Contemporary approaches in anal cancer radiotherapy: balancing efficacy and safety

Abstract

Introduction. The treatment of localized anal cancer was initially surgical; however, studies by Dr. Norman Nigro demonstrated that neoadjuvant chemotherapy combined with radiotherapy (5- fluorouracil and mitomycin C) can achieve complete responses, reducing the need for immediate surgical intervention. Technological advancements, including intensity-modulated radiation therapy (IMRT) and image-guided radiotherapy, have improved treatment precision and reduced toxicity. This review summarizes the evolution of radiotherapy and explores modern strategies for treatment personalization aimed at optimizing oncologic outcomes. Materials and Methods. In this review, we analyzed the scientific literature available through Google Scholar to summarize the evolution of radiotherapy in anal cancer. The focus is on current guidelines for IMRT contouring and planning, as well as strategies aimed at reducing toxicity and personalizing treatment. Criteria for defining target volumes, CTV and PTV margins, methods for protecting organs at risk, and dose delivery techniques, including the use of a simultaneous integrated boost, are also examined. Results. Chemoradiotherapy remains the standard treatment, achieving complete responses in the majority of patients. Modification or reduction of chemotherapy from the classical regimen in order to decrease toxicity may negatively impact oncological outcomes. Technological advances in radiotherapy enable the delivery of higher and more precise doses, while reducing both acute and late adverse effects. Contouring of all elective nodal regions is recommended in most stages, with the exception of selected early-stage tumors, and the dose delivered using the simultaneous integrated boost (SIB) technique should be adapted to the primary tumor and involved lymph nodes. Recent research also explores the role of proton therapy and personalized treatment approaches in locally advanced or recurrent disease. Conclusions. Treatment of anal cancer should be individualized, adjusting the intensity of therapy according to the stage and characteristics of the tumor. Modern radiotherapy technologies, including IMRT and image-guided radiotherapy, allow for dose optimization and reduction of toxicity. Emerging strategies, such as proton therapy and precise adjustment of target volumes, offer opportunities for treatment personalization and improvement of oncologic outcomes, while the application of contouring guidelines and atlases supports the safe and effective delivery of therapy.