Rectal complications associated with transperineal interstitial brachytherapy for prostate cancer

Perirectal seeds as a risk factor for prostate brachytherapy-related rectal bleeding

PURPOSE

To correlate rectal wall doses and perirectal seed numbers with late rectal bleeding after prostate brachytherapy.

METHODS AND MATERIALS

We studied 148 patients randomized to implantation with I-125 vs. Pd-103 at the VA Puget Sound HCS from 1998 through 2001 and for whom postimplant dosimetry was available. Implants were performed by standard techniques, using a modified peripheral loading pattern. A postimplant computed tomography (CT) scan (3 mm slice thickness) was obtained 1-4 h after implantation. Rectal doses were expressed as the R100, R200, and R300, defined as the rectal volume (cc) that received more than 100%, 200%, or 300% of the prescription dose, respectively. The rectum was considered to be a solid structure defined by the outer wall, without attempting to differentiate the inner wall or contents. In addition to conventional dose parameters, each patient's postimplant CT scan was reviewed for the number of seeds within 0, 0.1-2, and 2.1-4 mm of the outer rectal wall. The proximal edge of the seed was used for distance determinations from the outer rectal wall. Patients who reported Grade 1 or higher Radiation Therapy Oncology Group morbidity were contacted by telephone to obtain more details regarding their rectal bleeding. Those who reported persistent bleeding lasting for more than 1 month were categorized as Grade 2.

RESULTS

Patients had a wide range of rectal wall doses, with R100 values ranging from 0.0 to 10.4 cc (median, 0.95 cc). Similarly, the number of perirectal seeds within 0.0 to 2.0 mm of the rectum varied widely, ranging from 0 to 12 seeds (median: 1 seed). Seven patients (7 of 144 = 5%) developed persistent rectal bleeding, one of whom required a colostomy. Both rectal radiation doses and the number of perirectal seeds were higher in patients with persistent rectal bleeding. The number of perirectal seeds < or =2.0 mm of the rectal wall was higher in patients with rectal bleeding (p = 0.037), but the number of seeds 2-4 mm from the wall were not related (p = 0.72). In multivariate regression analysis including prostatic D90 (the dose that covers 90% of the postimplant prostate), preimplant transrectal ultrasound volume, R300, and the number of seeds < or =2 mm from the rectal wall as independent variables, only the R300 was statistically significantly associated with the likelihood of persistent rectal bleeding (p = 0.025).

CONCLUSION

A limited number of errant perirectal sources in itself does not appear to place patients at increased risk of rectal bleeding, providing that the overall rectal wall doses are within acceptable values.

Iodine seed prostate brachytherapy: an alternative first-line choice for early prostate cancer

This article on permanent iodine-125 seed prostate brachytherapy reviews the techniques, results, and patient selection issues for early prostate cancer. The long-term 10 y results of brachytherapy from Seattle, and their reproducibility in other centres both in the USA and UK are reported. The use of hormone therapy in brachytherapy and the value of combining external beam radiotherapy with a brachytherapy implant are discussed. Reviewed comparative data show the similarity of biochemical survival in patients treated with brachytherapy, radical prostatectomy, and external beam radiotherapy. The role of brachytherapy as a first-line treatment option for patients with prostate cancer is demonstrated.

High Dose Rate Brachytherapy as Prostate Cancer Monotherapy Reduces Toxicity Compared to Low Dose Rate Palladium Seeds

PURPOSE

We evaluated the potential for differing acute and chronic toxicities between 2 monotherapy methods of image guided conformal brachytherapy, high dose rate (HDR) brachytherapy alone and low dose rate (LDR) permanent palladium seeds.

MATERIALS AND METHODS

A total of 149 patients with biopsy proven, early stage prostate cancer were consecutively treated with interstitial brachytherapy as the sole method of treatment at William Beaumont Hospital between 1999 and 2001. Of the 149, 65 patients were treated with HDR using 192 iridium (192Ir), and 84 patients were treated with LDR using 103 palladium (103Pd). The majority of patients had clinical stage II, T1c or T2a disease, pretreatment prostate specific antigen less than 10 ng/ml and Gleason score 6 or less. Neoadjuvant hormones were used in 36% of patients for gland volume optimization. All treatments were performed transperineally with trans-rectal ultrasound guidance and fluoroscopy for verification of needle/seed positions. The HDR dose was 38 Gy delivered in 4 fractions, 2 times daily during 2 days. The LDR dose was 120 Gy. Acute and chronic toxicities were scored according to the Common Toxicity Criteria scale, version 2.0.

RESULTS

Median followup for all patients was 35 months. The 2 treatment groups were well-balanced with respect to age, clinical stage, prostate specific antigen, Gleason score, use of neoadjuvant hormones, pretreatment genitourinary symptoms, implanted gland volume and length of followup. Biochemical control (American Society for Therapeutic Radiology and Oncology definition) was 97% and 98% for LDR and HDR, respectively. HDR brachytherapy alone was associated with decreased acute rates of grade 1 to 3 dysuria (67% versus 36%, p <0.001), urinary frequency/urgency (92% versus 54%, p <0.001) and rectal pain (20% versus 6%, p = 0.017). These differences remained significant when patients who received prior hormonal therapy were excluded from analysis. Selected chronic toxicities were also decreased with HDR, including long-term urinary frequency and urgency, 32% (HDR) vs 56% (103Pd), p = 0.004. There were no differences in the rates of chronic dysuria, urinary incontinence, retention or hematuria. Urethral stricture rates were 8% in the HDR alone group vs 3% for 103 Pd (p = 0.177). The 3-year actuarial impotence rate was 45% for the LDR group and only 16% for HDR. The majority of complications were grade 1. No grade 4 toxicities were encountered in either group. HDR decreased treatment cost by 19%.

CONCLUSIONS

While HDR (192 iridium) and LDR (103Pd) monotherapy maintained the same biochemical control, the use of HDR brachytherapy as monotherapy was associated with decreased rates of acute urinary frequency, urgency, dysuria and rectal pain compared to LDR. Chronic urinary frequency, urgency and grade 2 rectal toxicities were also decreased with HDR. A dramatic decrease (66%) was noted in the rate of sexual impotency with HDR. In addition, patients treated with HDR did not remain radioactive after treatment. There was a decrease in cost from not purchasing seeds per patient. HDR monotherapy as prostate cancer treatment resulted in the same biochemical control with much lower toxicity. It is an accepted, convenient, cost-effective method of prostate brachytherapy for patients with favorable risk prostate cancer.

Influence of hormonal therapy on late rectal function after permanent prostate brachytherapy with or without supplemental external beam radiotherapy

PURPOSE

Recent clinical studies have reported a relationship between the use of hormonal therapy and degradation in rectal function after external beam radiotherapy. Using a patient-administered quality-of-life instrument, we evaluated the effect of hormonal therapy on late rectal function after permanent prostate brachytherapy with or without supplemental external beam radiotherapy.

METHODS AND MATERIALS

A total of 189 patients were mailed the Rectal Function Assessment Score (R-FAS), which consists of nine questions (score range 0-27, with higher scores indicative of poorer bowel function). Of the 189 surveys sent out, 187 (98.4%) were returned. Of the 187 patients, 149 (79.7%) were hormone naive, and 38 (20.3%) had received hormonal manipulation (median duration 4 months, range 3-36). The median follow-up for the entire group was 66.3 months. The effect of hormonal therapy on bowel function was evaluated by comparing the R-FAS scores across time, by each of the individual nine questions, and by means of a summary question evaluating the patient's perception of overall bowel function. The two groups were also evaluated in terms of clinical, treatment, and dosimetric parameters, including follow-up, age, Gleason score, clinical stage, pretreatment prostate-specific antigen level, number of pretreatment bowel movements/d, prostate volume, and rectal dosimetry.

RESULTS

The two groups were well matched in all clinical, treatment, and dosimetric parameters, except the patients receiving hormonal therapy had a statistically shorter follow-up (63.9 vs. 69.4 months, p <0.001) and higher pretreatment prostate-specific antigen level (12.0 vs. 9.8 ng/mL, p = 0.024). The R-FAS scores for the hormone-naive and hormonally manipulated patients were comparable (3.76 vs. 4.55, p = 0.083). In terms of the nine individual R-FAS questions, no statistically significant difference was reported for any question when stratified by hormonal status, including rectal bleeding (p = 0.735). Only 12% and 13% of hormone-naive and hormonally manipulated patients, respectively, reported bowel function to be worse after implantation. With time, a trend for improvement in the R-FAS was noted in both cohorts.

CONCLUSION

After permanent prostate brachytherapy, no statistically significant difference in bowel habits was discerned when stratified by hormonal status. In addition, only 12% of brachytherapy patients reported deterioration in bowel function after implantation.

Devastating complications after brachytherapy in the treatment of prostate adenocarcinoma

OBJECTIVE

To report a retrospective chart review of patients who developed recto-urethral fistula (RUF) or several bladder neck contracture (BNC) recurrences after brachytherapy for treating localized prostate cancer.

PATIENTS AND METHODS

In the past 3 years 18 patients with devastating complications after prostate brachytherapy were referred to our centre (RUF in 11, BNC in seven; mean age 63 years, range 60-81). All patients with RUF initially underwent diverting colostomy (six cystoprostatectomy with closure of the fistula, omental interposition and urinary diversion; one prostatectomy, bladder neck closure, fistula closure with omentum flap and continent vesicostomy). Three patients had the fistula closed with gracilis muscle flap using the York-Mason approach (one had a bladder neck closure and suprapubic tube; one elected to have no treatment). All patients with BNC had received three or more procedures to resect or incise their contracture. Four had diversion with a catheterizable segment, two used an indwelling Foley catheter and one uses intermittent catheterization.

RESULTS

All six patients who had cystoprostatectomy with urinary diversion have had no recurrence of their RUF. All three treated with the York-Mason procedure healed well. One developed recurrent prostate adenocarcinoma and two a secondary neoplasia in the prostate or rectum (leiomyosarcoma and neuroendocrine, respectively). The enterocystoplasty patient developed sepsis after colostomy reversal and subsequently died. In those patients with BNC, the four who underwent urinary diversion fared well; two tolerate the indwelling catheter poorly, and the seventh uses intermittent catheterization with occasional difficulty.

CONCLUSIONS

Brachytherapy with or without external irradiation can be associated with severe complications. RUF managed with aggressive anterior pelvic exenteration and urinary diversion can be associated with excellent results. The York-Mason procedure in patients with an adequate urinary continence mechanism and bladder dynamics may provide good functional results. The presence of a secondary malignancy in patients deserves further investigation. Many recurrences of a BNC tend be refractory to transurethral resection/incision; indwelling catheters are then poorly tolerated and patients may require a major reconstructive procedure.

Urinary and rectal complications of contemporary permanent transperineal brachytherapy for prostate carcinoma with or without external beam radiation therapy

BACKGROUND

Prostate brachytherapy is increasingly used to treat prostate carcinoma, alone or combined (combination therapy) with external beam radiation therapy (EBRT). This report cites the frequency and nature of urinary and rectal complications requiring unplanned interventions after contemporary brachytherapy with or without EBRT.

METHODS

A total of 177 consecutive patients underwent either brachytherapy (100 patients [56.5%]) or combination therapy (77 patients [43.5%]) for clinical T1-2 prostate carcinoma between July 1998 and July 2000. All the patients were analyzed with regard to disease characteristics, treatment details, and complications requiring unplanned interventions in up to 48 months of follow-up.

RESULTS

Catheter drainage for urinary retention was required for a median of 55 days (range, 3-330 days) in 36 patients (20%), including 24% after brachytherapy and 16% after combination therapy. Transurethral resection of the prostate (TURP) was performed at a median of 12 months (range, 8-18 months) after implantation in 5% of patients after brachytherapy and 14.5% of patients after combination therapy (P = 0.029). Colonoscopy with or without fulguration for rectal bleeding was performed in 37 of 158 patients (97 in the brachytherapy group and 61 in the combination therapy group) (23.4%) at a median of 17 months (range, 4-45 months), including 15 patients (15.5%) after brachytherapy and 22 patients (36%) after combination therapy (P = 0.002). Combination therapy resulted in fecal diversion in 6.6% of patients (P = 0.021), urinary diversion in 3.2% of patients (P = 0.148), and clean intermittent self-catheterization for recurrent stricture after multiple TURPs in 4.9% of patients (P = 0.055), none of which occurred after brachytherapy. Overall, 20.6% of patients underwent TURP or colonoscopy after brachytherapy, whereas 44.2% underwent those or more extensive unplanned procedures after combination therapy (P = 0.001).

CONCLUSIONS

Complications requiring unplanned procedures may occur after brachytherapy, and may be increased significantly after brachytherapy combined with EBRT. These data reinforce the concept that quality assurance and technique are important in prostate brachytherapy, but, even when these are in place, complications can occur, especially when EBRT is added to brachytherapy.

Brachytherapy for prostate cancer

The use of prostate brachytherapy for the treatment of early-stage, low-grade, low-volume carcinoma of the prostate continues to rise. Given the prolonged natural history of these early lesions, treatment failures may take many years or even a decade or more before becoming clinically evident. It is therefore likely that as the brachytherapy data mature, clinicians will be asked to help manage a potentially large cohort of men who have failed this local therapy--a scenario that will provide a number of unique challenges for the treatment of the disease and the management of the lower urinary tract. This article offers a contemporary review and suggestions with regard to the follow-up of patients who have undergone prostate brachytherapy, including low-dose rate permanent implants and high-dose rate temporary implants for the management of localized prostate cancer. In addition, current controversies in defining biochemical failure following radioactive implantation--including important data regarding the "prostate-specific antigen bounce" phenomenon--are discussed. Finally, a comprehensive review of the management of local recurrence following brachytherapy is offered.

[Curative radiotherapy of localized prostate cancer. Treatment methods and results]

Radiation oncology has undergone rapid technical development during the last few years. The further development of treatment planning systems and treatment machines had a major impact on the improvement of radiation therapy results in prostate cancer. This paper presents different treatment modalities and results. Currently available are three-dimensional conformal radiation, intensity modulated radiation therapy (IMRT), high dose rate brachytherapy, and low dose rate brachytherapy (seed implantation). All modalities offer the possibility for dose escalation, which is essential for curative treatment. Dose escalation using these techniques makes it possible to reduce the dose for the surrounding organs at risk. Three-dimensional conformal radiation therapy can be delivered with doses up to 78 Gy. The biochemical control rate is up to 90% depending on the risk factors T stage, initial PSA, and Gleason score. The incidence of late side effects is <10%. IMRT is a newer modality for percutaneous radiotherapy. By individual dose modification in the treatment fields, doses >80 Gy can be delivered in small treatment volumes. Treatment has to be highly precise to avoid dose peaks in the organs at risk, i.e., rectum and bladder. The preliminary data for remission and toxicity rates are promising, but it is too early for final conclusions. For cases with high-risk factors such as PSA >10 ng/ml, Gleason score >6, and stage T3, percutaneous radiation can be combined with neoadjuvant or adjuvant hormonal treatment. Randomized trials showed an improvement of the results in favor of combined treatment. HDR brachytherapy in combination with external radiation is a good option for dose escalation in patients with locally advanced tumors and/or other high-risk factors. The biochemical control rates are between 60 and 84%, late effects occur in less than 10%. Seed implantation (LDR brachytherapy) as sole treatment is indicated for prognostically favorable situations (PSA <10 ng/ml, Gleason score < or =6, and T1c or T2a tumors). The biochemical control rates are between 80 and 90%. Toxicity consists of urine retention and proctitis, occurring in 10-20% of the patients.

Permanent Prostate Brachytherapy in Men with Clinically Localised Prostate Cancer

Permanent prostate brachytherapy techniques are associated with excellent biochemical control for patients with localised prostate cancer. Ten-year data show that permanent prostate brachytherapy is compatible with external beam irradiation or radical prostatectomy. However, treatment protocols and techniques for prostate brachytherapy vary between centres and there is little conformity of treatment protocols. The selection of patients for monotherapy or combined external beam irradiation and brachytherapy is controversial. The role of neoadjuvant androgen deprivation also remains unanswered in patients with localised prostate cancer. In addition, post-implant dosimetry may in fact be more significant for predicting outcome than the addition of adjuvant therapies, and should be a requirement when performing prostate brachytherapy. Data now seem to support specific computed tomography (CT)-based criteria to evaluate implant quality and delivered dose to the prostate. Unfortunately, prostate oedema and poor imaging techniques are limiting factors for evaluating implant dosimetry. Treatment planning techniques that use new treatment planning computers may assist in improving the implant procedure and dosimetry and are now available.

Late rectal function after prostate brachytherapy

PURPOSE

Using a patient-administered quality of life instrument, to evaluate the effect of permanent prostate brachytherapy on late rectal function.

METHODS AND MATERIALS

One hundred eighty-nine prostate brachytherapy patients were mailed the Rectal Function Assessment Score (R-FAS), with a prestamped return envelope. The R-FAS consists of nine questions and a scoring range of 0-27, with higher scores indicative of poorer bowel function. One hundred eighty-seven (98.4%) surveys were returned. The median follow-up was 66.3 months (range 54-92 months). Clinical, treatment, and dosimetric parameters evaluated for bowel dysfunction included patient age, diabetes, hypertension, tobacco consumption, clinical T-stage, elapsed time since implant, prostate ultrasound volume, planning target volume, hormonal status, supplemental external beam radiation therapy (EBRT), isotope, average, median and maximum rectal doses, total implanted seed strength, values of the minimum dose received by 90% of the prostate gland (D(90)), and the percent prostate volume receiving 100%, 150%, and 200% of the minimum prescribed dose (V(100/150/200)).

RESULTS

The R-FAS score for the evaluated cohort was 3.92, which represented a slight improvement from the 1999 survey score of 4.15 (p = 0.29). Of the evaluated clinical, treatment, and dosimetric parameters, the number of preimplant bowel movements, a history of tobacco consumption, and the median rectal dose correlated with the R-FAS. Although lower rectal doses were noted with Pd-103, isotope did not predict for bowel function. Only 12% (23/187) of patients reported their bowel function to be worse after implantation. Patient perception of overall rectal quality of life was inversely related to the use of supplemental EBRT (p = 0.007).

CONCLUSION

Minor bowel changes are noted following prostate brachytherapy. The vast majority of patients did not report any deterioration in bowel function. In addition, the R-FAS continue to improve with time.

Permanent interstitial brachytherapy for the management of carcinoma of the prostate gland

PURPOSE

We summarize the permanent prostate brachytherapy literature, including biochemical outcomes, quality of life parameters and areas of controversy.

MATERIALS AND METHODS

The permanent prostate brachytherapy literature was reviewed using MEDLINE searches to ensure completeness.

RESULTS

Using various planning and intraoperative techniques the majority of the brachytherapy literature demonstrates durable biochemical outcomes for patients with low, intermediate and high risk features. For low risk patients there is no advantage to combining supplemental external beam radiation therapy with brachytherapy. In addition, supplemental external beam radiation therapy may not improve biochemical outcomes for patients at intermediate and high risk if the target volume consists of the prostate with a generous periprostatic margin. There is no defined role for adjuvant hormonal manipulation. Although a reliable set of pretreatment criteria to predict implant related morbidity is not available, severe urinary and rectal morbidity is rare. The incidence of brachytherapy induced erectile dysfunction is significantly greater than initially reported but the majority of patients respond favorably to sildenafil.

CONCLUSIONS

Continued refinements in brachytherapy planning and implementation techniques, postimplantation evaluation and continued elucidation of the etiology of urinary, bowel and sexual dysfunction should result in further improvements in biochemical and quality of life outcomes.

Practical considerations in permanent brachytherapy for localized adenocarcinoma of the prostate

Prostate brachytherapy has become an accepted treatment modality for localized prostate cancer. Long-term biochemical and biopsy data confirm the early positive impressions that brachytherapy is as valid a treatment option as radical prostatectomy or EBRT. Quality-of-life data also look promising, but more follow-up data are needed. Is brachytherapy as good as or perhaps better than radical prostatectomy? This question cannot be answered yet. Well-controlled, randomized studies are needed. In the meantime, the clinician will have to rely on the available published data.

[Iodine-125 transperineal prostate brachytherapy with preplanning technique: pre and post-implant dosimetry results analysis]

PURPOSE

Post-implant CT-based dosimetry is the only method of assessing the quality of permanent prostate brachytherapy. As a consequence of our permanent feedback with the preplanned technique, geometric and dosimetric criteria for optimal seed implantation are proposed and pre and post-implantation dosimetric results are presented.

PATIENTS AND METHODS

In 2000 and 2001, one hundred and twenty patients with early stage prostate cancer were treated with transperineal I-125 preplanned brachytherapy (RAPID Strand, Amersham Health). The prescription dose was 145 Gy to the planning target volume. For the pre-planning and post-implant dosimetry the Variseed 6.7 version software was used (Varian Medical Systems). The D90, V100 and V150 values, the position of the dose peak [Dose] peak) and the full width at half maximum (FWHM) on differential dose volume histogram from both planned and post-implant dosimetry were compared for all patients.

RESULTS

For preplanned dosimetry, the mean values for D90, V100, V150, [Dose] peak, FWMH were respectively of 199Gy, 100%, 70%, 220Gy, 113Gy. For post-implantation, these values became respectively of 157Gy, 90%, 62%, 220Gy, 194Gy.

CONCLUSION

In our practice, differences are noted between preplanned and post-implant dosimetry parameters that should be anticipated to assure optimal definitive result. A working methodology both for performing the preplanned dosimetry and for evaluating the post-implantation dosimetric results is proposed.

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

PURPOSE

To analyse predictive factors of acute urinary morbidity after transperineal permanent prostate brachytherapy.

METHODS AND MATERIALS

Sixty patients treated in a phase 2 study with iodine-125 brachytherapy (9/1998 to 2/2000) for localised prostate adenocarcinoma were analysed after at least 1-year follow-up. Prescribed dose was 144 Gy and all patients had a pre-planning and a post-implant dosimetry. Urinary morbidity was evaluated prospectively using the Radiation Therapy Oncology Group (RTOG) scale. We examined the relationship between pre-implant ultrasound prostate volume, post-implant CT-scan prostate volume, neoadjuvant hormonotherapy, total number of needles and seeds, post-implant dosimetry variables, first 30 vs. last 30 treated patients and post-implant urinary morbidity.

RESULTS

All patients experienced some degree of urinary distress symptoms after treatment. Symptoms were generally mild grade 1 in 56% and grade 2 in 10% lasting less than 6 months. Eight patients (13%) required bladder catheter for acute urinary obstruction. At 1-year follow-up, nine patients (15%) complained from persistent dysuria requiring in three cases endoscopic prostate resection. The percentage of urethra volume receiving 216 Gy (cut-off 40%) and the pre-implant prostate volume (cut-off 31 ml) were the only statistically significant predictor of grade 2-3 or persistent urinary morbidity on multivariate analysis.

CONCLUSION

Our short-term data suggest that both pre-implant prostate volume value and post-implant V.U. 150 value might be predictors for urinary morbidity after prostate brachytherapy.

Probability of late rectal morbidity in 125I prostate brachytherapy

PURPOSE

Rectal toxicity is a concern in prostate brachytherapy because it is difficult to avoid delivering a dose equal to, or greater than, the prescription dose to the anterior surface of the rectum. The purpose of this study was to define the probability that a patient will experience Grade 2 (bleeding/ulceration) late rectal morbidity after 125I prostate brachytherapy according to the rectal dosimetry.

METHODS AND MATERIALS

Ninety-eight consecutive patients who received monotherapy 125I prostate implants for treatment of Stage T1-T2, favorable-risk adenocarcinoma of the prostate were evaluated for Radiation Therapy Oncology Group Grade 2 late rectal morbidity. All reported incidences of late morbidity were retrospectively confirmed by colonoscopy. All patients had at least 15 months follow-up after implantation. The median follow-up was 32 months (range 15-54). The rectal dosimetry was based on a CT scan obtained at 3-9 weeks after implantation. The rectum was contoured on each CT image between the base and apex of the prostate. A dose-surface histogram was compiled for each implant, and the relative surface area that received a dose > or =100, > or =150, > or =200, > or =300, > or =400, and > or =500 Gy was recorded. The probability of developing late rectal toxicity was calculated by logistic regression analysis as a function of dose and the percentage of the rectal surface that received that dose.

RESULTS

Of the 98 patients, 10 developed Grade 2 late rectal morbidity. The percentage of the rectal surface that received 100, 150, 200, and 300 Gy was significantly greater (p < or =0.02) for patients who experienced late rectal morbidity. The probability of late rectal morbidity increased with both the dose and the percentage of the rectal surface that received that dose. The probability was < or =1% when 20%, 7%, and 0% of the rectal surface received 100, 150, and 200 Gy, respectively. The probability increased to < or =5% when 31%, 19%, and 9% of the rectal surface received these doses. The probability of late rectal morbidity can also be expressed in terms of the maximal rectal dose. The probability of late morbidity was 0.4%, 1.2%, and 4.7% when the maximal rectal dose was 150, 200, and 300 Gy, respectively.

CONCLUSION

The percentage of the rectal surface that receives a dose > or =100 Gy is predictive of Grade 2 (bleeding/ulceration) late rectal morbidity after 125I prostate brachytherapy. The probability of late morbidity depends on both the dose and the percentage of the rectal surface that received that dose. Our results indicate that the rectum can tolerate doses of 100, 150, and 200 Gy to approximately 30%, 20%, and 10% of the rectal surface with a < or =5% risk of late morbidity. Our results also indicate that the practical guideline for limiting the incidence of late morbidity to 1%, 3%, or 5% is to keep the maximal rectal dose to <200, 250, and 300 Gy, respectively.

Comparison of MRI pulse sequences in defining prostate volume after permanent implantation

PURPOSE

To determine the relative value of three MRI pulse sequences in defining the prostate volume after permanent implantation.

METHODS AND MATERIALS

A total of 45 patients who received a permanent 125I implant were studied. Two weeks after implantation, an axial CT scan (2 mm thickness) and T1-weighted, T1-weighted fat saturation, and T2-weighted axial MRI (3-mm) studies were obtained. The prostate volumes were compared with the initial ultrasound planning volumes, and subsequently the CT, T1-weighted, and T1-weighted fat saturation MRI volumes were compared with the T2-weighted volumes. Discrepancies in volume were evaluated by visual inspection of the registered axial images and the registration of axial volumes on the sagittal T2-weighted volumes. In a limited set of patients, pre- and postimplant CT and T2-weighted MRI studies were available for comparison to determine whether prostate volume changes after implant were dependent on the imaging modality.

RESULTS

T1-weighted and T1-weighted fat saturation MRI and CT prostate volumes were consistently larger than the T2-weighted MRI prostate volumes, with a volume on average 1.33 (SD 0.24) times the T2-weighted volume. This discrepancy was due to the superiority of T2-weighted MRI for prostate definition at the following critical interfaces: membranous urethra, apex, and anterior base-bladder and posterior base-seminal vesicle interfaces. The differences in prostate definition in the anterior base region suggest that the commonly reported underdose may be due to overestimation of the prostate in this region by CT. The consistent difference in volumes suggests that the degree of swelling observed after implantation is in part a function of the imaging modality. In patients with pre- and postimplant CT and T2-weighted MRI images, swelling on the T2-weighted images was 1.1 times baseline and on CT was 1.3 times baseline, confirming the imaging modality dependence of prostate swelling.

CONCLUSION

Postimplant T2-weighted MRI images provided superior prostate definition in all critical regions of the prostate compared with CT and the other MRI sequences tested. In addition to defining an optimal technique, these findings call two prior observations into question. Under dosing at the anterior base region may be overestimated because of poor definition of the prostate-bladder muscle interface. The swelling observed after implantation was lower on T2-weighted images as well, suggesting that a fraction of postimplant swelling is a function of the imaging modality. These findings have implications for preimplant planning and postimplant evaluation. As implant planning techniques become more conformal, and registration methods become more efficient, T2-weighted MRI after implantation will improve the accuracy of postimplant dosimetry.

American Brachytherapy Society recommendations for reporting morbidity after prostate brachytherapy

PURPOSE

To standardize the reporting of brachytherapy-related prostate morbidity to guide ongoing clinical practice and future investigations.

METHODS

Members of the American Brachytherapy Society (ABS) with expertise in prostate brachytherapy performed a literature review and, guided by their clinical experience, formulated specific recommendations for reporting on morbidity related to prostate brachytherapy.

RESULTS

The ABS recommends using validated, patient-administered health-related quality-of-life instruments for the determination of baseline and follow-up data regarding bowel, urinary, and sexual function. Both actuarial and crude incidences should be reported, along with the temporal resolution of specific complications, and correlated with the doses to the normal tissues. The International Prostate Symptom Score is recommended to assess urinary morbidity, and any dysuria, gross hematuria, urinary retention, incontinence, or medication use should be quantified. Likewise, the "Sexual Health Inventory for Men," which includes the specific erectile questions of the International Index of Erectile Function, is the preferred instrument for reporting sexual function, and the loss of sexual desire, incidence of hematospermia, painful orgasm (orgasmalgia), altered orgasm intensity, decreased ejaculatory volume, use of erectile aids, and use of hormones for androgen deprivation should be quantified. The ABS recommends adoption of the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer acute and late radiation morbidity scoring scheme for reporting rectal morbidity and noting the incidence of rectal steroid, laser, or antidiarrheal use.

CONCLUSION

It is important to focus on health-related quality-of-life issues in the treatment of prostate cancer, because the control rates are very similar between appropriate treatment modalities. The ABS recommends using the International Prostate Symptom Score, International Index of Erectile Function, and Radiation Therapy Oncology Group toxicity grading criteria for the determination of urinary, sexual, and bowel function, respectively. Additional parameters for reporting urinary, rectal, and sexual morbidities are presented. These morbidities should be correlated with the doses to the normal tissues. Some of these specific recommendations may be modified if and when new data become available.

The role of androgen deprivation therapy combined with prostate brachytherapy

Several prospective randomized clinical trials have demonstrated improved outcomes in men receiving androgen deprivation therapy (ADT) in combination with definitive local therapy (external-beam radiotherapy or surgery). ADT is commonly combined with prostate brachytherapy (PB) to "downsize" the prostate gland. As PB is increasingly used, more men are being treated with a combination of ADT and PB. The purpose of this article is to review the effects of ADT in men treated with PB. A structured literature review was performed. The effects of ADT on 3 separate outcomes were examined: (1) volume of the prostate gland, (2) treatment-related morbidity, and (3) disease-free survival. No prospective randomized trials addressing the effects of ADT combined with PB were discovered. There is evidence that prostate volume is reduced by 25% to 40% after 3 months of ADT. There is some evidence that ADT may be associated with increased acute urinary morbidity and decreased erectile function after PB. There is little evidence that disease-free survival in men treated with PB is improved with the addition of ADT. Neoadjuvant ADT before PB reduces prostate volume. ADT may lead to increased acute urinary morbidity and decreased erectile function after PB. No substantial effects of ADT on disease-free survival are apparent. Prospective randomized trials of PB and ADT are required.

Comparison of methods for calculating rectal dose after (125)I prostate brachytherapy implants

PURPOSE

To compare several different methods of calculating the rectal dose and examine how accurately they represent rectal dose surface area measurements and, also, their practicality for routine use.

METHODS AND MATERIALS

This study comprised 55 patients, randomly selected from 295 prostate brachytherapy patients implanted at the Vancouver Cancer Center between 1998 and 2000. All implants used a nonuniform loading of 0.33 mCi (NIST-99) 125I seeds and a prescribed dose of 144 Gy. Pelvic CT scans were obtained for each patient approximately 30 days after implantation. For the purposes of calculating the rectal dose, several structures were contoured on the CT images: (1) a 1-mm-thick anterior rectal wall, (2) the anterior half rectum, and (3) the whole rectum. Point doses were also obtained along the anterior rectal surface. The thin wall contour provided a surrogate for a dose-surface histogram (DSH) and was our reference standard rectal dose measurement. Alternate rectal dose measurements (volume, surface area, and length of rectum receiving a dose of interest [DOI] of > or =144 Gy and 216 Gy, as well as point dose measures) were calculated using several methods (VariSeed software) and compared with the surrogate DSH measure (SA(DOI)).

RESULTS

The best correlation with SA(144 Gy) was the dose volumes (whole or anterior half rectum) (R = 0.949). The length of rectum receiving > or =144 Gy also correlated well with SA(144 Gy) (R > or =0.898). Point dose measures, such as the average and maximal anterior dose, correlated poorly with SA(144 Gy) (R < or =0.649). The 216-Gy measurements supported these results. In addition, dose-volume measurements were the most practical (approximately 6 min/patient), with our surrogate DSH the least practical (approximately 20 min/patient).

CONCLUSION

Dose-volume measurements for the whole or anterior half rectum, because they were the most practical measures and best represented the DSH measurements, should be considered a standard method of reporting the rectal dose when calculating the DSH is not practical. Average or maximal anterior rectal doses are not reliable indicators of surface area dosimetry.

Intraoperative magnetic resonance: the future of surgery

Intraoperative magnetic resonance imaging (iMRI) is a new development in medicine that bridges the specialties of surgery and radiology. Deficiencies in the visualization of anatomical architecture and the perception of tumour boundaries in conventional open surgery have led to the integration of imaging within surgery. The superior soft tissue and multiplanar imaging features of magnetic resonance (MR) make this imaging modality superior to that of alternatives. The unique properties of MR to detect heat change and perfusion, and diffusion characteristics of tissue enhance the usefulness of this medium. Concurrent developments in computer aided image guidance and thermoablative technology, herald the era of minimally invasive tumour ablation. Applications have been developed for areas such as neurosurgery, general surgery, gynaecology and urology.

Gastrointestinal toxicity of transperineal interstitial prostate brachytherapy

PURPOSE

To characterize the severity and time course of rectal toxicity following transperineal prostate brachytherapy using prospectively recorded data, and to determine factors associated with toxicity.

METHODS AND MATERIALS

One hundred thirty-four patients with prostate cancer treated with transperineal brachytherapy from 1997 to 1999 had rectal toxicity data available for analysis. Patients with Gleason score (GS) > 6, prostate-specific antigen (PSA) > 6, or stage > T2a were treated initially with external beam radiation therapy followed by brachytherapy boost; patients with none of these features were treated with brachytherapy alone. Both iodine-125 and palladium-103 sources were used, and loaded according to a modified Quimby distribution. At each follow-up, toxicity was recorded according to a modified RTOG gastrointestinal scale.

RESULTS

Thirty-nine percent of patients experienced gastrointestinal toxicity, mostly Grade 1. Median duration of symptoms was 6 months. Two patients experienced Grade 3 toxicity, both of whom had minimal symptoms until their 12-month follow-up. There was no Grade 4 or 5 toxicity. The addition of external beam radiation therapy (p = 0.003), higher clinical stage (p = 0.006), and Caucasian race (p = 0.01) were associated with increased incidence of toxicity.

CONCLUSION

Most patients with rectal toxicity have very mild symptoms. There is a small risk of severe late toxicity. External beam radiation, higher stage, and race are associated with toxicity.

The role of external radiotherapy in patients treated with permanent prostate brachytherapy

To examine the difference in Prostate Specific Antigen (PSA)-Relapse Free Survival (RFS) in patients (pts) with prostate cancer treated with permanent prostate brachytherapy (PPB) alone (monotherapy) or combined modality PPB and external radiotherapy (CMT) by a matched pair analysis. There were 1476 pts who were treated loosely based on the American Brachytherapy Society criteria for monotherapy or CMT. PSA-RFS was based upon the Kattan modification of the ASTRO consensus panel definition. A computer generated matching process was undertaken to produce two equally weighted pairs of patients divided by treatment methodology and Kaplan-Meier PSA-RFS curves were generated and compared by chi(2) testing. All pts were treated between 1992 and 2000 with a 6-y PSA-RFS of 81.9%. The median follow-up was 34.7 months. Patients treated with CMT presented with higher pre-treatment PSA values, Gleason sum score, clinical stage, risk classification, and were more likely to be treated with neoadjuvant hormones. A matched-pair analysis with 314 pts in each group was created stratified by the addition of neoadjuvant hormones, Gleason score sum and the pretreatment PSA value. Actuarial 5-y PSA-RFS was 77.0% for the monotherapy group and 81.1% for the combined therapy group (P=0.54).chi(2) testing by pretreatment PSA value, Gleason score sum, risk stratification, isotope and the addition of neoadjuvant hormones failed to identify any group with a significant difference in 5-y PSA-RFS. In conclusion, this retrospective study presents a large cohort of patients treated with PPB that failed to identify a significant advantage for the addition of combined therapy. A matched pair analysis performed also failed to identify any significant difference based on treatment modality.

Brachytherapy for carcinoma of the prostate: techniques, patient selection, and clinical outcomes

Brachytherapy for prostate carcinoma has developed as either low dose rate permanent implants or high dose rate afterloading. Both approaches offer unsurpassed dose escalation and, particularly with permanent implants, the convenience of a single outpatient treatment. These therapies have now entered the mainstream of treatment options and are in the refinement phase of development. Techniques of implantation, treatment planning approaches, innovative fractionation schemes, and appropriate patient selection are the subject of current investigation. Treatment results are available beyond 10 years and appear equivalent or superior to other modalities. Although short term morbidity can be significant with brachytherapy, most current series report low long-term urinary and rectal complications. Meaningful quality of life studies and randomized cooperative group trials are now underway and should help define the role of brachytherapy in the near future.

External radiotherapy and permanent prostate brachytherapy in patients with localized prostate cancer•

We examined the difference in prostate-specific antigen (PSA)-freedom from recurrence (FFR) in patients with localized prostate cancer treated with permanent prostate brachytherapy (PPB) alone or external radiotherapy combined with PPB (RT-PPB). A total of 1476 patients with prostate cancer (T1/T2) were treated with PPB by following the American Brachytherapy Society criteria. Patient self-selection and preference allowed for an overlap of treatment methodologies and risk factors. Monotherapy consisted of 125I or 103Pd. RT-PPB consisted of RT followed by PPB. PSA-FFR was based on a published modification of the American Society for Therapeutic Radiology and Oncology definition. Cox regression analysis was performed to assess the role of Gleason sum, pretreatment PSA value, clinical stage, RT-PPB, the addition of hormones, and the minimum dose covering 90% of the prostate volume (D90 dose). Monotherapy was used for 1016 patients (79%), and RT-PPB was used for 281 patients (21%), with an overall 6-year PSA-FFR of 83.2% (median follow-up of 34.7 months; range, 6-91 months). Multivariate Cox regression analysis to predict PSA-FFR identified the following highly significant variables: pretreatment PSA value, Gleason sum, and the addition of hormones. When the D90% (D90 dose relative to the prescribed dose) was included as a variable, Cox regression identified only the following significant variables: D90%, pretreatment PSA, and Gleason sum. Cox regression failed to identify an improvement in PSA-FFR with RT-PPB or the addition of hormones. Although these conclusions question the role for RT-PPB, only a comparative trial will be able to answer this question definitively.

Dosimetric and radiographic correlates to prostate brachytherapy-related rectal complications

Despite rates of radiation proctitis reported in the 1% to 9% range in most series, there is little information regarding rectal morbidity and dosimetric parameters. Accordingly, we have analyzed computed tomography (CT)-based dosimetric parameters based on a series of patients with endoscopically proven radiation proctitis. Nine patients diagnosed with radiation proctitis on endoscopy were identified in a prior review of 160 consecutively treated patients at the University of Washington in 1997. For each proctitis patient, two patients with no rectal bleeding matched for prostate size, isotope, and dose were selected as controls. Axial CT images obtained 2 to 4 hour postoperatively were used for postimplant dosimetry. Dose volume histograms of the rectum, surface area of the outer rectal wall receiving > or = 100% of the prescribed dose, maximum rectal dose, and length of rectum receiving > or = 100% prescription were obtained. Preimplant CT scans were used to group patients into three categories based on the amount of apparent rectal contact with the prostate. All rectal dosimetric parameters were statistically different between patients with or without rectal bleeding. The mean surface area receiving at least 100% prescription dose was 3.1 cm(2) for the controls vs. 6.9 cm(2) for the rectal bleeders (P = 0.001). The volume of rectum receiving at least 100% of prescription dose was 0.6 cc for the controls vs. 2.5 cc for the bleeders (P = 0.00008). Patients with full prostate-rectal contact had significantly higher rectal dose parameters compared to those with partial or no rectal contact. All nine proctitis patients were in the full-rectal-contact group compared to only seven of 18 (39%) controls. This detailed dosimetric analysis shows higher rectal doses for patients with radiation proctitis, making it a potential method of identifying patients at higher risk for receiving excessive rectal doses based on the anatomic relationship between the rectum and prostate on CT scan. Published 2001 Wiley-Liss, Inc.

Quantification of late complications after radiation therapy

BACKGROUND

An increasing number of patients survive cancer after having received radiation therapy. Therefore, the occurrence of late normal tissue complications among long-term survivors is of particular concern.

METHODS

Sixty-three patients treated by radical surgery and irradiation for rectal carcinoma were subjected to an unconventional sandwich therapy. Preoperative irradiation was given in four fractions of 5 Gy each applied within 2 or 3 days; postoperative irradiation consisted mostly of 15 x 2 Gy (range, 20-40 Gy). A considerable proportion of these patients developed severe late complications (Radiother Oncol 53 (1999) 177). The data allowed a detailed analysis of complication kinetics, leading to a new model which was tested using data from the literature.

RESULTS

Data on late complications were obtained for eight different organs with a follow-up of up to 10 years. For the various organs, the percentage of patients being free from late complications, plotted as a function of time after start of radiation therapy, was adequately described by exponential regression. From the fit, the parameter p(a) was obtained, which is the percentage of patients at risk in a given year of developing a complication in a given organ during that year. The rate p(a) remained about constant with time. Following sandwich therapy, the annual incidence of complications in the bladder, ileum, lymphatic and soft tissue, and ureters was about the same (p(a)=10-14%/year), whereas complications in bone or dermis occurred at lower rates (4.7 or 7.5%/year, respectively).

DISCUSSION

Numerous data sets collected from published reports were analyzed in the same way. Many of the data sets studied were from patients in a series where there was a high incidence of late effects. Three types of kinetics for the occurrence of late effects after radiotherapy were identified: Type 1, purely exponential kinetics; Type 2, exponential kinetics, the slope of which decreased exponentially with time; Type 3, curves composed of two components, a fast initial decline followed by an exponential decrease. For each kind of kinetics, provided that the dose distribution is not too heterogeneous, the incidence of late effects appears to occur at exponential or approximately exponential kinetics, even many years after treatment. This implies that a random process might be involved in the occurrence of late radiation sequelae.

CONCLUSIONS

There might be a lifelong risk of developing late complications, of which patients and clinicians should be aware. It appears worthwhile to try to identify, in follow-up examinations of patients after radiation therapy, what kind of processes might be involved in triggering subclinical residual injury to develop into a clinically manifest late effect.

Argon plasma coagulation for rectal bleeding after prostate brachytherapy

PURPOSE

To better define the efficacy and safety of argon plasma coagulation (APC), specifically for brachytherapy-related proctitis, we reviewed the clinical course of 7 patients treated for persistent rectal bleeding. Approximately 2-10% of prostate cancer patients treated with 125I or 103Pd brachytherapy will develop radiation proctitis. The optimum treatment for patients with persistent bleeding is unclear from the paucity of available data. Prior reports lack specific dosimetric information, and patients with widely divergent forms of radiation were grouped together in the analyses.

METHODS AND MATERIALS

Seven patients were treated with APC at the Veterans Affairs Puget Sound Health Care System and the University of Washington from 1997 to 1999 for persistent rectal bleeding due to prostate brachytherapy-related proctitis. Four patients received supplemental external beam radiation, delivered by a four-field technique. A single gastroenterologist at the Veterans Affairs Puget Sound Health Care System treated 6 of the 7 patients. If the degree of proctitis was limited, all sites of active bleeding were coagulated in symptomatic patients. An argon plasma coagulator electrosurgical system was used to administer treatments every 4-8 weeks as needed. The argon gas flow was set at 1.6 L/min, with an electrical power setting of 40-45 W.

RESULTS

The rectal V100 (the total rectal volume, including the lumen, receiving the prescription dose or greater) for the 7 patients ranged from 0.13 to 4.61 cc. Rectal bleeding was first noticed 3-18 months after implantation. APC (range 1-3 sessions) was performed 9-22 months after implantation. Five patients had complete resolution of their bleeding, usually within days of completing APC. Two patients had only partial relief from bleeding, but declined additional APC therapy. No patient developed clinically evident progressive rectal wall abnormalities after APC, (post-APC follow-up range 4-13 months).

CONCLUSIONS

Most patients benefited from APC, and no cases of clinically evident progressive tissue destruction were noted. Although APC appears to be efficacious and safe in the setting of the rectal doses described here, caution is in order when contemplating APC for brachytherapy patients.

Radiation for prostate cancer

The balance between tumour control and normal tissue damage with conventional radiotherapy is critical to outcome and morbidity in the treatment of localised prostate cancer. Recent technological advances have allowed a reduction in the amount of normal tissue included in target treatment volumes. This reduces morbidity and allows dose escalation, theoretically increasing the likelihood of tumour control. The methods used to achieve dose escalation are discussed and the available evidence for their safety and efficacy, relative to conventional treatment, is reviewed. Although there are no randomised studies to provide evidence of increased survival, the available evidence supports the hypothesis that dose escalation produces survival rates equivalent to surgical series and provides a realistic choice for patients.