title: Segmental dosimetry, toxicity and long-term outcome in patients with prostate cancer treated with permanent seed implants.
abstract: WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: The development of side effects characteristic for the different treatment methods with impact on the patients' quality of life plays a growing role for individual patients with early stage prostate cancer. Using permanent brachytherapy a high dose to the prostate can be applied with a steep dose gradient to the normal tissue. However, small partial volumes of normal tissue may be exposed to high doses inducing special side effects including lower urinary tract symptoms and/or erectile dysfunction. In the literature there are only few publications so far regarding segmental dosimetry and its influence on side effects and the results are conflicting. We could not identify any dosimetric parameter in segmental dosimetry that may have an influence at certain time intervals on the development of side effects such as lower urinary tract symptoms or erectile dysfunction. However, we could state clearly that the preoperative situation is the most important factor for postoperative outcome.
  
  
  OBJECTIVE
  To report on the side effects of patients with low to low-intermediate risk prostate cancer treated with permanent interstitial brachytherapy with special emphasis on segmental dosimetry.
  
  
  METHODS
  A series of 186 consecutive patients treated for early stage prostate cancer receiving definitive I-125 brachytherapy (permanent seed implantation) between November 2001 and April 2005 at our institution were examined for the development of side effects. Morbidity was assessed prospectively using the International Prostate Symptom Score (IPSS) and the International Index of Erectile Function (IIEF-5) in a mean follow-up interval of 30 months. The scores were correlated with segmental dosimetry performed 6 weeks after the implantation.
  
  
  RESULTS
  The mean postoperative dose to 90% of the prostate volume (D90) was 180.2 Gy, the mean preoperative IPSS 7.2 and the mean IIEF-5 14.35, with all scores showing a maximum deterioration after 6 weeks with normalization after 24 months. After correlating the segmental dosimetry and the scores at different time intervals, only the baseline scores remained statistically significant in multivariate regression analysis at all time intervals (P < 0.00).
  
  
  CONCLUSIONS
  We could not demonstrate a correlation of segmental dosimetry with induction of side effects. There is no relationship between dose exposure of partial volumes and the development of radiation-induced toxicities. The preoperative situation regarding lower urinary tract symptoms and erectile function are the most important factors for postoperative outcome.
authors.affiliation: Clinic of Radiation Oncology, Hannover Medical School, Hannover, Germany. meyer.a@mh-hannover.de
authors.forename: Andreas
authors.initials: A
authors.lastname: Meyer
authors.forename: Julia
authors.initials: J
authors.lastname: Wassermann
authors.forename: Antje
authors.initials: A
authors.lastname: Warszawski-Baumann
authors.forename: Rolf
authors.initials: R
authors.lastname: Baumann
authors.forename: Stefan
authors.initials: S
authors.lastname: Machtens
authors.forename: Johann H
authors.initials: JH
authors.lastname: Karstens
authors.forename: Hans
authors.initials: H
authors.lastname: Christiansen
authors.forename: Axel
authors.initials: A
authors.lastname: Merseburger
authors.forename: Markus A
authors.initials: MA
authors.lastname: Kuczyk
authors.forename: Christoph
authors.initials: C
authors.lastname: von Klot
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000009:adverse effects* / Q000379:methods; D007172:Erectile Dysfunction / Q000209:etiology*; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D057234:Preoperative Period; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000150:complications / Q000532:radiotherapy*; D011788:Quality of Life; D011874:Radiometry / Q000379:methods*; D013997:Time Factors; D016896:Treatment Outcome; D014555:Urination Disorders / Q000209:etiology*
chemical_list: D007457:Iodine Radioisotopes