# SWOG 9346 (intermittent androgen deprivation)

Source: https://onco.cc/trials/swog-9346/  
OnCo record `swog-9346` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Taking breaks from hormone therapy for metastatic prostate cancer improved sex life and mood for a few months, but the trial could not rule out that it shortens life, so continuous treatment remained the standard.

## Summary

SWOG 9346 enrolled 3,040 men with newly diagnosed metastatic hormone-sensitive prostate cancer, gave them all 7 months of a luteinising hormone-releasing hormone analogue with an antiandrogen, and randomised the 1,535 whose PSA fell to 4 ng/mL or lower to continuous (765) or intermittent (770) androgen deprivation.

At a median 9.8 years, median survival was 5.8 years with continuous therapy and 5.1 years with intermittent, hazard ratio for death with intermittent therapy 1.10 (90 percent confidence interval 0.99 to 1.23). The upper boundary of that interval exceeded the prespecified non-inferiority threshold of 1.20, but there were too few events to establish inferiority either. The authors described the finding as statistically inconclusive, which is an unusually honest way to report a trial that cost a decade.

Intermittent therapy gave better erectile function and mental health at month 3 (p<0.001 and p=0.003) but not thereafter, and there was no significant difference in treatment-related high-grade adverse events.

The practical reading is that a man with metastatic disease should stay on continuous androgen deprivation, and that intermittent therapy is a reasonable discussion for non-metastatic disease, where the equivalent trials were less worrying. It is also a lesson in how expensive an inconclusive non-inferiority margin is.

## Fields

- Kind: Trial
- Status: mixed
- Last checked: 2026-09-25
- Also known as: SWOG 9346; S9346; INT-0162
- Registry id: NCT00002651
- Phase: 3
- Setting: Newly diagnosed metastatic hormone-sensitive prostate cancer with a PSA of 5 ng/mL or more, after 7 months of a luteinising hormone-releasing hormone analogue and an antiandrogen brought the PSA to 4 ng/mL or lower: continuous against intermittent androgen deprivation, with co-primary objectives of non-inferior survival (upper hazard ratio boundary 1.20) and quality of life at 3 months
- Sponsor: SWOG Cancer Research Network, funded by the National Cancer Institute
- Enrolled: 1535
- Result: Median survival 5.8 years with continuous against 5.1 years with intermittent androgen deprivation (hazard ratio 1.10, 90 percent confidence interval 0.99 to 1.23); non-inferiority not shown and inferiority not excluded. Erectile function and mental health better with intermittent therapy at 3 months only.
- Outcomes: Overall survival (median): Continuous androgen deprivation 5.8 years vs Intermittent androgen deprivation 5.1 years, HR 1.1

## Sources

- ClinicalTrials.gov NCT00002651: https://clinicaltrials.gov/study/NCT00002651
- SWOG 9346 (New England Journal of Medicine 2013): https://doi.org/10.1056/NEJMoa1212299

## Connected records

- cancers: [Metastatic hormone-sensitive prostate cancer](https://onco.cc/cancers/prostate-mhspc/), [Prostate cancer](https://onco.cc/cancers/prostate/)
- technologies: [Androgen deprivation & AR pathway inhibitors](https://onco.cc/technologies/androgen-deprivation/)
- companies: [SWOG Cancer Research Network](https://onco.cc/companies/swog/)
- terms: [Androgen deprivation therapy (ADT)](https://onco.cc/terms/adt/), [Hormone therapy](https://onco.cc/terms/hormone-therapy/), [PSA (prostate-specific antigen)](https://onco.cc/terms/psa/), [Quality of life and patient-reported outcomes (QoL, PRO)](https://onco.cc/terms/qol-pro/), [What androgen deprivation costs: the side of hormone therapy the survival curves do not show](https://onco.cc/terms/prostate-adt-burden/)
- trials: [CHAARTED (E3805)](https://onco.cc/trials/chaarted/), [HERO](https://onco.cc/trials/hero/), [PATCH (Prostate Adenocarcinoma Transcutaneous Hormone)](https://onco.cc/trials/patch-transdermal-oestradiol/)

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