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

[Conformational radiotherapy with multi-leaf collimators: one year experience at the Leon-Berard Centre]

Taking advantage of the renewal of a linear accelerator, the Radiation Therapy Department of the Centre Léon Bérard implemented, in collaboration with Philips Systèmes Médicaux, a conformal therapy set-up procedure using CT-scan for 3D treatment planning and a multileaf collimator that allows achievement of numerous irregular-shaped beams via the multileaf preparation system. The various elements of this equipment make possible well defined and structured procedures for treatment planning with different steps and essential tools used by this technique. We describe the means used and indicate future improvements that will lead to automation in order to provide good quality assurance, better security and substantial time saving. During the first year, 115 patients were treated with this new technique. They presented with central nervous system tumors (32 patients), lung cancer (29 patients), prostate cancer (20 patients), paranasal sinus tumors (14 patients) and tumors located in other sites (13 patients with soft sarcoma, hepato-bilary tumor, etc).

Potential clinical efficacy of intensity-modulated conformal therapy

PURPOSE

The purpose of this study was to examine the potential benefit of using intensity-modulated conformal therapy for a variety of lesions currently treated with stereotactic radiosurgery or conventional radiotherapy.

METHODS AND MATERIALS

Intensity-modulated conformal treatment plans were generated for small intracranial lesions, as well as head and neck, lung, breast, and prostate cases, using the Peacock Plan treatment-planning system (Nomos Corporation). For small intracranial lesions, intensity-modulated conformal treatment plans were compared with stereotactic radiosurgery treatment plans generated for patient treatment at the University of Florida Shands Cancer Center. For other sites (head and neck, lung, breast, and prostate), plans generated using the Peacock Plan were compared with conventional treatment plans, as well as beam's-eye-view conformal treatment plans. Plan comparisons were accomplished through conventional qualitative review of two-dimensional (2D) dose distributions in conjunction with quantitative techniques, such as dose-volume histograms, dosimetric statistics, normal tissue complication probabilities, tumor control probabilities, and objective numerical scoring.

RESULTS

For small intracranial lesions, there is little difference between intensity-modulated conformal treatment planning and radiosurgery treatment planning in the conformation of high isodose lines with the target volume. However, stereotactic treatment planning provides a steeper dose gradient outside the target volume and, hence, a lower normal tissue toxicity index. For extracranial sites, objective numerical scores for beam's-eye-view and intensity-modulated conformal planning techniques are superior to scores for conventional treatment plans. The beam's-eye-view planning technique prevents geographic target misses and better excludes healthy tissues from the treatment portal. Compared with scores for the beam's-eye-view planning technique, scores for intensity-modulated conformal plans using the Peacock Plan were significantly better for the lung and head and neck cases studied, equivalent for prostate cases, and inferior for breast cases.

CONCLUSION

Using the entire 3D data set to construct radiotherapy plans through virtual simulation is always advantageous, whether done for stereotactic radiosurgery, beam's-eye-view conformal therapy, or intensity-modulated conformal treatment. Intensity modulation of the photon beam further enhances treatment planning under specific conditions. In general, the intensity-modulated technique is advantageous for large, irregular targets with critical structures in close proximity. Intensity-modulated treatment planning does not appear advantageous for stereotactic radiosurgery or treatment of the intact breast.

Acute response of pig skin to irradiation with 12C-ions or 200 kV X-rays

The acute response of pig skin to treatment with high energy carbon ions (plateau region) at the Gesellschaft für Schwerionenforschung (GSI, Darmstadt, Germany) was compared with changes after 200 kV x-irradiation. Carbon doses isoeffective to the x-ray doses were computed with a recently established model for calculation of the biological effect of heavy ions. Clinical changes and physiological symptoms (blood flow, erythema, trans-epidermal water loss, skin hydration) were scored. The parameters analyzed were maximum and mean values of each symptom during days 24 to 70 after irradiation, and the quantal endpoints for the establishment of dose effect curves were the median values of these. With exception of the maximum change in the red blood cell concentration (p < 0.02) no significant differences could be found in the response to x-rays and RBE-corrected heavy ions. These results indicate that the model is valid for the calculation of biological effects of 12C-ions (plateau region) and may at least for epidermis be applied to treatment planning.

Computed tomography-magnetic resonance image fusion: a clinical evaluation of an innovative approach for improved tumor localization in primary central nervous system lesions

We describe our initial experience with the AcQSim (Picker International, St. David, PA) computed tomography-magnetic resonance imaging (CT-MRI) fusion software in eight patients with intracranial lesions. MRI data are electronically integrated into the CT-based treatment planning system. Since MRI is superior to CT in identifying intracranial abnormalities, we evaluated the precision and feasibility of this new localization method. Patients initially underwent CT simulation from C2 to the most superior portion of the scalp. T2 and post-contrast T1-weighted MRI of this area was then performed. Patient positioning was duplicated utilizing a head cup and bridge of nose to forehead angle measurements. First, a gross tumor volume (GTV) was identified utilizing the CT (CT/GTV). The CT and MRI scans were subsequently fused utilizing a point pair matching method and a second GTV (CT-MRI/GTV) was contoured with the aid of both studies. The fusion process was uncomplicated and completed in a timely manner. Volumetric analysis revealed the CT-MRI/GTV to be larger than the CT/GTV in all eight cases. The mean CT-MRI/GTV was 28.7 cm3 compared to 16.7 cm3 by CT alone. This translated into a 72% increase in the radiographic tumor volume by CT-MRI. A simulated dose-volume histogram in two patients revealed that marginal portions of the lesion, as identified by CT and MRI, were not included in the high dose treatment volume as contoured with the use of CT alone. Our initial experience with the fusion software demonstrated an improvement in tumor localization with this technique. Based on these patients the use of CT alone for treatment planning purposes in central nervous system (CNS) lesions is inadequate and would result in an unacceptable rate of marginal misses. The importation of MRI data into three-dimensional treatment planning is therefore crucial to accurate tumor localization. The fusion process simplifies and improves precision of this task.

Daily-diary evaluated side-effects of conformal versus conventional prostatic cancer radiotherapy technique

Conventional 4-field box radiotherapy technique induces high morbidity for patients with localized prostatic cancer. Using a patient daily diary, the present study compared side-effects after conventional radiotherapy with conformal radiotherapy for prostate cancer. Fifty-eight patients treated with the conventional technique (with or without sucralfate) were compared with 72 patients treated with conformal technique. The patient groups were compared with an age-matched control population. Patients treated with conformal technique were also evaluated regarding acute and late urinary problems. Results showed that patients treated with conformal technique reported significantly fewer side-effects as compared with conventional technique. Patients treated with sucralfate also showed slightly decreased intestinal morbidity in comparison to non-sucralfate group. Acute and late morbidity evaluated by the patients was decreased after conformal radiotherapy as compared with the conventional technique. Sucralfate may be of value if conformal radiotherapy is used for dose escalation in prostatic cancer patients.

Bladder movement during radiation therapy for bladder cancer: implications for treatment planning

PURPOSE

To describe and quantify bladder movement during radical radiation therapy (RT). To attempt to identify factors that predict for excessive alterations in bladder position. To use the above information to assist in defining the "adequate" planning target volume margin.

METHODS AND MATERIALS

Thirty patients with bladder cancer suitable for radical courses of RT were followed prospectively. Patients had an initial planning computerized tomography (CT) scan of the pelvis and three subsequent scans performed weekly during the treatment period. The following measurements were made on each scan in the midbladder slice: maximum anteroposterior (AP) and lateral bladder dimensions, AP rectal diameter, and the distance (margin) between the bladder walls (anterior, posterior, right, and left lateral) and the 95% isodose line. Various patient and tumor data, including bladder and bowel symptoms, were recorded to attempt correlation with bladder movement.

RESULTS

Bladder size: the median bladder size (area) over all scans in all patients was 36.9 cm2 (range: 16.2 to 80.9 cm2). The change in bladder area across each sequence varied from 3.3 to 29.1 cm2 (7-55% change in area between scans). Patients with bladders of larger than the median size on the planning scan (despite emptying) were more likely to have alteration in size than those with small bladders, and this change was in the direction of contraction (p = 0.01). Bladder displacement: bladder wall movement of > 1.5 cm was defined as "significant." Eighteen of 30 patients (60%) demonstrated "significant" movement of at least one bladder wall relative to the original isodose plot. Movement resulting in margin reduction occurred in 10 patients (33%). Two patients required treatment replanning due to consistently altered bladder position. There was no pattern to displacement through RT, and all walls were at approximately equal risk of movement. Factors influencing bladder movement: posterior bladder wall movement appeared to relate to "marked" (>2 cm) rectal diameter change. There was a trend for patients with larger amounts of residual bladder tumor (greater than the median) to exhibit more bladder movement; 11 of 14 "moved" compared with 7 of 16 patients with less residual tumor. Other clinical factors including age, sex, body size, acute RT reaction, and tumor stage did not appear to relate to bladder movement.

CONCLUSION

Bladder movement during RT is clinically relevant and is random with respect to both time and direction. We recommend, at least with respect to tumor-bearing regions of the bladder, that no less than a 2.0 cm margin should be allowed.

Comparing 3-, 4- and 6-fields techniques for conformal irradiation of prostate and seminal vesicles using dose-volume histograms

BACKGROUND AND PURPOSE

Comparing some isocentric coplanar techniques for conformal irradiation of prostate and seminal vesicles.

MATERIALS AND METHODS

Five conformal techniques have been considered: (A) a 3-fields technique with an antero-posterior (AP) field and two lateral (LAT-LAT) 30 degrees wedged fields; (B) a 3-fields technique with an AP field and two oblique posterior (OBL) 15 degrees wedged fields with relative weights of 0.8, 1 and 1, respectively; (C) a 4-fields technique (AP-PA and LAT-LAT); (D) a 6-fields technique (LAT-LAT and four OBL at gantry angles 45 degrees, 135 degrees, 235 degrees and 315 degrees) with all the fields having the same weight; (E) the same 6-fields technique with lateral fields double-weighted with respect to the oblique fields. The conformal plans have been simulated on 12 consecutive patients (stages B and C) by using our 3D treatment planning system (Cadplan 2.7). The contours of the rectum, the bladder and the left femoral head were outlined together with the clinical target volume (CTV) which included the prostate and the seminal vesicles. A margin of 10 mm was added to define the planning target volume (PTV) through automatic volume expansion. Then a 7 mm margin between the PTV and block edges was added to take the beam penumbra into account. Dose distributions were normalised to the isocentre and the reference dose was considered to be 95% of the isocentre dose. Dose-volume histograms and dose statistics of the rectum, the bladder and the left femoral head were collected for all plans. For the rectum and the bladder the mean dose (Dm) and the fraction of volume receiving a dose higher than the reference dose (V95) were compared. For the femoral head, the mean dose together with the fraction of volume receiving a dose higher than 50% (V50) were compared.

RESULTS

Differences among the techniques have been found for all three considered organs at risk. When considering the rectum, technique A is better than the others both when considering Dm and V95 (P = 0.002), while technique D is the worst when considering Dm (P < 0.002) and is also worse than techniques A, E (P = 0.002) and C (P = 0.003) when considering V95. Technique E is the best when considering the bladder mean dose (P = 0.002 against A and D, P < 0.01 against B and C) and technique C is the worst (P < 0.012). No relevant differences were found for the bladder V95. In the femoral heads, techniques A and E are worse than B, C and D (P < 0.003) when considering Dm and V50. Moreover, techniques B and D are better than C (P < 0.004) when considering V50.

CONCLUSIONS

There is no technique that is absolutely better than the others. Technique A gives the best sparing of the rectum; the bladder is better spared with technique E. These results are reached with a worse sparing of the femoral heads which should be carefully taken into account.

Conformal external beam treatment of prostate cancer

OBJECTIVES

This study reports the 5-year outcomes of treatment for patients with prostate cancer treated largely with conformal three-dimensional radiation therapy.

METHODS

Results are presented for 456 consecutive patients treated prior to December 31, 1993 whose pretreatment prostate-specific antigen (PSA) levels are known. Biochemical failure was defined as two consecutive rises in the PSA that equals or exceeds 1.5 ng/mL. Kaplan-Meier product limit methods, the log-rank test, and Cox regression models were used in evaluating the data. No patient was lost to follow-up.

RESULTS

The 5-year biochemically free of failure (bNED) rate for all patients was 61% and 57% at 7 years. In the group with pretreatment PSA less than 10 ng/mL, the 5-year bNED rate for patients with localized disease (T1,2AB disease, Gleason sum of 6 or less) was 85% and for those with locally advanced disease (T2C,3), 70%. In the group with pretreatment PSA of 10 to 19.9 ng/mL, the 5-year bNED rate for patients with localized disease was 66% and for those with locally advanced disease, 44%. In the group with pretreatment PSA of 20 ng/mL or above, the patients with localized or locally advanced disease had 5-year bNED rates of 31% and 21%, respectively.

CONCLUSIONS

The results of largely conformal three-dimensional external beam treatment of localized prostate cancer produced 5-year bNED results that are comparable to recent reports of nerve-sparing prostatectomy. Preliminary 7-year bNED results in all patients and in patients with localized tumors indicated a modest decrease in the cancer-free rate from that observed at 5 years, suggesting the results are durable.

Prostate cancer screening and management

Several other newer therapeutic modalities are being investigated to determine their potential role in the treatment of prostate cancer. Cryotherapy, microwave hyperthermia, laser therapy, and high-intensity focused ultrasound have all been introduced in recent years. Each of these techniques is based on a different principle, yet they all attempt to kill prostate cancer cells in a minimally invasive manner. Insufficient follow-up data are available to allow strong recommendations regarding these treatments.

Results of 3D conformal radiotherapy in the treatment of localized prostate cancer

PURPOSE

3D conformal radiotherapy (3D CRT) has been shown to decrease acute morbidity in the treatment of prostate cancer. Therapeutic outcome and late morbidity data have been accumulating. To evaluate the results of 3D CRT for the treatment of prostate cancer, we analyzed the outcome of a large series of patients treated with conformal techniques.

MATERIAL AND METHODS

From January 1987 through June 1994, 707 patients with localized prostate cancer were treated with 3D CRT. Patients with pathologically-confirmed pelvic lymph node metastasis, treated with pre-irradiation (preRT) androgen ablation, or treated post-prostatectomy were excluded. All had CT obtained specifically for treatment planning, multiple structures contoured on the axial images, and beam's-eye view conformal beams edited to provide 3D dose coverage. Median follow-up is 36 mos; 70 patients have been followed longer than 5.5 years. Six hundred three had T1-T2 tumors. PreRT prostate specific antigen (PSA) was available for 649 patients: median preRT PSA was 12.9 ng/ml, 209 patients had preRT PSA > 20 ng/ml. The median dose of radiation was 69 Gy; 102 patients received > or = 69 Gy. Biochemical failure was defined as: 1) two consecutive PSA rises over 2.0 ng/ml if nadir PSA < or = 2.0 ng/ml, 2) two consecutive PSA rises over nadir if nadir PSA > 2.0 ng/ml, or 3) initiation of hormonal therapy after RT. Complications were graded using the RTOG system.

RESULTS

PreRT PSA and Gleason score emerged as independent indicators of biochemical control (bNED). Patients with preRT PSA > 10 had a significantly worse bNED at 5 years than patients with preRT PSA < or = 10. Five-year bNED was determined according to preRT PSA: PSA < or = 4, 88%; PSA > 4 < or = 10, 72%; PSA > 10 < or = 20, 43%; and PSA > 20, 30%. Patients with Gleason score > or = 7 also had a significantly worse bNED than patients with Gleason score < 7. Patients were divided into two prognostic groups: a favorable group with PSA < or = 10, Gleason score < 7, and T1-T2 tumors, and an unfavorable group with PSA > 10, Gleason score > or = 7 or T3-T4 tumors and studied for the effect of dose on bNED status. The bNED at 5 years was 75% for the favorable group and 37% for the unfavorable group. In addition, a group that might be considered a surgical subset was reviewed: patients with PSA < or = 10, Gleason score < or = 7, and T1-T2 tumors who were < 70 years old. This subset had an 84% 5-year bNED rate and 98% 5-year overall survival. Complications with the techniques used here are very low: 3% risk at 7 years of Grade 3-4 complications and 1% risk at 7 years of Grade 3 bladder complications (no Grade 4).

CONCLUSION

3D CRT allows for treatment of prostate cancers with a very low risk of complications. Patients with relatively early disease as defined by preRT PSA, Gleason score < 7, and T1-2 tumors and patients who are candidates for radical prostatectomy have excellent 5-year bNED rates. Patients with adverse prognostic factors have a high risk of biochemical recurrence and are candidates for innovative therapy.

[Planned 3-dimensional low-volume conformal irradiation of a local prostatic carcinoma]

AIM

Recent data have shown a significant reduction of acute side effects by means of a three-dimensional planned conformal radiotherapy of carcinoma of the prostate compared to treatment techniques used before. Theoretically, an optimized field coverage of the planning target volume should result in a reduction of treated bladder and rectum volumes. We studied the effects of individualized blocks on treatment volumes, planning target volumes, irradiated bladder and rectum volumes on basis of three-dimensional treatment planning by means of beam's-eye-view technique.

PATIENTS AND METHOD

We compared dose-volume-histograms of 2 different planning models, a (fictitious) open 4-field-box-technique and a technique with conformal blocked fields designed from the beam's-eye-view display (prescribed dose 66 Gy, daily single fraction 2 Gy). Plans of 115 patients with localized prostate cancer treated from January 1994 to February 1996 were analyzed.

RESULTS

Using individualized fields treatment volume (covered by the 90%-isodose) was reduced by 23% on the average in comparison to the planning model without blocks. The averaged difference of treated volume and planning target volume, as a grade of efficiency of conformation, was reduced by 38% (496 cm3 303 cm3) using individualized blocks. 23% of the treated bladder volume and 13% of the treated rectum volume had been saved on the average. Nevertheless, at least 11.5% of the bladder volume and 27.6% of the contoured rectum volume were treated with the prescribed dose (55 Gy = 100%).

CONCLUSIONS

The comparison of dose-volume-histogram-data showed that especially high dose volumes of organs at risk had been saved by means of individualized blocks created from the beam's-eye-view. The blocks did not affect the dose distribution of the planning target volume adversely. Consequently the impact of these data on the extent of side effects and local tumor control has to be proven.

Focal therapy for prostate cancer 1996: maximizing outcome

OBJECTIVES

To summarize improvements in patient selection and the results of focal therapy for the management of localized prostate cancer.

METHODS

A contemporary series of patients managed with wide surgical excision, radiation therapy (three-dimensional conformal radiation, interstitial radiation, and charged-particle or proton therapy), and cryo-therapy were reviewed.

RESULTS

We used preoperative cancer grade, transrectal ultrasound, and serum prostate-specific antigen (PSA) in all patients, and cross-sectional imaging and bone scans in selected patients to allow for reasonably accurate cancer staging and selection of patients most likely to be cured by radical prostatectomy or radiation. In patients with extracapsular extension of prostate cancer, wide surgical excision and achievement of a clear surgical margin had therapeutic value. Newer radiation techniques resulted in a higher likelihood of prostate cancer control than previous techniques. Cryotherapy for patients with stages T1 through 3 prostate cancer was associated with a posttreatment undetectable PSA rate of 48% and a positive biopsy rate of 23%.

CONCLUSIONS

Patients with organ-confined and, therefore, curable prostate cancer can be identified. Well-performed radical prostatectomy, radiation, and cryotherapy are alternative treatments for the management of localized prostate cancer.

Neoadjuvant androgen suppression with radiation in the management of locally advanced adenocarcinoma of the prostate: experimental and clinical results

Conventional radiotherapy has been a standard treatment for the management of locally advanced T2c-4 prostatic carcinoma for over 2 decades. The routine use of serum PSA in follow-up makes it clear that > 80% of these patients will show evidence of failure by 10 years. Rebiopsy of those with a rising PSA shows locally persistent disease in the majority of cases. Increasing the radiation dose applied to the prostate increases local control but at the risk of higher morbidity. Experimental data using the Shionogi tumor mouse model suggest a potential gain from neoadjuvant androgen suppression without any increase in normal tissue morbidity. Two randomized trials comparing neoadjuvant androgen suppression prior to radiation therapy with radiation alone in humans show considerable short-term gains in local control and disease-free survival but mature data are still awaited. It is currently unknown whether the positive interaction between radiation and androgen suppression is synergistic or simply additive.

[The conformal radiotherapy of localized prostatic carcinoma: acute tolerance and early efficacy]

AIM

In a prospective trial early effectiveness and acute toxicity of conformal 3D-planned radiotherapy for localized prostate cancer was quantified using dose-volume-histogramms and evaluated with respect of treatment technique.

PATIENTS AND METHOD

Thirty-two men (44 to 80 years old) with locally advanced carcinoma of the prostate (stage B2 or C) have been treated by 3D-planned conformal radiotherapy using high energy photons. In 28/32 men treatment technique was a monoaxial bisegmental rotation with irregular fields. With single doses of 2.0 Gy a mean total dose of 63.9 +/- 4.9 Gy according to ICRU was applied within 46 +/- 4 days. Maximum dose was in the mean 105.1% +/- 3.8%. 3D treatment volume was 274.1 +/- 113.4 cm3. Median follow-up is 1.8 years (15 to 34 months). Toxicity was evaluated according to RTOG-EORTC by patient interview and physical examination on a weekly basis during radiotherapy and by regular follow-up.

RESULTS

Eleven patients had none, 15 mild (RTOG grade 1) and 6 moderate symptoms (RTOG grade 2, mainly diarrhoea, dysuria and polyuria). Acute complications leading to treatment interruption did not occur. In 16 patients symptoms disappeared within 6 weeks after radiotherapy. Only 2 men had symptoms which lasted longer than 3 months and were endoscopically examined. Up to now no late complications were detected. Incidence and severity of toxicity was significantly (p < 0.05) related to the size of treatment volume. Acute toxicity was found to depend statistically significant (p < 0.05) on the proportional volume of bladder and rectum, irradiated with more than 35 Gy. In 81% of the patients with pretherapeutic elevated PSA levels normalisation of PSA was observed. Overall mean PSA levels of 15.7 +/- 22.6 micrograms/l at the beginning of radiotherapy fell to 2.1 +/- 3.7 micrograms/l 6 weeks after irradiation. Only 1 Patient relapsed locally 22 months after radiation therapy.

CONCLUSION

We conclude that due to modern 3D-planned conformal techniques with optimization of treatment dose and improved protection of critical organs such as urinary bladder and rectum, radiotherapy allows an effective and well tolerated therapy of localized prostatic carcinoma.

Acute toxicity in pelvic radiotherapy; a randomised trial of conformal versus conventional treatment

BACKGROUND

A prospective, randomized clinical trial to assess the effect of reducing the volume of irradiated normal tissue on acute reactions in pelvic radiotherapy accured 266 evaluable patients between 1988 and 1993.

PURPOSE

This is the definitive analysis to assess the differences between the conformal and conventional arms of the trial.

MATERIALS AND METHODS

In both arms, patients were treated with 6 MV X-rays using a 3-field technique (in all but 5 cases) consisting of an anterior and two wedged lateral or posterior oblique fields; in the conventional arm, rectangular fields were employed, whereas in the conformal arm, the fields were shaped with customized blocks drawn according to the beam's-eye-view of the target volume. The most common dosage was 64 Gy in 2-Gy fractions 5 times a week, although a subgroup (of ca. bladder patients) were treated with 30-36 Gy in once-a-week 6 Gy fractions. Each patients completed a comprehensive acute toxicity scoring questionnaire concentrating on bowel and bladder problems, tiredness and nausea, before the start of treatment, weekly during and for 3 weeks after the end of treatment and then monthly for a further 2 months. compliance was excellent.

RESULTS

There were no differences between the patients in the two arms with respect to age, gender, tumour type (52% prostate, 41% bladder, 5% rectum, 2% other) fractionation/dosage, anterior field size, weight, or baseline symptoms. Substantial differences in normal-tissue volumes (rectum, bladder, etc.) were achieved: median high-dose volume (HDV) of 689 cm3 for the conformal technique versus 792 cm3 for the conventional. A clear pattern of an increase in symptoms during RT, followed by a decrease after RT, was observed for the patient group as a whole. However, a very extensive analysis has not revealed any (statistically) significant differences between the two arms in level of symptoms, nor in medication prescribed. The disparity between our findings and those of other, non-randomized studies is discussed.

CONCLUSIONS

The data on late effects must be collected and analyzed before any definite conclusions can be drawn on the benefits of conformal therapy in the pelvis.

Optimization of conformal radiation treatment of prostate cancer: report of a dose escalation study

PURPOSE

The development of conformal radiation technique including improved patient immobilization has allowed us to test the value of dose escalation in optimizing the radiation treatment of prostate cancer.

METHODS AND MATERIALS

Outcome is reported for 233 consecutive patients treated with conformal technique between March 1989 and October 1992. Dose was escalated from 68 Gy to 79 Gy. Patient status is reported at 3 years follow-up, which is available in all alive patients. Pretreatment and serial posttreatment prostate specific antigen (PSA) values are available for all patients. Biochemical freedom of disease (bNED) defines failure as PSA > 1.5 ngm/ml and rising on two consecutive measures. Dose response for bNED control of cancer and late morbidity are represented by logit response models fitted to the data. Kaplan-Meier methods, the log rank test, and Cox Regression models are also used.

RESULTS

No dose response is observed for bNED survival for patients with pretreatment PSA <10 ngm/ml comparing patients treated above or below 71.5 Gy or on multivariate analysis. Dose response is observed for bNED survival for pretreatment PSA groups of 10-19.9 ngm/ml and 20+ ngm/ml. The dose associated with 50% bNED survival at 3 years is 64 Gy and 76 Gy, respectively. The slope of the dose responses are 13 and 9%, respectively. Dose response is demonstrated for Grade 2 gastrointestinal (GI), Grade 2 genitourinary (GU), and Grade 3,4 combined GI and GU late morbidity. The slopes of the morbidity responses are steeper than for cancer control (19 to 21%).

CONCLUSIONS

Patients with pretreatment PSA < 10 ngm/ml do not benefit from dose escalation, and the serious late morbidity of conformal radiation at 70 Gy is < 3%. Patients with PSA values 10-19.9 ngm/ml and 20+ ngm/ml benefit from dose escalation beyond 70 Gy. Treatment beyond 75 Gy results in > 10% serious morbidity unless special precautions are taken to protect the rectal mucosa. All levels of severity of radiation morbidity show a dose response and combined with the dose response for bNED survival these data allow the optimization of treatment.

The effect of treatment positioning on normal tissue dose in patients with prostate cancer treated with three-dimensional conformal radiotherapy

PURPOSE

To prospectively assess the effect of supine vs. prone treatment position on the dose to normal tissues in prostate cancer patients treated with the three-dimensional conformal technique.

METHODS AND MATERIALS

Twenty-six patients underwent three-dimensional treatment planning in both the supine and prone treatment positions. The planning target volume and normal tissue structures were outlined on each CAT scan slice, and treatment plans were compared to assess the effect of treatment position on the volume of rectum, bladder, and bowel exposed to the high dose of irradiation.

RESULTS

The average dose to the rectal wall and the V95 (volume of rectal wall receiving at least 95% of the prescription dose) for the prone position were 64 and 24% of the prescription dose, respectively, compared to 72 and 29%, respectively, for the supine position (p < 0.05). When the average rectal wall dose was used as an endpoint, 14 of the 26 patients (54%) had an advantage for the prone position compared to 1 (4%) who demonstrated an advantage for the supine position (p < 0.0002). Similarly, when V95 of the rectal wall was used as a measure of comparison, 15 patients (58%) had an advantage for the prone position compared to 1 (4%) who demonstrated an advantage for the supine position (p < 0.0002). In 13 patients (50%), a change from supine to the prone position was associated with reduction of the V95 to levels < 30% of the prescription dose compared to 3 patients (11%) in whom such an advantage resulted from change of the prone to the supine position (p < 0.005). The effect of treatment position on the rectal wall dose was most pronounced in the region of the seminal vesicles. An increased volume of bowel was also noted in the supine position. The treatment position, however, had no significant impact on the dose to the bladder wall.

CONCLUSIONS

Three-dimensional conformal radiotherapy for prostate cancer in the prone position is associated with significant reduction of the dose to the rectum and bowel resulting in an improvement in the therapeutic ratio.

Long-term control of prostate cancer with radiation. Past, present, and future

This article details the methods of determining cancer-free status and addresses the long-term results of external beam radiation. It demonstrates that when similar patients are compared, the results of prostatectomy and radiation in early disease do not differ. The new technology in conformal radiation produces outcomes superior to conventional radiation technique in cure of cancer and reduction of serious complications.

Conformal irradiation of the prostate: estimating long-term rectal bleeding risk using dose-volume histograms

PURPOSE

Dose-volume histograms (DVHs) may be very useful tools for estimating probability of normal tissue complications (NTCP), but there is not yet an agreed upon method for their analysis. This study introduces a statistical method of aggregating and analyzing primary data from DVHs and associated outcomes. It explores the dose-volume relationship for NTCP of the rectum, using long-term data on rectal wall bleeding following prostatic irradiation.

METHODS AND MATERIALS

Previously published data were reviewed and updated on 41 patients with Stages T3 and T4 prostatic carcinoma treated with photons followed by perineal proton boost, including dose-volume histograms (DVHs) of each patient's anterior rectal wall and data on the occurrence of postirradiation rectal bleeding (minimum FU > 4 years). Logistic regression was used to test whether some individual combination of dose and volume irradiated might best separate the DVHs into categories of high or low risk for rectal bleeding. Further analysis explored whether a group of such dose-volume combinations might be superior in predicting complication risk. These results were compared with results of the "critical volume model," a mathematical model based on assumptions of underlying radiobiological interactions.

RESULTS

Ten of the 128 tested dose-volume combinations proved to be "statistically significant combinations" (SSCs) distinguishing between bleeders (14 out of 41) and nonbleeders (27 out of 41), ranging contiguously between 60 CGE (Cobalt Gray Equivalent) to 70% of the anterior rectal wall and 75 CGE to 30%. Calculated odds ratios for each SSC were not significantly different across the individual SSCs; however, analysis combining SSCs allowed segregation of DVHs into three risk groups: low, moderate, and high. Estimates of probabilities of normal tissue complications (NTCPs) based on these risk groups correlated strongly with observed data (p = 0.003) and with biomathematical model-generated NTCPs.

CONCLUSIONS

There is a dose-volume relationship for rectal mucosal bleeding in the region between 60 and 75 CGE; therefore, efforts to spare rectal wall volume using improved treatment planning and delivery techniques are important. Stratifying dose-volume histograms (DVHs) into risk groups, as done in this study, represents a useful means of analyzing empirical data as a function of hetereogeneous dose distributions. Modeling efforts may extend these results to more heterogeneous treatment techniques. Such analysis of DVH data may allow practicing clinicians to better assess the risk of various treatments, fields, or doses, when caring for an individual patient.

Three dimensional comparison of blocked arcs vs. four and six field conformal treatment of the prostate

PURPOSE

The purpose of this study is to compare five different techniques for treatment the prostate without seminal vesicles. Dose volume histograms and a time survey are the tools that were used for this analysis.

METHODS AND MATERIALS

For this study we compared 3D techniques using four and six field conformal treatments, to open and blocked 8 x 8 cm2 120 degrees bilateral arcs. All the plans were normalized to deliver 100% to the central axis, and full 3D calculations were performed. Blocked arcs were created using the 'average beam's eye view' (A-BEV) technique.

RESULTS

Analysis of the dose volume histograms revealed: (1) Arcs with blocks result in an improved dose distribution compared to standard arcs and four field 3DCRT techniques, (2) The DVH associated with blocked arcs, using block margins of 1.3 cm, resulted in a somewhat lower dose to the rectum but a 'tighter' margin around the prostate compared to the DVH generated using the six field 3DCRT technique.

CONCLUSION

This technique is for treatment of the prostate only, when treatment of the seminal vesicle is not required. The use of blocked arcs significantly improved the dose distribution compared to using standard arcs and 4-field conformal techniques. The DVHs associated with using blocked arcs is comparable to the SFC technique. It is likely to be less expensive, faster to set-up and may allow for safe dose escalation when only the prostate is receiving treatment.

Self-assessed sexual function after pelvic irradiation for prostate carcinoma. Comparison with an age-matched control group

BACKGROUND

Treatment of localized prostate carcinoma is often accompanied by disturbances in sexual function. The patient's own opinion and experience with these problems can be of great importance for his quality of life. In men older than 50 years, disturbances in sexual function are common. Treatment such as radiotherapy (RT), which can induce sexual dysfunction, should be evaluated in relation to the problems in an age-matched population without prostate carcinoma.

METHODS

Sexual function was evaluated with a self-assessment questionnaire using linear-analogue scales. The questionnaire was sent to 199 patients with prostate carcinoma, median age 71 years (range, 51-86 years), who had received pelvic RT with curative intent and to 200 age-matched men in northern Sweden. Mean follow-up time after RT was 48 months (range, 24-56 months).

RESULTS

The response rate was high: 141 (71%) and 181 (91%) in the control and patient groups, respectively. Field reduction and treatment pause during RT was not associated with decreased problems in the patient groups. A failure to achieve erection was indicated in 12% of the control subjects, 56% of the patients who had received (RT only) and 87% of the RT + castration (RT + A) patients. In general, patients < 70 years treated with RT+A indicated more sexual problems than the RT only patients < 70 years. There was a strong negative correlation between age and sexual problems in the RT + A < 70 years group. However, in patients < 70 years, sexual activity after RT only, was not significantly different from the age-matched control population.

CONCLUSIONS

Patients with prostate carcinoma treated with RT only indicated higher levels of sexual dysfunction than age-matched controls. This was most obvious in patients younger than 70 years, although their sexual activity was comparable to age-matched controls. The addition of castration to RT tended to increase sexual problems, especially in patients < 70 years. In men between 70 and 74 years, the maintenance of sexual function seems to be very susceptible to disturbances. For patients older than 74 years, decreased sexual function was not perceived as such a significant problem, despite abolished desire and erection.

Conformal technique dose escalation for prostate cancer: biochemical evidence of improved cancer control with higher doses in patients with pretreatment prostate-specific antigen > or = 10 NG/ML

PURPOSE

Conformal radiation technology results in fewer late complications and allows testing of the value of higher doses in prostate cancer.

METHODS AND MATERIALS

We report the biochemical freedom from disease (bNED) rates (bNED failure is Prostate Specific Antigen (PSA) > or = 1.5 ng/ml and rising) at 2 and 3 years for 375 consecutive patients treated with conformal technique from 66 to 79 Gy. Median follow-up was 21 months. Biochemical freedom from disease was analyzed for patients treated above and below 71 Gy as well as above and below 73 Gy. Each dose group was subdivided by pretreatment PSA level (< 10, 10-19.9, and > or = 20 ng/ml). Dose was stated to be at the center of the prostate gland.

RESULTS

There was significant improvement in bNED survival for all patients divided by a dose above or below 71 Gy (p = 0.007) and a marginal improvement above or below 73 Gy (p = 0.07). Subdividing by pretreatment PSA level showed no benefit to the PSA < 10 ng/ml group at the higher dose but there was a significant improvement at 71 and 73 Gy for pretreatment PSA 10-19.9 ng/ml (p = 0.03 and 0.05, respectively) and for pretreatment PSA > or = 20 ng/ml (p = 0.003 and 0.02, respectively).

CONCLUSIONS

Increasing dose above 71 or 73 Gy did not result in improved bNED survival for patients with pretreatment PSA < 10 ng/ml at 2 or 3 years. Further dose escalation studies may not be useful in these patients. A significant improvement in bNED survival was noted for patients with pretreatment PSA > or = 10 ng/ml treated above 71 or 73 Gy; further dose escalation studies are warranted.

A pilot survey of sexual function and quality of life following 3D conformal radiotherapy for clinically localized prostate cancer

PURPOSE

To assess the impact of high dose three-dimensional conformal radiotherapy (3D CRT) for prostate cancer on the sexual function-related quality of life of patients and their partners.

METHODS AND MATERIALS

Sixty of 124 consecutive patients (median age 72.3 years) treated with 3D CRT for localized prostate cancer were surveyed and reported being potent prior to treatment. The answers to survey questions assessing the impact of quality of life related to sexual function from these 60 patients and their partners forms the basis for this retrospective analysis.

RESULTS

Following 3D CRT, 37 of 60 patients (62%) retained sexual function sufficient for intercourse. Intercourse at least once per month was reduced from 71 to 40%, whereas intercourse less than once per year increased from 12 to 35%. Following treatment, 25% of patients reported that the change in sexual dysfunction negatively affected their relationship or resulted in poor self-esteem. This outcome was associated with impotence following treatment (p < 0.01). Patients who had partners and satisfactory sexual function appeared to be at a higher risk of having a negatively affected relationship or losing self-esteem if they become impotent (p < 0.05). Partners of patients who reported a negatively affected relationship or loss of self-esteem appear to be less likely to return the survey instrument used (p = 0.02).

CONCLUSIONS

More work is needed to evaluate the impact of radiotherapy and other treatments on the quality of life of patients and their partners to allow adequate informed consent to be given.

Do the results of systematic biopsies predict outcome in patients with T1-T2 prostate cancer treated with radiation therapy alone?

OBJECTIVES

The present study examines whether findings from systematic biopsies add any prognostic information in men with clinical Stage T1-T2 prostate cancer treated with external beam radiation therapy alone.

METHODS

Seventy-two men with clinical T1-T2 prostate cancer had ultrasound-guided quadrant or sextant prostate biopsies prior to treatment with external beam radiotherapy alone between January 1, 1988 and December 31, 1993. The median follow-up is 23 months (range, 11 to 65). Biochemical failure after irradiation was defined as a prostate-specific antigen (PSA) greater than 1.5 ng/mL (Hybritech assay) and rising.

RESULTS

The biochemical relapse-free survival was 90% at 36 months. The percentage of biopsies involved by cancer was not predictive of biochemical relapse-free survival on univariate analysis. Patients with less than 50% positive biopsies had similar biochemical relapse-free survival at 36 months compared to patients with 50% or more positive biopsies (93% versus 89%; P = 0.80). After stratifying according to pretreatment PSA level, the percentage of positive biopsies was not prognostic. A multivariate analysis demonstrated that pretreatment PSA level was the only variable that predicted relapse-free survival (P = 0.01).

CONCLUSIONS

At present, the results of ultrasound-guided quadrant or sextant biopsies do not add further prognostic information, beyond that provided by the pretreatment PSA level, in patients with T1-T2 prostate cancer treated with radiation therapy alone. Further follow-up will be required to confirm these results.

Lateral rectal shielding reduces late rectal morbidity following high dose three-dimensional conformal radiation therapy for clinically localized prostate cancer: further evidence for a significant dose effect

PURPOSE

Using conventional treatment methods for the treatment of clinically localized prostate cancer central axis doses must be limited to 65-70 Gray (Gy) to prevent significant damage to nearby normal tissues. A fundamental hypothesis of three-dimensional conformal radiation therapy (3DCRT) is that, by defining the target organ(s) accurately in three dimensions, it is possible to deliver higher doses to the target without a significant increase in normal tissue complications. This study examines whether this hypothesis holds true and whether a simple modification of treatment technique can reduce the incidence of late rectal morbidity in patients with prostate cancer treated with 3DCRT to minimum planning target volume (PTV) doses of 71-75 Gy.

METHODS AND MATERIALS

The 257 patients with clinically localized prostate cancer who completed 3DCRT by December 31, 1993 and received a minimum PTV dose of 71-75 Gy are included in this report. The median follow-up time was 22 months (range: 4-67 months); 98% of patients had follow-up of longer than 12 months. The calculated dose at the center of the prostate was < 74 Gy in 19 patients, 74-76 Gy in 206 patients, and > 76 Gy in 32 patients. Late rectal morbidity was graded according to the Late Effects Normal Tissue (LENT) scoring system. Eighty-eight consecutive patients were treated with a rectal block added to the lateral fields. In these patients the posterior margin from the prostate to the block edge was reduced from the standard 15 to 5 mm for the final 10 Gy, which reduced the dose to portions of the anterior rectal wall by approximately 4-5 Gy. Estimates of rates for rectal morbidity were determined by Kaplan-Meier actuarial analysis. Differences in morbidity percentages were evaluated by the Pearson chi-square test.

RESULTS

Grade 2-3 rectal morbidity developed in 46 out of 257 patients (18%) and in the majority of cases consisted of rectal bleeding. No patient has developed Grade 4 or 5 rectal morbidity. The actuarial rate of Grade 2-3 morbidity is 23% at 24 months and the median time to the development of Grade 2-3 complications is 15 months. A statistically significant dose effect is evident. The incidence of Grade 2-3 rectal morbidity increased as the dose at the center of the prostate increased (p = 0.05). In patients receiving minimum PTV doses of < or = 76 Gy the use of a rectal block significantly reduced the incidence of Grade 2-3 toxicity; 6 out of 88 (7%) with a block vs. 30 out of 137 (22%) without a block, (p = 0.003).

CONCLUSION

The incidence of late rectal morbidity with 3DCRT to minimum PTV doses of 71-75 Gy is acceptable and to date no Grade 4-5 rectal morbidities have been observed. In our experience, higher doses to the center of the prostate are associated with an increased likelihood of developing Grade 2-3 rectal morbidity but treatment techniques that reduce the total dose to the anterior rectal wall have reduced the incidence of late rectal morbidity. If clinical studies indicate improved tumor control with minimum PTV doses above 71 Gy, then dose escalation above 76 Gy to the center of the prostate should be pursued cautiously with treatment techniques that limit the total dose to the anterior rectal wall.

Accuracy of pelvic radiotherapy: prospective analysis of 90 patients in a randomised trial of blocked versus standard radiotherapy

The aim of this study was to assess the accuracy of pelvic radiotherapy during a trial of blocked radiotherapy at the Royal Marsden Hospital, UK. Prospective evaluation was performed on 90 patients receiving CT planned pelvic radiotherapy using weekly anterior-posterior and lateral portal films. Field placement errors (FPEs) were calculated by comparing field centres of each film with a designated point of interest. Data was evaluated to calculate the overall treatment simulator differences, the number of error free treatments, and mean treatment-simulator position and to evaluate the role of systematic versus random errors. Age, weight, disease site, position of treatment, fractionation, blocked versus conventional techniques were assessed for their effect on treatment accuracy. The mean absolute error between treatment and simulator films was anterior right-left (ARL) 0.25 cm, anterior superior-inferior (ASI) 0.32 cm, lateral anterior-posterior (LAP) 0.42 cm, and lateral superior-inferior (LSI) 0.28 cm. On average the field centre was displaced by 0.66 cm (standard deviation, S.D. = 0.34) from that intended. On each treatment day 29% of anterior films and 45% of lateral films had at least one 0.5 cm error. Overall 59% of treatments had at least one 0.5 cm error and 9% a 1.0 cm error. The field centre was more than 0.5 cm from the position intended in 66% of treatments and over 1 cm for 14% of treatments. Analysis of variance showed that both random and systematic errors occurred in all directions. Though random errors were of similar magnitude in all direction (variance sigma 2 = 0.06-0.09 cm2); systematic errors showed a 4-fold variation being greatest in the LAP direction (sigma 2 = 0.19 cm2) and least the ARL direction (sigma 2 = 0.048 cm2). No factor consistently predicted for worse outcome in all directions. Hypofractionated treatments were less accurate in the LSI direction (P > 0.05). Systematic errors were associated in the ARL direction with hypofractionation (P < 0.01) and, in the LSI direction with weight (P < 0.03) and age (P < 0.05). We conclude that significant random and systematic errors can occur during pelvic radiotherapy especially in the LAP direction. These results suggest that in the absence of a customised immobilisation device, to cover 95% of errors, margins of 0.6 cm for RL and SI directions and 0.9 cm for AP direction should be allowed between the planning and clinical target volumes. However, ideally, each centre should determine their own margin requirements according to local clinical practice.

Prostate carcinoma patients upstaged by imaging and treated with irradiation. An outcome-based analysis

BACKGROUND

The American Joint Committee on Cancer (AJCC) staging of prostate cancer relies upon digital rectal examination (DRE) findings, but suggests using all available information, including prostate imaging studies, prior to definitive treatment of prostate carcinoma. We have studied whether patients upstaged by imaging have a different outcome after treatment with external beam radiation therapy (RT) from those not upstaged.

METHODS

The records of 499 men with clinically localized adenocarcinoma of the prostate treated with only definitive external beam irradiation from January 1986 to December 1993 were reviewed. The 348 patients with any one or a combination of the following pretreatment imaging studies were considered eligible; transrectal ultrasound (TRUS), pelvic MRI, or endorectal MRI. Patients were assigned two clinical stages: one based upon palpation criteria alone (palpation stage) and the other allowing for any upstaging by imaging abnormalities (AJCC or imaging stage). The Kaplan-Meier method was used to estimate biochemical no evidence of disease (bNED) survival where a failure was defined as a prostate specific antigen (PSA) greater than 1.5 and increasing. Differences in outcome were evaluated by the log-rank test.

RESULTS

Overall upstaging by TRUS or MRI to any higher stage occurred in 115 of 312 palpation T1c-T2c patients (37%). These upstaged patients had an unexpected improvement in bNED survival (84% vs. 71%, P = 0.05) compared with those who were not upstaged due to the upstaged patients having a significantly greater number with a pretreatment PSA < 10 ng/mL. T1c patients were upstaged by imaging in 81% of the 94 patients. The 36-month bNED survival of palpation T1c and imaging T2 patients was similar (88% vs. 88%, P = NS), but both were significantly improved compared with the 36-month bNED survival for palpation T2 patients (88% vs. 71%, P = 0.04). There was no significant difference in 36-month bNED survival for imaging T2c (bilobar disease) patients compared with their original palpation stage disease. Upstaging to T3 occurred in 10% of palpation T1c-T2c patients. There was no difference in 36-month bNED survival for the imaging T3 patients compared with their original palpation stage (84% vs. 71%, respectively, P = 0.04). There was a significant improvement in the 36-month bNED survival for imaging T3 patients compared with palpation T3 patients (84% vs. 50% respectively, P = 0.01). Multivariate analysis demonstrated palpation stage to be a significant predictor of bNED survival (P = 0.001), while AJCC stage (including imaging) is not predictive.

CONCLUSIONS

Using the endpoint of bNED survival, upstaging by TRUS/MRI does not separate prostate cancer patients treated with RT into groups with different prognoses. Upon multivariate analysis, palpation stage alone, not AJCC stage including imaging upstaging, is a significant predictor of bNED survival.

Orchidectomy prior to definitive radiotherapy for localized prostatic cancer

PURPOSE

To identify potential survival benefits of cytoreductive orchidectomy performed prior to definitive radiation for localized prostate cancer.

METHODS AND MATERIALS

Between 1977-1988, all patients with localized prostatic cancer from the Wellington Region received definitive radiotherapy (n = 200). One referring urologist Peter M. Meffen (P.M.M.) had commenced a program of prior orchidectomy followed by definitive radiation treatment (median time to radiation therapy was 5 months, n = 30).

RESULTS

Five-year overall survival (OS) and relapse-free survival (RFS) for each stage were Stage A 82%, and 82%; Stage B 75%, and 61%; Stage C 57%, and 38%, respectively. Ten-year OS and RFS for each stage were Stage A 78%, and 72%; Stage B 51%, and 18%; Stage C 32% and 0%, respectively. Multivariate analysis identified prior orchidectomy treatment and histological grade as independently significant prognostic factors for OS and RFS. Factors influencing RFS were clinical stage, prior orchidectomy, and histological grade. Prior orchidectomy was associated with an increase in OS at 5 years when compared to those patients receiving radiotherapy alone, 86% vs. 69%, and maintained at 10 years, 82% vs. 46% (p < 0.05). The two groups were comparable by stage, histological grade, and age. There were no changes in the referral pattern during the study period.

CONCLUSIONS

Our results suggest that prior cytoreduction by orchidectomy has a beneficial effect on OS and RFS for patients with localized prostate cancer. It is unclear whether survival benefits are due to the cytoreductive therapy, the adjuvant therapy, or a combination of both. Further study in this area is warranted, ideally in the form of randomized prospective clinical trials.

Conventional vs. conformal radiotherapy for prostate cancer: preliminary results of dosimetry and acute toxicity

PURPOSE

To compare conformal radiotherapy using three dimensional treatment planning (3D-CRT) to conventional radiotherapy (Conven-RT) for patients with Stages T2-T4 adenocarcinoma of the prostate.

METHODS AND MATERIALS

A Phase III randomized study was activated in May 1993, to compare treatment toxicity and patient outcome after 78 Gy in 39 fractions using 3D-CRT to that after 70 Gy in 35 fractions using Conven-RT. The first 46 Gy were administered using the same nonconformal field arrangement (four field) in both arms. The boost was given nonconformally using four fields in the Conven-RT arm and conformally using six fields in the 3D-CRT arm. The dose was specific to the isocenter. The first 60 patients, 29 in the 3D-CRT arm and 31 in the Conven-RT arm, are the subject of this preliminary analysis.

RESULTS

The two treatment arms were first compared in terms of dosimetry by dose-volume histogram analysis. Using a subgroup of patients in the 3D-CRT arm (n=15), both Conven-RT and 3D-CRT plans were generated and the dose-volume histogram data compared. The mean volumes treated to doses above 60 Gy for the bladder and rectum were 28 and 36% for the 3D-CRT plans, and 43 and 38% for the Conven-RT plans, respectively (p < 0.05 for the bladder volumes). The mean clinical target volume (prostate and seminal vesicles) treated to 95% of the prescribed dose was 97.5% for the 3D-CRT arm, and 95.6% for the Conven-RT arm (p < 0.05). There were no significant differences in the acute reactions between the two arms, with the majority experiencing Grade 2 or less toxicity (92%). Moreover, no relationship was seen between acute toxicity and the volume of bladder and rectum receiving in excess of 60 Gy for those in the 3D-CRT arm. There was also no difference between the groups in terms of early biochemical response. Prostate-specific antigen levels at 3 and 6 months after completion of radiotherapy were similar in the two treatment arms. There was only one biochemical failure in the study population at the time of the analysis.

CONCLUSIONS

Comparison of the Conven-RT and 3D-RT treatment plans revealed that significantly less bladder was in the high dose volume in the 3D-CRT plans, while the volume of rectum receiving doses over 60 Gy was equivalent. There were no differences between the two treatment arms in terms of acute toxicity or early biochemical response. Longer follow-up is needed to determine the impact of 3D-CRT on long-term patient outcome and late reactions.

A comparison of four patient immobilization devices in the treatment of prostate cancer patients with three dimensional conformal radiotherapy

PURPOSE

To determine the variability of patient positioning during three-dimensional conformal radiotherapy (3D-CRT) for prostate cancer treated with no immobilization or one of four immunobilization devices, and to determine the effects of patient body habitus and pelvic circumference on patient movement with each individual inmobilization technique.

METHODS AND MATERIALS

To see whether our immobilization techniques have improved day-to-day patient movement, a retrospective analysis was carried out. A total of 62 patients treated at one facility on a single machine with 3D-CRT via a four-field box technique (anterior-posterior and opposed laterals) in the supine position with either no immobilization or one of four immobilization devices. Five groups of patients were compared: (a) group 1-no immobilization; (b) group 2-alpha cradle from the waist to upper thigh; (c) group 3-alpha cradle from waist to below the knees; (d) group 4-styrofoam leg immobilizer (below knees); and (e) group 5-aquaplast cast encompassing the entire abdomen and pelvis to midthigh with alpha cradle immobilization to their lower legs and feet. Prior to starting radiotherapy, portal films of all four treatment fields were obtained 1 day before treatment. Subsequently, portal films were then obtained at least once a week. Portal films were compared with the simulation films and appropriate changes were made and verified on the next day prior to treatment. A deviation of greater than 0.5 cm or greater was considered to be clincally significant in our analysis. We studied the difference among the types of immobilization and no immobilization by looking at the frequency of movements (overall, and on each of the three axes) that a patient had during the course of his treatment. Using a logistic regression model, the probability of overall and individual directional movement for each group was obtained. In addition, the effects of patient body habitus and pelvic circumference on movement were analyzed.

RESULTS

The maximum deviation was 2 cm and the median deviation was 1.2 cm. For each patient, the probability of movement ranged from 0 to 76%, with a mean of 39%. There was no significant difference seen in overall movement with any of the immobilzation devices compared to no immobilization, but there was less vertical (9 vs. 18%; p = 0.03) and AP (6 vs. 15%; p = 0.14) movement with the aquaplast than any other group. However, when examining the lateral direction, the aquaplast had significantly more movement (32 vs. 9%; p < 0.001). When accounting for body habitus and pelvic circumference, no immobilization device was effective in reducing movement in obese patients or in patients with pelvic circumference greater than 105 cm. The aquaplast group had a significantly increased amount of lateral movement with obesity (42 vs. 23%; p < 0.05), and with pelvic circumference >105 cm (33 vs. 29%; p < 0.05).

CONCLUSIONS

There was no significant reduction in overall patient movement noted with any of the immobilization devices compared to no immobilization. The aquaplast group had reduced vertical and AP movement of greater than 0.5 cm. There was significantly more lateral movement with aquaplast appreciated in obese patients or patients with pelvic circumferences greater than 105 cm. The aquaplast immobilization appears to be useful in reducing movement in two very clinicaly important dimensions (AP and vertical). Despite our findings, other immobilization may still be useful especially in the treatment of nonobese patients. It is clear that the optimal immobilization technique and patient positioning are yet to be determined.

Bony landmarks are not an adequate substitute for lymphangiography in defining pelvic lymph node location for the treatment of cervical cancer with radiotherapy

PURPOSE

Curative radiotherapy (RT) for carcinoma of the cervix requires adequate irradiation of regional lymph node groups. The best nonsurgical method of defining lymph node anatomy in the pelvis remains the lymphangiogram (LAG). This study was designed to determine if bony landmarks could accurately substitute for LAG as a means of determining lymph node position for the purpose of pelvic RT treatment planning.

METHODS AND MATERIALS

The post-LAG simulation films of 22 patients treated at the Fox Chase Cancer Center for cervical cancer were examined. On anterior/posterior (A/P) simulation films, the distance of lymph nodes was determined from the top, middle, and bottom of the sacroiliac joint, and at the pelvic rim, 1 and 2 cm above the acetabulum. On lateral (LAT) simulation films, lymph node position was measured at points 0, 4, and 8 cm along a line from the bottom of L5 to the anterior aspect of the pubic symphysis. Positive values represent lateral and anterior distances relative to the reference point on A/P and LAT films, respectively. Negative values represent distances in the opposite direction. The adequacy of standard pelvic fields as defined by the Gynecologic Oncology Group (GOG) (A/P: 1.5 cm margin on the pelvic rim; LAT field edge is a vertical line anterior to the pubic symphysis) was also examined. Data are expressed as the mean +/- two standard deviations, (i.e. 95% confidence level).

RESULTS

On A/P simulation films, the distance of visualized lymph nodes had mean values of -1.6 +/- 1.7 cm (range -4.1 to -0.4 cm), -1.3 +/- 1.5 cm (range -3.4 to 0.0 cm), and 1.2 +/- 1.8 cm (range -1.0 to 2.6 cm) from the sacro-iliac (SI) joint at the superior, middle, and inferior points, respectively. The mean distance of the nodes from the pelvic rim at points 1 and 2 cm above the acetabulum was 0.3 +/- 1.2 cm (range -0.6 to 1.8 cm) and 0.2 +/- 1.8 cm (range -1.6 to 2.1 cm), respectively. On LAT simulation films, the distance of lymph nodes from points 0, 4, and 8 cm from the previously described reference line had mean values of 2.0 +/- 1.0 cm (range 1.3 to 3.0 cm), 0.9 +/- 3.9 cm (range -1.9 to 5.1 cm), and 1.8 +/- 2.1 cm (range -0.8 to 3.5 cm), respectively. Ten of 22 (45%) patients would have had inadequate nodal irradiation if their fields had been designed according to standard GOG parameters. In all cases, these incompletely irradiated lymph nodes were from the lowest of the lateral external iliac group.

CONCLUSION

Great variability in pelvic lymph node location is demonstrated when LAG is used to directly visualize their location. Bony structures are inaccurate landmarks for pelvic lymph node position. The GOG standard pelvic fields are not consistently adequate to cover all lateral external iliac lymph nodes, although the clinical significance of this subgroup of lymph nodes is not known. At this time, LAG remains the ideal radiographic modality to define anatomic location of regional lymph nodes for pelvic RT treatment planning. The clinical importance of the most lateral group of external iliac lymph nodes in various stages of cervical cancer represents a potential area of future research.

Adverse effects after radical external beam radiotherapy of localized prostatic adenocarcinoma using two-dimensional dose-planning and a limited field technique

Adverse effects were assessed after definitive limited field, 2-dimensional CT-planned radiation treatment of localized prostatic adenocarcinoma. In 66 surviving patients, out of a total of 176 treated patients, personal interviews were performed and self-administered questionnaires distributed. The average follow-up was 6.6 years. Adverse effects with regard to bowel function and micturition were investigated, and graded 0-4 with increasing severity and impact on performance status, essentially according to the RTOG toxicity scoring system. Sexual functions were registered on visual analogue scales. The majority of adverse effects were considered minor (grade 1) and did not require any treatment. Late adverse effects on bowel and bladder or urethra that required treatment (grade 2-4) were reported in up to 8% (n = 5) of cases respectively. Late bowel side-effects that interfered with life style (grade 3-4) occurred in up to 3% (n = 2) of patients; the majority were rectal complications. Corresponding urinary side-effects were registered in up to 6% (n = 4) of the patients. Major surgical interventions were not required. Sexual functions were substantially affected in 60% of cases not administered endocrine treatment. Multivariate analyses could not identify patient or treatment risk factors related to complications.

The potential for normal tissue dose reduction with neoadjuvant hormonal therapy in conformal treatment planning for stage C prostate cancer

PURPOSE

Preirradiation hormonal cytoreduction of prostate cancer has been proven to reduce exposure of normal structures by decreasing the size of the target volume. Dose-volume histogram (DVH) analysis, however, does not always appear to demonstrate a strong positive benefit with the use of neoadjuvant hormone therapy. This study analyzes various other factors influencing dose to normal organs, which may determine the success or failure of neoadjuvant hormonal therapy in achieving its goals.

METHODS AND MATERIALS

Patients with bulky clinical Stage C adenocarcinoma of the prostate were given 3 months of hormone treatment consisting of oral Flutamide and monthly Zoladex injections prior to irradiation. Computerized tomography (CT) scans of the pelvis were obtained both prior to and following hormonal treatment. Treatment plans were generated by three-dimensional (3D) conformal treatment planning. The change in the volume of the prostate was assessed along with the percentage of prescribed dose delivered to the rectum and bladder. Various factors such as prostate size, bladder/rectum size, and organ shape were studied. Both dose-volume histograms (DVH) and dose-surface area histograms (DSH) were used for analysis.

RESULTS

Six of seven patients had reduction in the size of their prostates. The mean volumes of the prostate before and after hormonal manipulation were 129.1 +/- 32.9 standard deviation (SD) cm3 and 73.0 +/- 29.5 SD cm3, respectively (p = 0.0059). The volume of rectum receiving 80% of the prescribed dose was reduced in five of seven patients from a mean of 83.2 to 59.9 cm3 (p = 0.045). The volume of bladder receiving 80% of the prescribed dose was also reduced in five out of seven patients from a mean of 74.5 to 40.2 cm3 (p = 0.098). Correlation between the size of the prostate and volume of rectum and bladder treated was not always consistent: greater reduction in prostate size did not necessarily result in large decreases in dose to bladder or rectum. The total size of the bladder and rectum were found to be important factors in normal tissue radiation exposure; the benefits of hormone therapy may be lost if the bladder and rectum are allowed to decrease in size. Also, the bladder may be prone to sagging into the pelvis of some patients following hormone therapy, resulting in a less optimal therapeutic ratio.

CONCLUSION

Reduction in prostate size by neoadjuvant hormonal manipulation does decrease the amount of normal tissue irradiated in most patients. However, the correlation between the reduction in prostate size and amount of rectum or bladder treated is not linear if other variables are not controlled. Factors such as the shape of the organs, as well as the distensible nature of the bladder and rectum, play major roles in dose to normal tissues. These facts may mask the benefits of cytoreduction and could be obstacles in realizing consistent benefits from preirradiation hormonal treatment in the clinical setting if they are ignored.

Evaluation of changes in the size and location of the prostate, seminal vesicles, bladder, and rectum during a course of external beam radiation therapy

PURPOSE

To document the size and location of the prostate, seminal vesicles, bladder, and rectum throughout the course of external beam radiotherapy. The frequency and range of motion of these organs are quantified.

METHODS AND MATERIALS

Ten patients with localized carcinoma of the prostate had conventional simulation followed immediately by a treatment planning computed tomography scan (TPCT0). Once treatment was initiated, each patient had a weekly CT (TPCT1-N) before or after his daily treatment. Anatomical structures from CT were delineated on a computer workstation for analysis. The serial CT sets were spatially registered to the initial scan using image correlation software that brings into congruence the bony pelvis of the different scans. The location of the prostate, seminal vesicles, bladder, and rectum on subsequent scans were compared to TPCT0, as well as to each other.

RESULTS

Prostate volumes were observed to vary by an average of +/- 10% during the course of radiation therapy, while the seminal vesicle volumes varied by as much as 100%. Bladder and rectal volumes varied by +/- 30%. Compared to TPCT0, movement of the prostate was demonstrated in all patients. Quantitation of the center-of-mass (CM) showed motion of less than 1 mm in the left-right direction, while motion ranging from 0 to +/- 1 cm was observed in the anterior-posterior and superior-inferior directions. The individual standard deviations of these motions varied from approximately 1-5 mm. These variations were correlated to changes in the dimensions of the bladder and rectum.

CONCLUSIONS

Changes in the location of the prostate, seminal vesicles, and normal tissue volumes during the course of radiation therapy occur and have dosimetric consequences that may impact tumor control and normal tissue complication probabilities. Conformal therapy for prostate cancer will require the incorporation of knowledge of the anatomic relationships of these structures as a function of time. Therefore, these uncertainties must be taken into account when designing treatment plans and in considering dose escalation trials.

Localization of the prostatic apex for radiation treatment planning

PURPOSE

To determine whether retrograde urethrogram, or the combination of computed tomography (CT) scan/retrograde urethrogram is more accurate for locating the magnetic resonance imaging (MRI) designated prostatic apex, and to determine whether patients treated in our department with CT/urethrogram are receiving the prescribed minimal dose to the MRI identified prostatic apex.

METHODS AND MATERIALS

Seventeen patients with early stage prostate cancer were enrolled in a prospective study to determine the location of the prostatic apex. All of the patients agreed to undergo MRI in addition to retrograde urethrogram, and CT of the pelvis for three dimensional (3D) treatment planning. The prostatic apex was identified on each of the studies and measured from a reference point (the most superior portion of the pubic symphysis). The location of the prostatic apex as measured by retrograde urethrogram alone and by CT/urethrogram was compared to the location of the prostatic apex as measured by MRI. Because of MRI's ability for multiplanar capabilities, and high soft tissue contrast in the region of the prostate, it was assumed to be more accurate for identifying the location of the prostatic apex, and was used as the gold standard.

RESULTS

The location of the prostatic apex as determined by the urethrogram alone was on average 5.8 mm caudad to the location on MRI (p = 0.012), while the location of the prostatic apex as determined by CT/urethrogram was 3.1 mm caudad to the location on MRI (p = 0.150). If the prostatic apex is defined at 12 mm instead of 10 mm above the urethrogram tip, the statistically significant difference between the urethrogram and the MRI is no longer present. Based on these results, all 17 patients received the minimum prescribed dose to the prostatic apex.

CONCLUSION

CT/urethrogram correlates better with the location of the MRI determined prostatic apex, than does the urethrogram alone. Locating the prostatic apex 12 mm above the urethrogram tip better localizes the prostatic apex, while also avoiding the error that can potentially lead to a geographic miss. This in fact assures that all of our patients receive the minimum prescribed dose to this critical site of extraprostatic extension, while also decreasing the amount of normal tissue that is included in the treatment volume.

Prostate motion during standard radiotherapy as assessed by fiducial markers

From November 1993 to August 1994, 55 patients with localized prostate carcinoma had three gold seeds placed in the prostate under transrectal ultrasound guidance prior to the start of radiotherapy in order to track prostate motion. Patients had a planning CT scan before initial simulation and again at about 40 Gy, just prior to simulation of a field reduction. Seed position relative to fixed bony landmarks (pubic symphysis and both ischial tuberosities) was digitized from each pair of orthogonal films from the initial and boost simulation using the Nucletron brachytherapy planning system. Vector analysis was performed to rule out the possibility of independent seed migration within the prostate between the time of initial and boost simulation. Prostate motion was seen in the posterior (mean: 0.56 cm; SD: 0.41 cm) and inferior directions (mean: 0.59 cm; SD: 0.45 cm). The base of the prostate was displaced more than 1 cm posteriorly in 30% of patients and in 11% in the inferior direction. Prostate position is related to rectal and bladder filling. Distension of these organs displaces the prostate in an anterosuperior direction, with lesser degrees of filling allowing the prostate to move posteriorly and inferiorly. Conformal therapy planning must take this motion into consideration. Changes in prostate position of this magnitude preclude the use of standard margins.

Potency following high-dose three-dimensional conformal radiotherapy and the impact of prior major urologic surgical procedures in patients treated for prostate cancer

PURPOSE

To assess the impact of high-dose three-dimensional conformal radiotherapy (3DCRT) on potency in patients treated for clinically localized prostate cancer and to identify factors that might predict the outcome of sexual function following treatment.

METHODS AND MATERIALS

One hundred twenty-four consecutive patients treated with 3DCRT for localized prostate cancer at UCSF between 1991-1993 were included in this retrospective analysis. Patient responses were obtained from a mailed questionnaire, telephone interviews, or departmental records. Medial follow-up was 21 months.

RESULTS

Sixty patients reported having sexual function prior to 3DCRT, including 47 who were fully potent and 13 who were marginally potent. Of the remaining 64 patients, 45 were impotent, 7 were on hormones, 1 was status-postorchiectomy, and 11 were not evaluable. Following 3DCRT, 37 of 60 patients (62%) retained sexual function sufficient for intercourse. Of those with sexual function before irradiation, 33 of 47 (70%) of patients fully potent and 4 of 13 (31%) of patients marginally potent maintained function sufficient for intercourse (p < 0.01). Potency was retained in 6 of 15 (40%) patients with a history of a major urologic surgical procedure (MUSP) and in 31 of 45 (69%) with no history of a MUSP (p < 0.04). Transurethral resection of the prostate was the MUSP in eight of these patients, with four (50%) maintaining sexual function.

CONCLUSIONS

Patients who receive definitive 3DCRT for localized prostate cancer appear to maintain potency similar to patients treated with conventional radiotherapy. However, patients who are marginally potent at presentation or who have a history of a MUSP appear to be at increased risk of impotence following 3DCRT.

Three-dimensional treatment planning and conformal radiation therapy: preliminary evaluation

Preliminary clinical results are presented for 209 patients with cancer who had treatment planned on our three-dimensional radiation treatment planning (3-D RTP) system and were treated with external beam conformal radiation therapy. Average times (min) for CT volumetric simulation were: 74 without or 84 with contrast material; 36 for contouring of tumor/target volume and 44 for normal anatomy; 78 for treatment planning; 53 for plan evaluation/optimization; and 58 for verification simulation. Average time of daily treatment sessions with 3-D conformal therapy or standard techniques was comparable for brain, head and neck, thoracic, and hepatobiliary tumors (11.8-14 min and 11.5-12.1, respectively). For prostate cancer patients treated with 3-D conformal technique and Cerrobend blocks, mean treatment time was 19 min; with multileaf collimation it was 14 min and with bilateral arc rotation, 9.8 min. Acute toxicity was comparable to or lower than with standard techniques. Sophisticated 3-D RTP and conformal irradiation can be performed in a significant number of patients at a reasonable cost. Further efforts, including dose-escalation studies, are necessary to develop more versatile and efficient 3-D RTP systems and to enhance the cost benefit of this technology in treatment of patients with cancer.

Conformal treatment of prostate cancer with improved targeting: superior prostate-specific antigen response compared to standard treatment

PURPOSE

Conformal radiation therapy (CRT) decreases the morbidity of prostate cancer treatment, but no published data attest to the improved ability of CRT to control disease. Therefore, we compared Prostate-Specific Antigen (PSA) response at 1 year among similarly staged patients treated by conformal techniques to those treated with conventional approaches, looking for an early indicator of tumor response.

METHOD AND MATERIALS

Patients with locally advanced disease were treated by pelvic field followed by prostate field conedowns; those with early stage/low grade disease received only prostate field irradiation. Between October, 1987 and November, 1991, conventional treatments used rectangular beams with or without corner blocks. Neither urethrography nor immobilization casts were used for conventionally treated patients. Between April, 1989 and December, 1992, conformal treatments have used rigid immobilization and Computed Tomography-based, beams-eye-view field design. As such, our conformal approach allowed improved targeting. Median prescribed doses (minimal doses to the Planning Target Volume) were 70 Gy (66-73 Gy) and 70.2 Gy (64.8-75 Gy) for conventionally and conformally treated patients, respectively. Median daily fraction size was 1.8 Gy for conventional treatment and 2.0 Gy for conformal therapy. Baseline PSA data were available on 170 consecutive patients treated conformally and 90 consecutive patients treated conventionally.

RESULTS

Among those receiving only prostatic field irradiation, 12-month PSA values returned to normal in 96% and 85% of conformally and conventionally treated patients, respectively, when normalization was defined as < or = 4 ng/ml (p < 0.03) and in 76% vs. 55% of patients when PSA normalization was defined as < or = 1.5 ng/ml (p < 0.02). Among those receiving pelvic irradiation prior to prostatic conedown, PSA normalization (< or = 4 ng/ml) occurred in 82% and 61% (p < 0.01) of conformally and conventionally treated patients, respectively, and in 56% vs. 38% of patients when normalization was defined as < or = 1.5 ng/ml (p < 0.05). In a multivariate analysis, pretreatment PSA level (< or = 15 vs. > 15), and the use of conformal irradiation were statistically significant prognostic discriminants of PSA normalization at 1 year while total irradiation dose, clinical stage, and the addition of pelvic fields were not significant.

CONCLUSIONS

As measured by PSA normalization, conformal techniques with improved targeting produced responses that were significantly better than conventional techniques among patients treated with definitive irradiation. These results, coupled with our previously documented reduction of acute and chronic sequelae, support the continued use of CRT as a more effective method of treatment for prostate cancer.

Potential benefit of improved local tumor control in patients with prostate carcinoma

BACKGROUND

In the case of prostate carcinoma, radiation therapy is a locally applied treatment modality in a malignancy known for systemic dissemination. Because significant efforts and resources currently are being consumed to improve local tumor control, failure patterns and potential curative gain deserve appropriate assessment.

METHODS

From 1975-1989, 647 patients with clinically localized prostate carcinoma were definitively irradiated for biopsy-proven adenocarcinoma of the prostate. Failure patterns were examined, and survival advantage based on improvement in either local or distant disease control was calculated. Distant metastatic rate and cause-specific survival analyses were used as parameters by which to compare the outcome for patients in whom local tumor control was achieved with patients who experienced local failure, thereby assessing further the importance of the effectiveness of locally applied therapy.

RESULTS

Three hundred ninety-two (61%) patients at the time of this writing were clinically disease free. Sixty-two (10%) patients failed locally only, 133 (20%) distantly only, and 60 (9%) developed local and distant recurrent disease. Both local and distant failure rates were higher in patients with more advanced stage lesions at presentation, and distant failure rates significantly increased in patients with less differentiated tumors. Pretreatment prostate-specific antigen was found to be useful in predicting recurrence patterns. Overall, there appeared to be more potential for improvement in survival secondary to reducing distant metastasis. The distant survival advantage (DSA) of reducing distant metastases, compared with the local survival advantage (LSA) of improving local tumor control, was 26 versus 14%. Although DSA was greater than LSA within each stage category, the potential to improve survival was most significant in the Stage C group, where DSA was 35% and LSA 16%. Although LSA varied little according to tumor grade, DSA was dependent on tumor grade and varied from 13% for well differentiated lesions to 38% for poorly differentiated lesions. Distant failure free survival at 10 years was 63% for patients with local control and 45% for those with local failure (P = 0.01). Similarly, 10-year cause-specific survival was 75% in locally controlled patients compared with 48% for those with local recurrence (P < 0.001).

CONCLUSIONS

Although better local tumor control should translate into at least modest survival gain for patients with prostate carcinoma, additional advantage may be seen with improved systemic therapy or perhaps earlier diagnosis to reduce further the distant metastasis rate.

Do the current subclassifications of stage T3 adenocarcinoma of the prostate have clinical relevance?

OBJECTIVES

To compare the outcome of patients with T3a and T3c adenocarcinoma of the prostate and determine the utility of these substages as defined in the current American Joint Committee on Cancer and the International Union Against Cancer (AJCC/UICC) staging system.

METHODS

An analysis was performed of patients with T3 (clinical) prostate cancer treated with definitive irradiation at the Fox Chase Cancer Center between 1986 and 1993. The series was composed of 66 patients with T3a tumors and 44 patients with T3c tumors. The endpoints studied included freedom from biochemical relapse (bNED) and rates of clinical local and distant failure.

RESULTS

No statistically significant differences in freedom from biochemical relapse were observed when comparing patients with T3a and T3c disease (3 years bNED, 41%; difference not significant). Similarly, there was no difference in the patterns of clinical failure at 3 years when comparing patients with T3a and T3c disease (21% clinically detected distant metastases; < 10% local failure in either group). In a multivariate analysis, only a low baseline prostate-specific antigen (PSA) (eg, 20 ng/mL or less) independently predicted the likelihood of remaining biochemically free of disease.

CONCLUSIONS

Anatomic substaging that is based on the findings of the digital rectal examination does not distinguish meaningful prognostic substages among patients with T3 disease. PSA should be used to establish biochemical substaging of patients who present with T3 prostate cancer.

Primary radiation therapy in the treatment of localized prostatic cancer

Prostatic carcinoma is one of the leading causes of male cancer deaths. However, the routine diagnostic and therapeutic strategies have not yet been established. Although the outcome of surgical and radiotherapeutical approaches has frequently been reported to be comparable, the profile of side effects is different. This could offer the basis for selecting the treatment of choice in individual cases. During the last decade the radiotherapeutical technique has markedly improved, in part due to the achievements in the field of computer assisted tomography planning and conformal technique; the outcome of side-effects has decreased with concurrent increase in the rate of local control. The prescribing, recording and reporting of irradiation have also recently developed, as well as the staging of the disease. Therefore we consider it timely to review progress in this subject and to emphasize the role of radiotherapy in the treatment of localized prostatic cancer.

Radiotherapy of prostate cancer: established results and new developments

Radical radiotherapy has been established as an effective modality for eradicating localised prostate cancer. No satisfactory comparisons have been made with patients treated by total prostatectomy, but in surgically staged patients with negative lymph nodes survival after radiotherapy exceeds that of an aged matched population, cancer deaths occurring in only 6-15% of patients and 85% remaining free of local recurrence after 10 years. Results are predictably less satisfactory in surgically unstaged cases and for more advanced localised presentations. Nevertheless, radical radiotherapy achieves local control of disease in the majority of patients. Improved local control may be obtained by increasing radiation dose but at the expense of increased radiation-induced side-effects. Conformal radiotherapy and combined modality treatment with the neoadjuvant or adjuvant androgen deprivation show considerable promise as novel methods to improve the therapeutic ratio, and prospective randomised studies are underway to test these approaches.