Editor’s note: With China’s population undergoing demographic aging and growing public awareness of cancer screening, the clinical need for the management of urologic malignancies is steadily increasing. Radiotherapy, a mainstay of oncologic treatment, has evolved rapidly—progressing from old techniques to intensity‑modulated radiotherapy (IMRT), and from conventional fractionation regimens to stereotactic body radiation therapy (SBRT). Precision radiotherapy is now emerging as a pivotal modality in the management of urologic cancers. Professor Ningning Lu, affiliated to the National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, has dedicated years to the field of precision radiotherapy for urologic tumors, amassing substantial clinical expertise and a robust research portfolio. UroStream invited Professor Lu to deliver an in-depth review of the clinical applications of precision radiotherapy in urologic malignancies, thereby providing evidence-based insights and practical guidance for clinicians.01 UroStream: In the multidisciplinary management of urologic cancers, radiotherapy is playing an increasingly pivotal role. From a clinical perspective, how is precision radiotherapy integrated into therapeutic decision-making, and what is its clinical and therapeutic significance?
Professor Ningning Lu: Precision radiotherapy is the core approach to improving local control and preserving quality of life in patients with urologic malignancies, and its principle of precision permeates the entire radiotherapy workflow.
In target delineation, accurate contouring informed by multimodal imaging serves as the foundation of effective treatment. It is imperative to precisely delineate tumor boundaries, subclinical disease extent, and adjacent organs at risk (OARs). This step directly governs tumor control probability and modulates the risk of treatment-related complications. Equally critical are patient positioning stability and reproducibility during both simulation and treatment delivery.
In treatment planning, precision is attained through advanced dose‑calculation algorithms and optimization techniques that generate highly conformal dose distributions. This strategy ensures adequate tumor coverage while minimizing irradiation of nearby OARs—such as the rectum and bladder—thereby maximizing the therapeutic ratio.
In treatment delivery, accurate positioning verification and precise dose administration are paramount. For prostate cancer, for instance, the prostate, seminal vesicles, bladder, and rectum demonstrate substantial intrafractional and interfractional motion and deformation. Day-to-day fluctuations in bladder and rectum filling present notable challenges to consistent target alignment. Consequently, image-guided radiotherapy (IGRT) has become indispensable. A randomized trial comparing varying frequencies of cone‑beam computed tomography (CBCT) demonstrated that daily imaging significantly improved biochemical failure–free survival and reduced toxicity relative to weekly CBCT, highlighting the critical value of rigorous image guidance.
More recently, MR-guided adaptive radiotherapy has transitioned into clinical practice, advancing precision to an unprecedented level. MR‑Linac systems integrate high-field magnetic resonance imaging with a linear accelerator, enabling high-quality soft‑tissue images immediately before each fraction. Based on daily on-line acquired MR, targets are deformed and adjusted, and the treatment plan optimized online, effecting a transition from a “fixed plan” to an “individualized, patient‑specific” approach. Its principal advantage lies in real-time accommodation of organ motion and deformation, facilitating tighter conformity of tumor dose while sparing surrounding normal structures—rendering it particularly well suited to urologic malignancies.
02 UroStream: Compared with conventional non-adaptive precision radiotherapy, what advantages and value does MR-guided adaptive radiotherapy offer in the management of urologic cancers?
Professor Ningning Lu: For localized prostate cancer, radiotherapy remains a cornerstone curative modality. With SBRT now established as a standard option, the higher dose per fraction imposes stricter requirements for precision. Concurrently, we must prioritize preservation of quality of life—particularly urinary, bowel, and sexual function.
MR-guided adaptive radiotherapy dynamically accounts for daily anatomical variations of the prostate and adjacent organs at risk (OARs), enabling session-specific personalization of precision. This approach enhances target coverage while markedly reducing irradiation to the rectum, bladder, and neurovascular bundles.
Our clinical experience demonstrates that incorporating an adapt-to-shape workflow into hypofractionated regimens not only sustains tumor control but also mitigates both acute and late toxicities affecting the urinary and gastrointestinal tracts. Of particular note is the observed trend toward better preservation of sexual function. Among low‑ and intermediate-risk patients, sexual function preservation rates surpassed those achieved with conventional techniques. These findings confirm that MR-guided adaptive therapy augments organ preservation without compromising oncologic efficacy—delivering tangible benefits, especially for younger patients or those who place a high priority on functional outcomes.
03 UroStream: What potential breakthroughs and future applications do you foresee for MR-guided adaptive radiotherapy in urologic cancers?
Professor Ningning Lu: A key avenue for expanding the role of MR‑guided adaptive radiotherapy lies in precision dose escalation to localized lesions.
In postoperative recurrent prostate cancer, altered anatomy, fibrosis, adhesions, and bowels motility frequently constrain the safe delivery of curative doses with conventional radiotherapy. Our prospective study employed MR-guided adaptive boost to recurrent lesions, followed by conventional treatment to the prostate bed w/o pelvic lymph nodes. The preliminary results demonstrated both feasibility and safety: all enrolled patients completed therapy without experiencing grade ≥3 acute toxicity. MR guidance provided clear visualization of recurrent disease, facilitating precise dose escalation while shielding the bowel and bladder, thereby offering patients a meaningful opportunity for salvage cure.
In bladder‑preservation therapy for bladder cancer, we have explored adaptive focal boost to gross tumor volume as per pre-chemo images, followed by standard whole‑bladder w/o pelvic‑node irradiation. All patients completed the adapt-to-shape workflow with optimal target coverage and minimal toxicity. This strategy represents a promising approach to improving local tumor control while preserving bladder function.
04 UroStream: For patients with metastatic urologic cancers, what unique role can adaptive radiotherapy play?
Professor Ningning Lu: Accumulating evidence supports the use of radiotherapy in oligometastatic disease. Studies indicate that, in combination with systemic therapy, radiotherapy to either the primary tumor or all metastatic sites can lead to significantly improved outcomes in prostate cancer with low metastatic burden.
We designed a prospective study employing MR-guided radiotherapy for high-risk, very‑high-risk, pelvic‑node–positive, or oligometastatic patients, adopting whole‑disease–coverage hypofractionation schedule that included prostate, seminal vesicles and pelvic irradiation. This was the first study to demonstrate that MR-guided adaptive hypofractionated treatment is technically feasible and safe even when targeting large volumes. All patients completed treatment successfully, with low rates of acute and late toxicity and excellent tolerability. The 2-year in-field control reached 100%, providing a potent and safe modality for advanced disease and opening new possibilities for sustained disease control.
05 UroStream: In your view, where will the next breakthroughs in precision radiotherapy emerge?
Professor Ningning Lu: Future advances in precision radiotherapy will center on achieving both enhanced precision and greater efficiency.
From a technical standpoint, motion management will be pivotal. Investigators worldwide are developing predictive models for prostate, bladder, and rectal motion to improve targeting accuracy. MR‑Linac systems already incorporate intrafraction motion‑control modules, which enhance precision but currently result in slightly longer delivery time.
In terms of workflow innovation, “sim‑free” one-stop workflow—integrating simulation, planning, and delivery—has the potential to transform radiotherapy practice. In the future, treatment sessions could be shortened to less than 15 minutes.
From functional preservation in localized prostate cancer, to safe dose escalation in complex recurrences, to lesion eradication in oligometastatic settings, precision radiotherapy continues to expand its clinical impact. Through ongoing technological refinement and robust clinical research, we aim to provide more effective, convenient, and individualized treatment options across all stages of urologic malignancies, ultimately improving survival and quality of life.
Professor Ningning Lu
