# SWOG 9916: docetaxel and estramustine compared with mitoxantrone and prednisone for advanced refractory prostate cancer

Source: https://onco.cc/key-papers/paper-petrylak-swog-9916-docetaxel-estramustine-nejm-2004/  
OnCo record `paper-petrylak-swog-9916-docetaxel-estramustine-nejm-2004` (Key paper). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Published in the same issue as TAX 327 and reaching the same conclusion by a different route: docetaxel extends life in advanced prostate cancer. The extra drug it was paired with, estramustine, brought enough side effects that it was dropped from practice.

## Summary

Daniel Petrylak and the Southwest Oncology Group randomised 770 men with metastatic androgen-independent prostate cancer to docetaxel with estramustine or to mitoxantrone with prednisone; 674 were eligible for analysis. Overall survival was the primary endpoint.

The pair of trials published in the New England Journal of Medicine on 7 October 2004 is the reason docetaxel became standard. TAX 327 gave the better toxicity profile and the schedule that survived; SWOG 9916 gave the independent replication. The estramustine combination produced more febrile neutropenia, more nausea and vomiting and more cardiovascular events, and did not deliver a better survival result, so the simpler regimen won.

## Fields

- Kind: Key paper
- Last checked: 2026-09-25
- Also known as: SWOG 9916; Petrylak 2004 docetaxel estramustine
- Tags: prostate-evidence
- Journal: New England Journal of Medicine
- Year: 2004
- DOI: 10.1056/nejmoa041318
- Authors: Petrylak DP, Tangen CM, Hussain MH, et al.
- Findings: Median overall survival 17.5 months with docetaxel and estramustine against 15.6 months with mitoxantrone and prednisone (P equals 0.02; hazard ratio for death 0.80, 95 percent confidence interval 0.67 to 0.97).; Median time to progression 6.3 months against 3.2 months (P less than 0.001).; Declines in prostate-specific antigen of at least 50 percent in 50 percent against 27 percent (P less than 0.001).; Objective tumour responses in 17 percent against 11 percent of patients with bidimensionally measurable disease (P equals 0.30).; Grade 3 or 4 neutropenic fevers (P equals 0.01), nausea and vomiting (P less than 0.001) and cardiovascular events (P equals 0.001) were more common with docetaxel and estramustine; pain relief was similar in both groups.
- What it means: The confirmatory half of the 2004 result. Two independent trials, two different docetaxel regimens, the same direction of effect: this is why docetaxel was adopted quickly and why it survived the move into hormone-sensitive disease a decade later.
- Caveats: The comparison bundles docetaxel with estramustine, so the trial cannot say how much of the benefit or the harm each drug contributed; TAX 327 answered that by omitting estramustine.; 96 of 770 randomised men were ineligible, and the analysis is of the 674 eligible.; Cardiovascular events were significantly more common in the experimental arm, which is why estramustine is no longer used.

## Sources

- N Engl J Med 2004: https://doi.org/10.1056/nejmoa041318
- PubMed: https://pubmed.ncbi.nlm.nih.gov/15470214/

## Connected records

- key papers: [TAX 327: docetaxel plus prednisone or mitoxantrone plus prednisone for advanced prostate cancer](https://onco.cc/key-papers/paper-tannock-tax-327-docetaxel-prednisone-nejm-2004/)
- roadmaps: [Chemotherapy roadmap: mustard gas → curative combinations → the warhead inside smarter drugs](https://onco.cc/roadmaps/chemotherapy-roadmap/), [Prostate cancer roadmap: from Huggins and the discovery that a cancer can depend on a hormone, through the PSA epidemic and what it cost, the androgen receptor drugs, the DNA repair subset and PSMA, to a 2032 registry watch](https://onco.cc/roadmaps/prostate-roadmap/)
- cancers: [Metastatic castration-resistant prostate cancer](https://onco.cc/cancers/prostate-mcrpc/), [Prostate cancer](https://onco.cc/cancers/prostate/)
- fronts: [Chemotherapy](https://onco.cc/fronts/chemotherapy/)
- drugs: [Docetaxel](https://onco.cc/drugs/docetaxel/), [Estramustine](https://onco.cc/drugs/estramustine/), [Mitoxantrone](https://onco.cc/drugs/mitoxantrone/), [Prednisone](https://onco.cc/drugs/prednisone/)
- terms: [Castration-resistant prostate cancer (CRPC)](https://onco.cc/terms/castration-resistance/), [PSA (prostate-specific antigen)](https://onco.cc/terms/psa/)
- bottlenecks: [Acquired resistance to every therapy](https://onco.cc/bottlenecks/b-resistance/), [Toxicity and quality of life are undervalued](https://onco.cc/bottlenecks/b-toxicity-qol/)
- journals: [New England Journal of Medicine](https://onco.cc/journals/nejm/)

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