In a clinical trial, men with newly diagnosed, metastatic, hormone-sensitive prostate cancer who received chemotherapy straight away alongside hormone-blocking therapy lived more than a year longer than men who followed the standard treatment – which is to wait until the tumors have become resistant to hormone therapy before receiving chemotherapy.
The scientists running the National Cancer Institute-funded phase 3 trial are from Dana-Farber Cancer Institute and the Eastern Co-operative Oncology Group.
They say the dramatic results are likely to change current standard practice, which has been routine since the 1950s.
Principal trial investigator Dr. Christopher J. Sweeney, of Dana-Farber’s Lank Center for Genitourinary Oncology, presented the results at the 50th annual meeting of the American Society of Clinical Oncology (ASCO) on June 1, 2014 in Chicago, IL.
Approach ‘warrants being new standard treatment’
“This is the first study to identify a strategy that prolongs survival in newly diagnosed, metastatic prostate cancer,” says Dr. Sweeney, who adds:
“The benefit is substantial and warrants this being a new standard treatment for men who have high-extent disease and are fit for chemotherapy.”
The increase in survival seen on the trial is significantly longer than the 2-6 months typically seen in successful studies of other metastatic adult solid tumors, says Dr. Bruce E. Johnson, chief clinical research officer at Dana-Farber.
After skin cancers, prostate cancer is the most commonly diagnosed cancer in men in North America. Estimates from the National Cancer Institute forecast that in 2014, around 233,000 men in the US will discover they have prostate cancer, and 29,480 will die from causes linked to the disease.
The current practice for men newly diagnosed with prostate cancer that has already spread to other parts of the body, and whose tumors feed on male hormones, is to first administer drugs that block the hormones – androgen deprivation therapy (ADT).
However, in most cases, the tumors become resistant to ADT and the cancer progresses. It is only when this happens that the patients are started on chemotherapy.
Earlier chemo hampers cancer’s ability to repair cell damage
The new trial tested the idea that giving the men chemo earlier – at the same time as starting on ADT – would hamper the cancer cells’ ability to repair damage, which in turn would delay the onset of resistance.
The trial started in 2006 and recruited 790 men newly diagnosed with metastatic prostate cancer in over 340 centers. The patients were randomized to receive either hormone therapy alone or with chemotherapy (the drug used was docetaxel, brand name Taxotere) over 18 weeks.
In the hormone therapy only group, 124 patients were given chemo as well when their cancer worsened. In the hormone therapy plus chemo group, 45 patients whose disease progressed were given extra chemo.
Over a median follow-up of 29 months, 136 patients in the hormone therapy only group died, while 101 died in the group that received both hormone therapy and chemo.
This is equivalent to a median overall survival of 57.6 months for the men who received chemo earlier, compared with 44 months for the men who received it later – over a year of prolonged survival.
The benefit was even greater where the cancer had spread to major organs or the bones. Men with such high-extent disease who received chemo at the same time as hormone therapy had a median overall survival of 49.2 months, compared with 32.2 in the group that received chemo later – a difference of 17 months.
Dr. Sweeney says, “This study shows that early chemotherapy increases the chances that certain patients with metastatic prostate cancer have a longer time without symptoms from cancer, and also live longer.”
He further explains their findings in the video below:
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