Australian researchers have discovered that men with incurable prostate cancer, but without symptoms, who received immediate hormone treatment on the TROG 03.06 (TOAD) clinical trial, had an increase in survival over those who delayed treatment – with 80% still alive after six years, compared to 65% of men for whom treatment was delayed until they showed further symptoms or signs of progression.
The randomised, phase III trial, which was led by Australia, with contributions from New Zealand and Canada, was conducted to determine if immediate intervention with androgen deprivation therapy (ADT) would improve overall survival, compared with delayed ADT in prostate cancer patients with a rising Prostate Specific Antigen (PSA).
Radiation Oncologist and Trial Chair, Professor Gillian Duchesne, presented the results of the TOAD trial during the American Society of Clinical Oncology (ASCO) Annual Meeting, earlier this month.
“These are people who are no longer considered to be curable, but who may have a number of years ahead of them. It is therefore important to try to maintain quality of life for as long as possible, and avoid unnecessary treatment,” Professor Duchesne said.
“We were surprised to see that 80% of the patients in the immediate treatment arm were still alive at 6 years, and 65% in the delayed arm – emphasising how long men with prostate cancer live, even with incurable disease.
“Survival was 10% higher at 5 years, and 15% higher at 6 years for starting hormone therapy early. It seemed that there was also a benefit in the immediate arm to using an intermittent schedule, which allowed the men to have some time off from treatment.
“The trial found that more men on the immediate arm had side effects: 75% vs 50%, which was not surprising. The rate of cancer complications was the same, but they occurred later in the immediate group.”
Professor Duchesne said the results from the trial will have an impact on future treatments for men with terminal prostate cancer, giving them more options.
“Clinicians now have some evidence to offer to these men, for them to be able to make an informed decision about when they want to start treatment – earlier with the chance of living longer but with increased risk of side effects, or delaying treatment. We were unable to give them any figures before,” she said.
The trial was the first of its kind to tackle this question in the PSA area. Trial data will be combined with the results of a similar Canadian study, for a secondary analysis. A quality of life analysis is also being analysed, to assess the relative impact of immediate treatment on quality as well as quantity of life. The TOAD trial was coordinated by Cancer Council Victoria, in collaboration with TROG Cancer Research.