Discussion
In this study, the incidental PCa rate and predictive factors in
patients who underwent OP with a pre-diagnosis of BPH were evaluated and
significant findings emerged. The multivariate analysis showed that only
pathological DRE findings and presence of MeTS were significantly
associated with the incidental PCa risk after OP surgery. To our
knowledge, this study evaluated the highest number of parameters in the
prediction of incidental PCa detection after OP.
PCa can be detected by DRE when the prostate volume is ≥0.2 mL. PCa is
detected by a suspicious DRE finding alone in 18%
cases.12 In a multicentric study (11 centers, 1613
patients) Yoo et al. reported that the DRE finding was an independent
predictive factor for diagnosing incidental PCa in tissue-ablative
surgery for BPH, such as transurethral resection of the prostate and OP.
The rate of an abnormal DRE finding was 12.7% in the BPH group and
36.6% in the incidental PCa group, and the incidental PCa rate was
4.8% in all cases.13 Similarly, another retrospective
study including 218 patients showed that DRE and elderly age were
predictive factors for incidental PCa after BPH surgery (TURP and OP)
(14). In our study, we also found that the rate of an abnormal DRE
finding was significantly higher in the incidental PCa group (3.6% vs
45.8%, respectively). In light of all these results, in case of an
abnormal DRE finding prior to OP, the risk of PCa should always be
considered, and additional diagnostic tests, such as multiparametric MRI
and target biopsies can be added to the algorithm.
Although the association between MetS and PCa is not clear, there are
many studies that have revealed the higher risk of PCa development in
patients with MetS. In Finland, Laukkanen et al. followed up 1880
patients for 13 years and found that the risk of PCa development was
1.9-fold higher in patients with MetS.15 Similarly, in
a study evaluating the relationship between PCa and MetS and late-onset
hypogonadism, Kayali et al. showed a higher risk of PCa in the MetS
group compared to the patients without MetS (32.7% and 21.2%,
respectively).16 On the other hand, according to a
meta-analysis including 19 studies, no correlation was found between
MetS and PCa development; however, a significant correlation was present
between MetS and aggressive PCa development. The authors determined that
MetS increased the risk of high-grade (GS ≥ 7) and
advanced-stage (≥ T3) PCa at a rate of 36 and 37%,
respectively.17 In the current study, we showed that
MetS was significantly higher in the incidental PCa group. This is the
first study that evaluated the presence of MetS and incidental PCa after
OP.
PSA is organ-specific but it is not specific to cancer. It may be
elevated in BPH, prostatitis, and other non-malignant conditions. As an
independent variable, PSA is a better predictor of cancer than DRE or
TRUS.18 In a multicentric study, the authors reported
that the PSA level was significantly higher in the incidental PCa group
than in the BPH group (6.9 ng/mL and 4.7 ng/mL, respectively). In the
current study, the PSA levels were similar in the incidental PCa and BPH
groups (7.63 ng/mL and 7.47 ng/mL, respectively). Similarly, Antunes et
al. reported that the presence of a high PSA level was not associated
with incidental PCa detection after BPH surgery. They referred to the
possibility of other reasons, such as the use of urinary catheters and
presence of urinary retention increasing PSA levels.14Abedi et al. reported that the cut-off value of PSA in incidental PCa
detection was 3.8 ng/mL.7 We consider that high
prostate volume can be another possible factor that can change the PSA
level.
Many researchers have shown that PCa is associated with increasing age.
In autopsy reports, the prevalence of PCa has been reported as 29% in
men aged 30 to 40 years and 64% in those aged 60-70
years.7 A previous study showed that advanced age was
statistically significantly related to the findings of the surgical
specimen analysis. The mean age of patients with incidental PCa was
approximately six years greater than those with BPH.14In another study, Sakamoto et al. determined that at a cut-off value of
75 years, age was an independent predictive factor for incidental PCa in
TURP.19 Similarly, in the current study, the
incidental PCa group was older than the BPH group (73.6 and 69.2 years,
respectively), but age was not found to be a statistically significant
variable in the multivariate analysis.
AST/ALT ratio can predict several malignant tumors, such as pancreatic
cancer and breast cancer. Zhou et al. showed that the AST/ALT ratio was
significantly higher in PCa than in BPH, but they noted that this ratio
was not a good predictor of high-risk PCa detection.20In our study, we also evaluated the AST/ALT ratio and found it to be
higher in the incidental PCa group. Although this parameter was
statistically significant in the univariate analysis, it was not
significant in the multivariate analysis. NLR is common predictor factor
for many cancer types. Wang et al. evaluated this ratio in patients with
PCa by dividing them into two GS groups as ≤6 and ≥7 and reported that
NLR was significantly higher in the high GS group.21We also found that NLR was higher in the incidental PCa group (2.57 vs
3); however, the difference between the two groups was not statistically
significant. To our knowledge, none of the studies in the literature
evaluated inflammatory hematological parameters for incidental PCa after
OP. Our study has certain limitations. It had a retrospective design and
included the data of 430 patients. Some parameters that could be
associated with incidental PCa, such as a family history of PCa and
smoking and alcohol habits were not evaluated due to the retrospective
design. Despite these limitations, we consider our study to be important
because it included the evaluation of the highest number of parameters
in the prediction of incidental PCa detection after OP.