Radical prostatectomy and adjuvant radioactive gold seed placement: results of treatment at 5 and 10 years for clinical stages A2, B1 and B2 cancer of the prostate

Design of a Flexible Wasp-Inspired Tissue Transport Mechanism

Tissue transport is a challenge during Minimally Invasive Surgery (MIS) with the current suction-based instruments as the increasing length and miniaturisation of the outer diameter requires a higher pressure. Inspired by the wasp ovipositor, a slender and bendable organ through which eggs can be transported, a flexible transport mechanism for tissue was developed that does not require a pressure gradient. The flexible shaft of the mechanism consists of ring magnets and cables that can translate in a similar manner as the valves in the wasp ovipositor. The designed transport mechanism was able to transport 10wt% gelatine tissue phantoms with the shaft in straight and curved positions and in vertical orientation against gravity. The transport rate can be increased by increasing the rotational velocity of the cam. A rotational velocity of 25 RPM resulted in a transport rate of 0.8 mm/s and increasing the rotation velocity of the cam to 80 RPM increased the transport rate to 2.3 mm/s though the stroke efficiency decreased by increasing the rotational velocity of the cam. The transport performance of the flexible transport mechanism is promising. This means of transportation could in the future be an alternative for tissue transport during MIS.

Gold seed implantation in prostate brachytherapy

Interstitial brachytherapy for treatment of prostate cancer with radioactive gold--initially with liquid gold and later with seed technique--is based on an experience of more than four decades. With biopsy results approaching a 80% negative rate, and, at 5 years, a cancer specific survival of 100% for Stages A and B1, 90% for Stage B2, and 76% for Stage C, this form of treatment offers an effective and well-tolerated alternative mode of therapy for patients with localized prostate cancer.

[Radiotherapy after radical prostatectomy: indications, results and side effects]

BACKGROUND

Radiation therapy following radical prostatectomy in locally progressed prostate carcinoma has become increasingly important in the last few years as both adjuvant therapy in patients with pT3-tumors with or without positive margins and treatment for a PSA increase in local recurrence of disease. The background for this is the knowledge gained by using PSA that up to 60% of the patients with histopathologically confirmed pT3/4 tumors or involvement of the lymph nodes are systemically and/or locally progressive after 3 to 5 years if only surgical or radiation therapy was performed.

RESULTS

A number of studies, albeit exclusively retrospective, substantiated a significantly high local tumor control by radiotherapy after radical prostatectomy. This holds true for adjuvant therapy with a PSA in the "zero range" as well as with a PSA increase from the "zero range", whereby it must be taken into consideration that a certain percentage of treated patients with a PSA in the "zero-range" with or without positive margins actually do not need further therapy. Two retrospective studies demonstrated a significant better lengthening of "freedom from treatment failure" that is local and systemic progression of disease. Lengthening the survival time has, however, not yet been proven. With an increase in the PSA from the "zero range" after radical prostatectomy, there are indications that systemic metastatic spread already occurs with values higher than 2.5 to 4 ng/ml and the radiotherapy no longer has any curative intention.

CONCLUSIONS

Adjuvant RT following radical prostatectomy gives better local control rates and probably better rates of "freedom from treatment failure" in patients with locally advanced prostate cancer with positive margins and probably in patients with negative margins. However, in retrospective studies no advantage in overall survival was shown.

Survival of patients with localized prostate cancer treated with percutaneous transperineal placement of radioactive gold seeds: stages A2, B, and C

Between 1984 and 1991, a total of 177 patients with adenocarcinoma of the prostate were treated with transcutaneous, transperineal radioactive gold seeds. Of these 177 patients, 20 were determined to have pelvic lymph node involvement and were excluded from this review. The remaining 157 patients received a median radioactivity dose of 164 mCi with a median follow-up of 48 months. Cancer-specific survival at 5 years was 100% for stage A2 and B1, 90% for stage B2, and 76% for stage C cancer. Covariates of grade, total radioactivity administered, age of the patient, and number of seeds implanted did not influence disease-free survival in a statistically significant manner. Significant complications were observed in two patients. The survival rates of patients treated with 198Au seed implantation for localized cancer are equivalent or better when compared to historical data of patients treated with 125I implantation, external beam radiotherapy, combination radioactive gold seed implantation and external irradiation, and radical prostatectomy. In addition, these comparable survival rates using interstitial 198Au seeds may be achieved with less morbidity.

Adjuvant radiotherapy following radical prostatectomy--results of 56 patients

Patients with adenocarcinoma of the prostate with positive surgical margins and/or seminal vesicle invasion after radical prostatectomy (RP) have a high risk of local recurrence or distant spread of disease. Several investigators reported increased local control rates following adjuvant radiotherapy (RT). However, it is unclear whether this procedure, with or without hormonal therapy (HT), improves the outcome. From 1975 to 1987, 56 patients with adenocarcinoma of the prostate underwent adjuvant RT following RP (pathological stage C1, n = 19; stage C2, n = 17; stage D1, n = 20). In 27 of 56 patients an additional immediate orchiectomy was performed. 48 patients received 4000-5000 cGy to the pelvic lymphatics, including the prostatic fossa, followed by a boost to the prostatic fossa to complete 6400-7000 cGy, whereas 8 patients were treated to the prostatic fossa only. With a median follow-up of 89 months, the overall survival rate of patients with stages C1, C2 and D1 did not differ significantly (10-year overall survival rate 84, 74 and 71, respectively). The local control rate for 5- and 10-years was 96 and 90%, respectively. A significant advantage in overall survival (5- and 10-year rate: 92 versus 93% and 92 versus 63%; P < 0.05, respectively) and clinical disease-free survival (5- and 10-year rate: 92 versus 72% and 92 versus 49%; P < 0.05, respectively) was seen in 27 patients with orchiectomy compared with 29 patients without HT. A total of 15 patients (26%) developed at least one form of late toxicity, in most cases a mild proctitis, cystitis, or penile or leg oedema. However, 6 patients (11%) had severe grade 3 or 4 side-effects that necessitated a cystectomy in 2 cases as well as a colostomy in 2 cases. In all patients with grade 3 or 4 side-effects, 70 Gy as a tumour-encompassing isodose were applied. Adjuvant RT, following RP in stage C and D1 prostate cancer with positive surgical margins and/or seminal vesicle invasion increases local control. Whether immediate HT influences the outcome, as seen in this study, should be proven in prospective clinical trials.

Audit and its impact in the management of early prostatic cancer

An analysis was made of a prospective database of 614 men with newly diagnosed carcinoma of the prostate who presented between January 1978 and December 1990; 3-monthly updates were available on their clinical, haematological and biochemical parameters and 6-monthly updates on chest X-rays, bone scans and skeletal X-rays. It was found that 107 men (mean age 73.5 years) had early disease at presentation. Their management was based on regular surveillance and the treatment deferred until disease progression or development of symptoms. The audit of outcome measured various clinical events. Four patients (3.7%) developed local failure, 11 (10.3%) developed bone metastases, 3 (2.8%) died of cancer with a median survival of 6.3 years, and 34 (31.8%) died of intercurrent disease with a median survival of 2.6 years. The observed survival for 12 years of the whole group was similar to the expected survival for an age-matched population in Scotland. The standardised mortality ratio was 81 (95% confidence limits 57-112).

Use of percutaneous transperineal 198Au seeds to treat recurrent prostate adenocarcinoma after failure of definitive radiotherapy

Patients who fail external radiation therapy for prostatic cancer pose a therapeutic challenge. No further external radiation treatment can be delivered safely to the local lesion, although some patients are candidates for salvage surgery. In this study, 31 patients who failed prior external beam radiotherapy received percutaneous transperineal placement of gold seeds (198Au). Initial prostate volume was 17.7 cc and decreased to 10 cc 24 months after 198Au implantation. Of 15 patients biopsied at 12 months after treatment, 4 (27%) were positive, 6 (40%) were negative, and 5 (33%) showed prostate cancer with radiation changes. Two of three patients have died of prostate cancer, with an overall 5-year estimated survival of 67%. Interstitial brachytherapy was found to be an additional well-tolerated treatment modality in this group of 31 patients.

The effect of interstitial hyperthermia on the Dunning prostate tumor model

The effect of hyperthermia was examined on the Dunning prostate tumor model in rats. Hyperthermia was created by heating self-regulating interstitial seeds with an external oscillating magnetic field. The seed alloy was comprised of 70% nickel and 30% copper. One treatment with 50C seeds for two hours did not provide significant delay in tumor growth compared to controls. However, regimens with two treatments separated by either 48 hours or one week did cause significant delay (p = 0.0013 and p = 0.0096, respectively). These results suggest that an interstitial hyperthermia seed may provide an efficacious outpatient therapy for prostate cancer. Further, interstitial hyperthermia may be readily combined with existing radiotherapy with interstitial gold coated seeds to provide additive or synergistic anti-tumor effects.