[Indications for curietherapy of the prostate using permanent implants]

Analyse clinique et dosimétrique de 469 patients traités en France en 2005 par implantation prostatique de grains d'iode 125 IsoSeed Bebig: rapport pour le Comité économique des produits de santé (CEPS)

A French decree of February 3rd 2005, allowed the Iodin 125 seeds from several companies to be reimbursed after a permanent implantation brachytherapy for a prostate cancer. Within this frame, the French "Comité économique des produits de santé" (CEPS; Economic committee for health products) made mandatory the annual writing and publication of a follow-up study with three main aims; make sure that the seeds were used for prostate cancer patients with criterias corresponding to the national recommendations, analyze the quality of the dosimetric data, and report all side effects, complications and possible accidents. We therefore report here a clinical and dosimetric analysis of 469 patient cases treated in France in nine centers in 2005 with the Iodin 125 IsoSeed Bebig. This analysis shows that: 1) The national recommendations for selecting patients for exclusive prostate brachytherapy have been taken into account in 97% of the cases; 2) The dosimetric quality criterias totally fulfilled the recommendations in a large majority of cases; the intra-operative D90 was found to be superior to 145 Gy in 98% of the patients, and the intra-operative V100 was superior to 95% in 96% of the cases; 3) The early toxicity (mainly urinary) was found to be at the lower range of what is reported in the literature, with in particular a retention rate of 2.4%.

Influence sur les résultats des rebonds du PSA après curiethérapie de prostate: étude de 295 cas avec trois ans de suivi

PURPOSE

To assess the frequency of the PSA "bouncing" phenomenon after a significant follow-up in a series of patients treated by permanent implant brachytherapy for a prostate cancer. To look for the clinical and dosimetric parameters possibly linked to this transitory secondary PSA increase. To evaluate in which percentage of cases this bouncing could have mimicked a biochemical relapse according to the ASTRO consensus criteria.

PATIENTS AND METHODS

From January 1999, to December 2001, 295 patients were treated by a permanent prostate implantation (real-time technique, with free (125)I seeds- Isoseed Bebig-) by the Institut Curie-Hôpital Cochin-Hôpital Necker Paris group. The mean follow-up is 40.3 months (9-66 months). The PSA level was regularly checked, at least every 6 months. We defined as a "bouncing" all increase in PSA, starting at 0.1 ng/ml, subsequently followed by a spontaneous (without any treatment) decrease, with return to the previous level or lower. We particularly focused on the patients fulfilling the criteria for a biochemical relapse according to the ASTRO consensus (Three successive increases in PSA). A multivariate analysis tried to identify independent factors among the usual clinical and dosimetric parameters.

RESULTS

In our series, 161 patients (55%) showed a transitory PSA increase (bouncing) of at least 0.1 ng/ml; 145 patients (49%) a bouncing of 0.2 ng/ml, 93 patients (32%) a bouncing of 0.4 ng/ml and 43 patients (15%) a bouncing of at least 1 ng/ml. Mean PSA bounce was 0.8 ng/ml (0.1-4.1), and mean time to bounce was 19 months. Thirty-two patients (11% of the total number) presented three successive PSA increases with a significant (3 months) interval between the dosages, and therefore were to be considered as being in biochemical relapse according to the ASTRO consensus criteria. Actually, among those 32 patients, 18 (56%) subsequently showed a complete normalization of their PSA, without any treatment. Ten patients went on increasing their PSA, and were considered to be really in biochemical relapse. For the last 4 patients, the situation still remains ambiguous. In multivariate analysis, age<70 years (P<0.00001) and D90>200 Gy (P<0.003) were identified as independent factors for a PSA bouncing of at least 0.4 ng/ml.

CONCLUSIONS

The observed rate of 32% of patients showing a PSA bouncing of at least 0.4 ng/ml in our series is in good agreement with what has been previously reported in the literature. Age<70 years and D90>200 Gy were found to be independent factors predicting for such a secondary transitory increase in PSA. Interestingly, among 32 patients fulfilling the classical criteria of the ASTRO for a biochemical relapse, 18 (56%) subsequently showed a spontaneous PSA decrease, demonstrating that the ASTRO consensus is not well adapted to the biochemical follow-up of our patients undergoing permanent implant prostate Brachytherapy.

Curiethérapie interstitielle des cancers localisés de prostate par implants permanents d'iode 125

Brachytherapy with permanent implants is a validated method of treatment of prostate adenocarcinomas of favourable prognosis. Its technology is based on endorectal ultrasonography and on peroperative visualisation of the implant and the dose distribution. A strict selection of the patients is necessary before this localised treatment. An active collaboration between urologists, radiophysicists and radiation oncologists is necessary during all the process of selection, treatment and follow-up of the patients. An assessment of the carcinologic and functional results is necessary. Recommendations are formalized by a joint collaboration between members of the AFU and of the SFRO.

[What systematic work-up should be required for the patient with localized adenocarcinoma of the prostate?]

The systematic work-up for patient with clinically localised prostate cancer must allow a reconciliation of all the necessary elements to propose one or several therapeutical options. The evaluation must take into account the life's expectancy, and must precise the cancer progression and prognostic factors. The life expectancy depends out age, performance status and comorbidities. Digital rectal exam, PSA and Gleason score analysis are systematic. These tests allow the specialist to decide whether or not to complete the progression work-up by bone scan and pelvic CT. This first work-up should define if a patient will benefit from some curative local treatment. In case of palliative treatment or deferred treatment, the work-up highlights the specialist to decide the medical supervision. Some exams, systematic or not, are very specific from each therapeutic modality considered; they allow to precise individually the efficacy and toxicity prognostic factors for each therapeutic strategy. The final therapeutic decision is based at first on this objective data even if they are probabilistic, and finally on informed patients preferences.