Template-based Intensity-Modulated Radiation Therapy: A Cost-effective Intensity-Modulated Radiation Therapy Planning Procedure for Prostate Cancer.

INTRODUCTION: Intensity-modulated radiation therapy (IMRT) has been widely accepted for the treatment of prostate cancer. In comparison with traditional three-dimensional conformal radiation therapy (3D-CRT), it improves local control while minimizing side effects. However, IMRT comes at a significantly higher cost. In this report, we describe the development of template-based IMRT (TB-IMRT) planning for prostate cancer that does not require additional resources above 3D-CRT. METHODS: Twenty patients previously treated using 3D-CRT were retrospectively planned using the TB-IMRT planning technique. Planning target volume coverage, dose to organs at risk, and resource usage were compared between 3D-CRT and TB-IMRT techniques. RESULTS: All 3D-CRT and TB-IMRT plans met the planning guidelines. TB-IMRT compared better than 3D-CRT in terms of the homogeneity index (0.039 ± 0.007 vs. 0.052 ± 0.008) and conformity index (0.866 ± 0.024 vs. 0.752 ± 0.054). TB-IMRT also provided better sparing of organs at risk. Planning times were significantly less for TB-IMRT (average 13.43 ± 2.18 minutes) compared with conventional plans (45.4 ± 17.0 minutes). Times required for patient-specific quality assurance were similar between TB-IMRT and 3D-CRT. CONCLUSIONS: The TB-IMRT technique for prostate allows for all the potential benefits of IMRT without any additional resources above conventional 3D-CRT.

A three-isocenter jagged-junction IMRT approach for craniospinal irradiation without beam edge matching for field junctions.

PURPOSE: Traditionally craniospinal irradiation treats the central nervous system using two or three adjacent field sets. We propose a technique using a three-isocenter intensity-modulated radiotherapy (IMRT) plan (jagged-junction IMRT) which overcomes problems associated with field junctions and beam edge matching and improves planning and treatment setup efficiencies with homogenous target dose distribution. METHODS AND MATERIALS: Treatments for 3 patients with a prescription of 36 Gy in 20 fractions were retrospectively planned with jagged-junction IMRT and compared to conventional treatment plans. Planning target volume (PTV) included the whole brain and spinal canal to the S3 vertebral level. The plan used three field sets, each with a unique isocenter. One field set with seven fields treated the cranium. Two field sets treated the spine, each set using three fields. Fields from adjacent sets were overlapped, and the optimization process smoothly integrated the dose inside the overlapped junction. RESULTS: For jagged-junction IMRT plans vs. conventional technique, the average homogeneity index equaled 0.08 ± 0.01 vs. 0.12 ± 0.02, respectively, and conformity number equaled 0.79 ± 0.01 vs. 0.47 ± 0.12, respectively. The 95% isodose surface covered (99.5 ± 0.3)% of the PTV vs. (98.1 ± 2.0)%, respectively. Both jagged-junction IMRT plans and the conventional plans had good sparing of organs at risk. CONCLUSIONS: Jagged-junction IMRT planning provided good dose homogeneity and conformity to the target while maintaining a low dose to organs at risk. Results from jagged-junction IMRT plans were better than or equivalent to those from the conventional technique. Jagged-junction IMRT optimization smoothly distributed dose in the junction between field sets. Because there was no beam matching, this treatment technique is less likely to produce hot or cold spots at the junction, in contrast to conventional techniques. The planning process is also simplified as only one IMRT plan is required for the entire target volume.

Evaluation of dosimetric parameters and disease response after 125 iodine transperineal brachytherapy for low- and intermediate-risk prostate cancer.

PURPOSE: To analyze dosimetric outcomes after permanent brachytherapy for men with low-risk and "low-tier" intermediate-risk prostate cancer and explore the relationship between the traditional dosimetric values, V100 (volume of prostate receiving 100% of the prescribed dose) and D90 (minimum dose to 90% of the prostate), and risk of biochemical failure. METHODS AND MATERIALS: A total of 1,006 consecutive patients underwent implantation between July 20, 1998, and Oct 23, 2003. Most (58%) had low-risk disease; the remaining 42% comprised a selected low-tier subgroup of intermediate-risk patients. The prescribed minimum peripheral dose (MPD) was 144 Gy. All implants used 0.33 mCi 125I sources using a preplan technique featuring right-left symmetry and a strong posterior-peripheral dose bias. Sixty-five percent of patients had 6 months of androgen deprivation therapy. Postimplantation dosimetry was calculated using day-28 CT scans. RESULTS: With a median follow-up of 54 months, the actuarial 5-year rate of freedom from biochemical recurrence (bNED) was 95.6% +/- 1.6%. Median D90 was 105% of MPD, median V100 was 92%, median V150 was 58%, and median V200 was 9%. Dosimetric values were not predictive of biochemical recurrence on univariate or multivariate analysis. Analysis of dosimetric values by implantation number showed statistically significant increases in all values with time (D90, V100, V150, and V200; p < 0.001), but this did not translate into improved bNED. CONCLUSIONS: In contrast to some previous studies, dosimetric outcomes did not correlate with biochemical recurrence in the first 1,006 patients treated with 125I prostate brachytherapy at the British Columbia Cancer Agency. Despite a median D90 of only 105% of MPD, our bNED rates are indistinguishable from series that reported higher D90 values.

Long-term survivorship of esophageal cancer patients treated with radical intent.

To investigate the recent trends in definitive management of esophageal cancer, the records of 138 consecutive patients treated with radical intent in a single institution between 1995 and 2003 were reviewed and analyzed. The median follow-up period was 5.7 years (range 1.1 to 10.4 years). Seventy-seven patients were treated with radiation therapy (RT) only and 61 with combined regimens (CRT), in which RT was combined with either radical surgery or chemotherapy, or both. The overall survival of the entire cohort was 32% over two years and 20% over five years. The survivorship in the RT group was 17% over two years and 5% over five years. In the CRT group, 51% and 35% survived over two and five years, respectively. From all the potential prognostic factors examined by univariate and multivariate analyses, only male sex and use of CRT were strongly associated with better survivorship. There was no significant difference in the outcomes among the different regimens of CRT. Survivorship was not affected by the location or histology of the tumour, clinical stage, dose of RT or use of endoluminal brachytherapy in addition to external beam RT. There was a greater tendency to use RT only more often in older patients, but patient age did not affect survivorship. The proportion of patients treated with CRT did not change significantly over the last versus the first four years of the observed period. Combined regimens are undoubtedly superior to RT as a single modality. The long-term survivorship of patients in a subgroup of our patients treated with combined modality protocols compared favourably with the previously reported results in the literature and specifically in prospective randomized trials. However, the optimal combined modality regimen is yet to be defined.

Hemoglobin levels do not predict biochemical outcome for localized prostate cancer treated with neoadjuvant androgen-suppression therapy and external-beam radiotherapy.

PURPOSE: To investigate whether hemoglobin (Hb) levels affect outcome in men with localized prostate adenocarcinoma (LPA) treated with neoadjuvant androgen-suppression therapy (NAST) and external-beam radiotherapy (EBRT). METHODS AND MATERIALS: A total of 563 men with LPA treated with NAST (median: 5.3 months) and EBRT who had Hb levels during treatment were retrospectively reviewed. Patient, tumor, and treatment variables, including the following Hb variables, were subjected to univariate and multivariable analyses to identify factors that predict biochemical control (bNED) and overall survival (OS): pre-EBRT Hb, Hb nadir during EBRT, and change in Hb from pre-EBRT to nadir during EBRT. RESULTS: Median PSA follow-up was 4.25 years. Forty-nine percent of men were anemic during EBRT, with a median Hb of 13.4 g/dL, and 68% experienced a decline in Hb from pre-EBRT to during EBRT of median 0.6 g/dL. Five-year Nadir+2 bNED and OS rates were similar for anemic and nonanemic patients during EBRT. High percent-positive biopsies, PSA and Gleason score, and use of AA monotherapy predicted worse bNED. High stage and age predicted worse OS. Hb variables were not predictive of bNED or OS. CONCLUSIONS: Anemia is a common side effect of NAST and is usually mild. Hb levels, however, do not predict biochemical control or survival.

Computed tomography determination of prostate volume and maximum dimensions: a study of interobserver variability.

OBJECTIVE: (1) To evaluate the reproducibility of prostate volume, maximum dimensions and geometrical center coordinates determination using computed tomography (CT) and (2) to identify patterns of interobserver variability. MATERIALS AND METHODS: Forty patients, suitable for our brachytherapy program, were selected for the study. All patients underwent CT scanning and the prostate volumes were determined by three radiation oncologists. Measurements of geometrical center coordinates, maximum organ dimensions in the anterior-posterior (AP), lateral (Lat) and longitudinal (Long) axes as well as prostate volumes were recorded. This yielded 840 measurements of seven variables for analysis. The means and corresponding standard deviations (SD) of each variable were calculated for each patient. The SDs were then averaged and presented as indices of dispersion. Average variations from the mean were also calculated for each observer along with the SDs. RESULTS: Analysis of the geometrical center coordinates revealed acceptable variability amongst observers. For the AP, Lat and Long coordinates the SDs were 0.78, 0.89 and 1.72 mm, respectively. The corresponding values for the maximum organ dimensions were 2.54, 2.72 and 4.43 mm, respectively. While the volumes outlined by observer B were less than or equal to the mean in 95% of cases and those of observer C were greater than or equal to the mean in 93% of cases, the volumes of observer A were equally distributed above and below the mean (48% in both cases). CONCLUSION: The determination of the geometrical center coordinates was reproducible amongst observers. The largest variations were seen with the Long axis. The volume determination is more variable. However, a characteristic trend was seen amongst observers when their volumes were compared to the mean volumes of the group.

Testosterone recovery following prolonged adjuvant androgen ablation for prostate carcinoma.

BACKGROUND: This study was conducted to describe the rate and completeness of the recovery of testosterone production following prolonged temporary androgen ablative therapy in men with prostate carcinoma undergoing curative radiation therapy. METHODS: Two-hundred and sixty-seven men treated with between 3 months and 3 years of adjuvant androgen ablation (AA) were followed at 6-month intervals following cessation of their androgen deprivation therapy. A comparative group of 518 men not undergoing AA were also followed. RESULTS: Drugs used included low dose cyproterone/stilboestrol (CPA/DES) in combination (56%) and 1 month depot (18%) and 3 month depot (25%) leutinizing hormone releasing hormone agonist (LHRHa). Seventy-nine percent of men in the current study recovered normal testosterone levels (10nmol/L), and 93% recovered levels of at least 5nmol/L. In comparison, men who had never received androgen ablative therapy showed a fall of testosterone, with 17% having sub-normal levels after 3 years. Median time to testosterone recovery was 10 months. Factors associated on multivariate analysis with delayed testosterone recovery included advanced age (P = 0.008), low pre-therapy testosterone (P = 0.04), and the use of 3 month LHRHa preparations as compared with CPA/DES (P = 0.002) or 1 month LHRHa preparations (P = 0.015). The duration of drug use was not significantly associated with time to testosterone recovery. CONCLUSIONS: Long-acting LHRHa preparations appear to have a more prolonged action than previously supposed. Most men treated for up to 2 years recover normal testosterone levels after cessation of adjuvant androgen ablation, and the limited data available in the current study on patients treated for 3 years also suggests most will recover.