Home›Rheumatology› Volumetric inaccuracies in nasopharyngeal carcinoma primary tumor segmentation may reduce tumor control probability
Volumetric inaccuracies in nasopharyngeal carcinoma primary tumor segmentation may reduce tumor control probabilityImproved Segmentation Accuracy May Improve Treatment for Nasopharyngeal Carcinoma
Frontiers in MedicinePublished September 8, 2026DOI ↗Editorial oversight: Dr. Amelia Tan, PhD · Internal Medicine & Chronic Disease
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Key Takeaway
Note that low volumetric accuracy in nasopharyngeal carcinoma segmentation may reduce tumor control probability.
This guideline-based study evaluates the impact of volumetric and anatomical accuracy on CTVp consistency, dosimetric parameters, and tumor control probability (TCP) in patients with nasopharyngeal carcinoma. The analysis focuses on the differences between original and adjusted CTVp segmentation and the consistency of GTVnx across different observers.
The findings indicate that anatomical accuracy is high, with a median true positive rate (TPR) of 89.5% to 100% and precision of 80% to 92%. In contrast, volumetric accuracy is substantially lower, with a median TPR of 63.88% to 73.92% and precision of 47.08% to 70.29%. While consistency between original and adjusted CTVp showed only tiny differences (Median DSC: 0.84 vs. 0.85; Median HD95: 6.53 vs. 6.27 mm; ICC: 0.98 vs. 0.99), GTVnx consistency across observers was lower than CTVp consistency (Median DSC: 0.63, Median HD95: 8.21 mm, ICC: 0.92).
Dosimetric parameters and TCP based on treatment plans from different observers showed a decrease, with an average decrease of D95, EUD, and TCP of 7.38 Gy, 5.24 Gy, and 17.13% respectively. The authors conclude that primary tumor segmentation inaccuracies in nasopharyngeal carcinoma are predominantly volumetric rather than anatomical. These findings suggest that low volumetric accuracy may potentially reduce TCP, highlighting the importance of precise volumetric segmentation in treatment planning.
How this fits prior evidence
This study addresses a gap in technical radiotherapy planning for nasopharyngeal carcinoma. While prior evidence established that TPC induction chemotherapy improves outcomes and anti-PD-1 based chemo-immunotherapy is the first-line standard for recurrent or metastatic disease, this study focuses on the technical accuracy of primary tumor segmentation. It specifically highlights how volumetric inaccuracies, rather than anatomical ones, may impact dosimetric parameters and tumor control probability.
Researchers evaluated how different ways of mapping out tumors in patients with nasopharyngeal carcinoma affect radiation treatment. They compared the accuracy of anatomical shapes versus the actual volume of the tumor. The study focused on how these measurements impact the consistency of treatment plans and the probability of controlling the tumor.
The findings showed that while the anatomical shape of the tumor was mapped accurately, the actual volume was much harder to measure correctly. When the volume was not accurately captured, treatment plans showed a decrease in several key metrics, including the dose delivered to the tumor and the overall probability of controlling the cancer.
Because accurate volume measurements are so important, these results suggest that precise mapping is a vital step in radiation planning. Patients should discuss these technical details with their oncology team to understand how specific mapping techniques affect their individual treatment plan.
What this means for you:
Accurate volume measurements of tumors are important for ensuring consistent and effective radiation treatment plans.
Common questions
What did the study find about tumor mapping?
The study found that while the anatomical shape of the tumor was mapped with high accuracy, the actual volume was much harder to measure correctly. This suggests that volume accuracy is a critical factor in creating consistent radiation treatment plans for patients with nasopharyngeal carcinoma.
How does volume accuracy affect treatment?
When volume measurements were less accurate, the study showed a decrease in several key factors, including the dose delivered to the tumor and the tumor control probability. This highlights why precise volume mapping is important for the effectiveness of the treatment.
What is the difference between anatomical and volumetric accuracy?
Anatomical accuracy refers to the shape of the tumor, which showed high accuracy in the study. Volumetric accuracy refers to the size or volume of the tumor, which was found to be substantially lower in accuracy compared to the shape.
BackgroundConsensus guidelines for target volume segmentation have been issued for nasopharyngeal carcinoma (NPC) radiotherapy, yet prior studies have largely overlooked anatomical accuracy in this context.MethodsSixteen NPC patients were enrolled. GTVnx and prophylactic clinical target volume of primary tumor (CTVp) were independently contoured by three radiation oncologists and one senior radiologist to obtain observer segmentations (OSs) and reference GTVnx. Original CTVp of OS were adjusted according to reference GTVnx. CTVp consistency was evaluated with Dice Similarity Coefficient (DSC), 95th Hausdorff Distance (HD95) and Intraclass Correlation Coefficient (ICC). Impacts of volumetric and anatomical accuracy were evaluated with precision and true positive rate (TPR), dosimetric parameters and tumor control probability (TCP).ResultsAnatomical accuracy was strikingly high (median anatomical TPR: 89.5%–100%; precision: 80%–92%), volumetric accuracy was substantially lower (median volumetric TPR: 63.88%–73.92%; precision: 47.08%–70.29%). Tiny differences were observed in CTVp consistency between original and adjusted CTVp (Median DSC: 0.84 vs. 0.85, Median HD95: 6.53 vs. 6.27 mm, ICC: 0.98 vs. 0.99), which were both higher than that of GTVnx consistency across OSs (Median DSC: 0.63, Median HD95: 8.21 mm, ICC: 0.92). Treatment plans based on OS resulted in decreased D95, EUD and TCP (average decrease of D95, EUD and TCP: 7.38 Gy, 5.24 Gy and 17.13%).ConclusionsIn NPC, primary tumor segmentation inaccuracies are predominantly volumetric rather than anatomical. Low volumetric accuracy may potentially reduce TCP. Under consensus guidelines, high anatomical accuracy in GTVnx segmentation may contribute to consistent CTVp segmentation.
