How long should hormonal treatment be given to patients with locally advanced prostate cancer?

This study compared 6-month and 18-month courses of hormonal anti-androgen treatment and radiotherapy (RT) in patients with locally advanced prostate cancer (LAPC). The results showed that 18-month treatment was most effective, especially when used with high dose brachytherapy RT.

Androgens (such as testosterone) are a type of hormone which some forms of PC use to grow. One of the most common treatments for PC is the use of anti-androgen drugs, which block the hormone from working. These are frequently used with RT. There are several doses of RT which refer to the strength of the laser being used. 

Brachytherapy is a type of RT. It involves placing radioactive sources inside the patient (in the tumor) to kill cancer cells. It is not known whether a short or long dose of anti-androgen therapy is most effective for patients with LAPC and which type or dose of RT is best used with it.

1051 patients with LAPC were divided into two groups. The first group received anti-androgen treatment for 6 months (526 patients). The second group received anti-androgen treatment for 18 months (525 patients). Patients in both groups also received RT. Depending on each patient, 66 Gy, 70 Gy, 74 Gy or brachytherapy RT were given. Gy is the unit of measurement for RT doses. Patients were followed for 10 years.

18-month treatment reduced the risk of cancer progression in sites beyond the prostate by 30% compared with 6-month treatment. 18-month treatment reduced the risk of cancer recurrence within the prostate by 40%. 18-month treatment also reduced the risk of developing tumors in the bone by 38%.

18-month treatment also boosted the effects of all types of RT. Compared to 6-month treatment, 18-month treatment reduced the risk of cancer progression beyond the prostate by 45% with 66 Gy RT, 33% with 70 Gy RT, 17% with 74 Gy and 39% with brachytherapy.

Brachytherapy was the RT that gave patients the best chance of not developing tumors beyond the prostate, regardless of anti-androgen treatment duration. 19.7% of patients who received brachytherapy developed cancer beyond the prostate. This was compared to 26.1% of patients who received 66 Gy, 26.7% who received 70 Gy and 24.9% who received 74 Gy.

18-month treatment reduced patients’ mortality risk by 30%. Brachytherapy reduced patients’ mortality risk by 35% compared to other RT, regardless of anti-androgen treatment duration.

The authors concluded that 18-month hormonal treatment and brachytherapy RT improved the outcomes for patients with LAPC.

The RT dose was not randomly assigned to patients and so there may have been some bias. This study was limited by the fact that brachytherapy RT was not widely available during the study so not all patients had access to it.