[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.