Prediction of toxicity and quality of life for patients undergoing intensity modulated radiotherapy

The study determined the incidence of genitourinary toxicity and the quality of life in patients after intensity-modulated radiotherapy.

Patients with localized prostate cancer (cancer that has not spread) may be treated using a high-energy radiation that kills cancer cells (radiotherapy). Application of radiotherapy in treatment of cancer patients must be undertaken with care to reduce exposure of healthy tissue and limit the side effects of treatment. Intensity-modulated radiotherapy uses advanced technology to manipulate beams of radiation to conform to the shape of a tumor, minimizing the exposure of the surrounding tissues.

This study evaluated the effectiveness of intensity-modulated radiotherapy in terms of genitourinary toxicity (toxicity affecting the reproductive organs and urinary system)  and quality of life in patients with localized prostate cancer.

The study involved 268 patients with localized prostate cancer. All patients underwent high-dose intensity-modulated radiotherapy and were followed for an average of 5 years. They were screened for symptoms of cancer using an eight question assessment tool (International Prostate Symptom Score) previous to and subsequent to therapy. This helped in establishment of whether there was success in management of cancer and improvement of the patient’s quality of life. An International Prostate Symptom Score of between zero and seven was associated with mild symptoms (137 patients), between eight and nineteen was associated with moderate symptoms (111 patients) and between 20 and 35 was associated with severe symptoms (20 patients).

Patients with severe symptoms at the beginning of the study had a no increase in their International Prostate Symptom Score. Patients with moderate symptoms at the beginning of the study had an average score increase of two.  Patients with mild symptoms at the beginning of the study had an average score increase of four. Score increases indicated worsening of the cancer for the patients.

18–34% of patients with mild symptoms at the beginning of the study transferred into the intermediate or severe group by the end of the study.

Of the patients with intermediate symptoms at the beginning of the study, 32–39% transferred into the mild symptom group and 2–11% transferred into the severe symptom group by the end of the study.

Among patients with severe symptoms at the beginning of the study, 50–75%transferred to the moderate or mild symptom group by the end of the study.

The 5-year incidence of grade 2 genitourinary toxicity was 23%. Of these, 49% resolved during follow-up with the average time to resolution being 38 months.

These findings may help to counsel patients with localized prostate cancer, who can be reassured that the risk of genitourinary toxicity and worsening of quality of life after high-dose intensity modulated radiotherapy was low.

Even though the data was obtained prospectively (forward-looking), the patients were not treated in a prospective manner.