Comparison Of Differences In Recurrent Serum PSA Measurements With Reference Change Value

Yıl 2017, Cilt: 31 Sayı: 1, 25 - 31, 26.05.2017

Müge Gül Güleçoğlu Önem Sezer Uysal

Öz

Objective: Prostate
cancer is one of the most common cancers in men. The prostate-specific antigen
is a biochemical parameter that is often used to diagnose and monitor prostate
cancer. Since the intra-individual variability of the prostate-specific antigen
is high, it is important to assess the significance of the change between two
consequtive measurements from one individual. In our study, it was aimed to
avoid unnecessary PSA requests by investigating whether the difference in
recurrent serum PSA measurements exceeded Reference Change Value (RCV).

Material and method: PSA requests for a total of 4154
patients were retrospectively analyzed. A total of 268 individuals having
repeated test results with first PSA result ranging from 2-10 ng/mL were
selected. Analytical variability for total PSA was found as 5.1% and RCV was
calculated as 52%.

Results: While there was a decrease in serum PSA levels in 126
(47%) of the 268 patients who were included in the study, there was an increase
in 142 (53%). Among 142 patients whose PSA levels had increased in the second
measurement, 26 had increases exceeding the RCV. In our study, we found that
only 9.7% of patients with recurrent PSA requests had an increment above RCV.

Conclusion: When the increase in PSA values is evaluated, it
should be checked if it exceeds the RCV value and interpreted accordingly. The
significance of these elevations is controversial since most of the increment
percent in PSA observed in our study did not exceed RCV.

Anahtar Kelimeler

Prostate specific antigen, reference change value, biological variation

Tekrarlayan serum PSA ölçümlerindeki farklılıkların referans değişim değeri ile karşılaştırılması

Öz

Amaç: Prostat kanseri, erkeklerde en sık görülen
kanserlerden biridir. Prostat spesifik antijen (PSA), prostat kanseri tanısında
ve izleminde sıklıkla kullanılan biyokimyasal bir parametredir. Prostat
spesifik antijenin birey içi değişkenliğinin yüksek olmasından dolayı, bir
bireyden art arda yapılan iki ölçüm arasındaki değişimin anlamlılığını
değerlendirmek önem arz etmektedir. Çalışmamızda, tekrarlayan serum PSA
ölçümlerindeki farklılığın Referans Değişim Değerini (RCV) aşıp aşmadığı
araştırılarak, gereksiz PSA istemlerinin önüne geçmek amaçlanmıştır.

Gereç ve yöntem: Toplam 4154 hastaya ait PSA istemleri retrospektif
olarak analiz edildi. Farklı zaman aralıklarında sonucu bulunan ve ilk PSA
sonucu 2-10 ng/mL arasında değişen 268 kişi seçildi. Total PSA için analitik
değişkenlik % 5,1 olarak bulundu. RCV %52 olarak hesaplandı.

Bulgular: Çalışmaya aldığımız 268 kişinin 126 (%47)’sının serum
PSA seviyelerinde düşme olurken 142 (%53)’sinin serum PSA seviyelerinde artış
görüldü. PSA düzeyleri ikinci ölçümde artmış saptanan 142 hastadan 26’sında
%52’lik RCV değerini aşacak düzeyde yükselme gözlendi. Çalışmamızda tekrarlayan
PSA istemi olan hastaların sadece %9,7’sinde RCV düzeyini aşan bir oransal
yükselme olduğunu saptadık.

Sonuç: PSA değerlerindeki yükselme değerlendirilirken RCV
değerini aşıp aşmadığı dikkate alınarak yorum yapılmalıdır. Çalışmamızda
PSA’daki oransal yükselmelerin çoğu RCV’yi aşmadığından, bu yükselmelerin
anlamı tartışmalıdır.

Anahtar Kelimeler

Prostat spesifik antijen, referans değişim değeri, biyolojik değişkenlik

Kaynakça

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