Chemotherapy for oligometastatic prostate cancer

Second Chance for Cure: Stereotactic Ablative Radiotherapy in Oligometastatic Disease

PURPOSE

Local ablative therapy, such as radiotherapy or surgery, plays a key role in treatment of patients with oligometastatic disease. Stereotactic ablative body radiotherapy (SABR) comes to the fore as a safe and effective treatment for patients with a limited number of metastases, even those located in hard-to-reach body sites. Many researchers have suggested that metastatsis-directed therapy could improve long-term progression-free survival (PFS) and overall survival (OS) in patients with oligometastases.

PATIENTS AND METHODS

This was a retrospective, single-arm, observational study conducted between July 2015 and February 2022. In our institute, 60 patients with controlled primary tumors and one to five metastases were treated with SABR. Prescribed radiation doses ranged from 12 to 60 Gy administered in one to seven fractions. We aimed to determine whether metastatic-directed therapy using SABR for all oligometastases affects OS and PFS and whether the primary tumor or metastatic site influences OS/PFS.

RESULTS

The most common primary malignancy types were prostate (n = 14), colorectal (n = 10), lung (n = 7), and breast cancers (n = 6). The median follow-up was 30 months, ranging from 9 to 79. The 1-, 3-, and 5-year PFS and OS rates were 54.9%, 37.0%, and 37.0% and 98.3%, 84.4%, and 73.8%, respectively, and the median time to first progression was 15 (range, 2-32) months. Twenty-four (40%) patients had no recurrence. In our analysis, primary tumor site was not an independent prognostic factor. The metastatic site may influence on patient outcome in cases of localized bone and liver metastases.

CONCLUSION

In our retrospective analysis, SABR was associated with favorable levels of PFS and OS in patients with oligometastases. The limitations of our study were lacking high-level evidence, and randomized studies to compare SABR and palliative standard of care are mandatory.

Imaging modalities in synchronous oligometastatic prostate cancer

Purpose

Along with a number of other malignancies, the term “oligometastatic” prostate cancer has recently emerged. It represents an attempt to define a subtype of cancer with a limited metastatic load that might perform more favorably than a distinctly disseminated disease, or even one that may be managed in a potentially curative way. Since there is currently a knowledge gap of what imaging modalities should be utilized to classify patients as having this type of tumor, we aimed to shed light on the role of conventional and marker-based imaging in the setting of synchronous oligometastatic prostate cancer as well as summarize the available evidence for its clinical application.

Methods

A literature search on December 15th 2017 was conducted using the Pubmed database.

Results

Functional imaging techniques like ⁶⁸Ga PSMA. ⁶⁸Ga PSMA PET-CT has currently been shown the best detection rates for the assessment of nodal, bone and visceral metastases, especially for smaller lesions at low PSA levels.

Conclusions

Functional imaging helps detect low-burden disease metastatic patients. However, these imaging modalities are not available in every center and thus clinicians may be prone to prescribe systemic treatment rather than referring patients for cytoreductive treatments. We hope that the ongoing prospective trials will help guide clinicians in making a more personalized management of synchronous metastatic patients.