What are the ways to confirm the diagnosis of prostate cancer? The main diagnostic methods for prostate cancer include clinical presentation, rectal examination, PSA examination, transrectal ultrasound and its guided prostate puncture biopsy. Rectal examination is the most economical, non-invasive, and complication-free way to detect prostate cancer and is not limited by equipment. However, the diagnostic value of rectal examination is slightly lower. Although rectal examination can easily detect advanced prostate cancer, it can only detect about 33% of early prostate cancer, and the results of rectal examination vary among experienced doctors. Although an elevated PSA (prostate-specific antigen) does not necessarily mean prostate cancer, it still plays a unique and irreplaceable role in the diagnosis of prostate cancer compared to rectal examinations and transrectal ultrasound. If the PSA is 4-10 μg/L, the probability of prostate cancer is 25%-35%; if the PSA is >10 μg/L, the probability of prostate cancer is 50%-80%. Generally, if the PSA is >50μg/L, it is almost certain to be prostate cancer. Transrectal ultrasound is more accurate than transabdominal ultrasound for the diagnosis of prostate cancer. Most of the prostate cancers appear as hypoechoic nodules in the periprostatic zone on transrectal ultrasound. However, prostate cancer of different nature may also appear as isoechoic or even hyperechoic. Transrectal ultrasound can also be used to assist in localizing and performing a puncture biopsy of the prostate at the same time as the examination. MRI (magnetic resonance imaging) has limited usefulness in diagnosing early prostate cancer, but is generally slightly more accurate than CT in staging already diagnosed prostate cancer. It is more specific than CT in diagnosing local lymph node metastasis and tumor invasion of surrounding tissues and organs. The recent development of MRSI analysis has improved its accuracy in the diagnosis and staging of prostate cancer. However, due to the high cost of the equipment, its use is not yet widespread. Bone scan is mainly used to check whether a patient has bone metastasis. When patients have a serum PSA of less than 40 μg/L, very few patients usually develop bone metastases. It is not usually recommended for asymptomatic patients unless they have symptoms associated with bone metastases. Transrectal ultrasound-guided prostate puncture is the primary means of confirming the diagnosis of prostate cancer. It is performed by puncturing the prostate with a puncture biopsy target under the localization of the transrectal ultrasound probe, with particular emphasis on suspicious areas, and removing strips of tissue for pathologic analysis. The finding of tumor cells by puncture is called a positive result, while the opposite is called a negative result. The earliest method used was the 6-stitch puncture, which has been gradually replaced by the 8-stitch or 10-stitch puncture. A negative result on the first puncture does not completely rule out the possibility of prostate cancer. Depending on the situation, the doctor will advise the patient whether a second puncture or further observation or even other further tests are needed. Since the tissue obtained from the puncture is small and not a complete representation of the entire prostate tissue, the results of the puncture pathology are not the final pathological findings. Prostate puncture is an invasive test, so complications such as infection and bleeding may occur, but it is a routine test to diagnose prostate cancer and the pain is usually not obvious. The diagnosis of prostate cancer requires a combination of various factors, but the final diagnosis can only be made when the tumor cells are actually seen, so prostate puncture biopsy is now an essential test and is the “gold standard” for determining the diagnosis.