Neoadjuvant vs. adjuvant ADT yields similar survival rates for prostate cancer

Issue: May 25, 2015

Patients with intermediate- or high-risk prostate cancer demonstrated similar biochemical relapse-free survival, distant metastasis-free survival and OS regardless of whether they received androgen deprivation in the neoadjuvant or adjuvant settings, according to study results.

Perspective from Padraig Warde, MB, ChB, BAO, FRCPC

Patients with localized prostate cancer typically undergo androgen deprivation therapy (ADT) in the neoadjuvant setting, concurrent with radiation therapy.

Michael A. Weller, MD, of Cleveland Clinic, and colleagues assessed whether patients who underwent ADT in the adjuvant setting experienced different outcomes.

The analysis included 515 patients treated with radiation therapy and ADT from 1995 to 2002. Of these patients, 311 underwent ADT in the neoadjuvant setting, beginning 2 to 3 months before the start of radiation therapy. The other 204 patients underwent ADT in the adjuvant setting, immediately after the completion of radiation therapy.

At 10 years, results for the entire patient population indicated biochemical relapse-free survival was 61%, distant metastasis-free survival was 80%, and OS was 66%.

Weller and colleagues reported no significant differences in 10-year biochemical relapse-free survival (60% vs. 63%; P=.98), distant metastasis-free survival (80% vs. 80%; P=.6) and OS (67% vs. 65%; P=.98) among patients who underwent neoadjuvant ADT vs. adjuvant ADT.

“[The results suggest] the synergy between radiation therapy and androgen deprivation is independent of the sequencing of both modalities and that the initiation of radiation therapy does not need to be delayed for a course of neoadjuvant ADT,” Weller and colleagues concluded.

Disclosure: See the full study for a list of the researchers’ relevant financial disclosures.

Perspective

Padraig Warde, MB, ChB, BAO, FRCPC

Androgen deprivation therapy in combination with external beam radiation therapy (EBRT) is a standard of care for patients with high-risk or locally advanced prostate cancer. Although the benefit of this strategy in improving OS and cause-specific survival has been demonstrated in multiple randomized clinical trials, there is continued controversy about the timing of ADT administration. The issue is whether it should be given before and with radiation therapy (neoadjuvant/concurrent administration) or started after radiation therapy has finished (adjuvant administration). In a series of 515 patients treated in a standardized fashion with 6 months of ADT and high-dose EBRT, Weller and colleagues found that outcomes — specifically biochemical recurrence-free survival and OS — were not influenced by the sequencing of ADT administration. The researchers suggest that “the synergy between radiation therapy and ADT is independent of the sequencing of both modalities and that initiation of radiation therapy does not need to be delayed for a course of neoadjuvant ADT.” However, this single-institution report illustrates one of the major problems of performing randomized clinical trials to address this and similar issues in treatment: It is considerably underpowered to demonstrate equivalence in the two treatment approaches and, therefore, the researchers’ recommendation needs to viewed in this light. The investigators also recommend that randomized clinical trials be conducted to help firmly establish optimal duration and timing of ADT in this setting, and indeed this is what needs to be done.

Padraig Warde, MB, ChB, BAO, FRCPC

Princess Margaret Cancer Centre

Disclosures: Warde reports no relevant financial disclosures.

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Sources/Disclosures

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Source: Weller MA. Clin Genitourin Cancer. 2014;doi:10.1016/j.clgc.2014.12.009.