Best of GU Cancers 2015: Dr. Thrasher’s picks and more

March 6, 2015

New, large-scale studies on active surveillance, IMRT complications, and robotic versus open prostatectomy were among the highlights of this year’s Genitourinary Cancers Symposium.

Many of the hot-button issues in urologic oncology-active surveillance for low-risk prostate cancer, robotic versus open prostatectomy, and the obesity paradox in kidney cancer, to name a few-came to the forefront at the recently concluded Genitourinary Cancers Symposium in Orlando, FL.

The meeting, co-sponsored by the American Society of Clinical Oncology, American Society for Radiation Oncology, and the Society of Urologic Oncology, has grown in size and stature, and this year’s event was no exception. We present the meeting’s highlights below, many of which were selected as “top picks” by Urology Times Editorial Consultant J. Brantley Thrasher, MD, of the University of Kansas Medical Center, Kansas City. (Dr. Thrasher’s abstract selections are marked by an asterisk.)

Localized prostate cancer

Adding early bicalutamide (Zoladex), 150 mg, to standard of care provided a significant overall benefit in men with locally advanced prostate cancer in the Scandinavian Prostate Cancer Group 6 study. However, this benefit did not appear in men with localized disease. (*Abstract 2)

In the randomized ASCENDE-RT trial, an Iodine-125 low-dose-rate brachytherapy boost outperformed an external radiation therapy boost in rendering unfavorable-risk prostate cancer patients biochemically disease free. (*Abstract 3)

A 30-gene signature of indolent prostate cancer significantly improved prognostic accuracy compared with a model using Gleason score alone in both treated and untreated cohorts. Study authors say the signature “has the potential to guide men to active surveillance and avoid overtreatment.” (*Abstract 10)

A study from Germany found that long-term use of testosterone undecanoate (AVEED) in hypogonadal men who are regularly monitored does not increase prostate cancer. Dr. Thrasher said the finding “is especially interesting given the press on testosterone and its risks.” (*Abstract 17)

Gastrointestinal complications following intensity-modulated radiation therapy are not only common, but costly, adding more than $3,000 to the cost of care for a Medicare beneficiary, according to a large study reported in Urology Times. “I believe more studies of this nature are needed as health care dollars are becoming increasingly scarce, and we need to truly evaluate the cost versus benefit ratio of our new technologies,” Dr. Thrasher said. (*Abstract 31)

In a comparison of open versus robot-assisted radical prostatectomy involving nearly 700,000 patients-“maybe the largest that we will see,” Dr. Thrasher said- the robotic approach was associated with less morbidity but at a higher cost than open surgery, as reported in Urology Times. The cost efficiency of robotic surgery can be improved by limiting operating room time, most likely achieved by high-volume surgeons, researchers said. (*Abstract 33)

Prostate cancer remains “a significant cause of mortality when diagnosed as a second cancer, especially if the interval from prior cancer is greater than 5 years,” according to study authors examining men in the SEER database. The finding suggests that treating aggressive prostate cancer may be reasonable in many men with prior cancers, they said. (*Abstract 34)

NEXT: More localized PCa, and advanced PCa

 

In a study of men on active surveillance, the pathology features of those undergoing surgery following surveillance were found more similar to men undergoing surgery after diagnosis with intermediate-risk prostate cancer than those diagnosed with very low-risk disease. “Additional follow-up of this and other cohorts is needed to assess long term clinical outcomes following delayed RP,” the authors wrote. (*Abstract 40) A second analysis of active surveillance, including data on 945 Canadian men, found differences in outcomes depending on whether the patient was low or intermediate risk at diagnosis. Compared to patients with low-risk prostate cancer, those with intermediate-risk cancer had a nearly fourfold higher chance of dying from the disease within 15 years. (Abstract 163)

An examination of the National Cancer Data Base showed that the use of radical prostatectomy in patients with localized disease increased significantly across risk groups from 2004 to 2011, whereas radiotherapy utilization declined. Rates of observation increased but remain low, researchers said. (*Abstract 42)

While women have made significant inroads in the urology work force, only 11% of U.S. urologists are female and women comprise only 4% of urologists with an oncology focus. Female urologists’ income is lower then men’s in both oncology and non-oncology fields, researchers reported. (*Abstract 72)

A review of three commercially available prostate cancer biomarkers-Prolaris, Decipher and Oncotype DX-concluded that the tests “have not yet fully justified their claimed clinical utilities.” Researchers pointed out that direct comparisons of the markers’ performance is difficult and that no prospective studies have been reported to validate them. (*Abstract 135)

Advanced prostate cancer

Overall survival improvement with abiraterone acetate (ZYTIGA) compared with placebo in men with progressive metastatic castration-resistant prostate cancer was statistically significant after a median follow-up of more than 4 years in a study reported by Urology Times. Data showed that with the occurrence of 96% of the planned deaths, abiraterone plus prednisone reduced the risk of death by 19% (p=.0033) versus placebo and prednisone, and after adjustment for crossover from placebo to abiraterone, the treatment effect was even more pronounced, with a 26% decrease (p<.0001) in the adjusted risk of death. (*Abstract 142)

Three studies examining cholesterol metabolism and statins are “very interesting and add to a growing body of data claiming their benefits in prostate cancer,” Dr. Thrasher pointed out. In one study, men receiving androgen deprivation therapy (ADT) after radiation therapy, statin use was associated with improved overall and prostate cancer-specific survival and improved quality of life. A second study found that men using statins at the time of ADT initiation had a significant increase in time to progression on ADT. The authors of a third study wrote their results suggest that the local cholesterol metabolism of the prostate tumor “is tightly linked with mortality.” (*Abstracts 145, 148, and 12)

Long-term, preliminary results from a phase II trial showed a robust immune response with sipuleucel-T (Provenge) that continues 2 years after completing treatment in men with biochemically recurrent prostate cancer. (Abstract 171)

The incidence of prostate cancer is higher among men with a history of testicular cancer (12.6%) than among those without a history of testicular cancer (2.8 %), a case-control study of nearly 180,000 men suggests. Men who have had testicular cancer were also more likely to develop intermediate- or high-risk prostate cancers. (Abstract 177)

NEXT: Kidney, bladder cancer

 

Kidney cancer

Study findings suggest that patients with locally advanced kidney cancer should not be treated with either adjuvant sorafenib (Nexavar) or sunitinib (Sutent). The average period to disease recurrence was similar between those who received sorafenib or sunitinib after surgery (5.6 years) and those treated with placebo (5.7 years). (Abstract 403)

A study appeared to validate the obesity paradox in metastatic renal cell carcinoma, with body mass index appearing as an independent prognostic factor for improved survival. The finding was observed in clear cell RCC only. “We hypothesize that lipid metabolism may be modulated by the fat laden tumors cells,” the authors wrote. (Abstract 405)

Bladder cancer

Patients who received chemotherapy after cystectomy demonstrated an approximately 30% lower risk of death than those who underwent surgery alone, an analysis showed. (Abstract 292)

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