| Background:In the word, the morbidity of prostate cancer takes the second place in all the malignant cancers. In2007, the center of Shanghai disease control and prevention reported the prostate cancer incidence was11.81in100thousand, and took the fifth place in male malignant tumors. As the expected life extension of population and the growing use of prostate specific antigen (PSA) test, more and more men are diagnosed with prostate cancer. Of these newly diagnosed prostate cancer,70%are only organ-confined and may be suitable for a curative therapy. Radical prostatectomy and external-beam radiotherapy are the two standard treatments, however, with serious complications after surgery, some patients refuse to receive these therapy. High intensity focused ultrasound (HIFU) therapy, with the minimally invasive procedure, can treat localized and advanced prostate caner as primary therapy, in addition, it can be a salvage option for other therapy failure.HIFU is a new and developed technical mature in late20th century. Transrectal HIFU is a kind of heat treatment system and has the transrectal ultrasound probe, which is special for the urologists use. The probe, with the characteristics of good penetrability、directionality and focus, can focus on high energy in the goal area. Under computer control, the target organ tissues will generate irreversible coagulative necorosis. The main mechanism of HIFU therapy is that the thermal effect, which focus the energy on tissues to make the tumor cells70C or higher, resulting in the tumor cells occur coagulative necrosis and cell death. Cavitation is the creation or movement of gas in an acoustic field. As the tissue compresses and expands with exposure to the acoustic waves, gas is extracted creating bubbles. These bubbles interact with the acoustic field and begin to oscillate violently. The bubbles collapse and create high-velocity jets that disrupt cell membranes. Microstreaming refers to the raid movement of liquid outside an oscillating bubble generate through cavitation forces. When the bubbles oscillate, nearby tissues are subjected to shearing forces that can also disrupt cell membranes.In addition, HIFU can induce the cells undergo apoptosis, and it is perhaps one important late-occurred biological effects. By relieving immune depression and secreting immune facilitating factors, HIFU can remove this kind of immune depression and effectively increase the anti-tumor immunity in patients after surgical castration.There are some advantages for treating prostate cancer with transrectal HIFU:1、no incision and super minimal invasive;2、it can be duplicated, and especially suitable for the local recurrence after sugery or advanced prostate cancer as a palliative treatment;3、the therapy is convenient and could treat as a out-patient surgery;4、it can damage the primary focal prostate cancer, and can treat the local prostate cancer as a palliative resection. In addition, it can improve the overall treatment effects when use its immune effects or combined with endocrine therapy.Two devices are currently available for the HIFU treatment of prostate cancer: Sonablate (USA) and Ablatherm (France). The Ablatherm includes three treatment parameters:standard、HIFU re-treatment and salvage treatment. Sonablate equipment do need no special operating bed and the patients is placed in the lithotomy position, moreover, it is more flexible for treatment parameters setting and can adjust the focal length、ultrasonic energy and power transfer to the target area, and at the same time, through transverse and sagittal low-energy、real-time imagine and software monitoring of tissue changes, the device enables users to tailor treatment to the particular characteristics of a patient’s prostate and disease burden.Transrectal HIFU is generally performed with the patients under spinal or general anesthesia. The ultrasound probe is inserted gently into the rectum and focus the energy on the target tissue, with the mechanism coordination, the end goal is to create overlapping lesions until the whole gland is treated. Patients often require a urethral or suprapubic catheter for several days after surgery. At present, the treatment of ultrasonic frequency is1～4MHz, the focus sound intensity not les than1000W per square cm and each focus point in4～5s, with these, the focus temperature can reach above70℃, and with the high temperature,it is only0.25s to kill the tumor cells,so,it is effectively to destroy the tumor cells.In all the literatures reported about the HIFU as the primary therapy for the prostate cancer, followed up from6months to6.4years. In most cases, the PSA nadir reached after3to6months and PSA nadir≤0.5ng/ml in61%to91%patients. The negative transrectal prostate biopsy was found in68%to93.4%patients. HIFU can get good tumor-control.All the literatures reported no adverse reaction. The common postoperative complications include bladder outlet obstruction(BOO)、incontinence、epididymitis and urinary tract infection and all had mild clinical manifestations. The serious complication urethral rectal fistula rate was only up to4%, adversely, there was a patients died of acute myocardial infarction during follow-up.HIFU makes it suitable as a salvage treatment option for patients with recurrence after other types of primary treatment, namely after radical prostatectomy、 external-beam radiotherapy and proton implant treatment, and can received good clinical results. In addition, HIFU dose not preclude the use of other future treatment modalities:that is, cryotheray、external-beam radiotherapy and laparoscopic prostatectomy, and get some clinical effects.Objective:Summarizing the features of mechanism and clinical results about HIFU treating localized prostate cancer; investigating the feasibility of HIFU treating localized prostate cancer and to provide a selective treatment for localized prostate cancer, additionally,to assess the independent predictor of2-year biochemical free survival rate(BFSR) after HIFU therapy..Methods:Searching the documents utilized by the CNKI、CBM and PubMED, according to the retrieved results, summaried about the mechanism and clinical results about HIFU treating localized prostate cancer. A total of85localized prostate cancer patients, divided into low、intermediate and high risk group, received HIFU therapy using Sonablate500from Dec2002to Oct2009, and preoperation,collected the patients characteristics, including patients age、PSA level at prostate cancer diagnosis and the number receiving antiandrogen therapy before HIFU treatment.Postoperation, dynamicly observated blood PSA level in3months、6momths、12months and24months, and prostate biopsy in6months and12months. Recorded the patients’complications. The Phoenix definition of biochemical failure was used (PSA nadir+2ng/ml). Analyzed the dates with SPSS13.0software and P<0.05was considered as significant differences.Results:1.The mechanism of tissues necrosis in HIFU therapy include ablation、 microstreaming、cavitation and radiation forces, and the primary mechanism is coagulative necrosis induced by ablation, which can induce local hyperthermia in target tissues. The target tissues are also believed to undergo apoptosis, in addition, the patients after surgical castration can increase their anti-tumor immunity and relieve immune depression.2.In the word, the incidence of prostate cancer takes the second position in the male malignant tumor. In2007, the center of Shanghai disease control and prevention reported the prostate cancer incidence was11.81in100thousand, and took the fifth place in male malignant tumors. As the expected life extension of population and the growing use of PSA test, more and more men are diagnosed with prostate cancer. Of these newly diagnosed prostate cancer,70%are only organ-confined and may be suitable for a curative therapy. Radical prostatectomy and external-beam radiotherapy are the two standard treatments, however, with serious complications after surgery, some patients reruse to receive these therapy. HIFU therapy, with the minimally invasive procedure, can treat localized and advanced prostate caner as primary therapy, in addition, it can be a salvage option for other therapy failure.3.In most localized prostate cancer cases, the PSA nadir was reached3to6months after the HIFU treatment and was <or=0.5ng/ml in61%to91%of the cases, furthermore, the negative transrectal prostate biopsy is68%to93.4%in the patients, and the5-year biochemical free survival rate(BFSR) is in30%to70%cases.4.All the literatures covered there is no untoward effects during surgery, but after operation, the complications differ significantly. The bladder outlet obstruction (BOO) and urinary tract infection (UTI) occurred in12.0%to25.6%and16.0%to23.8%cases respectively, in addition, the highest incidence of urinary incontinence (UI) and epididymitis is12%and7.6%, the highest incidence of serious complication urethral-recto fistula is4.0%, unfortunately, there is a report about the patient died of acute myocardial infarction(AMJ) after surgery.5.The mean follow-up was24.3months (range7to45months). After HIFU therapy, serum PSA decreased at3、6、12months in each group, and with significant differences compared with PSA level, respectively(F=2487.4, P<0.001). A PSA nadir<or=0.5ng/ml was recorded in77.6%(66/85) of the patients, at low intermediate and high risk group, the number was91.2%(31/34)、83.3%(30/36) and33.3%(5/15), and with significant differences compared(F=20.978, P<0.001).6. After6and12months,the negative biopsy rate were72.9%(62/85) and51.8%(43/83),and the rate in patients at low, intermediate and high risk were91.2%(31/34)、72.2%(26/36)、33.3%(5/15)(χ2=17.453,P<0.001) and79.4%(27/34)、41.4%(14/34)、13.3%(2/15)(χ2=22.490, P<0.001)respectively The actuarial2-year BFSR was57.8%(48/82), and at low、intermediate and high risk group was91.2%(31/34)、50.0%(17/34)、0%respectively (χ2=36.233, P <0.001) 7.Kaplan-Meier analysis (include age、hormone treatment、danger group、surgery time and PSA nadir) found different danger-group、surgery time and PSA nadir had significant influence on the2-year BFSR results(P<0.001), however, the Cox analysis (include danger group、surgery time and PSA nadir) found the only significant factor was danger-group(B=1.388, P<0.001)8.During the follow-up survey, no case died of surgical complications, and all the patients suffered slight complications.25cases had mild hematuria、2cases with transient UI and10cases with epididymitis, they all recovered after receiving conservative management.3patients with repeatedly urinary retention urinate smoothly after receiving transurethral resection of prostate (TURP).1(1.2%) had serious recto-urethral fistula and did not need surgery.Conclusions:1.This study demonstrates the effectivity achieved with HIFU treatment in localized prostate cancer patients. It can get effective cancer control in low-and intermediate-risk localized prostate cancer patients, specially in low-risk group; nevertheless, for patients with high-risk prostate cancer, HIFU monotherapy does not result in satisfactory cancer control.2.The different PSA before surgery is the only factor that can effect the2-year BFSR after HIFU treatment of the localized prostate cancer patients.3.The1-month antiandrogen therapy before surgery has no affect on the2-year BFSR after HIFU treatment of the localized prostate cancer patients. |
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