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

Self-assessment questionnaire for evaluating urinary and intestinal late side effects after pelvic radiotherapy in patients with prostate cancer compared with an age-matched control population

BACKGROUND

Pelvic irradiation to patients with prostate cancer is accompanied by urinary and intestinal reactions. In men older than 60 years, treatment-induced problems should be evaluated in relation to problems in an age-matched nonirradiated population.

METHODS

In the present study, problems in the urinary tract and intestine were evaluated with a self-assessment questionnaire using the linear-analogue scale. The questionnaire was mailed out to 200 patients and to an age-matched population 24-56 months after irradiation.

RESULTS

Twenty-five percent of the control group and 50% of the patient group reported some kind of problem in the urinary tract. The most common urinary problems in the control group and in the patient group, respectively, were urgency (19 and 42%), starting problems (22 and 33%), and leakage (11 and 32%). In the control and patient groups, 14 and 59%, respectively, reported some kind of gastrointestinal problems. The most common intestinal problems in the control and patient groups were respectively, mucus (4 and 38%), cramp (5 and 14%), leakage (2 and 27%), and blood (2 and 36%). Ninety percent of the patients' problems were minor.

CONCLUSION

Pelvic irradiation induced a relatively large number of minor problems, evaluated with a self-assessment questionnaire and compared with an age-matched population of men, of approximately similar magnitude as with a physician's systematic evaluation. The most important urinary factors were urgency and leakage. The most important intestinal factors were blood, mucus, and leakage. The results support the ongoing efforts to use 3-D computed tomography-based conformal therapy to decrease irradiation dose to the rectum and bladder.

Early prostate cancer: the national results of radiation treatment from the Patterns of Care and Radiation Therapy Oncology Group studies with prospects for improvement with conformal radiation and adjuvant androgen deprivation

Long-term outcome of the Patterns of Care Study and the Radiation Therapy Oncology Group are used to demonstrate the national average results of treating early prostate cancer in the United States. A group of patients with stage T1B2 disease and pathologically negative lymph nodes showed excellent 10-year survival rates and freedom from clinical evidence of disease, while prostate specific antigen (PSA) correlations in 10-year survivors indicate that 88% were clinically free of cancer and had a PSA level of less than 4.0 mg./nl., and 65% had a PSA level of less than 1.5 ng./ml. The latter group represented clinical and biochemical cures. The improvement noted in outcome of locally advanced prostate cancer treatment by Radiation Therapy Oncology Group prospective trials combining androgen deprivation and radiation therapy is presented. These trials will be extended to the poor prognosis group with stage T1,2 disease. The advantages of conformal therapy in acute and late morbidity are illustrated with preliminary evidence of improved PSA response as a result of improved technique and higher dose associated with conformal 3-dimensional treatment.

Treatment related sequelae following external beam radiation for prostate cancer: a review with an update in patients with stages T1 and T2 tumor

The primary goal of radical radiation therapy in men with localized prostate carcinoma is cure and a secondary but important goal is to achieve cure without treatment related sequelae, such as loss of continence, rectal injury, loss of potency and the need for castration. A literature review of 2,611 men undergoing irradiation for all stages of localized prostatic carcinoma documented a 0.2% incidence of treatment related mortality, 1.9% severe complications, 0.9% incontinence and 33 to 60% maintenance of full potency 5 or more years after treatment. A separate analysis was made of 331 patients with only early tumors (stages T1 and T2) treated with conventional external beam radiation therapy to doses of 63 to 74 Gy. from 2 individual centers (Massachusetts General Hospital and M.D. Anderson Hospital) and 1 multi-institutional group (Radiation Therapy Oncology Group). Median followup was 6.1 years; however, in 2 series followup ranged to 14 years. This analysis revealed frequencies of treatment associated sequelae of 0% for mortality, 0% severe complications, 0.4% urinary incontinence, 5.4% genitourinary structures (1.2% persisting), 5.1% hematuria (0.9% persisting) and 5.4% rectal bleeding (0.6% persisting). This composite analysis of men undergoing irradiation for stages T1 and T2 tumors with conventional fractionation and doses indicates that acute morbidity is minor and usually transient, severe injury is rare, most late gastrointestinal and genitourinary symptoms of radiation injury are neither permanent nor debilitating, and few symptoms of radiation injury develop beyond 5 years from treatment. These data, combined with the low progression rates (using prostate specific antigen criteria) following irradiation of men with early tumors, further substantiate the primary role of radical radiotherapy in the treatment of surgical risk adversive patients.

Three-dimensional conformal radiation therapy in localized carcinoma of the prostate: interim report of a phase 1 dose-escalation study

Acute morbidity, late complications and tumor response were evaluated in 324 prostate cancer patients treated with 3-dimensional conformal radiation therapy in a phase I dose-escalation study. This radiotherapy technique targeted the prostate and seminal vesicles but effectively excluded the surrounding normal tissues. The minimum tumor dose was 64.8 to 66.6 Gy. in 87 patients, 70.2 Gy. in 138, 75.6 Gy. in 69 and 81.0 Gy. in 30. The treatment was well tolerated with minimal acute morbidity, observed in 15% of the patients who required medication for relief of rectal symptoms and in 34% for urinary symptoms. Two patients (0.6%) to date have had grades 3 and 4 late complications (Radiation Therapy Oncology Group morbidity grading system). The 3-year actuarial probability of survival with a normal serum prostate specific antigen level was 97% for patients with stages T1c and T2a, 86% with stage T2b, 60% with stage T2c and 43% with stage T3 disease. A multivariate analysis demonstrated that initial prostate specific antigen (20 ng./ml. or less versus more than 20 ng./ml.), stage (T2c or less versus T3) and Gleason score (6 or less versus 7 or more) were each significant independent variables that affected subsequent chemical relapse. The acute and long-term toxicities have been less compared with traditional treatment techniques. After the maximal tolerable dose with 3-dimensional conformal radiotherapy is established, future studies will test whether high dose conformal therapy has the potential to improve local tumor control and survival of patients with localized prostatic carcinoma.

Prostate cancer

Prostate cancer is the most common noncutaneous malignancy diagnosed in American men, and in 1994 it will pass lung cancer as the most common cancer diagnosed in the United States, with an estimated 200,000 new cases. The molecular biology of prostate carcinogenesis is rapidly advancing, and it is clear that, to a degree, prostate cancer is a heritable disease. The use of serum prostate-specific antigen (PSA) as a screening tool has been widely accepted by the medical community, although the evidence to support the efficacy of screening is not yet available. The curative approaches to organ-confined, clinically localized prostate cancer include radiation therapy, radical prostatectomy, and close observation in selected patients. The absence of well-designed clinical trials contributes to the confusion surrounding which curative treatment is the best option in individual patients. The standard approach to patients with evidence of extracapsular spread without distant metastases has been external-beam radiotherapy, although the results with radiation therapy alone in these patients has left considerable room for improvement. Innovative combined-modality approaches are currently being investigated at a number of institutions for these poor-prognosis patients. Three-dimensional conformal radiation therapy is currently being investigated at multiple institutions and offers some hope for improved results. The treatment of metastatic disease remains hormonal manipulation, although the exact nature of optimal androgen deprivation is currently a matter of considerable debate. In patients with hormone-refractory disease newer regimens using novel chemotherapy regimens offer some promise.

Patterns of radiation treatment of elderly patients with prostate cancer

BACKGROUND

The patterns of radiation care of elderly patients with prostate cancer treated with radiation therapy have not been described. As our population ages and screening increases the number of patients diagnosed, this becomes an important issue.

METHODS

The U.S. national surveys in prostate cancer conducted by the Patterns of Care Study in radiation oncology and the prostate cancer database from the Department of Radiation Oncology of the Fox Chase Cancer Center (Philadelphia, PA) have been used to compare processes and outcomes of conventional radiation treatment with conformal three-dimensional (3D) radiation treatment in elderly patients (older than or equal to 70 years) compared with younger patients.

RESULTS

The U.S. national averages for treating elderly patients with prostate cancer with radiation therapy show equivalent outcomes as those achieved by younger patients. These include all parameters of cancer control and treatment-related late morbidity. Studies from the Fox Chase Cancer Center demonstrate a reduction in acute treatment-related symptoms and equal late morbidity associated with conformal 3D-planned treatment as compared with conventional techniques despite an 8% increase in radiation dose. Therefore, radiation treatment should not be withheld from appropriately selected elderly patients with prostate cancer because of concerns about the patient's tolerance of treatment.

CONCLUSION

Radiation therapy is given to patients with prostate cancer without age bias. The results of treatment are similar for elderly and younger patients. The advantages of the conformal 3D radiation technique is apparent for elderly and younger patients in whom acute symptoms are reduced compared with those produced by the conventional radiation technique.

Comparison of a conformal nonaxial boost with a four-field boost technique in the treatment of adenocarcinoma of the prostate

PURPOSE

A comparative study of a standard four-field boost technique and a customized nonaxial external beam technique for the treatment of adenocarcinoma of the prostate was performed to quantify rectal and bladder sparing.

METHODS AND MATERIALS

Sixteen patients with localized carcinoma of the prostate who underwent simulation and treatment planning computed tomography formed the basis of this study. The prostate, seminal vesicles, lymph node, pelvic bones, rectum, bladder, and skin volumes were contoured from the CT slices to the three-dimensional treatment planning system. Each patient was planned for both standard four-field and nonaxial techniques to a boost treatment dose of 24 Gy to the prostate. Isodose plans were chosen on the basis of adequate tumor coverage and normal tissue sparing.

RESULTS

The volumes of the prostate, rectum, and bladder ranged from 46-148 cc, 25-196 cc, and 50-378 cc, respectively. Data analysis demonstrated a statistically significant reduction (p < 0.01) in normal tissue irradiation with the nonaxial external beam technique at dose levels of 15 and 20 Gy.

CONCLUSION

The nonaxial four-field external beam technique appears to be superior to the standard four-field approach in reducing the volume of high dose irradiation to the adjacent rectum and bladder.

Neoadjuvant hormonal therapy improves the therapeutic ratio in patients with bulky prostatic cancer treated with three-dimensional conformal radiation therapy

PURPOSE

To determine the extent of reduction of volume of normal tissue structures exposed to high doses of radiation therapy (RT) after administration of neoadjuvant hormonal therapy (NHT) in patients with bulky, geometrically unfavorable prostatic cancers.

METHODS AND MATERIALS

Twenty-two patients with bulky prostatic cancers were treated with a 3 month course of neoadjuvant leuprolide acetate and eulexin prior to three-dimensional (3-D) conformal radiotherapy. Patients were included if 3-D treatment planning revealed that either > 30% of the rectal wall would receive 95% of the prescription dose (D95) (n = 13); > or = 50% of the bladder wall would receive D95 (n = 10); or that any volume of small bowel would receive > or = 65% of the prescription dose (n = 16). All patients underwent simulation and conformal treatment planning before and after NHT. Pre and posthormone cumulative dose volume histogram (DVH) calculations for all normal tissue structures were analyzed and compared for each patient.

RESULTS

The median percentage of target volume reduction after NHT was 25% (range: 3-52%). Ten of 13 patients (78%) whose prehormone rectal DVH demonstrated > 30% of the rectal wall receiving D95 responded to NHT with a median 25% (range: 16-48%) reduction of rectal volume receiving the D95. A median reduction of 50% (range: 6-64%) of the bladder volume receiving D95 was observed in nine of ten patients (90%), while 13 of 16 (81%) showed a reduction of small bowel volume to a median percentage of 88% (range: 67-100%) of the prehormonal values.

CONCLUSION

Neoadjuvant hormonal therapy is an effective method for decreasing the size of bulky prostatic tumors as well as for optimizing the geometry of the target volume in relation to the adjacent normal tissue structures prior to radiation therapy. Such an approach allows for reduction of the volume of normal tissues exposed to high doses in the majority of treated patients. Currently, studies are underway to determine whether NHT will lead to a decreased likelihood of long-term complications associated with radiotherapy of bulky, geometrically unfavorable prostatic tumors, and permit the safe delivery of escalated dose levels using conformal treatment techniques.

Technical factors affecting morbidity in definitive irradiation for localized carcinoma of the prostate

PURPOSE

The impact of some technical factors on morbidity was analyzed in 738 patients with histologically confirmed carcinoma of the prostate treated with definitive irradiation.

METHODS AND MATERIALS

The records of all patients were reviewed, and morbidity of irradiation was evaluated according to severity. All patients were followed up for a minimum of 3 years (median observation, 6.5 years).

RESULTS

The most frequent Grade 2 (moderate) intestinal complication was proctitis, which was observed in 5% of the patients, followed by enteritis (1%) and anal-rectal fibrosis or stricture (about 1%). Incidence of Grade 3 (severe) proctitis was less than 1% and small bowel obstruction, 0.2%. One patient developed radiation-induced ileitis complicated with peritonitis, which was fatal. The most frequent Grade 2 urinary complication was urethral stricture (5%) and cystitis with significant symptoms or hematuria (2%). A vesicosigmoid and a rectovesical fistula (.4%) were noted, which required colostomy. One patient with hemorrhagic cystitis (.2%) required an ileal bladder, and two cases of ureteral stricture (.3%) required surgical correction. Most cases of Grade 2-3 intestinal or urinary morbidity appeared within 2-5 years after therapy (8% moderate and 3% severe cumulative intestinal morbidity at 10 years, and 9% and 3%, urinary). The actuarial incidence of rectosigmoid Grade 2 and 3 morbidity was 10% for patients treated to the pelvic lymph nodes and the prostate and 3% for those treated to the prostate only (p = 0.04). The difference in urinary morbidity in these two groups of patients was not statistically significant. There was also no significant correlation of morbidity with boost portal size for prostate irradiation. Patients treated with a stationary portal technique that delivered higher doses to the urinary bladder had a significantly greater incidence of urinary morbidity (18% cumulative) compared with patients treated with rotational techniques (5%) (p < 0.1). However, patients treated with pelvic fields and rotational techniques had a higher intestinal and rectosigmoid morbidity (11%) than patients treated to the prostate only (< or = 5%) (p = 0.05). No statistically significant difference in intestinal or urinary morbidity was related to doses of irradiation (60-70 Gy).

CONCLUSION

Volume treated and, to a lesser extent, dose of irradiation at tolerance levels are important factors influencing significant morbidity in patients with carcinoma of the prostate treated with definitive irradiation. With recent advances in three-dimensional (3-D) treatment planning and conformal radiation therapy techniques, it is imperative to precisely determine optimal volumes and doses of irradiation required to achieve the highest local-pelvic tumor control while minimizing morbidity to enhance the role of irradiation in the management of localized carcinoma of the prostate.

Conformal radiotherapy at the Royal Marsden Hospital (UK)

Conformal radiotherapy seeks to allow increased intensity of radiation by reducing the volume of normal tissues within the treatment volume. Techniques have developed secondary to improvements in three-dimensional imaging and accessible treatment technology is based on computer-controlled multileaf collimators to create an irregular radiation beam shape. Preliminary clinical work in the Royal Marsden Hospital seeks to quantify the toxicity reduction achievable by conformal techniques in the context of a prospective randomized pelvic radiotherapy trial which has now recruited 240 patients. The data accumulated during this trial will allow comparison of conformal and conventional radiotherapy and also analysis of the impact of dose and volume of a particular organ on both acute and late toxicity. Assessments have revealed that conformal techniques reduced significantly the treatment volume of normal tissues, e.g. by a mean of 54% for rectum and 42% for bladder. However, a relationship between volume and acute toxicity has not been established. Late toxicity is currently being analysed. Dose escalation trials in thoracic and in pelvic tumours are planned.

Three-dimensional conformal radiation therapy in locally advanced carcinoma of the prostate: preliminary results of a phase I dose-escalation study

PURPOSE

The acute morbidity of doses of 64.8-75.6 Gy and preliminary observations of late complications and tumor response using 3-dimensional conformal radiation therapy in carcinoma of the prostate are assessed.

METHODS AND MATERIALS

123 patients (Stage A2-12, B1-17, B2-43, C-51) were irradiated to the prostate and seminal vesicles using a 3-dimensional conformal radiation therapy technique. The median follow-up time was 15.2 months. The minimum tumor dose was 64.8-66.6 Gy in 49 patients, 70.2 Gy in 46, and 75.6 Gy in 28. Toxicity was scored according to the Radiation Therapy Oncology Group morbidity grading system.

RESULTS

This technique of 3-dimensional conformal radiation therapy was well-tolerated with minimal acute morbidity. Only 32% of patients had grade 2 or 3 acute morbidity requiring short-term medication for relief of urinary symptoms or diarrhea. Only one patient (0.8%) has so far developed a severe (grade 4) late complication. Serum prostate specific antigen concentrations normalized in 67% of patients (64/96) within 1-14 months (median 4.5 months) after treatment and were progressively decreasing at last measurement in an additional 22% (21/96). Abnormal rising prostate specific antigen levels were observed in 15 patients, 11 of whom have already developed other evidence of relapsing disease.

CONCLUSION

Acute toxicity for the doses tested with this 3-dimensional conformal radiation therapy technique is reduced compared to traditional treatment techniques, and the initial tumor response as assessed by prostate specific antigen measurement is highly encouraging with prostate specific antigen levels returning to normal in the majority of patients. Based on these results, a further increase of the dose to 81 Gy has been implemented in accordance with the schema of an ongoing Phase I dose-escalation study.

Predictors of survival after a positive post-irradiation prostate biopsy

PURPOSE

Considerable debate persists in the urologic oncology literature with regard to the optimum management of patients with a positive post-irradiation prostate biopsy. This analysis characterizes a group of such patients who have had a favorable course without intervention.

METHODS AND MATERIALS

Between 1956 and 1991, 116 patients have had a positive prostate biopsy 12 or more months post-irradiation without hormonal intervention or evidence of distant relapse. The population had an age range of 42 to 82 years (median - 61). American Joint Committee on Cancer stages included 1 T1, 70 T2, 44 T3, and 1 T4. Median actuarial survival for the entire population was 14.4 years (range = 2.2-21.5 years) from presentation and 5.2 years from re-biopsy.

RESULTS

Fifty-one of the 116 patients developed metastases subsequent to re-biopsy and 65 remain free from distant relapse. Among these 65 patients, 50 remain alive and otherwise well, 11 have died of other causes, and only four have succumbed to their local disease. The best predictor of distant relapse subsequent to re-biopsy was digital rectal exam. Forty-one of the 51 patients later developing metastases had an abnormal digital rectal exam compared to 37 of 65 with sustained distant control (p = .01).

CONCLUSION

These data demonstrate that long-term, disease-free (other than re-biopsy) survival is common following a "positive" post-irradiation biopsy without intervention especially among patients with a normal digital rectal exam. Therefore, routine re-biopsy without clinical indications is not a useful practice.

Rate of relapse following treatment for localized prostate cancer: a critical analysis of retrospective reports

PURPOSE

Controversy exists over the optimal treatment for patients with clinically localized prostate cancer. Almost all of the treatment results are from non-randomized trials and interseries comparison is difficult since the apparent success of a treatment, as judged by the actuarial freedom from relapse and survival data, depends on patient selection criteria and post-treatment evaluation, in addition to the efficacy of the therapeutic intervention. In this report the calculation of a hazard function is used to estimate and compare the rate of relapse for the different treatments.

METHODS AND MATERIALS

Clinical reports from major surgery and radiation oncology treatment institutions were analyzed. The actuarial recurrence data were used to calculate the annual rate of recurrence within each series.

RESULTS

For all but the lowest volume tumors, patients continue to be at risk of relapse for as long as these series have been followed. Despite the heterogeneity of patient populations, the recurrence rates by stage are similar for patients treated with surgery or irradiation. This result is consistent with pathologic data from prostatectomy specimens which indicate that for lesions > 12 cm3 (approx. 3 cm in diameter) there is high likelihood of extraprostatic disease.

CONCLUSION

Treatment outcome for patients with localized prostate cancer may be more dependent on the inherent tumor biology than the particular type of treatment. Accordingly, the expectation and recommendation of a treatment must take into consideration the continued risk of relapse with either radiation therapy or surgery. There are, as yet, insufficient data regarding the impact of screening and earlier diagnosis on the curability of patients with localized prostate cancer.

Localized carcinoma of the prostate (stages T1B, T1C, T2, and T3). Review of management with external beam radiation therapy

BACKGROUND

Optimal treatment for patients with localized carcinoma of the prostate is controversial. Radiation therapy is an established modality in the management of these patients, and several reports indicate the results are comparable to those achieved with radical prostatectomy. Recently effectiveness of therapy for carcinoma of the prostate is being evaluated in light of post-treatment prostate-specific antigen (PSA) determinations.

METHODS

A review was performed of multiple publications and data from selected institutions with large experience in the management of carcinoma of the prostate. Survival and clinical incidence of local recurrence and distant metastases were analyzed as well as preliminary data on postirradiation PSA levels. Factors that affect the outcome of therapy and relevant clinical trials are discussed.

RESULTS

Reported differences in the age of patients treated with radical prostatectomy (59-63 years), irradiation (63-69 years), or observation (69-75.5 years) were identified. The effect of surgical staging on outcome of irradiation was significant. In multiple series of patients clinically and radiographically staged, the 5-year disease-free survival (DFS) with external irradiation was 95-100% for clinical stage T1a, 80-90% for Stage T1b,c, and 50-70% for clinical Stage T3. A correlation has been identified between the initial PSA levels and the probability from freedom of chemical failure (PSA elevation) after definitive irradiation. In five series comprising 814 patients with Stage T1c and T2 tumors, the DFS (end point chemical failure) was 95%, with initial PSA of less than 4 ng/ml, 83-92% with 4.1-10 ng/ml, 35-85% with 10.1-20 ng/ml, and 10-63% with PSA higher than 20 ng/ml. In the various series, follow-up ranged from a median of 1.5 years to a minimum of 4 years. In two series of 225 and 201 patients receiving doses of 7500-8000 cGy, less morbidity has been observed with three-dimensional treatment planning conformal radiation therapy than with conventional irradiation. New directions for future clinical trials are discussed, including dose escalation studies; use of high linear energy transfer to improve locoregional tumor control; and combination of irradiation and androgen suppression to enhance local tumor control, decrease distant metastasis, and improve survival. Preliminary results of a randomized study recently reported by RTOG strongly suggest that the use of goserelin acetate and flutamide decreases the incidence of clinical local recurrence (12.4% in 225 patients) compared with a control group treated with irradiation alone (25.2% in 230 patients) and enhances disease-free survival.

CONCLUSIONS

Although modern approaches to the management of patients with localized carcinoma of the prostate with irradiation are effective, investigators must continue to critically assess policies of treatment, develop appropriately designed prospective clinical trials, and define the optimal management of patients with localized carcinoma of the prostate.

Immobilization improves the reproducibility of patient positioning during six-field conformal radiation therapy for prostate carcinoma

PURPOSE

To determine the magnitude of patient positioning errors associated with six field conformal therapy for carcinoma of the prostate, and to assess the impact of alpha-cradle immobilization on these errors.

METHODS AND MATERIALS

The records of 22 patients, treated at two of the treatment facilities within our department, using computed tomography-planned conformal six field therapy for carcinoma of the prostate, were reviewed. At one facility (UCD), patients were routinely treated with immobilization, while at the other (UCSF) no rigid immobilization was used. Portal films of patients treated at both facilities were subsequently reviewed, and the deviation of each portal from the simulation film was determined (simulation-to-treatment variability). In addition, for each patient, the average deviation of each portal film from the average portal film (treatment-to-treatment variability) was determined.

RESULTS

The mean and median simulation-to-treatment variability was 0.4 cm for those patients treated with immobilization, versus 0.6 cm for those treated without immobilization. The 90th percentile of simulation-to-treatment variability was 0.7 cm for those patients treated with immobilization, versus 1.1 cm for those not immobilized. There was a significant reduction in the number of portals observed with errors of > or = 0.50 cm (132/201 vs. 37/87, 66% vs. 43%; p < 0.001), 0.75 cm (184/201 vs. 59/87, 92% vs. 68%; p < 0.001), and 1.0 cm (196/201 vs. 74/87, 98% vs. 85%; p < 0.001) for patients treated with immobilization. There was also a significant reduction in the number of patients with treatment-to-treatment variability > or = 0.5 cm (1/10 vs. 8/12; p = 0.01) for patients treated with immobilization.

CONCLUSION

The use of immobilization devices significantly reduces errors in patient positioning, potentially permitting the use of smaller treatment volumes. Immobilization should be a component of conformal radiation therapy programs for prostate carcinoma.

Conformal radiotherapy of the pelvis: assessment of acute toxicity

During the last 3 years the Royal Marsden Hospital (RMH) has conducted a prospective randomised trial of conformal pelvic radiotherapy in which dose/volume data and acute toxicity scores have been determined prospectively. Pending completion of the trial, a preliminary analysis has been undertaken of the volume reductions achieved, and of some of the symptom scores. The average symptom score increased during radiotherapy, more markedly for bowel than bladder symptoms. In comparing total doses of 30-38 Gy with 56-65 Gy, watery bowel motions were more frequent with the higher doses (p = 0.013) but in the high-dose group neither this symptom nor tenesmus correlated with volume of rectum treated to at least 90% of the prescribed dose. We conclude that the assessment of the impact of volume on the level of acute symptoms in pelvic radiotherapy is complex, and requires analysis of a range of symptoms, dose levels and normal-tissue volumes. The degree of symptom reduction from conformal radiotherapy will emerge from the RMH randomised trial within the next 12 months.