Conformal static field radiation therapy treatment of early prostate cancer versus non-conformal techniques: a reduction in acute morbidity

Targeting MicroRNAs in Prostate Cancer Radiotherapy

Radiotherapy is one of the most important treatment options for localized early-stage or advanced-stage prostate cancer (CaP). Radioresistance (relapse after radiotherapy) is a major challenge for the current radiotherapy. There is great interest in investigating mechanisms of radioresistance and developing novel treatment strategies to overcome radioresistance. MicroRNAs (miRNAs) are small, non-coding RNAs that regulate gene expression at the post-transcriptional level, participating in numerous physiological and pathological processes including cancer invasion, progression, metastasis and therapeutic resistance. Emerging evidence indicates that miRNAs play a critical role in the modulation of key cellular pathways that mediate response to radiation, influencing the radiosensitivity of the cancer cells through interplaying with other biological processes such as cell cycle checkpoints, apoptosis, autophagy, epithelial-mesenchymal transition and cancer stem cells. Here, we summarize several important miRNAs in CaP radiation response and then discuss the regulation of the major signalling pathways and biological processes by miRNAs in CaP radiotherapy. Finally, we emphasize on microRNAs as potential predictive biomarkers and/or therapeutic targets to improve CaP radiosensitivity.

Progress and controversies: Radiation therapy for prostate cancer

Radiation therapy remains a standard treatment option for men with localized prostate cancer. Alone or in combination with androgen-deprivation therapy, it represents a curative treatment and has been shown to prolong survival in selected populations. In this article, the authors review recent advances in prostate radiation-treatment techniques, photon versus proton radiation, modification of treatment fractionation, and brachytherapy-all focusing on disease control and the impact on morbidity. Also discussed are refinements in the risk stratification of men with prostate cancer and how these are better for matching patients to appropriate treatment, particularly around combined androgen-deprivation therapy. Many of these advances have cost and treatment burden implications, which have significant repercussions given the prevalence of prostate cancer. The discussion includes approaches to improve value and future directions for research.

Radiotherapy doses of 80 Gy and higher are associated with lower mortality in men with Gleason score 8 to 10 prostate cancer

PURPOSE

Men with Gleason score (GS) 8-10 prostate cancer (PCa) are assumed to have a high risk of micrometastatic disease at presentation. However, local failure is also a major problem. We sought to establish the importance of more aggressive local radiotherapy (RT) to ≥80 Gy.

METHODS AND MATERIALS

There were 226 men treated consecutively with RT ± ADT from 1988 to 2002 for GS 8-10 PCa. Conventional, three-dimensional conformal or intensity-modulated (IM) RT was used. Radiation dose was divided into three groups: (1) <75 Gy (n = 50); (2) 75-79.9 Gy (n = 60); or (3) ≥80 Gy (n = 116). The endpoints examined included biochemical failure (BF; nadir + 2 definition), distant metastasis (DM), cause-specific mortality, and overall mortality (OM).

RESULTS

Median follow-up was 66, 71, and 58 months for Groups 1, 2, and 3. On Fine and Gray's competing risk regression analysis, significant predictors of reduced BF were RT dose ≥80 Gy (p = 0.011) and androgen deprivation therapy duration ≥24 months (p = 0.033). In a similar model of DM, only RT dose ≥80 Gy was significant (p = 0.007). On Cox regression analysis, significant predictors of reduced OM were RT dose ≥80 Gy (p = 0.035) and T category (T3/4 vs. T1, p = 0.041). Dose was not a significant determinant of cause-specific mortality. Results for RT dose were similar in a model with RT dose and ADT duration as continuous variables.

CONCLUSION

The results indicate that RT dose escalation to ≥80 Gy is associated with lower risks of BF, DM, and OM in men with GS 8-10 PCa, independently of androgen deprivation therapy.

Five-year prospective patient evaluation of bladder and bowel symptoms after dose-escalated radiotherapy for prostate cancer with the BeamCath® technique

PURPOSE

Late side effects were prospectively evaluated up to 5 years after dose-escalated external beam radiotherapy (EBRT) and were compared with a previously treated series with conventional conformal technique.

METHODS AND MATERIALS

Bladder and bowel symptoms were prospectively evaluated with the Prostate Cancer Symptom Scale (PCSS) questionnaire up to 5 years posttreatment. In all, 257 patients completed the questionnaire 5 years posttreatment. A total of 168 patients were treated with the conformal technique at doses<71 Gy, and 195 were treated with the dose-escalated stereotactic BeamCath technique comprising three dose levels: 74 Gy (n=68), 76 Gy (n=74), and 78 Gy (n=53).

RESULTS

For all dose groups analyzed together, 5 years after treatment, urinary starting problems decreased and urinary incontinence increased in comparison to baseline values. No increase in other bladder symptoms or frequency was detected. When comparing dose groups after 5 years, both the 74-Gy and 78-Gy groups reported increased urinary starting problems compared with patients given the conventional dose (<71 Gy). No increased incontinence was seen in the 76-Gy or the 78-Gy groups. Bowel symptoms were slightly increased during the follow-up period in comparison to baseline. Dose escalation with stereotactic EBRT (74-78 Gy) did not increase gastrointestinal late side effects after 5 years in comparison to doses<71 Gy.

CONCLUSION

Dose-escalated EBRT with the BeamCath technique with doses up to 78 Gy is tolerable, and the toxicity profile is similar to that observed with conventional doses<71 Gy.

Managing locally advanced prostate cancer: a urologist??s and a patient??s perspective

A 60-year-old man presented to his general practitioner with prostatic symptoms and high blood pressure. Based upon a prostate-specific antigen level of 44 ng/ml and further investigations (digital rectal examination, transrectal ultrasound-guided needle biopsy, and magnetic resonance imaging, ultrasound and bone scans), the patient was diagnosed with locally advanced (cT3, N0, M0) prostate cancer. Here, the urologist and the patient describe treatment from their respective viewpoints. Following discussion of the advantages and disadvantages of the various therapeutic options, radiotherapy plus hormonal therapy (bicalutamide 150 mg) was chosen as the approach that best suited the patient's lifestyle. In this review, the patient and the urologist consider the impact of the chosen treatment in terms of efficacy, tolerability and quality of life.

The efficacy of conventional external beam, three-dimensional conformal, intensity-modulated, particle beam radiation, and brachytherapy for localized prostate cancer

Technologic advances in radiation treatment planning and delivery have generated popular interest in the different radiation therapy techniques used in treating patients with localized prostate cancer. Throughout the past decade, high-energy (> 4 MV) linear accelerators have largely replaced Cobalt machines in external beam radiation therapy (EBRT) delivery. Conventional EBRT has been used to treat prostate cancer successfully since the 1950s. By switching to computed tomography-based planning, three-dimensional conformal radiation therapy provides better relative conformality of dose than does conventional EBRT. Intensity-modulated radiation therapy (IMRT) has further refined dose conformality by spreading the low-dose region to a larger volume. However, the potential long-term risks of larger volumes of normal tissues receiving low doses of radiation in IMRT are unknown. Particle-beam radiation therapy offers unique dose distributions and characteristics with higher relative biologic effect and linear energy transfer. Transperineal prostate brachytherapy offers the shortest treatment time with equivalent efficacy without significant risk of radiation exposure. The addition of hormonal therapy to radiation therapy has been shown to improve the outcome of radiation therapy.

Iodine-125 brachytherapy for prostate cancer: First published Australian experience

With the emergence of new imaging and implant techniques, prostate brachytherapy has become increasingly popular over the last decade. Brachytherapy promises to deliver twice the biologically effective dose as conventional external beam treatments without increasing the dose to tissues surrounding the prostate. However, there are few or no published Australian series of its efficacy in the clinic. We present the experience of one of the first centres in Australia to offer this service to its patients: a series from Sir Charles Gairdner Hospital in Western Australia. We present data on the efficacy of brachytherapy in maintaining prostate specific antigen levels, as well as the rate of urinary, rectal and sexual complications. Our results compare favourably with other brachytherapy and external beam treatment series. We believe that with the increasing trend towards dose escalation and novel therapies, standardized measurements of success and failure need to be better defined, and that randomized trials comparing modalities are needed to improve the management of prostate cancer.

Reducing the toxicity associated with the use of radiotherapy in men with localized prostate cancer

The risk for serious complications associated with modern radiotherapy is relatively low. Compared with conventional radiotherapy, 3DCRT and IMRT allow higher doses to be given more safely. The use of IMRT increases the time and effort required by physicians and physicists. Although there is a clear move toward IMRT, 3DCRT is considered standard. The quality assurance procedures for and fundamental questions regarding IMRT are evolving, including the radiobiologic consequences of altered time-dose fractionation and the greater dose heterogeneity in the target. Defining an accurate target volume and routinely correcting for set-up error and organ movement before each treatment promise to reduce the complications associated with EBRT in the next 5 years. Complications following prostate brachytherapy are better understood now than 10 years ago. Dosimetric or patient selection factors that correlate with a higher risk for complications, such as acute retention, strictures, severe prolonged urinary symptoms, fistulas, proctitis, and impotence, often can be accounted for or avoided. Finally, the role of radiation protectors is beginning to be addressed. It is hoped that these advances will eliminate toxicity associated with radiotherapy and increase cure rates.

A randomized trial of supine vs. prone positioning in patients undergoing escalated dose conformal radiotherapy for prostate cancer

BACKGROUND AND PURPOSE

The optimal treatment position for patients receiving radical radiation therapy for prostate cancer has been a source of controversy. To resolve this issue, we conducted a randomized trial to evaluate the effects of supine and prone positioning on organ motion, positioning errors, and dose to critical organs during escalated dose conformal irradiation for localized prostate cancer and patient and therapist satisfaction with setup technique.

PATIENTS AND METHODS

Twenty eight patients were randomized to commence treatment immobilized in the supine or prone position and were subsequently changed to the alternate positioning for the latter half of their treatment. Patients underwent CT simulation and conformal radiotherapy planning and treatment in both positions. The clinical target volume encompassed the prostate gland. Alternate day lateral port films were compared to corresponding simulator radiographs to measure the isocentre positioning errors (IPE). Prostate motion (PM) and total positioning error (TPE) were measured from the same films by the displacements of three implanted fiducial markers. Dose volume histograms (DVHs) for the two treatment positions were compared at the 95, 80 and 50% dose (D%) levels. The patients and radiation therapists completed weekly questionnaires regarding patient comfort and ease of setup.

RESULTS

Seven patients, who started in the supine position, subsequently refused prone position and received their whole treatment supine. Small bowel in the treatment volume, not present in the supine position, prevented one patient from being treated prone. PM in anterior posterior direction was statistically significantly less in the supine position (P<0.05). There was no significant difference in superior inferior PM for the two treatment positions. No statistically significant difference between supine and prone positioning was observed in isocentre positioning error (IPE) or total positioning error (TPE) due to a policy of daily pre-treatment correction. However, more pre-treatment corrections were required for patients in the prone position. The DVH analysis demonstrated larger volumes of the bladder wall, rectal wall and small bowel within the D95, D80 and D50% when comparing the planning target volumes (PTVs) actually treated for prone positioning. When the prone PTV was expanded to account for the greater PM encountered in that position, a statistically significant difference (P<0.007) was observed in favour of the supine position at all dose levels. In the prone position, four patients had small bowel within the 60 Gray (Gy) isodose and in the supine position, no patients had small bowel in the 60 or 38Gy volumes. Supine position was significantly more comfortable for the patients and setup was significantly easier for the radiation therapists. The median patient comfort score was 0.79 (Standard deviation (SD) 0.03) supine and 0.45 (SD 0.05) prone (P<0.001) The therapist convenience of setup was 0.80 (SD 0.016) supine and 0.54 (SD 0.025) prone (P<0.005). No statistically significant difference was seen for the other parameters studied.

CONCLUSIONS

We demonstrated significantly less PM in the supine treatment position. There was no difference for either treatment position in IPE or TPE, however, more pre-treatment corrections were required in the prone position. Prone position required a larger PTV with resulting increased dose to critical organs. There were statistically significant improvements at all dose levels for small bowel, rectal wall and bladder wall doses in the supine position once corrections were made for differences in organ motion. Linear analogue scores of patient comfort and radiation therapist convenience demonstrated statistically significant improvement in favour of the supine position. Supine positioning has been adopted as the standard for conformal prostatic irradiation at our centre.

Acute morbidity related to treatment volume during 3D-conformal radiation therapy for prostate cancer

PURPOSE

To investigate the relation between acute toxicity and irradiated volume in the organs at risk during three-dimensional conformal radiation therapy for prostate cancer.

METHODS AND MATERIALS

From January to December 2001, we treated 132 prostate cancer patients to a prescribed target dose of 70 Gy. Twenty-six patients (20%) received irradiation to the prostate only (Group P), 86 patients (65%) had field arrangements encompassing the prostate and seminal vesicles (Group PSV) while 20 (15%) received modified pelvic fields (Group MPF). A four-field conformal box technique was used. Acute toxicity according to the RTOG scoring system was prospectively recorded throughout the course of treatment.

RESULTS

Overall, radiation was well tolerated with 11%, 16% and 35% Grade 2 gastro-intestinal (GI) toxicity and 19%, 34% and 35% Grade 2 or higher genito-urinary (GU) toxicity in Groups P, PSV and MPF, respectively. In univariate and multivariate analyses treatment group was a significant predictor for Grade 2 or higher acute morbidity. In multivariate logistic regression, the rectum dose-volume histogram parameters were correlated to the incidence of acute Grade 2 GI toxicity, with the fractional volumes receiving more than 37-40 Gy and above 70 Gy showing the statistically strongest correlation. The fractional bladder volume receiving more than 14-27 Gy showed the statistically strongest correlation with acute GU toxicity.

CONCLUSIONS

3D-CRT radiation therapy to 70 Gy for prostate cancer was well tolerated. Only two of the 132 patients in the cohort experienced acute bladder toxicity Grade 3, none had Grade 3 rectal toxicity. Uni- and multivariate analyses indicated that the volume treated was a significant factor for the incidence of Grade 2 or higher acute morbidity.

Acceptability of short term neo-adjuvant androgen deprivation in patients with locally advanced prostate cancer

PURPOSE

To determine the acceptability of short term neo-adjuvant maximal androgen deprivation (MAD) to patients treated with external beam radiation for locally advanced prostate cancer.

METHODS

Between 1996 and 2000, 818 patients with locally advanced, but non-metastatic, prostate cancer were entered into a randomised clinical trial (TROG 96.01), which compared radiation treatment alone with the same radiation treatment and 3 or 6 months neo-adjuvant MAD with goserelin and flutamide. Relevant symptoms, and how troublesome they were to the patient, were scored using a self-assessment questionnaire. This was completed by the patient at registration, and at specified times during and after treatment. Patients taking flutamide had liver function tests checked at regular intervals.

RESULTS

All patients have completed at least 12 months follow-up after treatment. Nearly all patients completed planned treatment with goserelin, but 27% of patients in the 6-month MAD treatment arm, and 20% in the 3-month arm, had to stop flutamide early. This was mainly due to altered liver function (up to 17% patients) and bowel side effects (up to 8% patients). However, although flutamide resulted in more bowel symptoms for patients on MAD, there was significant reduction in some urinary symptoms on this treatment. Acute bowel and urinary side effects at the end of radiation treatment were similar in all treatment arms. Side effect severity was unrelated to radiation target volume size, which was reduced by MAD, but symptomatology prior to any treatment was a powerful predictor. Of the 36% of patients who were sexually active before any treatment, the majority became inactive whilst on MAD. However, sexual activity at 12 months after radiation treatment was similar in all treatment arms, indicating that the effects of short term MAD on sexual function are reversible.

CONCLUSION

Despite temporary effects on sexual activity, and compliance difficulties with flutamide, short-term neo-adjuvant MAD was not perceived by patients to be a major inconvenience. If neo-adjuvant MAD in the way tested can be demonstrated to lead to improved biochemical control and/or survival, then patients would view these therapeutic gains as worthwhile. Compliance with short-term goserelin was excellent, confirming that LH-RH analogues have a potential role in more long-term adjuvant treatment. However, for more protracted androgen deprivation, survival advantages and deleterious effects need to be assessed in parallel, in order to determine the optimal duration of treatment.

Inverse and forward optimization of one- and two-dimensional intensity-modulated radiation therapy-based treatment of concave-shaped planning target volumes: the case of prostate cancer

BACKGROUND

Intensity-modulated radiation therapy (IMRT) was suggested as a suitable technique to protect the rectal wall, while maintaining a satisfactory planning target volume (PTV) irradiation in the case of high-dose radiotherapy of prostate cancer. However, up to now, few investigations tried to estimate the expected benefit with respect to conventional three-dimensional (3D) conformal radiotherapy (CRT).

PURPOSE

Estimating the expected clinical gain coming from both 1D and 2D IMRT against 3DCRT, in the case of prostate cancer by mean of radiobiological models. In order to enhance the impact of IMRT, the case of concave-shaped PTV including prostate and seminal vesicles (P+SV) was considered.

MATERIALS AND METHODS

Five patients with concave-shaped PTV including P+SV were selected. Two different sets of constraints were applied during planning: in the first one a quite large inhomogeneity of the dose distribution within the PTV was accepted (set (a)); in the other set (set (b)) a greater homogeneity was required. Tumor control probability (TCP) and normal tissue control probability (NTCP) indices were calculated through the Webb-Nahum and the Lyman-Kutcher models, respectively. Considering a dose interval from 64.8 to 100.8 Gy, the value giving a 5% NTCP for the rectum was found (D(NTCP(rectum)=5%)) using two different methods, and the corresponding TCP(NTCP(rectum)=5%) and NTCP(NTCP(rectum)=5%) for the other critical structures were derived. With the first method, the inverse optimization of the plans was performed just at a fixed 75.6 Gy ICRU dose; with the second method (applied to 2/5 patients) inverse treatment plannings were re-optimized at many dose levels (from 64.8 to 108 Gy with 3.6 Gy intervals). In this case, three different values of alpha/beta (10, 3, 1.5)were used for TCP calculation. The 3DCRT plan consisted of a 3-fields technique; in the IMRT plans, five equi-spaced beams were applied. The Helios Inverse Planning software from Varian was used for both the 2D IMRT and the 1D IMRT inverse optimization, the last one being performed fixing only one available pair of leaves for modulation. A previously proposed forward 1D IMRT 'class solution' technique was also considered, keeping the same irradiation geometry of the inversely optimized IMRT techniques.

RESULTS

With the first method, the average gains in TCP(NTCP(rectum)=5%) of the 2D IMRT technique, with respect 3DCRT, were 10.3 and 7.8%, depending on the choice of the DVHs constraints during the inverse optimization procedure (set (a) and set (b), respectively). The average gain (DeltaTCP(NTCP(rectum)=5%)) coming from the inverse 1D IMRT optimization was 5.0%, when fixing the set (b) DVHs constraints. Concerning the forward 1D IMRT optimization, the average gain in TCP(NTCP(rectum)=5%) was 4.5%. The gain was found to be correlated with the degree of overlapping between rectum and PTV. When comparing 2D IMRT and 1D IMRT, in the case of the more realistic set (b) constraints, DeltaTCP(NTCP(rectum)=5%) was always less than 3%, excepting one patient with a very large overlap region. Basing our choice on this result, the second method was applied to this patient and one of the remaining. Through the inverse re-optimization of the treatment plans at each dose level, the gain in TCP(NTCP(rectum)=5%) of the inverse 2D technique was significantly higher than the ones obtained by applying the first method (concerning the two patients: +6.1% and +2.4%), while no significant benefit was found for inverse 1D. The impact of changing the alpha/beta ratio was less evident in the patient with the lower gain in TCP(NTCP(rectum)=5%).

CONCLUSIONS

The expected benefit due to IMRT with respect to 3DCRT seems to be relevant when the overlap between PTV and rectum is high. Moreover, the difference between the inverse 2D and the simpler inverse or forward 1D IMRT techniques resulted in being relatively modest, with the exception of one patient, having a very large overlap between rectum and PTV. Optimizing the inverse planning at each dose level to find TCP(NTCP(rectum)=5%)e level to find TCP(NTCP(rectum)=5%) can improve the performances of inverse 2D IMRT, against a significant increase of the time for planning. These results suggest the importance of selecting the patients that could have significant benefit from the application of IMRT.

Primary radiation therapy for localized prostate cancer

Prostate cancer in men is similar to breast cancer in women; both cancers rank first, respectively, in incidence and are normally responsive to radiation therapy. In addition, advances in mammography help detect earlier breast cancers, and the development and refinement of prostatic specific antigen (PSA) has resulted in early detection of low-stage localized prostate cancers. This has generated debate over the proper management of localized prostate cancer. While there have not been any controlled, prospective, randomized trials of sufficient power to compare the various local therapies, based on the current available data, the three commonly used local modalities, surgery, and external beam radiation therapy and brachytherapy (radioactive seed implant), have similar efficacy controlling the disease up to 10 years in many patients. Technological advances in treatment delivery and planning have improved the treatment of prostate cancer with external-beam radiotherapy using three-dimensional conformal radiotherapy (3DCRT), ultrasound-guided transperineal implant, or intensity-modulated radiotherapy (IMRT), as well as proton or neutron beam based therapies.

Neoadjuvant androgen withdrawal prior to external radiotherapy for locally advanced adenocarcinoma of the prostate

BACKGROUND

It is unclear whether positive interactions between radiation and androgen withdrawal for patients with locally advanced prostate cancer is synergistic or additive. The present study aimed to clarify the significance of neoadjuvant androgen ablation prior to external radiotherapy in a human prostate LNCaP tumor model and in patients with locally advanced prostate cancer.

METHODS

Comparisons were made between the effect of castration prior to radiation on the growth of subcutaneous LNCaP tumors implanted into male nude mice and their serum prostate-specific antigen (PSA) levels, and the results of castration or radiation alone. Twenty-nine patients with histologically proven and locally advanced adenocarcinoma of the prostate were treated with luteinizing hormone-releasing hormone analog at least 3 months before, during, and after external radiation therapy with a total dose of 70 Gy. The toxicity and response to this therapy were evaluated.

RESULTS

Treatment combining castration and radiation resulted in synergistic inhibition of LNCaP tumor growth and a significant delay in the emergence of androgen-independent recurrence as opposed to either treatment alone. The external radiotherapy was completed in 28 patients (96.6%), resulting in a reduction of serum PSA levels in all 28 patients to below 1.0 ng/mL. All patients were alive after a mean follow-up period of 34 months (range 11-53) with a 3-year PSA relapse-free survival rate of 83.7%. Among several factors examined, only the Gleason score was significantly associated with PSA relapse-free survival in univariate analysis, but not in multivariate analysis. Thirteen of 28 patients (46%) and 7 of 28 (25%) also showed at least one form of gastrointestinal or genitourinary toxicity, respectively. Of these patients, 8 with gastrointestinal toxicities, and 1 with genitourinary toxicity, experienced acute complications higher than grade 3.

CONCLUSION

The experimental findings objectively suggested the use of neoadjuvant androgen withdrawal prior to radiation therapy. Although our clinical experience is preliminary, combined androgen ablation and radiation therapy may also be effective in controlling locally advanced prostate cancer, with tolerable side-effects.

Prospective evaluation of urinary and intestinal side effects after BeamCath stereotactic dose-escalated radiotherapy of prostate cancer

BACKGROUND

New data suggest that a higher radiation dose will improve outcome in treatment of localized prostate cancer. External beam radiotherapy (EBRT) may on the other hand induce disturbances in the patient's urinary and intestinal function. Since 1997, 195 patients have been treated with a stereotactic boost of 4-8 Gy added to conventional 70 Gy EBRT. Late side effects were prospectively evaluated 3 years after dose-escalated EBRT.

METHODS

Urinary and intestinal problems were prospectively evaluated with a validated self-assessment questionnaire, the Prostate Cancer Symptom Scale (PCSS). Two hundred and eighty-seven patients completed the questionnaire at the 1 year follow-up, and 153 at 3 years after treatment. Pre-treatment mean age was 66 years. One hundred and sixty-eight patients were treated with the conformal technique and 195 were treated with the dose-escalated stereotactic BeamCath technique. Mean total dose in the conformal group (< or =70 Gy) was 66 Gy (60.8-70.4 Gy). The dose-escalated group consists of three dose levels, 74 Gy (n = 68), 76 Gy (n = 74), and 78 Gy (n = 53).

RESULTS

Analyzing the whole population 3 years after treatment, urgency and starting problems decreased in comparison to pre-treatment. A minor increase in urinary incontinence was reported 3 years after treatment in comparison to pre-treatment. No increases in other urinary symptoms were reported. Intestinal symptoms were slightly increased during the follow-up period in comparison to pre-treatment. Dose escalation with stereotactic EBRT (74-78 Gy) did not increase gastrointestinal or genitourinary late side effects at 1 year or 3 years in comparison to doses < or =70 Gy.

CONCLUSIONS

The stereotactic BeamCath EBRT technique facilitates safe dose escalation of patients with prostate cancer.

[Hormono-radiotherapy of non-metastatic prostate cancers]

Patients presenting with non-metastatic cancer of prostate have a high probability of relapse if they are treated by either surgery alone or irradiation alone, when poor prognosis factors are present. Clinical stage (> or = T3a), Gleason score, and PSA level (> 20 ng/mL) are the more significant factors. It is likely that many patients can draw benefit of combined androgenic suppression and radiotherapy. However, despite results of European and American trials published the last decade, a number of questions remain without a clear response, especially on the modalities of treatment according to the characteristics of the disease.

Practice patterns for prostate cancer in nine central and northern Italy radiation oncology centers: a survey including 1759 patients treated during two decades (1980-1998)

PURPOSE

Prostate cancer patients in Italy are offered the choice of the full spectrum of possible treatment options for their disease, but the diffusion of the more recent technological refinements among the Radiation Oncology centers is not homogeneous and there is a need to establish a reference "historical" data source. This retrospective study describes the changing patterns in prostate cancer patient practice and the therapeutic results obtained in nine Radiation Oncology centers of Northern and Central Italy (five in Northern Italy and four in Central Italy).

METHODS AND MATERIALS

A total of 1759 prostate cancer patients, radically treated in the nine radiotherapy (RT) centers between 1980 and 1998, made up the study population. Data collected for each patient included clinical, pathologic, therapeutic features, and toxicity. The overall survival, disease-specific survival (DSS), and clinical relapse-free survival (RFS) were calculated for the whole series and for the subsets of patients defined by different clinical, pathologic, and therapeutic features, according to three accrual periods (A, 1980-1990; B, 1991-1994; and C, 1995-1998). Univariate and multivariate analyses were performed to identify prognostic factors related to survival and late adverse effects (cystitis and proctitis) probability.

RESULTS

Patient accrual increased markedly during the 2 decades considered, and the percentage of cases with Stage C or D disease dropped from 49% (period A) to 43% (period B) to 37% (period C) (p < 0.0001, chi-square). The baseline prostate-specific antigen value was available for 10%, 76%, and 95% of the cases treated in the three different periods. The major changes in the therapeutic options were an increase in dose to the prostate (>66 Gy in 44%, 84%, and 93% of the patients treated in period A, B, and C, respectively); a reduction in treated volumes, including pelvic lymphatic drainage (56-39% before 1995, 22% thereafter); and an increase in cases treated in association with hormonal therapy (50% before 1991, 80% thereafter). Lower energy (<10 MV) photon beams were progressively abandoned (12% before 1990 vs. 6-7% thereafter), along with an increase in the use of blocks (60% in the last 4 years of the study vs. about 30-40% before 1995) and "conformal" RT (applied in 41% of cases treated after 1994). The actuarial RFS, DSS, and overall survival rate at 5 years was, respectively, 60% +/- 2%, 75% +/- 2%, 66% +/- 2% for period A; 74% +/- 2%, 90% +/- 1%, 83% +/- 2%, for period B; and 67% +/- 5%, 90% +/- 2%, 79% +/- 5% for period C. The actuarial overall survival, DSS, and RFS rate for the whole series of 1759 patients was 77% +/- 1%, 86% +/- 1%, and 68% +/- 1% at 5 years, respectively. Multivariate analysis showed that only American Urologic Association stage, grade, dose to the prostate, accrual period, association with hormonal treatment after (or both after and before) RT (only in terms of DSS and RFS), and baseline prostate-specific antigen value (only for RFS) retained prognostic significance in the final Cox model.

CONCLUSION

The increase in the accrual of prostate cancer patients radically treated with RT has been accompanied by considerable changes in the clinical features at presentation, as well as in the staging and treatment procedures. Patients treated more recently had better survival results. An earlier stage and more favorable grade were linked with better overall, DSS, and RFS at multivariate analysis. Lower prostate-specific antigen baseline values were also related to better RFS. Better results were obtained with higher radiation doses, and the dose to tumor seemed the most important treatment-related prognostic factor. The toxicity (cystitis and proctitis, every Radiation Therapy Oncology Group grade) was substantially the same in the different accrual periods, but larger treated volumes and higher doses appeared to increase the incidence of late effects.

A practical approach to inverse planning for high-precision dose escalated conformal prostate radiotherapy

The problem of choosing the best gantry angles and beam weights for dose-escalated conformal prostate treatment planning is formulated using a mixed-integer linear programming approach, to account for tumour dose homogeneity and dose-volume constraints. The formulation allows the number of beams to be restricted and for some of the beams to be compulsory. The present planning algorithm interfaces with and utilizes the three-dimensional planning capabilities of a commercial treatment planning system. A case study is illustrated, which represents a particularly challenging planning problem due to a large planning target volume and an unusually small bladder. Treatment plans with different numbers of beams are generated to compare with each other and with the standard six-field plan. Significant improvement is shown in the reduction of hot regions within the femoral heads and rectal wall, while not unduly compromising homogeneity constraints for the tumour.

Simulation for localized prostate cancer: a comparison of urethrography techniques

Forty-five patients having conventional fluoroscopic, or CT scan simulation of the prostate gland from January 1999 to June 1999 were studied. Patients were consecutively assigned (not randomized) in groups of 15 to 3 different urethrography techniques: air contrast alone (group 1), hypaque contrast alone (group 2), and xylocaine jelly and hypaque contrast (group 3). Outcome measures were pain scores, visualization of the apex (indicated by urethrogram tip), and frequency of corrections necessary on the basis of verification port films. Group 3 patients had the lowest mean pain score and required fewer lateral setup corrections at the time of portal imaging on the first day of treatment. A comparison of radiographs also revealed that group 2 and 3 patients (hypaque contrast) had better delineation of the prostatic anatomy than group 1 patients (air contrast). We found that of the 3 techniques tested, urethrography utilizing xylocaine jelly and hypaque was associated with the least amount of pain, least amount of corrective shifts, and best quality in defining the prostatic anatomy.

Complications from radiotherapy dose escalation in prostate cancer: preliminary results of a randomized trial

OBJECTIVE

To compare early and late side effects in prostate cancer patients with Stage T1b-T3 disease randomized to receive 70 Gy or 78 Gy.

METHODS

There were 189 patients randomized with a minimum follow-up of 2 years, that were available for this analysis. All patients were initially treated with a 4-field box to an isocenter dose of 46 Gy at 2 Gy per fraction. In the 70-Gy arm, treatment was continued to a reduced volume using a 4-field box technique. In the 78-Gy arm, treatment was continued to a reduced volume using a conformal 6-field arrangement. Side effects were graded on a 1-4 scale, adapted from Radiation Therapy Oncology Group and Late Effects Normal Tissue Task Force criteria.

RESULTS

No significant differences in acute rectal or bladder toxicity were seen between the two treatment techniques (p > 0.6 for all comparisons). The 5-year Kaplan-Meier risks of Grade 2 or higher late bladder toxicity were 20% and 9% for 70-Gy and 78-Gy groups, respectively (log rank, p = 0.8). The 5-year risks of Grade 2 or higher late rectal toxicity were 14% and 21% for 70 Gy and 78 Gy, respectively (p = 0.4). Dose-volume histogram analysis of the 78-Gy patients showed a significant correlation between the percentage of rectum irradiated to 70 Gy or greater and the likelihood of developing late rectal complications. Patients with more than 25% of the rectum receiving 70 Gy or greater had a 5-year risk of Grade 2 or higher complications of 37% compared to 13% for patients with 25% or less (p = 0.05). All three Grade 3 complications occurred when greater than 30% of the rectum received 70 Gy or more.

CONCLUSION

The overall rate of complications was similar in both treatment arms. However, there is evidence for a significant increase in late rectal complications when more than 25% of the rectum received 70 Gy or greater. This parameter may serve as a benchmark for the design of future three-dimensional conformal trials.

A prospective comparison of three systems of patient immobilization for prostate radiotherapy

PURPOSE

The study compared the setup reliability of 3 patient immobilization systems, a rubber leg cushion, the alpha cradle, and the thermoplastic Hipfix device, in 77 patients with cT1-T3, N0, M0 prostate cancer receiving conformal radiotherapy.

METHODS AND MATERIALS

Port films were analyzed and compared to simulation films to estimate the setup errors in the three coordinate axes (anterior-posterior, cranial-caudal, medial-lateral). A total vector error was calculated from these shifts.

RESULTS

The Hipfix was found significantly superior to the other two devices in reducing mean setup errors in all axes (p < 0.005). The average field-positioning error with the Hipfix ranged from 1.9 mm to 2.6 mm for all axes, whereas the deviation for the other two systems ranged from 2.7 to 3. 4 mm. Errors greater than 10 mm were virtually eliminated with the Hipfix system. There was a reduction in the mean total vector error in the alpha cradle and Hipfix patient cohorts over time, reflecting improved efficacy as a result of experience.

CONCLUSION

There was a significant difference in the performance of each immobilization device. The Hipfix was consistently more reliable in reducing setup errors than the other devices.

Prostate position late in the course of external beam therapy: patterns and predictors

PURPOSE

To examine prostate and seminal vesicles position late in the course of radiation therapy and to determine the effect and predictive value of the bladder and rectum on prostate and seminal vesicles positioning.

METHODS AND MATERIALS

Twenty-four patients with localized prostate cancer underwent a computerized tomography scan (CT1) before the start of radiation therapy. After 4-5 weeks of radiation therapy, a second CT scan (CT2) was obtained. All patients were scanned in the supine treatment position with instructions to maintain a full bladder. The prostate, seminal vesicles, bladder, and rectum were contoured. CT2 was aligned via fixed bony anatomy to CT1. The geometrical center and volume of each structure were obtained and directly compared.

RESULTS

The prostate shifted along a diagonal axis extending from an anterior-superior position to a posterior-inferior position. The dominant shift was to a more posterior-inferior position. On average, bladder and rectal volumes decreased to 51% (+/-29%) and 82% (+/-45%) of their pretreatment values, respectively. Multiple regression analysis (MRA) revealed that bladder movement and volume change and upper rectum movement were independently associated with prostate motion (p = 0.016, p = 0. 003, and p = 0.052 respectively).

CONCLUSION

Patients are often instructed to maintain a full bladder during a course of external beam radiation therapy, in the hopes of decreasing bladder and small bowel toxicity. However, our study shows that large bladder volumes late in therapy are strongly associated with posterior prostate displacement. This prostate displacement may result in marginal miss.

Defining the appropriate radiation dose for pretreatment PSA < or = 10 ng/mL prostate cancer

PURPOSE

To investigate whether a dose response exists for biochemical no evidence of disease (bNED) control in prostate cancer patients with pretreatment prostate-specific antigen (PSA) < or = 10 ng/mL and to identify the patient subgroups affected.

METHODS AND MATERIALS

Between 5/89 and 10/97, 488 T1-T3 NX-0 M0 prostate cancer patients with PSA < or = 10 ng/mL were treated with three-dimensional conformal radiation therapy (3D-CRT) alone. Median and mean pretreatment PSA values were 6.3 and 6.2, respectively. Gleason scores of 2-6 and 7-10 were noted in 386 and 102 men, respectively. AJCC 1992 palpation T1-T2AB tumors were noted in 415 patients. Perineural invasion (PNI) was noted in 60 men. Mean and median age was 67 and 68 years, respectively. Dose to the center of the prostate ranged from 6260 cGy to 8409 cGy with a mean and median of 7423 cGy and 7278 cGy, respectively. Patients were stratified into three groups according to dose: <7250 cGy, 7250-7599 cGy, and > or =7600 cGy. Median dose in these three groups was 7067 cGy, 7278 cGy, and 7734 cGy, respectively. Univariate analysis was performed to determine differences in bNED control (American Society for Therapeutic Radiology and Oncology [ASTRO] Consensus Guidelines definition of failure) by dose group for the entire cohort, for 310 good prognosis patients (T1-T2A, Gleason score 2-6, absence of PNI), and for 178 poor prognosis patients (T2B-T3 or Gleason score 7-10 or presence of PNI) (1). Multivariate analysis (MVA) was performed to determine if dose was an independent predictor of bNED control. Median follow-up was 36 months.

RESULTS

A dose response was not demonstrated for the entire group of patients with pretreatment PSA < or =10 ng/mL. Doses of <7250 cGy, 7250-7599 cGy, and > or =7600 cGy were associated with 5-year bNED control rates of 73%, 86%, and 89%, respectively (p = 0.12). MVA demonstrated prognosis group (p = 0. 038) to be the only independent predictor of bNED control. Good prognosis patients had a 5-year bNED of 85% and no dose response was seen. The subgroup of poor prognosis patients demonstrated a 5-year bNED control rate of 81% and a dose response was seen for those receiving > or =7600 cGy, compared to the two lower dose groups (94% vs. 75% vs. 70%; p = 0.0062). MVA for the poor prognosis subset demonstrated dose (p = 0.01) to be the only independent predictor for improved bNED control.

CONCLUSIONS

The poor prognosis subset of PSA < or =10 ng/mL prostate cancer patients benefit from dose escalation. A dose response is not demonstrated for prostate cancer patients with pretreatment PSA < or =10 ng/mL and other favorable features.

Conformal irradiation of concave-shaped PTVs in the treatment of prostate cancer by simple 1D intensity-modulated beams

BACKGROUND

In the case of concave-shaped PTVs including prostate (P) and seminal vesicles (SV), intensity-modulated radiation therapy (IMRT) should improve the therapeutic ratio of the treatment of prostate cancer.

PURPOSE

Comparing IMRT by simple 1D modulations with conventional 3D conformal therapy (i.e. non-IMRT) in the treatment of concave-shaped PTVs including P+SV.

MATERIALS AND METHODS

For five patients having a concave-shaped PTV (P+SV) previously treated at our Institute with conformal radiotherapy, conventional 3- and 4-fields conformal plans were compared with IMRT plans in terms of biological indices. IMRT plans were generated by using five equi-spaced beams with a partial shielding of the rectum obtainable with our single-absorber modulation technique (Fiorino C, Lev A, Fusca M, Cattaneo GM, Rudello F, Calandrino R. Dynamic beam modulation by using a single dynamic absorber. Phys. Med. Biol. 1995;40:221-240). The modulation was one-dimensional and the shape of the beams was at single minimum in correspondence with the 'core' of the rectum; the beam intensity in the minimum was set equal to 20 or 40% of the open beam intensity. All plans were simulated on the CADPLAN TPS using a pencil-beam based algorithm (with 18 MV X-rays). Tumour control probability (TCP) and normal tissue complication probabilities (NTCPs) (for rectum, bladder and femoral head) were calculated for all situations when varying the isocentre dose from 60 to 90 Gy. Dose distributions were corrected taking dose fractionation into account through the linear-quadratic model; for the TCP/NTCP estimations the Webb-Nahum and the Lyman-Kutcher models were respectively applied. Three different scores were considered: (a) increase of TCP while keeping rectum NTCP equal to 5% (TCP(5%)); (b) increase of the uncomplicated tumour control probability (P+); (c) increase of the biological-based scoring function (S+), developed by Mohan et al. (Mohan R, Mageras GS, Baldwin B, Clinically relevant optimization of 3D conformal treatments. Med. Phys. 1992;19:933-944). The impact of the uncertainty in the knowledge of the parameters of the biological models was investigated for TCP(5%).

RESULTS

(a) The average gain in TCP(5%) when considering IMRT against non-IMRT conformal plans was 7.3% (range 5.0-13.5%); (b) the average increase of P+ was 3.4% (range: 1. 0-8.5%); and (c) the average increase of S+ was 5.4% (range 2.9-12. 4%). The largest gain was found for one patient (patient 5) showing a significantly larger overlapping between PTV and rectum.

CONCLUSIONS

Simple 1D-IMRT may clearly improve the therapeutic ratio in the treatment of concave-shaped PTVs including P and SV. In the range of clinically suitable values, the impact of the uncertainty of the parameters n and sigma(alpha) does not significantly alter the main results concerning the gain in TCP(5%). The reported gain in terms of P+ and S+ should be considered with great caution because of the intrinsic uncertainties of the model's parameters and, for bladder, because the 'true' DVH (considering variations of the shape and dimension due to variable filling) may be very different from the DVH calculated on a single CT scan. Further investigations should consider inversely-optimised 1D and 2D-IMRT plan in order to compare them in terms of cost-benefit.

Ultrasound-based stereotactic guidance of precision conformal external beam radiation therapy in clinically localized prostate cancer

OBJECTIVES

Use of external beam radiation fields that conform to the shape of the target improves biochemical control in prostate cancer by facilitating dose escalation through increased sparing of normal tissue. By correcting potential organ motion and setup errors, ultrasound-directed stereotactic localization is a method that may improve the accuracy and effectiveness of current conformal technology. The purpose of this study was to quantify the precision of the transabdominal ultrasound-based approach using computed tomography (CT) as a standard.

METHODS

Thirty-five consecutive men participated in a prospective comparison of daily CT and ultrasound-guided localization at Fox Chase Cancer Center. Daily CT prostate localization was completed before the delivery of each final boost field. In the CT simulation suite, transabdominal ultrasound-based stereotactic localization was also performed. The main outcome measure was a three-dimensional comparison of prostate position as determined by CT versus ultrasound.

RESULTS

Sixty-nine daily CT and ultrasound prostate position shifts were recorded for 35 patients. The magnitude of difference between the CT and ultrasound localization ranged from 0 to 7.0 mm in the anterior/posterior, 0 to 6.4 mm in the lateral, and 0 to 6.7 mm in the superior/inferior dimension. The corresponding directed average disagreements were extremely small: anterior/posterior, -0.09 +/- 2.8 mm SD; lateral, -0.16 +/- 2.4 mm SD; and superior/inferior, -0.03 +/- 2.3 mm SD). Analysis of the paired CT-ultrasound shifts revealed a high correlation between the two modalities in all three dimensions (anterior/ posterior r = 0.88; lateral r = 0.91; and superior/inferior r = 0.87).

CONCLUSIONS

Ultrasound-directed stereotactic localization is safe and as accurate as CT scanning in targeting the prostate for conformal external beam radiation therapy. The application of this technology to current conformal techniques will allow the reduction of treatment margins in all dimensions. This should diminish treatment-related morbidity and facilitate further dose escalation, resulting in improved cancer control.

Endoscopic scoring of late rectal mucosal damage after conformal radiotherapy for prostatic carcinoma

PURPOSE

To describe rectal mucosal damage in an endoscopic study after conformal radiotherapy of prostate cancer and to correlate this with clinical outcome.

MATERIALS AND METHODS

Flexible rectosigmoidoscopy was performed on 44 patients who voluntarily accepted the examination. The median follow-up was 29 months (20-41 months) after 3-D-planned conformal radiotherapy of prostate cancer (66 Gy at the ICRU Reference point, 2 Gy per fraction). To enable a systematic topographic description of endoscopic findings the rectum was divided into four sections. Additionally we differentiated between anterior, posterior, right and left lateral rectal wall. Due to the lack of an existing valid graduation system for radiation induced proctitis, we introduced a six-scaled rectoscopy score for describing and reporting endoscopic findings based on the standardization of the endoscopic terminology published by the ESGE (European Society for Gastrointestinal Endoscopy). Endoscopic findings were compared to the EORTC/RTOG morbidity score. In addition, since 3-D dose distribution of organs at risks was available, a correlation could be made between the location of the rectal lesions and the absorbed dose at that level.

RESULTS

In general, endoscopic findings increased from the proximal rectum to the anorectal transition, as well as from the posterior to the anterior rectum wall. Telangiectasia grade 1 and 2 were observed at the whole circumference, only telangiectasia grade 3 were limited to the high dose region at the anterior rectum wall. Similar results were found for congested mucosa (reddening and edematous mucosa). Correlation with symptoms, 7/9 patients who suffered from intermittent rectal bleeding (EORTC/RTOG grade 2) had multiple telangiectasia grade 2-3 and/or congested mucosa grade 3 and microulcerations. However, the same extent of mucosal damage (rectoscopy score 2-3) was found in seven out of 35 patients who have never developed a period of macroscopic rectal bleeding.

CONCLUSION

Rectoscopy offers the possibility of detecting signs of tissue dysfunction below the level of subjective symptoms. Systematic analytic examinations such as rectoscopy, in addition to clinical examinations, as already foreseen in the LENT-SOMA-score, will be necessary due to the fact that even telangiectatic lesions have been observed for asymptomatic patients. For the opportunity of sharing and comparing data collected from endoscopy after radiotherapy a graduation system as proposed based on a standardisation of the endoscopic terminology will be necessary.

Association of prostate size with urinary morbidity following mixed conformal neutron and photon irradiation

PURPOSE

This study was designed to characterize the relationship between the observed rate of postradiation genitourinary (GU) complications and the prostate gland size.

METHODS AND MATERIALS

Two hundred seventy-three patients received conformal neutron and photon irradiation to the prostate seminal vesicles. Data on post-treatment urinary morbidity were collected and examined in relationship to a number of clinical and technical factors.

RESULTS

With a median follow-up of 30 months (range 7-61), the 4-year rate of Grade 2 or higher GU complications was 21%. On univariate analysis, the risk of complications was significantly associated with prostate size and neutron beam arrangement. On multivariate analysis, only the prostate size was significantly associated with the risk of GU morbidity. Patients with a preradiation prostate volume more than 74 cc had a two and a half fold increase in the risk of complications compared to patients with smaller glands.

CONCLUSION

Patients with an enlarged prostate have a significantly higher risk of chronic GU complications. Although these data were obtained for patients receiving combined neutron and photon irradiation, it is likely that these data would also be applicable for those patients receiving photon irradiation as well. These observations may add an additional rationale for the study of preirradiation hormonal treatment.

Efficacy of selective alpha-1 blocker therapy in the treatment of acute urinary symptoms during radiotherapy for localized prostate cancer

PURPOSE

To determine the efficacy of an alpha-1 adrenoreceptor blocking agent for acute urinary symptoms in patients treated with radiotherapy for localized prostate cancer.

METHODS AND MATERIALS

Between 1987 and 1995, 743 patients with clinically localized prostate cancer were treated with 3D-CRT. A total of 275 (37%) patients developed Grade 2 acute urinary symptoms as defined by the RTOG morbidity scoring system. Terazosin hydrochloride (THC), a selective alpha-1 adrenoceptor blocking agent, was given to 119 (43%) patients for treatment of their urinary symptoms, whereas nonsteroidal anti-inflammatory medications (NSAID) were administered to 71 patients (26%). Thirty-one patients (11%) were treated with other medications, and 54 (20%) did not seek pharmacologic intervention for their urinary symptoms. Patients were monitored weekly to assess changes in urinary urgency, frequency, and nocturia.

RESULTS

Treatment with THC resulted in a significant resolution of urinary symptoms in 79 of 119 patients (66%), while 26 (22%) had moderate improvement, and 14 (12%) had minimal to no response to this drug. In contrast, only 11 of 71 (16%) of the patients treated with NSAIDs experienced significant symptom relief, 20 (28%) had moderate improvement, and 40 (56%) had minimal to no response. The difference in the significant symptomatic improvement between THC and NSAID therapy (66% vs. 16%) was highly significant (p < 0.001). For patients treated with THC, a higher likelihood of significant symptom relief was observed in patients who did not receive neoadjuvant androgen ablation (p = 0.04) and in those who were younger than 65 years of age (p = 0.02).

CONCLUSION

Alpha-1 selective adrenoceptor blocking agents are effective in ameliorating the acute urinary symptoms in patients receiving radiotherapy for localized prostate cancer. Although this was not a randomized prospective study, the data suggest that NSAIDs were less effective in relieving radiation-induced urinary symptoms.

Recent advances in the treatment of prostate cancer

As new evidence for prostate cancer treatment has emerged in the last few years, longstanding controversies in the treatment of prostate cancer have resurfaced. A number of long-held tenets of prostate cancer therapy have been revisited, sometimes with surprising and challenging results. Although neoadjuvant hormonal therapy prior to radical prostatectomy decreases positive surgical margin rates, longer follow-up is needed to support survival improvement of this combined modality therapy. Androgen deprivation combined with radiation therapy appears to improve disease-free survival (and survival in one series) in patients with locally advanced cancer. Another approach to locally advanced prostate cancer using three-dimensional conformal radiation therapy may improve long term outcome. The data are currently insufficient to conclude that interstitial low dose rate brachytherapy is equivalent to conventional treatments: patients with small tumor volumes and low Gleason grade seem to obtain more benefit, whereas for large tumors with higher gleason grades this approach seems inferior to conventional treatments. In advanced prostate cancer recent data suggest that immediate hormonal therapy improves survival. In this group of patients the use of maximum androgen blockade remains controversial but may adversely affect quality of life compared to orchiectomy alone. Intermittent hormonal therapy may improve quality of life, although effect upon survival is unknown. Chemotherapy in combination with androgen deprivation is currently being studied as front-line therapy in advanced prostate cancer. Palliative benefit of chemotherapy for hormone refractory prostate cancer remains an important endpoint; survival advantage has not been seen in any randomized trials. Suramin may delay disease progression in hormone refractory prostate cancer. Many aspects of prostate cancer treatment will remain controversial until results of large, randomized trials with longer follow-up are available.

Variability of the location of internal mammary vessels and glandular breast tissue in breast cancer patients undergoing routine CT-based treatment planning

PURPOSE

To determine the variability of position of internal mammary vessels (IMV) and glandular breast tissue (GBT) in patients undergoing breast-conserving radiation therapy. To assess the frequency and magnitude of tangential field border shifts based on preradiation therapy (RT) computed tomography (CT) imaging in breast cancer patients.

METHODS AND MATERIALS

Five hundred and ninety breast cancer patients irradiated between 9/94 and 3/98 underwent routine CT-based treatment planning. Two analyses were performed. First, the position of IMV and GBT, outlined on the central axis CT image, was determined relative to the midsternum in 111 patients irradiated during a 12-month period. In the second analysis, the difference between anticipated (pre-CT) and actual (CT-based) tangential field borders was assessed in 254 patients irradiated during a 2-year period.

RESULTS

In the first analysis, the depth of the IMVs varied from 1 to 6 cm (median 2.4 cm). The lateral distance from the midsternum also varied widely (range 1.7 to 3.7 cm, median 2.5 cm). Similar variability was found in the position of the GBT. In the second analysis, CT information led to changes of anticipated field borders in 65% of patients. The lateral border was shifted in 56% of patients (anteriorly 18%, posteriorly 38%). When the patients were segregated based on internal mammary node (IMN) treatment, the medial border was shifted in 49% of patients when the IMNs were treated in the tangential fields and in 24% when the GBT only was treated. The frequency of lateral field border shifts was similar in both groups.

CONCLUSIONS

The position of IMVs and GBT varies widely in breast cancer patients. Tangential field borders based on surface anatomy may not be ideal. Among 254 breast cancer patients, the field borders were shifted in 65% of patients when CT information was available. Thus, in most breast cancer patients, field borders are shifted when CT-based treatment planning is used.

Three dimensional conformal photon radiotherapy at a moderate dose level of 66 Gy for prostate carcinoma: early results

BACKGROUND

The therapeutic outcome and toxicity of 3-D conformal photon external beam therapy of prostate cancer is well documented in the literature. Progress is still in work for optimization of treatment strategies by risk-adapted dose escalation studies to improve local tumor control without increase of radiation side effects.

PATIENTS AND METHODS

We present our experience of 291 patients treated between January 1994 and August 1997 with a 3-D planned four-field box technique and a central dose of 66 Gy. Biochemical response of patients with radiotherapy alone (group 1, n = 72 pts.) has been analyzed in detail. Acute radiation side effects are given for all patients (n = 291), late radiation side effects are given for patients treated between Jan 1994 and Jan 1996 with a median follow-up of 22 months (n = 115 pts.).

RESULTS

We have observed a biochemical response (nadir PSA < 1 after 12 months, < 2 after 6 months) for patients treated with radiotherapy alone without hormone manipulation in 67%. Incidence of late rectal and bladder morbidity (grade 2 and 3) was 9.4% and 4%, respectively.

CONCLUSION

Compared to other reports our results indicate a high rate of local tumor control (early biochemical response) and a low rate of late morbidity. Nevertheless, we will start a risk-adapted dose escalation study up to 74 Gy for unfavorable subgroups (G2-3, Gleason Score > 7, PSA > 10) to improve treatment outcome.

The benefit of Beam's eye view based 3D treatment planning for cervical cancer

PURPOSE

The aim of this study was to evaluate the possibility of Beam's eye view (BEV) based three dimensional (3D) treatment planning, to reduce portions of organs at risk included in the treated volume without increasing the risk of geographical miss in external beam therapy of cervical cancer.

MATERIALS AND METHODS

Three dimensional dose distribution of BEV based 3D treatment plans was compared to the 3D dose distribution derived from a four-field-box-technique using standard portals. A total of 20 patients with cervical cancer stage FIGO IIB and FIGO IIIB was included. Dose distribution in the target volumes and in the organs at risk of BEV based treatment planning, was compared to the dose distribution of the standard field technique using dose-volume-histograms.

RESULTS

In 4/20 patients (20%) a geographical miss at the cervix uteri was observed for the standard field technique. The BEV based treatment planning resulted in an adequate coverage of target volume and additionally in a reduction of portions of bladder and bowel volume included in the treated volume (-13.5, -10%). In contrast the BEV based technique resulted in an increase of portions of the rectum volume included in the treated volume compared to standard portals due to a shift of the rectum by the enlarged cervix uteri from its posterior to a lateral position. An overall 7% reduction of treated volume was observed, although the maximum width of lateral fields increased for the BEV technique. Moreover, we have found a remarkable impact of bladder fillings on the amount of bowel and bladder volume included in the treated volume.

CONCLUSION

BEV based 3D treatment planning for external beam therapy of cervical cancer offers a possibility to avoid geographical miss of part of the CTV with reduced portions of bladder and bowel volume included in the treated volume.

Acute morbidity reduction using 3DCRT for prostate carcinoma: a randomized study

PURPOSE

To study the effects on gastrointestinal and urological acute morbidity, a randomized toxicity study, comparing conventional and three-dimensional conformal radiotherapy (3DCRT) for prostate carcinoma was performed. To reveal possible volume effects, related to the observed toxicity, dose-volume histograms (DVHs) were used.

METHODS AND MATERIALS

From June 1994 to March 1996, 266 patients with prostate carcinoma, stage T1-4N0M0 were enrolled in the study. All patients were treated to a dose of 66 Gy (ICRU), using the same planning procedure, treatment technique, linear accelerator, and portal imaging procedure. However, patients in the conventional treatment arm were treated with rectangular, open fields, whereas conformal radiotherapy was performed with conformally shaped fields using a multileaf collimator. All treatment plans were made with a 3D planning system. The planning target volume (PTV) was defined to be the gross target volume (GTV) + 15 mm. Acute toxicity was evaluated using the EORTC/RTOG morbidity scoring system.

RESULTS

Patient and tumor characteristics were equally distributed between both study groups. The maximum toxicity was 57% grade 1 and 26% grade 2 gastrointestinal toxicity; 47% grade 1, 17% grade 2, and 2% grade > 2 urological toxicity. Comparing both study arms, a reduction in gastrointestinal toxicity was observed (32% and 19% grade 2 toxicity for conformal and conventional radiotherapy, respectively; p = 0.02). Further analysis revealed a marked reduction in medication for anal symptoms: this accounts for a large part of the statistical difference in gastrointestinal toxicity (18% vs. 14% [p = ns] grade 2 rectum/sigmoid toxicity and 16% vs. 8% [p < 0.0001] grade 2 anal toxicity for conventional and conformal radiotherapy, respectively). A strong correlation between exposure of the anus and anal toxicity was found, which explained the difference in anal toxicity between both study arms. No difference in urological toxicity between both treatment arms was found, despite a relatively large difference in bladder DVHs.

CONCLUSIONS

The reduction in gastrointestinal morbidity was mainly accounted for by reduced toxicity for anal symptoms using 3DCRT. The study did not show a statistically significant reduction in acute rectum/sigmoid and bladder toxicity.

The Role of Radiotherapy in the Treatment of Carcinoma of the Prostate: A Survey of Clinical Practices in Lombardy, Italy, by the Airo-Lombardia Cooperative Group

Aims and background

We report the results of a survey performed in 1994 by the AIRO-Lombardia Cooperative Group, on the clinical patterns of radiation treatment for prostatic carcinoma in Lombardy, Italy, involving all radiotherapy centers serving an overall local population of about 8,800,000 people.

Methods

A questionnaire was sent to all 13 radiotherapy centers throughout Lombardy, asking for demographic and treatment details concerning the local population of patients with a localized (T1-4, N0-1, M0) carcinoma of the prostate treated with radiotherapy; 12 centers responded, making the basis for the present report.

Results

Analysis of collected data showed that in Lombardy: a) approximately 400 patients per year are irradiated for a localized carcinoma of the prostate, accounting for less than 30% of the total expected number of patients with this disease presentation; b) a complete staging (with PSA, transrectal ultrasonography, abdomino-pelvic CT or MRI scan and total-body bone scan) is performed in over 95% of patients before initiating radiotherapy; c) significant differences exist between radiotherapy centers as regards treatment planning and delivery.

Conclusions

An urgent need exists for implementing procedures aimed at standardizing radiotherapy procedures within Lombardy.

Update on the treatment of prostate cancer with external beam irradiation

BACKGROUND

We review the recent changes in the radiotherapeutic management of clinically localized prostate cancer, including the implementation of three-dimensional (3-D) conformal radiation therapy (3DCRT), biochemical disease-free survival (bNED control) using conventional and 3DCRT techniques, and the morbidity of these treatment strategies.

METHODS

The components of 3DCRT are discussed, including patient immobilization, 3-D treatment planning, multileaf collimation, and electronic portal imaging. bNED control rates from institutions using conventional and 3DCRT techniques are compared. The gastrointestinal (GI) and genitourinary (GU) morbidity from prospective trials using conventional doses of radiation are compared to data from 3DCRT series. bNED control rates stratified by pretreatment prostate-specific antigen (PSA) are compared between surgical and radiation series.

RESULTS

bNED control rates (3-5 years) for patients treated with conventional and 3DCRT techniques ranged from 44-70% and 30-72% with pretreatment PSA levels 4-10 and 10-20, respectively. Although direct comparisons are difficult between treatment modalities, no difference in bNED control stratified by pretreatment PSA was observed between surgical and radiation patients.

CONCLUSIONS

Patients with clinically localized prostate cancer treated with 3DCRT demonstrate durable bNED control at 5 years. Conformal radiation techniques, multileaf collimation, electronic portal imaging, and patient immobilization have reduced acute and chronic GI and GU morbidity while allowing safe dose escalation in an effort to further improve local control and overall survival.

Comparison of 2D and 3D algorithms for adding a margin to the gross tumor volume in the conformal radiotherapy planning of prostate cancer

PURPOSE

To evaluate the adequacy of tumor volume coverage using a three-dimensional (3D) margin-growing algorithm compared to a two-dimensional (2D) margin-growing algorithm in the conformal radiotherapy planning of prostate cancer.

METHODS AND MATERIALS

Two gross tumor volumes (GTV) were segmented in each of 10 patients with localized prostate cancer; prostate gland only (PO) and prostate with seminal vesicles (PSV). A predetermined margin of 10 mm was applied to these two groups (PO and PSV) using both 2D and 3D margin-growing algorithms. The 2D algorithm added a transaxial margin to each GTV slice, whereas the 3D algorithm added a volumetric margin all around the GTV. The true planning target volume (PTV) was defined as the region delineated by the 3D algorithm. The adequacy of geometric coverage of the GTV by the two algorithms was examined in a series of transaxial planes throughout the target volume.

RESULTS

The 2D margin-growing algorithm underestimated the PTV by 17% (range 12-20) in the PO group and by 20% (range 13-28) for the PSV group when compared to the 3D-margin algorithm. For the PO group, the mean transaxial difference between the 2D and 3D algorithm was 3.8 mm inferiorly (range 0-20), 1.8 mm centrally (range 0-9), and 4.4 mm superiorly (range 0-22). Considering all of these regions, the mean discrepancy anteriorly was 5.1 mm (range 0-22), posteriorly 2.2 (range 0-20), right border 2.8 mm (range 0-14), and left border 3.1 mm (range 0-12). For the PSV group, the mean discrepancy in the inferior region was 3.8 mm (range 0-20), central region of the prostate was 1.8 mm ( range 0-9), the junction region of the prostate and the seminal vesicles was 5.5 mm (range 0-30), and the superior region of the seminal vesicles was 4.2 mm (range 0-55). When the different borders were considered in the PSV group, the mean discrepancies for the anterior, posterior, right, and left borders were 6.4 mm (range 0-55), 2.5 mm (range 0-20), 2.6 mm (range 0-14), and 3.9 mm (range 0-45), respectively. Underestimation of the required margin with the 2D algorithm occurred when the transaxial definition of the GTV shifted in position significantly between successive adjacent slices, resulting in transaxial discrepancies of up to 22 mm and 55 mm, respectively, for the PO and PSV groups. In the superior regions, the 2D algorithm was inadequate, often providing a margin of less than 3 mm compared to the 10 mm margin delineated by the 3D algorithm.

CONCLUSION

This study illustrates that target margins added by a laminar method in the transaxial plane are inadequate for covering a 3D tumor volume so that a margin-growing algorithm which fully takes into account the 3D shape of the GTV should be used. If a 2D-margin method is utilized, an appreciation of spatial margins in 3D is required.

111Indium-capromab pendetide in the evaluation of patients with residual or recurrent prostate cancer after radical prostatectomy. The ProstaScint Study Group

PURPOSE

Standard diagnostic methods are limited for detecting distant metastases in patients with prostate cancer in whom the only evidence of disease after radical prostatectomy is a detectable prostate specific antigen (PSA) level. We evaluated the role of immunoscintigraphy with the radiolabeled monoclonal antibody, 111indium ((111)In)-capromab pendetide, to differentiate between local and distant recurrence in this patient population.

MATERIALS AND METHODS

We enrolled 183 men who had undergone radical prostatectomy in whom PSA later increased. Gamma camera images were acquired twice after infusion of a single dose of (111)In-capromab pendetide.

RESULTS

Immunoscintigraphy revealed disease in 108 of 181 patients (60%) with interpretable scans. The antibody was localized most frequently to the prostatic fossa (34% of the cases), abdominal lymph nodes (23%) and pelvic lymph nodes (22%). Of the 181 men the scan localized the antibody outside the prostatic fossa in 42%. Half of the positive localizations in the fossa were confirmed by biopsy.

CONCLUSIONS

These findings suggest that immunoscintigraphy with (111)In-capromab pendetide can assist in determining the extent of disease in patients who have increasing PSA after prostatectomy.

Radiation-associated morbidity in patients undergoing small-field external beam irradiation for prostate cancer

PURPOSE

To quantify complication rates after small-field external beam irradiation for adenocarcinoma of the prostate in a uniformly treated patient population with long follow-up using a simple tool designed to identify subtle treatment-related side effects; and to identify clinical and technical variables associated with increased morbidity after irradiation.

METHODS AND MATERIALS

A total of 441 patients with nonmetastatic adenocarcinoma of the prostate treated at the Joint Center for Radiation Therapy between 1985 and 1989 were eligible for analysis. Gastrointestinal, genitourinary, and sexual function were assessed retrospectively using a patient self-scoring, five-grade toxicity scale. Seven clinical and 15 technical variables were recorded for each patient. The association between the clinical and technical variables and rectal, bladder, and sexual side effects was examined. The 375 patients who received small-field (<12.5 x 12.5-cm) external beam irradiation via a four-field box on a 6-MV (n = 74, or 20% of patients), 8-MV (n = 140, or 37%), or 15-MV (n = 161, or 43%) linear accelerator form the basis for the study. Ninety-one percent of patients received treatment with 1.8-2.0 Gy fractions to a delivered dose of at least 66 Gy. Follow-up was complete through 62 months in living patients, with five (1%) of the entire group lost to follow-up.

RESULTS

A total of 137 of 354 evaluable patients (39%) reported rectal complications after treatment; however, 20 patients(6%) had heme-positive stools as their only symptom and 66 (19%) had mild symptoms not requiring treatment. Only 14% of the entire group required intervention. Of 356 patients, 117 (33%) evaluable for bladder complications developed genitourinary changes: In 14 patients (4%) asymptomatic hematuria occurred, 71 (20%) had mild symptoms not requiring treatment, and 32 (9%) required treatment. Of the 171 patients who were potent prior to radiation, 106 (62%) reported impotence after treatment. No statistically significant association was identified between any clinical or technical variables (including machine energy) assessed and complications.

CONCLUSIONS

In this retrospective review, treatment-related bowel and bladder side effects were not identified in the majority of patients despite the use of a grading system designed to identify subtle changes. Impotence, however, was common. Although pretreatment clinical characteristics varied among patients, they could not be used to predict the subsequent development of complications. The only treatment-related characteristic that varied in this study was machine energy, which did not correlate with complications.

Three-dimensional conformal radiotherapy and dose escalation: where do we stand?

Three-dimensional conformal radiotherapy is an effective means of delivering high doses of radiation with enhanced precision. Several institutions have gained substantial experience using this modality for patients with clinically localized prostate cancer. Reports from these centers have demonstrated not only excellent tolerance despite the administration of higher radiation doses, but improved biochemical and local control outcomes as well. Meticulous attention to treatment technique and dose volume histogram analysis are critical for the safe implementation of these higher doses. The emergence of intensity-modulated treatment planning has provided the opportunity at our institution to further escalate the radiation dose to 86.4 Gy while still respecting the surrounding normal tissue tolerance. Phase I studies will need to continue to define more clearly the maximal dose of radiation that can be delivered safely with this modality. Current studies indicate a direct correlation between dose and prostate-specific antigen (PSA) relapse-free survival response for patients with intermediate and high-risk prognostic features. These patients likely represent the ideal cohort for future studies designed to investigate the impact of dose on biochemical and disease-free survival outcome.

Radiation therapy versus radical prostatectomy in the PSA era: a urologist's view

In the absence of a randomized trial directly comparing outcomes in men with localized prostate cancer treated by radical prostatectomy with treatment by radiation therapy, only an approximate answer regarding the relative efficacies of these modalities can be achieved. However, retrospective studies which examined outcomes based on pretreatment parameters intrinsic to the tumors have demonstrated that when stratified by grade and prostate specific antigen (PSA), the rates of cancer control for these therapies are similar at 5 years posttreatment. These modalities differ in other important ways, including acute toxicity, patient satisfaction, posttreatment quality of life, and ease of salvage of treatment failures. A consideration of all of these factors is necessary to arrive at the appropriate choice of therapy for each patient.