Complete response with early introduction of cabazitaxel in a patient with multiple lung metastases of castration-resistant prostate cancer following the early detection of metastases using liquid biopsy: a case report
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Cabazitaxel (CBZ) chemotherapy for metastatic castration-resistant prostate cancer (mCRPC) is believed to be palliative because the radiological response rate is low and a durable response is rare. Here, we describe a rare case of a patient with mCRPC who was treated with CBZ chemotherapy and showed a durable radiological response and a complete biochemical response.
A 43-year-old man with prostate cancer and metastasis of the pubic bone underwent neoadjuvant androgen deprivation and docetaxel therapy, followed by laparoscopic prostatectomy, extended lymphadenectomy, and metastatectomy in 2014. Pathological examination revealed residual adenocarcinoma in the prostate and pubic bone (pathological T stage 3b, positive surgical margin). Following the operation, he received adjuvant radiation therapy (66 Gy) to the pelvic floor. His serum prostate-specific antigen (PSA) level decreased to < 0.01 ng/mL but gradually increased following docetaxel chemotherapy. Imaging findings indicated five tiny nodules in the bilateral lungs. Biopsy specimens are difficult to obtain and might not reflect the precise extent of the disease owing to heterogeneity in patients with CRPC. Thus, we performed liquid biopsy to isolate circulating tumor cells (CTCs), and overall 156 CTCs were detected per 7.5 mL. Almost all CTCs were androgen receptor-negative in the nucleus. We diagnosed the five nodules as lung metastases from docetaxel-resistant CRPC with few AR-signaling-dependent cancer cells. The patient was initiated on CBZ chemotherapy (25 mg/m2) according to the standard protocol in August 2016, instead of using a second-generation AR-targeting agent. After 2 cycles of CBZ chemotherapy, PSA level decreased to < 0.01 ng/mL and the lung metastases completely disappeared, with a reduced CTC count of < 5. To date, the patient has been receiving intermittent CBZ chemotherapy.
We presented a rare case of a patient with mCRPC who was successfully treated with early CBZ chemotherapy. The early detection of metastasis using liquid biopsy enabled the introduction of early CBZ chemotherapy for docetaxel-resistant mCRPC.
KeywordsCabazitaxel Castration-resistant prostate cancer Circulating tumor cells
Circulating tumor cells
metastatic castration-resistant prostate cancer
Cabazitaxel (CBZ) is a next-generation taxane that is indicated for the treatment of patients with metastatic castration-resistant prostate cancer (mCRPC) who were previously treated using a docetaxel-containing regimen . However, CBZ chemotherapy for patients with mCRPC is believed to be palliative because the radiological response rate is low and a durable response is rare. Here, we describe a rare case of a patient with mCRPC who was treated with CBZ chemotherapy and demonstrated a durable radiological response and a complete biochemical response.
The patient was initiated on CBZ (25 mg/m2) according to the standard protocol in August 2016, instead of a second-generation AR-targeting agent (enzalutamide or abiraterone) . Following 2 cycles of CBZ chemotherapy, the PSA level decreased to < 0.01 ng/mL and the lung metastases completely disappeared, with a reduced CTC count of < 5. To date, the patient has been receiving intermittent CBZ chemotherapy.
We experienced a patient with mCRPC who was successfully treated with CBZ chemotherapy. The patient exhibited multiple lung metastases of CRPC, and a complete response was noted with the early introduction of CBZ.
Unmet needs in patient management include the ability to monitor treatment effects and the early detection of metastasis. A common shortcoming of a CTC enrichment system is its reliance on the positive selection of CTCs with antibodies against EpCAM, suggesting the limited ability to identify CTCs with reduced EpCAM expression because of epithelial–mesenchymal transition (EMT) [4, 5, 6]. In fact, in our patient, antibodies targeting EpCAM and CD45 were only detected in 31% of CTCs, suggesting the limited ability to detect CTCs according to EpCAM. Microfluidics involves several separation methods that facilitate the manipulation of extremely small volumes of biological fluids, thereby enabling the detection of de-differentiated CRPC with EMT.
We present a rare case of a patient with mCRPC who was successfully treated with early CBZ chemotherapy. The early detection of metastasis using liquid biopsy enabled the introduction of early CBZ chemotherapy for docetaxel-resistant mCRPC.
Eriko Suzuki provided technical assistance.
TK, HH, and MO made substantial contributions to conception and design. TK and HH made substantial contributions to the laboratory analysis and interpretation of data; TK and MO made substantial contributions to the acquisition of clinical data and their interpretation. TK and HH have been involved in drafting the manuscript. MO has been involved in critically revising the manuscript for important intellectual content. TK, HH, and MO gave their final approval of the version to be published.
This study was supported in part by Grants-in-Aid for Scientific Research (#17 K11158 to T. Kosaka) from the Ministry of Education, Culture, Sports, Science, and Technology of Japan. This funding supported the collection of CTC. The study was supported in part by research Grant to T. Kosaka from the Takeda Science Foundation, Japan. The funding supported the analysis of CTC.
Ethics approval and consent to participate
Our study was designed as a retrospective analysis and approval was obtained from the Keio University School of Medicine an Ethical Committee (#20140159 and #20150242).
Consent for publication
Written informed consent was obtained from the patient for publication of this case report.
The authors declare that they have no competing interests.
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