Prostat Kanserinde Radyoterapi
Özet
Prostat kanseri tedavisinde cerrahi, radyoterapi (RT) ve sistemik tedaviler uygulanmakta olup, özellikle lineer akseleratörler ve görüntülü kılavuz tekniklerindeki gelişmelerle eksternal radyoterapi (ERT) cerrahiye göre avantajlı konuma gelmiştir. Teknolojinin ilerlemesiyle hayatımıza giren IMRT, 3D-CRT, IGRT, SBRT ve VMAT gibi modern radyoterapi teknikleri, tümör kontrolünü maksimuma çıkarırken rektum ve mesane gibi çevre dokuların gördüğü zararı en aza indirmektedir. Prostat kanser hücrelerinin alfa-beta oranının düşük (1,5) olması nedeniyle uygulanan hipofraksiyone ve yüksek dozlu tedaviler, tümör dokusuna normal dokudan daha fazla etki ederek tedavi yanıtını optimize eder. ERT uygulamalarında hastanın ek hastalıklarına ve dozaj seviyelerine bağlı olarak sistit, hematüri, üretral darlık gibi genitoüriner yan etkiler ile enterit, diyare gibi gastrointestinal reaksiyonlar, erektil disfonksiyon ve uzun vadede sekonder malignensiler görülebilmektedir. Modern tedavi planlamalarında ters planlama yeteneğine sahip bilgisayarlı sistemler ve tomografi/MR görüntülemeleriyle hedef doku çizimleri netleştirilmekte, böylece yan etkiler genellikle konservatif yöntemlerle kontrol altında tutulabilmektedir. Günümüzde bu güncel radyoterapi yöntemlerinin kullanılmasıyla normal dokular başarıyla korunmakta, hastalığı kontrol altına alma oranları artmakta ve özellikle lokal ileri prostat kanserinde radyoterapinin kullanımı giderek yaygınlaşmaktadır.
In the treatment of prostate cancer, surgery, radiotherapy (RT), and systemic therapies are applied, and external radiotherapy (ERT) has become advantageous over surgery due to developments in linear accelerators and image-guided techniques. Modern radiotherapy techniques such as IMRT, 3D-CRT, IGRT, SBRT, and VMAT, introduced through technological advancements, maximize tumor control while minimizing damage to surrounding tissues like the rectum and bladder. Due to the low alpha-beta ratio (1.5) of prostate cancer cells, hypofractionated and high-dose treatments optimize the therapeutic response by exerting a greater effect on tumor tissue compared to normal tissue. Depending on the patient's comorbidities and dosage levels, ERT applications can cause genitourinary side effects such as cystitis, hematuria, and urethral stricture, gastrointestinal reactions like enteritis and diarrhea, erectile dysfunction, and long-term secondary malignancies. In modern treatment planning, target tissue delineation is refined using inverse-planning computer systems and CT/MR imaging, allowing side effects to be managed primarily through conservative methods. Today, the utilization of these contemporary radiotherapy methods successfully preserves normal tissue, increases disease control rates, and continuously expands the role of radiotherapy, particularly in locally advanced prostate cancer.
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