In radiation oncology, positioning reproducibility during treatment, not just planning precision, may be an overlooked driver of head and neck cancer outcomes. New evidence on oral stents suggests reducing toxicity and improving treatment completion deserve the same clinical focus as delivery technology itself.
Key Takeaways
- Treatment completion is an underrecognized outcome variable. Head and neck cancer regimens run six to seven weeks and often combine chemotherapy with radiation; cumulative toxicity, opioid dependence, and dose interruptions can prevent patients from finishing treatment as planned, directly affecting outcomes.
- Positioning reproducibility, not just planning precision, determines delivered dose. Day-to-day anatomical shifts, such as tongue position relative to the target volume, can cause dose distributions to drift from what was planned, increasing healthy-tissue exposure even when the original treatment plan was highly precise.
- Oral stents show measurable long-term benefit. An MD Anderson study of 462 oropharyngeal cancer survivors found that tongue-deviating and tongue-depressing stents were associated with better taste, appetite, and swallowing outcomes at a median follow-up of 68 months, and a separate cohort study linked intraoral stent use to significantly lower oral mucositis severity.
- Oral mucositis is modifiable, not inevitable. A Cochrane review confirmed that interventions such as keratinocyte growth factor can reduce the risk of mucositis, reinforcing that toxicity many clinicians treat as an unavoidable side effect can, in some cases, be measurably reduced.
- Digital workflows are removing the historical barrier to access. Intraoral scanning and 3D printing now let programs fabricate customized oral stents without an on-site dental lab, with newer semi-automated design methods further cutting turnaround time — a shift that could extend this class of intervention beyond major academic centers.
Radiation oncology has spent decades transforming what precision means. Advances in imaging, treatment planning, adaptive replanning, and delivery technologies have moved the field toward previously higher levels of accuracy. Yet one variable remains underappreciated in the broader conversation about cancer care outcomes: whether patients can complete the treatment course as planned.
Head and neck cancer patients endure some of the most demanding treatment protocols in oncology. This may include six to seven weeks of radiotherapy, often in combination with chemotherapy, which can lead to cumulative toxicity and thus opioid dependence, nutritional complications, dose reductions, and treatment interruptions. When patients cannot complete treatment as planned, clinical outcomes suffer. As the field pursues ever greater treatment precision, are we paying enough attention to the variables that determine whether that precision actually reaches the patient?
Positioning precision is emerging as an underappreciated variable in radiation oncology outcomes
The Positioning Variable
Modern radiotherapy depends on consistently reproducing patient anatomy across all fractions. Treatment plans are designed around specific geometries: the position of the tongue relative to the target volume, the location of critical organs at risk relative to the beam path, and the anatomical relationship between healthy and cancerous tissue. When these geometries shift day to day, treatment precision does not translate to delivery. Dose distributions vary, healthy tissue receives incremental radiation exposure, and cumulative toxicity can increase.
Traditional immobilization approaches rely on standardized thermoplastic masks and non-custom bite blocks. These provide baseline positioning consistency but cannot fully account for the substantial anatomical variability between patients. Oral stents, prosthetic devices placed in the mouth during treatment, have been used for decades to displace normal tissues away from high-dose radiation zones and to improve positioning reproducibility across the treatment course. What has changed in recent years is the evidence supporting their clinical impact and the workflows that make them accessible.
What the Evidence Shows
A prospective observational study from The University of Texas MD Anderson Cancer Center provides some of the strongest evidence to date. Stieb and colleagues examined long-term patient-reported outcomes in 462 oropharyngeal cancer survivors following intensity-modulated radiation therapy (IMRT).1 At a median follow-up of 68 months, patients treated with unilateral neck radiation who received a tongue-deviating oral stent had significantly better long-term taste and appetite outcomes than those without stents.
Among patients treated with bilateral neck radiation for base of tongue cancers, tongue-depressing stents were associated with reduced long-term dysphagia and mouth or throat sores. Another dosimetric study from the institution by Grant and colleagues found significantly greater oral mucosa sparing for patients using a tongue-deviating stent when treated with IMRT.2 These findings suggest that positioning-related choices during treatment planning influence not only acute tolerability but also functional outcomes years later.
Evidence for oral stent benefits extends beyond MD Anderson. Inoue and colleagues examined intraoral stent use during radiotherapy for maxillary and nasal cavity cancers.3 In their cohort study, patients using an intraoral stent experienced significantly lower severity of oral mucositis compared to those treated without one. Because oral mucositis is a leading cause of treatment interruption and opioid dependence in head and neck radiotherapy, interventions that reduce its severity have direct implications for treatment completion.
Broader systematic evidence supports the underlying premise. A Cochrane review by Riley and colleagues confirmed that oral mucositis is a modifiable outcome, finding that keratinocyte growth factor can meaningfully reduce the risk of oral mucositis in adults undergoing cancer treatment.4 The consistent finding across the mucositis literature is that treatment-related toxicity is not an unavoidable consequence of cancer therapy. It can be measurably reduced through targeted interventions, whether pharmacologic, positional, or procedural.
Historically, the operational challenge with oral stents has been that traditional fabrication requires dental oncology expertise and days of turnaround time, which has limited their use outside major academic centers. Recent MD Anderson work has demonstrated a digital workflow using intraoral scanning and 3D printing to fabricate customized oral stents in less time and without on-site dental laboratory infrastructure.5 A subsequent paper describes further advances toward semi-automated design, reducing manual effort while maintaining clinical quality.6 Making this class of intervention accessible to more radiation oncology programs could translate into meaningful improvements in the patient experience of treatment.
Implications for Clinical Practice
The evidence points toward a broader observation. Much of the field’s recent investment has focused on treatment planning, imaging accuracy, and delivery hardware. These investments have produced meaningful advances. But the evidence increasingly suggests that supportive interventions that reduce toxicity and improve positioning reproducibility deserve similar focus as distinct clinical quality metrics.
For healthcare systems, reducing treatment-related toxicity reduces downstream costs associated with pain management, nutritional support, dose modifications, and treatment interruptions. Improved treatment completion rates correlate with better outcomes. For clinicians, the evidence suggests explicit consideration of toxicity-reduction strategies during treatment planning. Are we optimizing for treatment plan precision without optimizing for delivery reproducibility? Are we accepting toxicity outcomes as unavoidable when the evidence suggests they can be reduced? Are we tracking treatment completion as a clinical quality metric alongside tumor control and survival?
Looking Forward
The next generation of advances in radiation oncology will likely come not from any single technology, but from the integration of precision planning with precision delivery and better supportive care. As the field continues to invest in treatment innovation, the highest-value opportunities may lie in helping more patients receive the precise treatment their plans describe, with fewer interruptions and better long-term outcomes. That is not just a clinical opportunity. It is a healthcare system opportunity worth prioritizing.
References
[1] Stieb S, Perez-Martinez I, Mohamed ASR, Rock S, Bajaj N, Deshpande TS, Zaid M, Garden AS, Goepfert RP, Cardoso R, Ferrarotto R, Reddy JP, Phan J, Morrison WH, Rosenthal DI, Koay EJ, Frank SJ, Fuller CD, Gunn GB; MD Anderson Head and Neck Cancer Symptom Working Group. The impact of tongue-deviating and tongue-depressing oral stents on long-term radiation-associated symptoms in oropharyngeal cancer survivors. Clin Transl Radiat Oncol. 2020 Jun 9;24:71-78. doi: 10.1016/j.ctro.2020.05.014. PMID: 32642562; PMCID: PMC7334797.
Access: PubMed | Free full text (PMC7334797) | DOI: 10.1016/j.ctro.2020.05.014
[2] Grant SR, Williamson TD, Stieb S, Shah SJ, Fuller CD, Rosenthal DI, Frank SJ, Garden AS, Morrison WH, Phan J, Moreno AC, Reddy JP, Cardoso RC, Liu AY, Wu RY, Gunn GB. A dosimetric comparison of oral cavity sparing in the unilateral treatment of early stage tonsil cancer: IMRT, IMPT, and tongue-deviating oral stents. Adv Radiat Oncol. 2020 Aug 25;5(6):1359-1363. doi: 10.1016/j.adro.2020.08.007. eCollection 2020 Nov-Dec. PMID: 33305099; PMCID: PMC7718552.
Access: PubMed | Free full text (PMC7718552) | DOI: 10.1016/j.adro.2020.08.007
[3] Inoue Y, Yamagata K, Nakamura M, Ohnishi K, Tabuchi K, Bukawa H. Are intraoral stents effective for reducing the severity of oral mucositis during radiotherapy for maxillary and nasal cavity cancer? J Oral Maxillofac Surg. 2020 Jul;78(7):1214.e1-1214.e8. doi: 10.1016/j.joms.2020.02.009. Epub 2020 Feb 13. PMID: 32165135.
Access: PubMed | DOI: 10.1016/j.joms.2020.02.009
[4] Riley P, Glenny AM, Worthington HV, Littlewood A, Fernandez Mauleffinch LM, Clarkson JE, McCabe MG. Interventions for preventing oral mucositis in patients with cancer receiving treatment: cytokines and growth factors. Cochrane Database Syst Rev. 2017 Nov 28;11(11):CD011990. doi: 10.1002/14651858.CD011990.pub2. PMID: 29181845.
Access: PubMed | Cochrane Library | DOI: 10.1002/14651858.CD011990.pub2
[5] Tino R, Roach MA, Fuentes GD, Agrawal A, Zaid M, Cooper DJ, Bajaj N, Lin R, Xiao L, Mayo LL, Wiederhold LR, Shah SJ, Tate MK, Chronowski GM, Reddy JP, Mezera M, Mann JM, Augspurger M, Otun AO, Chambers MS, Koay EJ. Development and clinical implementation of a digital workflow utilizing 3D-printed oral stents for patients with head and neck cancer receiving radiotherapy. Oral Oncol. 2024 Oct;157:106944. doi: 10.1016/j.oraloncology.2024.106944. Epub 2024 Jul 17. PMID: 39024700.
Access: PubMed | DOI: 10.1016/j.oraloncology.2024.106944
[6] Agrawal A, Tino RB, Zaid M, Roach M, Xiao L, Chambers MS, Lee A, Koay EJ. Autostent: a semi-automated approach to designing customized 3D-printed oral radiation stents for patients with head and neck cancer. Radiat Oncol. 2025 Nov 17;20(1):170. doi: 10.1186/s13014-025-02727-3. PMID: 41250211; PMCID: PMC12625475.
Access: Free full text (PMC12625475) | Journal (Radiation Oncology) | DOI: 10.1186/s13014-025-02727-3
Conflict of Interest Disclosure
The foundational technology referenced in this article was developed at The University of Texas MD Anderson Cancer Center and licensed to Kallisio, Inc., where Rajan Patel serves as Founder and Chief Executive Officer. MD Anderson has an institutional financial interest in Kallisio, Inc., and this relationship is managed in accordance with MD Anderson’s Conflict of Interest Management and Monitoring Plan. Anna Lee, M.D., has no direct financial interest in Kallisio, Inc.
Acknowledgments
The authors acknowledge clinical collaborators and researchers at Stanford Health Care, Roswell Park Comprehensive Cancer Center, and other institutions whose research and clinical implementation efforts have informed the perspective presented in this article.
Featured image: A patient model wearing a short face mask is positioned in a computed tomography (CT) scanner to obtain images of a tumor before radiation therapy. © 2019 – 2026 National Cancer Institute (NCI). Licensed under the Unsplash License
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