- In this retrospective study of men who had surgery for muscle-invasive bladder cancer, the incidence of incidentally detected prostate cancer (iPC) was 31%
- Patients with iPC showed a trend toward more favorable five-year overall survival compared with those without iPC
- Patients with low-risk iPC cases showed significantly better five-year overall survival than those without iPC, although this significance was lost on multivariate analysis
- If no PC is identified by systemic prostate biopsy or transurethral resection of the prostate, a more limited surgery for BC may be appropriate
Prostate cancer is detected incidentally in 24% of cases of men with muscle-invasive bladder cancer (BC) who undergo radical cystoprostatectomy. Data are mixed about the prognostic impact of this finding. Most studies show that incidental prostate cancer (iPC) does not affect the overall survival (OS) of patients with BC, but some studies have linked it to worse OS.
Researchers Shulin Wu, MD, PhD, lab manager, Urology Pathology Research Laboratory, Chin-Lee Wu, MD, PhD, associate pathologist and director of Genitourinary Pathology Services at Massachusetts General Hospital and the Mass General Cancer Center, and colleagues recently reported a surprising result in International Urology and Nephrology: Patients with BC who also had iPC showed a trend toward more favorable five-year OS when compared to those without iPC.
The researchers selected 122 patients from a Mass General database who underwent radical cystoprostatectomy for localized BC between 2002 and 2012 and did not have a prior diagnosis of PC. Of those, 38 (31%) had iPC, and within that group, 17 patients (45%) had clinically significant iPC. The median follow-up period was 40 months.
Statistically significant findings include:
- Patients with iPC were older than patients without iPC (median 71 vs. 64 years)
- Patients with iPC had a higher preoperative prostate-specific antigen (PSA) level than those without iPC (median 3.1 vs. 1.4 ng/mL)
- Patients with clinically significant iPC were more likely to have node-positive BC than those with clinically insignificant iPC
Prognostic Role of iPC
There was a nonsignificant trend toward better five-year OS in BC patients who also had iPC than in those without iPC (58% vs. 53%).
BC patients with clinically insignificant PC had a better five-year OS than those with clinically significant PC (60% vs. 56%), but again, the difference was not statistically significant.
Among patients with iPC, survival was similar in those with a Gleason score of 3 + 4 and those who had a Gleason score of 3 + 3 and low PSA. These two groups together, designated as having low-risk iPC, had significantly better five-year OS than patients without iPC.
However, this significance was lost on multivariate analysis, in which the only significant independent prognostic factors were positive surgical margins and more recent year of surgery. The use of neoadjuvant chemotherapy, which has increased over time, may explain why later surgery was associated with improved OS.
Implications for Patient Management
This research suggests that if no PC is identified by a systemic prostate biopsy or transurethral resection of the prostate before BC surgery, a more limited surgery for BC may be selected.
In addition, findings suggest that age and PSA are positively associated with iPC, and BC patients with low-risk iPC identified during radical cystoprostatectomy could affect BC progression. After further research confirms these results, clinicians may have access to additional therapy that can improve survival for a subset of patients with BC.
A Common Pathway for Carcinogenesis?
In Cancer Biology & Therapy, the same research team previously demonstrated that aromatase, a key enzyme in the conversion of androgens to estrogens, is involved in BC progression. They believe the current study supports the idea that androgen receptor signaling might be involved in BC carcinogenesis and progression.
Specifically, patients with iPC showed reduced frequencies of positive nodes, high histologic grade, perineural invasion and distant BC metastasis, compared with patients who did not have iPC, even though these differences were not statistically significant. Thus, the better OS observed in BC patients with iPC could be the result of pathological characteristics rather than the presence of iPC.
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