivered in 3-6 fractions. LC and PFS were reported in 15 and 12 papers, respectively. LC was reported as a crude percentage in 13 studies, with 100% rate in seven and 63.2-98.0% in six reports. Five studies reported actuarial LC (2-year LC: 70.0-100%). PFS was reported as a crude rate in 11 studies (range 27.3-68.8%). Actuarial 2-year PFS was reported in four studies (range 30.0-50.0%). SBRT tolerability was excellent, with only two patients with grade 3 acute toxicity and two patients with grade 3 late toxicity. SBRT for LN oligorecurrences from PCa in safe and provides optimal LC. However, the long-term effect on PFS and OS is still unclear as well as which patients are the best candidate for this approach.