Radiation Oncology: A Question-Based Review

54
Intermediate- and High-Risk Prostate Cancer

John P. Christodouleas and Theodore L. DeWeese

image Background


Estimate the annual incidence and mortality of prostate cancer in the U.S.

~230,000 Dx of and ~27,000 deaths from prostate cancer annually in the U.S.

Where does prostate cancer rank as a cause of cancer death in men in the U.S.?

Prostate cancer is essentially tied with colorectal cancer as the 2nd most common cause of cancer death behind lung cancer.

What % of newly diagnosed prostate cancer is cT3 or higher?

12%–28% of men with newly diagnosed prostate cancer have cT3 Dz or higher.

What % of newly diagnosed prostate cancer is Gleason ≥7 on Bx?

In the U.S., ~1 in 3 of all newly diagnosed prostate cancer in a screened population is Gleason ≥7. (Andriole GL et al., NEJM 2009)

What % of newly diagnosed prostate cancer are Gleason ≥8 on Bx?

In the U.S., ~1 in 10 of all newly diagnosed prostate cancer in a screened population is Gleason ≥8. (Andriole GL et al., NEJM 2009)

Estimate the risk of Gleason ≥7 prostate cancer in a man who has pre-Bx PSA of <4 ng/mL.

In a man with a pre-Bx PSA <4 ng/mL, the risk of Gleason ≥7 is ~PSA × 2.

In which portion of the prostate is the prostatic capsule not clearly defined?

At the apex of the prostate, the prostatic capsule is not clearly identifiable. Some authors argue that the prostate does not have a true capsule but rather simply has an outer fibromuscular band that continuously transitions to periprostatic tissues and organs. The transition at the apex is particularly difficult to identify. (Ayala AG et al., Am J Surg Pathol 1989)

In which portion of the prostate is ECE most commonly found?

ECE is most commonly found in the posterolat portion of the prostate at the prostatic neurovascular bundle.

image Workup/Staging


By the D–Amico criteria, which localized prostate cancer pts are considered to have intermediate-risk Dz?

A pt has intermediate-risk prostate cancer if he has any or all of the following 3 risk factors (but no high-risk factors): stage T2b, Gleason 7, and pre-Tx PSA 10–20 ng/mL. (D–Amico A et al., J Urol 2001)

By the D–Amico criteria, which localized prostate cancer pts are considered to have high-risk Dz?

A pt has high-risk prostate cancer if he has any or all of the following 3 risk factors: stage ≥T2c, Gleason ≥8, and pre-Tx PSA >20 ng/mL. (D–Amico A et al., J Urol 2001)

What is the Roach equation that estimates risk of pathologic ECE in prostate cancer pts?

Roach equation for ECE risk:

ECE% = ([3/2] × PSA) + ([Gleason − 3] × 10)

What is the Roach equation that estimates risk of pathologic seminal vesicle involvement in prostate cancer pts?

Roach equation for seminal vesicle risk:

SV% = PSA + ([Gleason − 6] × 10)

What is the Roach equation that estimates risk of pathologic LN involvement in prostate cancer pts?

Roach equation for LN risk:

LN% = ([2/3] × PSA) + ([Gleason − 6] × 10)

The Roach equations were developed from prostate cancer pts who had surgery in which yrs?

The Roach equations were developed from prostate cancer pts who had surgery between 1982–1996 (i.e., mainly in the pre-PSA era). These tools likely overestimate risks in pts diagnosed in the post-PSA era.

What is the sensitivity and specificity of endorectal coil MRI for determining the presence of prostatic ECE?

The estimates for the sensitivity and specificity of endorectal coil MRI as a predictor of prostatic ECE vary widely, between 13%–95% (sensitivity) and 49%–97% (specificity). The experience of the radiologist appears to play an important role in the accuracy of the tool.

What is the sensitivity and specificity of endorectal coil MRI for determining the presence of seminal vesicle invasion by prostate cancer?

The estimated sensitivity of endorectal coil MRI to predict seminal vesicle invasion by prostate cancer varies widely from 23%–80%. The estimates for specificity of seminal vesicle invasion are superior and vary between 81%–99%.

If an endorectal coil MRI is ordered as part of the workup for prostate cancer, how long after Bx should it take place?

There is no consensus on the role of endorectal coil MRI as part of the workup for prostate cancer. However, if an MRI is ordered, wait 6–8 wks after Bx to avoid artifact caused by post-Bx hemorrhage.

image Treatment/Prognosis


What are the Tx options for a man with localized intermediate-risk prostate cancer?

Tx options for a man with intermediate-risk prostate cancer:

1.     EBRT +/− short-term androgen suppression (AS) (4–6 mos) +/− brachytherapy (brachy) boost

2.     Brachy +/− AS

3.     Prostatectomy (less ideal for pt with >1 intermediate risk factor).

If he has a life expectancy <10 yrs, also consider active surveillance.

What are the Tx options for a man with localized high-risk prostate cancer?

Tx options for a man with high-risk prostate cancer:

1.     EBRT + long-term AS (2–3 yrs) +/− pelvic node RT +/− brachy boost

2.     Prostatectomy (less ideal for high-risk pts)

Estimate the 5-yr biochemical failurefree survival (bFS) for D–Amico intermediate- and high-risk prostate cancer pts treated with prostatectomy alone.

After prostatectomy alone, 5-yr bFS is ~65% for intermediate-risk and ~35% for high-risk prostate cancer pts. (D–Amico A et al., J Urol 2001)

Estimate the 10-yr bFS for prostate cancer pts with cT2b and ≥cT2c Dz treated with prostatectomy alone.

After prostatectomy alone, 10-yr bFS is ~62% for cT2b and ~57% for ≥cT2c. (Han M et al., Urol Clin N Am 2001)

Estimate the 10-yr bFS for prostate cancer pts with Gleason 3 + 4 = 7 and 4 + 3 = 7 Dz treated with prostatectomy alone.

After prostatectomy alone, 10-yr bFS is ~60% with Gleason 3 + 4 = 7 and ~33% with 4 + 3 = 7. (Han M et al., Urol Clin N Am 2001)

Estimate the 10-yr bFS for prostate cancer pts with Gleason 8–10 Dz treated with prostatectomy alone.

After prostatectomy alone, 10-yr bFS is ~29% with Gleason 8–10 Dz. (Han M et al., Urol Clin N Am 2001)

Estimate the 10-yr bFS for prostate cancer pts with a pretreatment prostate-specific antigen (pPSA) from 10–20 and >20 ng/mL treated with prostatectomy alone.

After prostatectomy alone,10-yr bFS ~57% with pPSA 10–20 ng/mL and 48% with pPSA >20 ng/mL are 57% and 48%, respectively. (Han M et al., Urol Clin N Am 2001)

What are the benefits of neoadj AS prior to radical prostatectomy?

The benefits of neoadj AS prior to prostatectomy include decreased + margin and LN positivity rates. This has been shown in multiple randomized trials. In addition, a longer duration of neoadj therapy (6–8 mos vs. 3 mos) is associated with improvements in these pathologic outcomes. (Kumar S et al., Cochrane Database Sys Rev 2006)

Why is neoadj AS prior to radical prostatectomy not commonly used?

Despite improvement in pathologic outcomes with neoadj AS prior to prostatectomy, long-term bFS rates do not appear to be improved. This negative result has been found in multiple randomized studies. (Kumar S et al., Cochrane Database Sys Rev 2006)

What is the role of adj AS therapy after prostatectomy?

In prostate cancer pts found to have node + Dz after prostatectomy, immediate adj AS is indicated and improves OS (Messing EM et al., Lancet Oncol 2006). There appears to be no OS or CSS in node– men after prostatectomy (Wirth MP et al., Euro Urol 2004), though the RCT evaluating this question used only an antiandrogen instead of a GnRH agonist or total AS with both.

What study established the role of adj AS for node+ pts after prostatectomy? What is the main criticism of this study?

Messing et al. showed an OS benefit of immediate adj AS vs. observation for node+ prostate cancer pts after prostatectomy (MS 13.9 yrs vs. 11.3 yrs, respectively). The main criticism of this study is that AS was not initiated in the observation arm until clinical Dz progression rather than an elevated absolute PSA or PSA velocity. (Lancet Oncol 2006)

Is LDR brachy alone appropriate for intermediate- or high-risk Dz? Describe 1 study that argues against LDR brachy.

Per the American Brachytherapy Society guidelines, LDR brachy alone is not appropriate for high-risk Dz but may be considered for highly selected pts with intermediate-risk Dz (Nag S et al., IJROBP 1999). A retrospective study by D–Amico et al. (JAMA 1998) found that LDR brachy alone was associated with worse 5-yr biochemical progressionfree survival (bPFS) compared to prostatectomy and EBRT alone in both intermediate- and high-risk subgroups. However, several single-institution series suggest that well-selected intermediate-risk pts receiving a high-quality implant have excellent outcomes after LDR brachy alone (5-yr bPFS >95%) (Taira AV et al., IJROBP 2009).

What is the role of neoadj AS and LDR brachy for pts with intermediate- or high-risk prostate cancer?

Per the American Brachytherapy Society guidelines, neoadj AS may be used to cytoreduce large prostates (Nag S et al., IJROBP 1999). However, several large retrospective studies have failed to show that AS improves cancer control outcomes in combination with LDR brachy.

What is the role of EBRT + LDR brachy for intermediate- and high-risk prostate cancer?

EBRT + LDR brachy without AS is not commonly used in pts with high-risk Dz. However, multiple institutional series have shown good long-term outcomes in intermediate-risk pts (10-yr bPFS 79%–90%; Ragde H et al., Cancer 2000; Sylvester JE et al., IJROBP 2003). There has been 1 RCT of combination EBRT +/− LDR brachy boost in pts with intermediate- and high-risk Dz (Sathya JR et al., JCO 2005). This study compared iridium implant (35 Gy over 48 hrs) + EBRT (40 Gy) vs. EBRT alone (66 Gy) and found that the combined Tx improved biochemical/clinical failure rates (29% vs. 61%) and 2-yr post-RT positive prostate Bx rates (24% vs. 51%), suggesting that LDR brachy may be a reasonable way to dose escalate in these pts. The major weakness of this RCT is the relatively low dose and the lack of AS in the control arm.

What is the role of EBRT + HDR brachy for localized intermediate- and high-risk prostate cancer?

EBRT + HDR brachy is not commonly used in pts with intermediate- and high-risk prostate cancer. However, long-term data from Demanes et al. and other authors have shown good long-term results in both intermediate- and high-risk pts (10-yr bPFS of 87% and 63%, respectively) (Am J Clin Oncol 2009). There has been 1 RCT of EBRT +/− HDR brachy boost: Hoskin et al. (Radioth Oncol 2007). This study included low-, intermediate-, and high-risk pts, comparing EBRT (37.75 Gy in 2.75 Gy) + HDR (17 Gy in 8.5 Gy) vs. EBRT alone (55 Gy in 2.75 Gy), and found improved biochemical relapsefree survival (mean 5.1 yrs vs. 4.3 yrs) without excess toxicity. Most pts in both arms (~75%) had neoadj AS. The major weakness of this RCT is the relatively low dose in the control arm. Further, the study did not control for AS use.

What studies support the use of short-course (4–6 mos) AS with EBRT in localized intermediate-risk prostate cancer?

The 1st study to show a benefit to short-course AS in locally advanced prostate cancer was RTOG 8610, though all of these pts were high risk as defined by the D–Amico criteria. None of the published studies of short-course AS specifically studied intermediate-risk pts. RTOG 9408 enrolled all risk group pts (but mainly intermediate risk) and found a 12-yr OS benefit to the addition of short-course AS (McGowan DG et al., abstract IJROBP 2010). In addition, intermediate-risk pts were included in D–Amico et al. (JAMA 2004), Laverdiere et al. (J Urol 2004), and Denham et al. (Lancet Oncol 2005TROG 96.01), all of which showed improved Dz-specific outcomes with the addition of short-course AS to EBRT. It is unclear whether dose escalation mitigates the benefit of short-course AS in intermediate-risk pts.

Describe the study design and results of RTOG 8610, which studied the benefit of short-course AS in locally advanced prostate cancer.

RTOG 8610 enrolled 456 men with cT2-T4 (bulky) prostate cancer. N1 pts were eligible if below the common iliac. All were treated with EBRT (65–70 Gy) and randomized to 4 mos of AS (beginning 2 mos prior to EBRT) or observation with AS at relapse. 10-yr OS and MS favored the short-course AS arm (43% vs. 34% and 8.7 yrs vs. 7.3 yrs, respectively) though the difference was NSS. Short-course AS improved 10-yr CSM (23% vs. 36%) and distant failure (35% vs. 47%). (Roach M et al., JCO 2008)

Describe the study design and results of RTOG 9408, which studied the benefit of short-course AS in locally confined prostate cancer.

RTOG 9408 enrolled 2,028 pts with T1b-T2b, PSA ≤20, prostate cancer. Pts were randomized to EBRT alone (68.4 Gy) +/− 4-mo AS beginning 2 mos prior to EBRT. 12-yr OS favored the short-course AS arm (51% vs. 56%). (McGowan DG et al., abstract IJROBP 2010).

Describe the study design and results of TROG 96.01, which studied the benefit of short-course AS in locally advanced prostate cancer.

TROG 96.01 enrolled 818 pts with T2b-T4 prostate cancer treated with EBRT (66 Gy in 2 Gy). Pts were randomized to 0, 3, or 6 mos of AS starting 2 mos prior to EBRT. With only a median follow-up of 5.9 yrs, the 3- and 6-mo AS arms had improved LF, biochemical failure, and freedom from salvage Tx compared to the no-AS arm. The 6-mo arm also had improved distant failure and prostate cancer–specific survival (PCSS) compared to the no AS arm. As of yet, there are no OS differences among any of the 3 arms and no consistent cancer control differences between 3- and 6-mo arms. (Denham JW et al., Lancet Oncol 2005)

Describe the study design and results of the RCT by D–Amico et al., which studied the benefit of short-course AS in locally advanced prostate cancer.

D–Amico et al. (DFCI trial) enrolled 206 men with cT1b-T2b and 1 of the following: PSA 10–40 ng/mL or Gleason 7–10 or ECE/seminal vesicle invasion by MRI. Pts were randomized to EBRT alone (70 Gy) +/− 6 mos of AS beginning 2 mos prior to EBRT. The AS arm had improved 8-yr OS (74% vs. 61%). Unplanned subset analysis suggested that benefit may be limited to men without significant comorbidities. (JAMA 2008)

When should AS be started in a prostate cancer pt being treated with EBRT and AS?

In prostate cancer pts being treated with EBRT + AS, AS is usually started 2 mos prior to the start of EBRT. Preclinical experiments suggest that neoadj AS may improve prostate cancer RT sensitivity compared to concurrent AS, possibly due to improved tumor oxygenation with neoadj AS. Furthermore, the RCTs that established the role of short-course AS started it neoadjuvantly (RTOG 8610, D–Amico trial, TROG 96.01). However, RTOG 9413, which compared neoadj/concurrent vs. adj short-course AS showed no bPFS benefit (or detriment) to neoadj AS.

Describe the study design and results of RTOG 9413, which studied the benefit of the sequence of short-course AS and pelvic node RT in locally advanced prostate cancer.

RTOG 9413 had a 2 × 2 factorial design. It randomized 1,323 intermediate- and high-risk pts to 4 mos of AS beginning 2 mos prior to or immediately following EBRT. The 2nd randomization was regarding RT field size: whole pelvis (WP) RT vs. prostate and seminal vesicles only (PSVO). After a median follow-up of 7 yrs, there was no difference in PFS in the neoadj vs. adj AS arms and no difference in PFS in the WP and PSVO arms. Interpretation of this trial is limited by the fact that there was an unexpected interaction between the 2 randomizations of this study. (Lawton C et al., IJROBP 2007)

What is the appropriate duration of neoadj AS prior to EBRT in prostate cancer pts?

Prostate cancer pts who are treated with neoadj AS usually rcv 2 mos of AS prior to EBRT. However, there is only 1 published RCT on the optimal duration of neoadj AS in localized prostate cancer: Crook et al. (IJROBP 2009). This RCT enrolled 378 men with localized prostate cancer of any risk group, and all were treated with EBRT (66–67 Gy) without concurrent AS. Pts were randomized to 3 mos vs. 8 mos of neoadj AS. 5-yr freedom from failure (FFF) did not differ between the Tx arms. In an unplanned subgroup analysis, 5-yr DFS was improved for high-risk pts (71% vs. 42%) (Crook J et al., IJROBP 2009). RTOG 9910 evaluated 2 mos vs. 7 mos of neoadj therapy, though no results have yet been reported.

What studies support the role of long-term AS in localized high-risk prostate cancer pts treated with EBRT?

An OS benefit of long-term AS in high-risk pts after EBRT was 1st shown in RTOG 8531. Multiple subsequent RCTs have also shown improved prostate cancer outcomes: the Casodex Early Prostate Cancer trial, EORTC 22863, RTOG 9202, and EORTC 22961.

Describe the study design and results of RTOG 8531, which studied the benefit of the long-term AS in locally advanced prostate cancer.

RTOG 8531 enrolled 945 men with cT3 (nonbulky), pT3 after prostatectomy, or N1 prostate cancer. All were treated with EBRT (definitive dose: 65–70 Gy; postop dose: 60–65 Gy) and randomized to adj AS indefinitely or observation with AS at relapse. Adj AS improved 10-yr OS (49% vs. 39%), 10-yr CSM (16% vs. 22%), 10-yr LF (23% vs. 38%), and 10-yr distant failure (24% vs. 39%) (WP). On subset analysis, benefits were limited to the subset with Gleason ≥7 and were especially important in the subset with Gleason ≥8 (Pilepich MV et al., IJROBP 2005).

Describe the study design and results of the Casodex Early Prostate Cancer trial, which studied the benefit of the long-term adj Casodex in locally advanced prostate cancer.

The Casodex Early Prostate Cancer trial randomized 8,113 men with prostate cancer to observation or long-term Casodex after local therapy (RT, prostatectomy, observation). The duration of Casodex was either 2 yrs or until progression. In the subgroup of RT pts (1,730 men), after a median follow-up of 7.2 yrs, adj long-term Casodex did not result in OS or PCSS. However, in the subgroup of locally advanced pts (cT3-T4 or N1), there was an OS and PCSS benefit. These findings, however, were the results of an unplanned subset analysis. (See WA et al., J Cancer Res Clin Oncol 2006)

Describe the study design and results of EORTC 22863, which studied the benefit of long-term AS in locally advanced prostate cancer.

EORTC 22863 enrolled 412 men with cT3-T4/any grade or cT1-T2/WHO grade 3 prostate cancer. All were treated with EBRT (70 Gy) and randomized to 3 yrs of adj AS (beginning with EBRT) or observation with AS at relapse. Long-term AS improved 5-yr OS (78% vs. 62%), CSS (94% vs. 79%), LF (1.7% vs. 16.4%), and distant failure (9.8% vs. 29.2%). (Bolla M et al., Lancet 2002)

Describe the study design and results of RTOG 9202, which studied the benefit of the long-term AS in locally advanced prostate cancer.

RTOG 9202 enrolled 1,541 men with cT2c-T4, PSA <150. All were treated with 2 mos of neoadj AS and 2 mos of concurrent AS + EBRT (65–70 Gy). Pts were randomized to an additional 2 yrs of adj AS or observation with AS at relapse. Long-term AS was not associated with OS in the entire cohort, though it did show improved 10-yr CSS (89% vs. 84%), local progression (12% vs. 22%), and DM (15% vs. 23%). In an unplanned subgroup analysis, long-term AS improved 10-yr OS in pts with Gleason ≥8 (45% vs. 32%). (Horwitz EM et al., JCO 2008)

Describe the study design and results of the EORTC 22961 RCT, which compared short-course and long-term AS with EBRT in localized prostate cancer.

EORTC 22961 enrolled 1,113 men with cT2c-T4/N0 or cT1c-T2b/pN1-N2 prostate cancer and randomized to EBRT (70 Gy) with 6 mos vs. 3 yrs of neoadj, concurrent, and adj AS. Men receiving 3 yrs of AS had superior OS (5-yr OS 85% vs. 81%) and CSM (5-yr CSM 3.2% vs. 4.7%). Long-term overall QOL did not significantly differ between the 2 arms. (Bolla M et al., NEJM 2009)

What is the appropriate duration of long-term AS in localized high-risk prostate cancer pts treated with EBRT?

RTOG 9202 and EORTC 22961 suggested that long-term (2–3 yrs) AS is superior to short-course AS in high-risk pts. However, the optimum duration of long-term AS has not been well studied.

What is the role of pelvic nodal RT in localized intermediate- and high-risk prostate cancer?

The major RCTs that established the role of RT in locally advanced prostate cancer generally irradiated pelvic nodes. However, the role of pelvic nodal RT in localized prostate cancer has been specifically studied in 3 RCTs: RTOG 7706, RTOG 9413, and GETUG-01, and none showed a cancer control benefit to irradiating pelvic nodes. Yet, all of these trials included men who may have been at low risk for harboring nodal Dz. Pelvic nodal RT may still be warranted in men at very high risk of harboring nodal Dz, though who these pts are is controversial.

What is the appropriate EBRT dose for intermediate- and high-risk prostate cancer?

Men with intermediate- and high-risk prostate cancer who do not rcv AS should be treated to total EBRT doses of ≥74 Gy (in 2 Gy/fx). There have been at least 4 EBRT dose escalation studies including intermediate- and high-risk pts: the MDACC dose escalation trial, PROG 9505, the Dutch dose escalation trial, and the MRC RT01 trial. All 4 RCTs have shown at least improved biochemical control with dose-escalated EBRT. The role of high-dose EBRT is less clear in the setting of AS. The Dutch dose escalation trial allowed AS, but only a minority of men rcv it (22%; Peeters ST et al., JCO 2006). The MRC RT01 trial mandated neoadj and concurrent AS, and 5-yr outcomes favored dose escalation.

Describe the study design and results of the MDACC RCT that studied the benefit of dose escalation in localized prostate cancer.

The MDACC dose escalation trial enrolled 301 pts with cT1b-T3 prostate cancer. None were treated with AS. 21% were low risk, 47% were intermediate risk, and 32% were high risk. Pts were randomized to 70 Gy vs. 78 Gy. Dose escalation improved 8-yr FFF (78% vs. 59%). This improvement was seen in the low- and high-risk subsets but not in the intermediate-risk subset. 8-yr CSS was not significantly different (99% vs. 95%), nor was 8-yr OS (78% vs. 79%). (Kuban D et al., IJROBP 2008)

Describe the study design and results of the PROG 9508 RCT, which studied the benefit of dose escalation in localized prostate cancer.

The PROG 9509 RCT on dose escalation enrolled 393 pts with T1b-T2b, PSA <15 ng/mL prostate cancer. Pts were randomized to 70.2 Gy or 79.2 Gy. CD RT to the prostate only was given by proton RT prior to 50.4 Gy with photon RT to the prostate and seminal vesicle. Dose escalation improved 5-yr freedom from biochemical failure (80% vs. 61%) and 5-yr LC (48% vs. 55%). In an unplanned analysis, a significant improvement in freedom from biochemical failure was seen in both low- and intermediate-risk subsets. (Zietman AL et al., JAMA 2005)

Describe the study design and results of the MRC RT01 RCT, which studied the benefit of dose escalation in the setting of neoadj and concurrent AS for localized prostate cancer.

The MRC RT01 trial enrolled 843 men with cT1b-T3a, PSA <50 prostate cancer. All men were treated with 3–6 mos of neoadj and concurrent AS and randomized to EBRT 64 Gy or 74 Gy. The dose escalation arm improved 5-yr bPFS (71% vs. 60%). LC, freedom from salvage AS, and DMFS favored the dose escalation arm, though these endpoints were not statistically different. (Dearnaley DP et al., Lancet Oncol 2007)

What is the role of primary AS alone for localized high-risk prostate cancer?

AS alone for localized high-risk prostate cancer may be considered for men who cannot tolerate local management or who have a short life expectancy (<5 yrs). However, SPCG-7 showed that the addition of EBRT to long-term AS conferred a survival advantage in high-risk men.

Describe the design and results of the Scandinavian RCT (SPCG-7) that studied the long-term AS +/− EBRT in locally advanced prostate cancer.

SPCG-7 enrolled 875 men with cT1b-T2, N0 WHO grade 2–3 or cT3, any grade, N0 prostate cancer. All men were treated with total AS for 3 mos → an antiandrogen alone (flutamide) indefinitely. Pts were randomized to EBRT (70 Gy) starting after 3 mos of AS or no local therapy. With median follow-up of 7.6 yrs, the addition of EBRT improved 10-yr OS (70% vs. 61%) and 10-yr CSS (88% vs. 76%). The 10-yr prostate cancer–specific mortality was reduced by half with EBRT (12% vs. 24%). (Widmark A et al., Lancet 2009)

What is the role of definitive prostate RT in men with node+ prostate cancer?

There has been no RCT to determine whether men with node+ prostate cancer benefit from local RT. A retrospective review by Zagars et al. (J Urol 2001) suggested that EBRT in addition to long-term AS confers an OS benefit to node + pts. Subset analyses from RTOG 8531 suggest that long-term AS + EBRT confers OS benefit compared to EBRT alone in node+ pts. However, long-term biochemical control (PSA <1.5 ng/mL) was still poor (10% at 9 yrs) (Lawton C et al., JCO 2005).

image Toxicity


What are the most common acute and late side effects of definitive prostate RT?

1.     Acute side effects: fatigue, urinary urgency/frequency, proctitis/diarrhea

2.     Late side effects: erectile dysfunction (inability to maintain an erection for intercourse), cystitis, proctitis (frequency/bleeding)

Estimate the rate of grade 3 or higher late GU or GI RT toxicity with IMRT for prostate cancer.

Numerous retrospective studies suggest that grade 3 or higher late GU or GI RT toxicity is rare (1%).

Estimate the rate of erectile dysfunction in previously potent men 2+ yrs after Tx with definitive prostate RT.

Approximately 50% of men who were previously potent will no longer be able to maintain erections for intercourse 2+ yrs after definitive prostate RT. (Robinson JW et al., IJROBP 2002)

Does the use of short-course or long-term AS affect acute or late GU and GI RT toxicity in prostate cancer pts?

No. Multiple studies have evaluated the effect of AS on GU and GI RT toxicity. There appears to be no strong effect.

What are the common short-term and long-term side effects of AS?

1.     Short-term side effects: hot flashes, decreased libido, fatigue

2.     Long-term side effects: gynecomastia, anemia, decreased muscle mass, decreased bone density, obesity, mood changes, dyslipidemia, insulin resistance, possibly diabetes and coronary artery Dz

(Higano CS, Urology 2003Keating NL et al., J Clin Oncol 2006)

What are common side effects associated with antiandrogen therapy, and how long is the Tx course?

Common side effects of bicalutamide, which is most commonly prescribed due to its favorable toxicity profile, include breast tenderness and gynecomastia (50%) as well as loss of libido, diarrhea, and hepatotoxicity. It is generally prescribed for the 1st 2–4 wks with a GnRH analog.