Metastatic castration-resistant Prostate cancer (mCRPC) is a very late stage of prostate cancer with poor prognosis. Although there are several treatment strategies available for mCRPC, these drugs are not always effective for every patient. Also, it's still not clear what's the best therapeutic choice for a certain group of patients.

In the previous works of the investigators, a subtype of prostate cancer, intraductal carcinoma of the prostate (IDC-P) was studied. The investigators have reported in their two published papers that, IDC-P is an adverse pathological type associated with rapid disease progression. They also found in another study that, for patients with IDC-P, Abiraterone seemed to have better treatment efficacy than Docetaxel-based chemotherapy as first-line treatment for mCRPC, in terms of either PSA-response and PSA-progression free survival. So, in this study, the investigators hope to design a prospective study to verify the predictive ability of IDC-P in the first-line treatment of mCRPC.

With disease progression, the drug resistance will inevitably occur in all patients after the treatment of CRPC. However, the exact mechanism of this process is not yet known. So, in this study the investigators are also trying to explore some of the genes related to the treatment efficacy by means of the next generation sequencing.

Inclusion Criteria:

1. Age: ≥40 years old
2. Positive IDC-P status confirmed by pathological examination.
3. Bone or visceral metastatic disease confirmed by image examination.
4. Castration resistant confirmed according to the criteria of 2014 EAU guidelines.
5. The ECOG score of the patient is ≤1
6. Expected survival over 3 months
7. Blood routine test: neutrophil ≥1.5 × 10^9, platelets >100 × 10^9 and hemoglobin ≥90g/L
8. Blood biochemical indexes: bilirubin≤1.5×Upper limit of normal; AST≤2.5×Upper limit of normal; serum creatinine≤1.5×Upper limit of normal; serum calcium≤12.0mg/dL.
9. Coagulation function: Prothrombin time ≤1.5×Upper limit of normal
10. The following diseases were not found within 12 months: myocardial infarction, severe or unstable angina pectoris, asymptomatic heart failure, cardiovascular and cerebrovascular accident or transient ischemic attack, etc.
11. All patients should sign informed consent.

Exclusion Criteria:

1. Patients who had other types of cancer besides prostate cancer were excluded.
2. Patients With non-acinar adenocarcinoma except intraductal carcinoma of the prostate, including ductal adenocarcinoma, neuroendocrine carcinoma or small cell carcinoma of the prostate.
3. Prior chemotherapy or abiraterone for the treatment of mCRPC.
4. Patients with renal decompensation requiring hemodialysis or peritoneal dialysis.
5. Patients with severe active clinical infection
6. Patients with coagulopathy or bleeding
7. Patients who received major surgery or severe trauma within the first 4 weeks before admission.
8. Patients with a history of allogeneic organ transplantation or bone marrow transplantation
9. Patients with known or suspected allergy to research drugs.

Only male patient can enter this study

The administration methods of the two groups are different, therefore, the investigators decide not to use masking.