Meme Kanserinde Sağkalım Durumunu Etkileyen Faktörlerin İncelenmesi: Eğilim Skoru Analizi

Öz

Amaç: Eğilim skoru (ES), incelenen değişkenlerdeki sistematik hatanın düzeltilmesi ya da ortadan kaldırılabilmesi amacıyla özellikle gözlemsel çalışmalarda kullanılan bir yöntemdir. Rosenbaum ve Rubin (1983) tarafından geliştirilen bu yöntem, bireyin ortak değişkenlere göre ilgili gruba atanmasının koşullu olasılığı olarak tanımlanır. Bu çalışmada, ES ile eşleştirme yapılarak meme kanseri nedeniyle ölümü etkileyen faktörlerin incelenmesi amaçlandı. Yöntem: Çalışmada, 423 meme kanseri hastasına ilişkin veri seti kullanıldı. Sağkalım durumu üzerine yaş, tümör büyüklüğü, radyoterapi, hormon terapisi, aksiller lenf nodu tutulumu değişkenlerinin etkisi incelendi. Veri setinde yaş değişkeni bakımından gruplar arası heterojenlik olduğu için en yakın komşu yöntemi kullanılarak eşleştirme yapıldı. Bulgular: Eşleştirme sonrası yaş değişkeninin etkisi ortadan kaldırıldı. 1:1 eşleştirme sonrası tümör büyüklüğü (p=0,009) ve aksiller pozitif lenf nodu tutulumu ≥4 (p=0,026) değişkenlerinin sağkalım durumu üzerinde anlamlı etkisinin olduğu belirlendi. 2:1 eşleştirme sonrası tümör büyüklüğü (p=0,004), radyoterapi (p=0,017) ve aksiller pozitif lenf nodu tutulumu ≥4 (p=0,001) değişkenlerinin sağkalım durumu üzerinde anlamlı etkisinin olduğu belirlendi. Sonuç: Heterojen yapıdaki verilerin doğrudan analiz edilmesi verideki gerçek etkilerin göz ardı edilmesine neden olabileceği için mutlaka ES yöntemi kullanılarak eşleştirme yapılmalıdır. Bu yöntemin en önemli dezavantajı ise eşleştirme nedeniyle veri kaybı olmasıdır. Bu nedenle çok sayıda birimle çalışılması verideki bilgi kaybının önüne geçecektir.

Anahtar Kelimeler

• Eğilim skoru
• eşleştirme
• lojistik regresyon
• meme kanseri
• en yakın komşu yöntemi

Examination of Factors Affecting Survival Status in Breast Cancer: Propensity Score Analysis

Öz

Objective: The propensity score (PS) is a method used especially in observational studies to correct or eliminate the systematic error in the variables studied. The method developed by Rosenbaum and Rubin (1983) is defined as the conditional probability of assigning the individual to the relevant group according to common variables. The aim of this study was to investigate the factors affecting the death of breast cancer by matching with PS. Methods: In this study, 423 breast cancer patients were used. The effects of age, tumor size, radiotherapy, hormone therapy, axillary lymph node involvement on survival were investigated. Since there was heterogeneity among the groups in terms of age variables, 1:1 and 2:1 matching was done by using the nearest neighbor method. Results: The effect of age variable after matching was eliminated. After 1:1 matching, tumor size (p=0.009) and axillary positive lymph node involvement ≥4 (p=0.026) were found to have a significant effect on survival. After 2:1 matching, tumor size (p=0.004), radiotherapy (p=0.017) and axillary positive lymph node involvement ≥4 (p=0.001) were found to have a significant effect on survival. Conclusion: Since the direct analysis of the heterogeneous structure data may lead to neglecting the actual effects in the data, it must be matched using the PS method. The most important disadvantage of this method is data loss due to matching. Therefore, working with a large number of units will prevent the loss of information in the data.

Anahtar Kelimeler

• Propensity score
• matching
• logistic regression
• breast cancer
• nearest neighbor method

Kaynakça

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