吳芃諺、裘坤元、李建儀

台中榮民總醫院 外科部 泌尿科

Peng-Yen Wu, Kun-Yuan Chiu, Jain-Ri Li

Division of Urology, Department of Surgery, Taichung Veterans General Hospital

 

Purpose: The oligometastasis is defined as the precence of three or fewer metastatic lesions in a case with malignancy. Metastasis-directed therapy (MDT) has been reported beneficial for patients with oligometastatic colorectal cancer and renal cell carcinoma. There is a lack of data on metastasectomy for oligometastatic patients. In this study we report the outcomes of patients treated with surgical excision of oligometastatic prostate cancer in our institution.

Materials and Methods: Patients who were diagnosed with prostate cancer with 1~3 metastatic lesions and received surgical excision at Taichung Veterans General Hospital from January, 2009 to October, 2019 were included. The clinicopathologic characteristics, treatments and outcomes were recorded.

Results: Two cases were included in this report. The first case was a 60-year-old male with metachronous recurrence in the left 6^th rib and L1 spine detected with whole body bone scan 6 years after the radical prostatectomy (initial staging pT3bN1M0). The pre-MDT PSA level was 11.59 ng/mL. The patient received intensity-modulated radiation therapy for L1 spine and segmental resection of the left 6^th rib, with a PSA decline of 87.58% after MDT (post-MDT PSA: 1.44 ng/mL). The biochemical recurrence was noted 3 months after the surgery and the radiological relapse with distant metastasis in multiple sites was noted 5 months later on the PET scan. The systemic treatment with abiraterone was prescribed thereafter and the patient was followed for more than 2 years after the MDT. The other case was a 63-year-old male with prostate cancer with synchronous metastasis in the right pubic bone. The patient received neoadjuvant hormonal therapy with triptorelin for 6 months and then underwent radical prostatectomy and segmental resection of the right pubic bone. The pre-treatment PSA level was 7.55 and the PSA level after neoadjuvant hormonal therapy was 0.127. The post-MDT PSA was undetectable. The patient was followed for 8 months without biochemical recurrence.

Discussion: All of our cases experienced a significant PSA decline after the metastasis-directed therapy. Reviewing the available articles on oligometastasectomy for prostate cancer, one retrospective study, using the new imaging modalities to detect metastatic lesions, such as choline-PET/CT, PSMA-PET/CT and whole body MRI, reported an average pre-MDT PSA at 4.2 ng/mL and a median time between MDT and radiological relapse at 14 months. Among those with metastatic recurrence, 69% of the cases were oligometastatic. Since we were using conventional images, including contrast CT and whole body bone scan, to detect metastasis, our cases reports pre-MDT PSA at 7.55~11.59 ng/mL, and the case with metachronous oligometastasis was found with multiple metastasis 8 months after the MDT, which may indicates the possible presence of multiple micrometastasis at detection of metastatic lesion. The new imaging techniques have higher accuracy to detect metastasis with low PSA levels, which would contributes to the better disease-free survival. Further research is needed to analyze the survival impact.