Prostate and Kidney Cancer News From the 2013 Genitourinary Cancers Symposium

Approximately 2350 urologists, oncologists, surgeons, radiation oncologists, and other oncology healthcare professionals gathered in Orlando, Florida, to attend the 2013 Genitourinary Cancers Symposium. The symposium, sponsored by the American Society of Clinical Oncology, the American Society for Radiation Oncology, and the Society of Urologic Oncology, allows attendees to learn about the latest strategies for preventing, detecting, and treating cancers arising in the genitourinary organs. Following are summaries of some of the noteworthy abstracts presented at the symposium.

 

Adjuvant Radiotherapy Reduces Risk of PSA Failure, Compared With Wait-and-See Approach, in Locally Advanced Prostate Cancer

Extended follow-up of the German ARO 96-02 trial adds to the evidence that adjuvant radiotherapy reduces the risk of biochemical failure following radical prostatectomy in locally advanced prostate cancer (stage T3) versus a wait-and-see (WS) approach. Adjuvant radiotherapy reduced the risk of biochemical failure (rising prostate-specific antigen [PSA] level) by 49% at 10 years in this trial.

“Our long-term follow-up shows that it is incorrect to say that adjuvant radiation for patients with positive surgical margins stage is overtreatment. It is clear that adjuvant radiotherapy reduces biochemical evidence of disease after 10 years. It is quite important that we had a low rate of side effects, with only 1 case of grade 3 late toxicity,” stated presenting author Thomas Wiegel, MD, from the University of Ulm, Germany.

The study randomized 385 men with stage T3 prostate cancer following radical prostatectomy in a 1:1 ratio of adjuvant radiotherapy versus a WS approach. A unique feature of this study—compared with other phase 3 trials in this setting—was that patients randomized to adjuvant radiotherapy received treatment following surgery before they were found to have an undetectable PSA level (<.05 ng/mL). The median number of positive nodes was 8; median follow-up was 112 months.

After exclusions for a variety of reasons, an intent-to-treat analysis was based on 114 patients in the adjuvant radiotherapy arm and 159 in the WS arm. All patients had stage T3 disease; 27% had T3c (extension of cancer to the seminal vesicles). The majority of patients had Gleason scores ranging from 7 to 9.

The rate of 10-year freedom from biochemical failure was 56% in the adjuvant radiotherapy arm versus 35% in the WS arm, a significant absolute difference of 21% favoring adjuvant treatment (P = .00002).

No significant benefit was observed for adjuvant radiotherapy regarding metastasis-free survival or overall survival, although the trial was not powered to show this benefit.

The relative risk of biochemical failure was reduced for patients with positive surgical margins, higher PSA level, stage T3a/b, and higher Gleason scores.

Wiegel said that late toxicity rates were low, compared with previous trials conducted by SWOG and EORTC in this setting.

Formal discussant Anthony D’Amico, MD, of the Dana-Farber Cancer Center, Harvard Medical School, Boston, Massachusetts, said that until results of 2 ongoing trials evaluating adjuvant radiotherapy versus delayed radiotherapy are available, the decision to initiate adjuvant radiotherapy should be based on the number of risk factors, including Gleason score, surgical margins, extension into the seminal vesicles, and nodal status.

Reference
Wiegel T, Bottke D, Bartkowiak D, et al. Phase III results of adjuvant radiotherapy (RT) versus wait-and-see (WS) in patients with pT3 prostate cancer following radical prostatectomy (RP)(ARO 96-02/AUO AP 09/95): ten years follow-up. Presented at: 2013 Genitourinary Cancers Symposium; February 14-16, 2013; Orlando, FL. Abstract 4.

 

Eighteen Months of Hormone Therapy Leads to Survival Similar to 36 Months in Combination With Radiation

Patients with high-risk prostate cancer treated with radiation and hormones as their primary therapy had similar survival with 18 months of hormone therapy, compared with 36 months, according to results of a randomized phase 3 study.

“Hormone ablation therapy makes most men’s lives miserable,” stated presenting author Abdenour Nabid, MD, of the Centre Hospitalier Universitaire de Sherbrooke in Sherbrooke, Canada. Specifically, he said that the “castration syndrome” of lack of libido, erectile dysfunction, and hot flashes compromises quality of life. Other symptoms include fatigue, weight gain, and mood irritability, and a small number of men have cardiovascular effects.
“Shorter-term hormone therapy could have a big impact on the lives of men with prostate cancer, reducing the quantity and intensity of its unpleasant side effects as well as treatment costs. We hope these results will convince doctors that they can stop hormone therapy after 1.5 years instead of 2 to 3 years,” he told listeners.

The optimal duration of androgen ablation therapy in high-risk prostate cancer is controversial. An EORTC study conducted in 2009 found that 6 months of androgen ablation in this setting was inferior to 36 months. The present study was designed to show that 18 months was superior to 36 months.

The study randomized 630 patients with node-negative, high-risk prostate cancer to radiotherapy to the pelvic area and prostate bed plus 18 months of androgen ablation therapy versus 36 months of androgen ablation therapy (bicalu- tamide 1 month plus goserelin every 3 months).

Demographic and disease characteristics of the study population were well balanced between the 2 arms. The median age was 71 years, the median PSA was 16 ng/mL, and the median Gleason score was 8. Most patients had stage T2-T3 disease.

“These were truly high-risk patients,” Nabid noted.

At a median follow-up of 77 months, mortality was similar in the 2 arms: 22.9% in the shorter-duration hormone-therapy arm versus 23.8% in the longer-duration arm. Among 147 deaths reported, 116 were not due to prostate cancer but to other causes.

At 5 years, overall survival rates were 92.1% versus 86.8% for the 2 arms, respectively, and 10-year survival rates were 63.6% versus 63.2%, respectively. Disease-specific survival rates at 5 years were 97.6% versus 96.4%, respectively, and 10-year disease-specific survival rates were 87.2% in both arms.

“Importantly, the number of men dead due to prostate cancer was identical at 10 years,” he stated.

Bruce Roth, MD, of Washington University in St. Louis, Missouri, was encouraged by these findings. He said that he wanted to examine the full peer-review publication of the study, but he was hopeful that the study would be practice-changing.

Reference
Nabid A, Carrier N, Martin A-G, et al. High-risk prostate cancer treated with pelvic radiotherapy and 36 versus 18 months of androgen blockade: results of a phase III randomized study. Presented at: 2013 Genitourinary Cancers Symposium; February 14-16, 2013; Orlando, FL. Abstract 3.

 

African Americans and Elderly Are at Increased Risk of High-Risk Prostate Cancer

Elderly men and African American men whose prostate cancer was detected by PSA are at increased risk of developing high-risk prostate cancer, according to a large, population-based, retrospective study. The findings imply that PSA testing may be warranted in elderly and African American men to find high-risk cancers so that they can be treated early, but more research is needed to demonstrate that early detection and treatment for high-risk prostate cancer can improve outcomes.

These findings are interesting in light of the US Preventive Services Task Force (USPSTF) recommendation to curtail routine PSA testing.

“If we stop PSA screening altogether [as recommended by the USPSTF], there is no other method to detect this form of prostate cancer sufficiently early to have the best chance of helping this group of high-risk patients. The findings of this study will help physicians and certain patients make more informed decisions on whether or not they want to proceed with PSA testing, although more research (and longer follow-up) is needed to determine the effects of early detection and intervention on outcome in these high-risk patients,” stated lead author Hong Zhang, MD, PhD, of the University of Rochester, New York.

The study found that about 40% of cases of high-risk, PSA-detected prostate cancer occur in men over the age of 75 years, and elderly men are 9.4 times more likely than men under the age of 50 years to be at high risk. African American men of any age are more likely than white men to have high-risk disease.

The study identified 70,345 men from the SEER registry data diagnosed with early-stage (T1c), node-negative, prostate cancer between 2004 and 2008. The investigators determined the probability of developing low-, intermediate-, and high-risk prostate cancer based on PSA criteria and Gleason stage. Low risk was defined as PSA <10 mg/L and Gleason score of 6 or lower; intermediate risk was defined as PSA 10-20 mg/L and/or Gleason score of 7; and high-risk disease was defined as PSA of >20 mg/L and/or Gleason score of 8 or higher; 47.6% were found to have low-risk disease, 35.9% intermediate-risk, and 16.5% high-risk.

Men over the age of 75 years accounted for 11.8% of the entire study population but comprised 24.3% of intermediate- and 26.1% of high-risk disease. African American men had a 50% higher chance of developing intermediate-stage prostate cancer, compared with white men, and an 84% increased likelihood of developing high-risk prostate cancer than white men (P <.01 for both comparisons).

Reference
Zhang H, Travis LB, Messing EM, et al. PSA-detected prostate cancer in the United States: a population-based study of 70,345 men with AJCC stage T1cN0M0 disease. Presented at: 2013 Genitourinary Cancers Symposium; February 14-16, 2013; Orlando, FL. Abstract 50.

 

Surveillance Is as Safe as Surgery for Management of Small Kidney Masses in Elderly

In elderly patients in whom small asymptomatic kidney masses are found on imaging, surveillance is as safe and effective as surgery, especially in patients who are not good surgical candidates and/or who have comorbidities. In a retrospective analysis of more than 8300 elderly patients with small kidney masses, surveillance and surgery led to comparable kidney cancer–specific mortality, but surgery was associated with a higher risk of cardiovascular complications and all-cause mortality.

“Our analysis indicates that physicians can comfortably tell an elderly patient, especially a patient that is not healthy enough to tolerate anesthesia and surgery, that the likelihood of dying of kidney cancer is low and that kidney surgery is unlikely to extend their lives. However, since it is difficult to identify which tumors will become lethal, elderly patients who are completely healthy and have an extended life expectancy may opt for surgery,” stated lead author William C. Huang, MD, of the New York University Medical Center, New York City.

The study used SEER registry data linked to Medicare claims for patients aged 66 years or older to identify 8317 patients diagnosed with small renal masses (ie, under 1.5 inches in diameter); 5706 (69%) underwent surgery and 2611 (31%) underwent surveillance.

At a median follow-up of 4.8 years, 2078 deaths were reported (25% of the population); 277 deaths (3%) were due to kidney cancer. The rate of kidney cancer–specific death was identical with both surveillance and surgery. In an analysis adjusted for patient and disease characteristics, patients who were managed with surveillance had a significantly lower risk of death from any cause as well as a lower risk of a cardiovascular event.

The authors concluded that surveillance with modern imaging techniques is a safe option for management of small renal masses in elderly patients.

Reference
Huang WC, Pinheiro LC, Russo P, et al. Surveillance for the management of small renal masses: utilization and outcomes in a population-based cohort. Presented at: 2013 Genitourinary Cancers Symposium; February 14-16, 2013; Orlando, FL. Abstract 343.

 

Detection of Prostate Cancer Increases With 10 to 12 Biopsy Specimens

Urologists across the United States have largely adopted the evidence- based practice of obtaining 10 to 12 core biopsies of the prostate for the diagnosis of prostate cancer, and this practice has led to an increase in the rates of detection of prostate cancer, according to the results of one of the largest studies ever done in this setting.

“Segregation of prostate biopsy cores into 10-12 unique vials per biopsy has been adopted by urologists across sites of service, and it appears to be the de facto national standard of care,” stated presenting author Carl A. Olsson, MD, of Integrated Medical Professionals, LLC, New York City.

The massive study included more than 4.2 million specimens collected from about 440,000 biopsies. Data were collected from an annual mean of 1756.7 urologists in 765.6 practices in the United States. Biopsy rates and core-sampling patterns were assessed in patients whose biopsies were submitted to either a national reference library (NRL) or a laboratory integrated into a urology group practice (UPL).

The investigators analyzed the association between the rates of positive biopsies and the number of specimens per biopsy according to needle biopsy and anatomic pathology sampling. The analysis excluded saturation biopsies. For each year studied, the positive biopsy rate and the number of specimens per biopsy were recorded for both NRL and UPL, separately and combined.

In 2005, the positive biopsy rate was 38.2%, and the number of specimens per biopsy was 7.9; by 2011, the positive biopsy rate was 42.6%, and the number of specimens per biopsy was 10.7.

“The transition point was in 2008, suggesting that urologists were responding to published literature and guidelines recommending increased prostate sampling. Physicians utilizing UPL adopted these changes earlier than those using the NRL,” Olsson indicated in the poster.
The steepest increase in the number of specimens obtained occurred between 2005 and 2008, which was during the development of core-sampling regimens. The number of specimens obtained did not differ significantly across practice settings.

Reference
Olsson CA, Kapoor DA, Mendrinos SE, et al. Utilization and cancer detection by U.S. prostate biopsies (2005-2011). Presented at: 2013 Genitourinary Cancers Symposium; February 14-16, 2013; Orlando, FL. Abstract 107.