Some patients with androgen-independent prostate cancer can safely take a break from treatment.
Intermittent chemotherapy may be an option for some men with androgen-independent prostate cancer (AIPC), researchers found.
“We wanted to see if we could improve the quality of life for these patients by giving them time away from chemotherapy and possibly extend the time their cancer is controlled,” said lead investigator Tomasz Beer, MD, associate professor of medicine and director of the prostate cancer program at the Oregon Health & Science University in Portland.
“Essentially, what we proved is that in selected subjects, chemotherapy holidays are feasible and provided meaningful breaks from treatment.”
Survival in patients with metastatic, chemotherapy-naïve AIPC often is improved with 10 to 12 cycles of docetaxel-containing chemotherapy, he said. Additional management has not been well defined, however. For their investigation, the researchers examined retreatment with the same regimen after a treatment holiday.
In this study, patients treated with docetaxel at a dose of 36 mg/m2 plus either high-dose calcitriol (DN-101; 45 µg) or placebo administered weekly for three of every four weeks could suspend treatment if they met specific criteria. PSA levels were monitored every four weeks and CT scans were obtained every eight weeks in patients with measurable disease during the treatment holiday. Treatment was resumed if serum PSA rose by 50% or more and was 2 ng/mL or higher, or when there was other evidence of disease progression.
A total of 250 men participated. Of those, 18% entered the intermittent chemotherapy arm of the study. These men previously had responded well to chemotherapy. The median duration of the first chemo holiday was 18 weeks.
On resumption of chemotherapy, the majority of patients responded to treatment. Specifically, 45.5% of men responded with a greater than 50% reduction in their PSA level from their post-holiday baseline, Dr. Beer’s group reported in Cancer (2008;112:326-330). Another 45.5% had stable PSA levels for at least 12 weeks and 9.1% experienced disease progression. The study was not powered to compare chemotherapy holiday outcomes between the two arms.
“Because we know holidays are a good thing, we want to find ways to make them even longer,” Dr. Beer said, noting that side effects such as hair loss, nausea, loss of appetite, and increased risk for infection are major quality of life issues for these patients.