RadOnc Smart Review

In our first three episodes, we mastered the standard approach for a "Stupp-eligible" patient with glioblastoma. But as you know, many of our patients do not fit this mold. They are older, have a lower performance status, or present with the formidable challenge of recurrent disease. Today, we address these special cases head-on. We'll build a framework for treating elderly and frail patients, review the evidence for re-irradiation, and discuss the role of the novel technology, Tumor-Treating Fields.

In our first two episodes, we built the modern diagnostic framework for high-grade gliomas, focusing on anaplastic oligodendrogliomas and astrocytomas. Today, we turn our attention to the most common and most formidable of these tumors: glioblastoma, IDH-wildtype. For years, this diagnosis came with a grim prognosis. But in 2005, one trial created a paradigm shift, establishing the bedrock of modern neuro-oncology. We will do a deep dive into the Stupp protocol and explore why, despite nearly two decades of research, it remains our standard of care.

In our last episode, we established the modern molecular framework for diagnosing high-grade gliomas and detailed the management of anaplastic oligodendroglioma. Today, we explore the other side of that coin. We will master the management of anaplastic astrocytoma by dissecting the pivotal CATNON trial, and we’ll tackle a challenging new entity introduced in the 2021 WHO classification: the IDH-mutant astrocytoma, Grade 4, a tumor that looks lower-grade under the microscope but carries a much graver prognosis based on its genetics.

Welcome back to Rad Onc Smart Review, CNS Edition.T his is Episode 1 of our new series on CNS oncology, titled: Modern Classification & Anaplastic Oligodendroglioma Evidence. For decades, we treated high-grade gliomas based on what a pathologist saw under a microscope. But in the last ten years, a molecular revolution has completely rewritten the textbook. You cannot treat what you can't accurately diagnose, and the modern diagnosis of glioma is now an integrated, molecular one. Today, we will establish this critical diagnostic framework. Then, we will apply it by taking a deep dive into the management of anaplastic oligodendroglioma, synthesizing the two landmark trials that define its standard of care.

This is Episode 20B: Anal Cancer Part 4: Guidelines, Toxicity, Follow-Up & Future Directions. Over the last three episodes, we've built a comprehensive understanding of anal cancer, from its foundational anatomy and staging, to the landmark trials that established definitive chemoradiation, and the technical details of modern IMRT planning. We've learned the 'what,' 'why,' and 'how' of our standard of care. In this final episode of our anal cancer series, we bring everything together. We will synthesize the key recommendations from the landmark 2025 ASTRO Clinical Practice Guideline, which now serves as our primary evidence-based roadmap. We'll then discuss practical strategies for managing acute and late toxicities, outline the evidence-based approach to post-treatment surveillance, and look ahead at the future directions of anal cancer research.

In our last episode, we established the foundations of anal cancer therapy, proving that definitive chemoradiation with 5-FU and Mitomycin-C is the organ-preserving standard of care. But while this approach is highly effective, it is also notoriously toxic. The older 3D radiation techniques often led to severe side effects and treatment breaks that compromised outcomes.Today, we focus on the modern "how." We'll explore how IMRT has revolutionized our ability to treat this disease. We'll walk through a detailed, dose-painted IMRT planning workshop. And finally, we'll use a case to discuss the management of special populations you will frequently encounter: HIV-positive patients, those with high-risk disease, and those with recurrence.

In our last episode, we laid the foundation for anal cancer management, establishing definitive concurrent chemoradiation as the sphincter-sparing standard of care, thanks to the pioneering work of Dr. Nigro and the pivotal ACT I and EORTC trials. We know why we use chemoradiation. Today, we focus on how to optimize it.Modern chemoradiation for anal cancer is a finely tuned balance of three critical components: the right chemotherapy, the right radiation dose, and the right timing. Getting any of these wrong can compromise cure rates or lead to unnecessary toxicity. Today, we’ll dissect the evidence for each of these pillars. We'll compare the key chemotherapy agents, Mitomycin C versus Cisplatin. We’ll justify modern, risk-adapted radiation dose escalation. And we will stress the crucial importance of completing treatment on schedule, without breaks.

We've arrived at our final primary site in the lower GI tract: anal cancer. In many ways, this disease is the ultimate success story for radiation oncology. It is one of the few solid tumors where we have moved from a paradigm of radical, mutilating surgery to a non-operative, organ-preserving standard of care, with definitive chemoradiation as the backbone. Today, we'll trace the history of this remarkable shift. We’ll start with the fundamentals of anatomy and staging that make anal cancer unique. Then we'll cover the revolutionary Nigro protocol that started it all, and finally, dive deep into the pivotal trials that fine-tuned this approach, answering the key questions of which chemotherapy drugs to use and for how long.

Today, we shift our focus to managing advanced and recurrent rectal cancer. We will outline the systemic therapy options for metastatic colorectal cancer, including the roles of specific chemotherapies and biologics based on molecular markers. We'll then discuss the critical management of lateral pelvic lymph nodes. Finally, we'll delve into the complex, yet often life-saving, principles of pelvic re-irradiation for recurrent rectal cancer.

Today, we're stepping into the treatment planning suite. We'll walk through the entire process, from patient education and simulation setup to the meticulous art of target volume delineation and the critical science of dose selection and OAR constraint application. This episode is your hands-on guide to building a high-quality rectal cancer radiation plan.