Clinical investigation
Prostate
Quality of life of patients after permanent prostate brachytherapy in relation to dosimetry

https://doi.org/10.1016/j.ijrobp.2005.03.046Get rights and content

Purpose: To investigate changes in quality of life (QoL) after permanent prostate brachytherapy and to correlate these changes with postimplant dosimetry based on magnetic resonance (MR) images.

Methods and Materials: For this study, 127 patients with low-stage prostate cancer and treated with brachytherapy received a QoL questionnaire at five time points: before treatment and at 4 weeks, 6 months, 1 year, and 2 years after treatment. The questionnaire included the RAND-36 generic health survey, the cancer-specific European Organization for Research and Treatment of Cancer (EORTC) core questionnaire, the tumor-specific EORTC prostate cancer module, and the American Urological Association symptom index. Postimplant dosimetry was based on registered T1 spin echo transversal, T2 turbo spin echo transversal, and T2 turbo spin echo sagittal MR images and CT images taken 4 weeks after implantation of the iodine-125 seeds. Calculated parameters were prostate volume, prostate volume receiving 100% (V100) and 150% (V150) dose, dose to 90% of the prostate volume (D90), maximum dose in 1-, 2-, and 5-cm3 rectum volume, distance between prostate and anterior rectum wall, and the maximum dose in 1%, 2%, and 5% urethra volume. Analysis of variance for repeated measures was used for comparison of the means of all variables in the different questionnaires. Linear regression analysis (stepwise) was used to investigate the correlations between QoL parameters and dosimetry parameters.

Results: On average, only the QoL at 4 weeks after implant was significantly different from (worse than) the QoL at the other time points. Regression analysis showed a significant correlation between changes in bowel problems and the maximum dose in 2-cm3 rectum volume, between changes in urinary symptoms and prostate volume, and between changes in urinary problems and the D90 value of the prostate.

Conclusions: The QoL for patients with permanent prostate implants was worse in the first months after treatment but returned to baseline values 1 year after implant. Significant correlations were found between dose distribution and QoL.

Introduction

Localized prostate cancer can be treated with prostatectomy, external beam radiotherapy, and brachytherapy (1, 2, 3, 4, 5). With all techniques, a comparable tumor control is achievable, but differences are found in the treatment-related problems and the quality of life (QoL) of the patients during treatment (3, 6, 7, 8, 9). The American Brachytherapy Society has published guidelines for the reporting of treatment-related morbidity after prostate brachytherapy (10). The relationship between toxicity and the dose distribution after permanent prostate brachytherapy has been investigated in many studies (11, 12, 13, 14, 15, 16). Mostly, the toxicity is determined according to the Radiation Therapy Oncology Group (RTOG) scales or the Common Toxicity Criteria (17, 18). Different studies resulted in opposite predictors because of different patient groups (11, 15, 16). Beside the evaluations of toxicity by the physician, QoL reflects the patient’s perspective. Litwin et al. (19) showed that physicians underscored problems after treatment compared with results of self-administered patient questionnaires.

Studies investigating the relationship between postimplant dose calculations and QoL measured by questionnaires are scarce. Merrick et al. (20, 21) found that tobacco consumption was the strongest predictor of late urinary problems, and no predictor was found to predict changes in bowel function. Locke et al. (22) investigated factors for the risk of retention and the duration of retention. They found that the only predicting factor was postimplant prostate volume. The dose distributions in these studies were based on CT. Inaccuracies in the dose distribution were caused by swelling of the prostate due to the insertion of the needles (23, 24) and inter- and intraobserver variabilities in delineation of the organs (25, 26, 27, 28). The variabilities in contouring become smaller when the quality of the images improves. To distinguish the prostate and rectum wall or the prostate and bladder, MR images are more useful than CT (29, 30, 31).

The goal of this study was to investigate changes in QoL, scored with a combination of self-administered questionnaires, after a permanent prostate brachytherapy implant and to correlate these changes with postimplant dosimetry based on MR images.

Section snippets

Patients

This study is an analysis of patients with low-stage prostate cancer (Stage T1 or T2) and treated with brachytherapy at the Department of Radiotherapy, University Medical Center Utrecht (Utrecht, The Netherlands) between December 2000 and June 2003. In this period, we collected data for 127 patients.

Implantation and evaluation method

During the implantation of radioactive I-125 seeds, an intraoperative plan was made with the system for Sonographic Planning for Oncology Treatment (SPOT; Nucletron, Veenendaal, The Netherlands).

Dosimetry

The mean and standard deviation of the dosimetry and implant-specific parameters are presented in Table 1. We used two techniques for insertion of the iodine seeds: manual insertion of RAPID Strands (type 6711; Amersham, Eindhoven, The Netherlands) and automatic delivery of selectSeeds with the seedSelectron (Nucletron). Comparable dosimetric results were achieved with both techniques (41).

The urethra was visible on MR images of 44 patients.

For the regression analysis, a set of independent

Discussion

Brachytherapy is a common treatment method for prostate cancer. It is important to make a seeds configuration such that the prostate is irradiated with the prescribed dose while the dose to the critical organs is minimized. Postplanning is necessary to determine the actual dose delivered to the prostate and surrounding tissues. In this study, we correlated postimplant dosimetry data with QoL data. Patients answered a QoL questionnaire at five times (one before and four after treatment) to

Acknowledgments

We thank Paul Westers from the Center of Biostatistics, Utrecht, for his assistance with statistical analysis.

References (46)

  • K.M. Snyder et al.

    Defining the risk of developing Grade 2 proctitis following I-125 prostate brachytherapy using a rectal dose–volume histogram analysis

    Int J Radiat Oncol Biol Phys

    (2001)
  • N. Salem et al.

    Predictive factors of acute urinary morbidity after iodine-125 brachytherapy for localised prostate cancerA phase 2 study

    Radiother Oncol

    (2003)
  • F.M. Waterman et al.

    Probability of late rectal morbidity in I-125 prostate brachytherapy

    Int J Radiat Oncol Biol Phys

    (2003)
  • C.A. Lawton et al.

    Long-term treatment sequelae following external beam irradiation for adenocarcinoma of the prostateAnalysis of RTOG studies 7506 and 7706

    Int J Radiat Oncol Biol Phys

    (1991)
  • A. Trotti

    The evolution and application of toxicity criteria

    Semin Radiat Oncol

    (2002)
  • M.S. Litwin et al.

    Differences in urologist and patient assessments of health related quality of life in men with prostate cancerResults of the CaPSURE database

    J Urol

    (1998)
  • G.S. Merrick et al.

    Late rectal function after prostate brachytherapy

    Int J Radiat Oncol Biol Phys

    (2003)
  • G.S. Merrick et al.

    Long-term urinary quality of life after permanent prostate brachytherapy

    Int J Radiat Oncol Biol Phys

    (2003)
  • J. Locke et al.

    Risk factors for acute urinary retention requiring temporary intermittent catheterization after prostate brachytherapyA prospective study

    Int J Radiat Oncol Biol Phys

    (2002)
  • F.M. Waterman et al.

    Edema associated with I-125 or Pd-103 prostate brachytherapy and its impact on post-implant dosimetryAn analysis based on serial CT acquisition

    Int J Radiat Oncol Biol Phys

    (1998)
  • G.S. Merrick et al.

    The dependence of prostate postimplant dosimetric quality on CT volume determination

    Int J Radiat Oncol Biol Phys

    (1999)
  • B. Al-Qaisieh et al.

    Impact of prostate volume evaluation by different observers on CT-based post-implant dosimetry

    Radiother Oncol

    (2002)
  • J. Crook et al.

    Interobserver variation in postimplant computed tomography contouring affects quality assessment of prostate brachytherapy

    Brachytherapy

    (2002)
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