Dosimetric parameters predictive of nasolacrimal duct obstruction after carbon-ion radiotherapy for head and neck carcinoma

Abstract

Background and purpose: Little information is available on the risk factors for nasolacrimal duct obstruction after radiotherapy for head and neck tumors. We investigated the incidence and predictive dosimetric parameters for nasolacrimal duct obstruction following carbon-ion radiotherapy for head and neck tumors. Materials and methods: Twenty-eight patients with head and neck non-squamous cell carcinoma were analyzed in this single-institution prospective study. More than half of the tumors were located in the nasal cavity and maxillary sinus. Carbon-ion radiotherapy consisting of 57.6 or 64.0 Gy(relative biological effectiveness; RBE) in 16 fractions was administered. Nasolacrimal duct obstruction was recorded according to Common Terminology Criteria for Adverse Events version 4.0. Cutoff values were determined using receiver operating characteristic (ROC) curve analysis. VX indicates the volume irradiated with X Gy (RBE). Results: The median follow-up period was 60.3 months. Incidences of Grade 1 and 2 nasolacrimal duct obstructions were 46% (13/28) and 7% (2/28), respectively; no Grade 3 or greater toxicities were recorded. Throughout the dose range, the volumes of the irradiated nasolacrimal ducts were significantly higher in the obstruction-positive patients than in the obstruction-negative patients (p < 0.001 for V10, V20, V30, V40, V50, and V60). Cutoff values determined by the ROC curve analysis classified the obstructionpositive patients with an accuracy of >96% over the entire range of V10-V60. Conclusion: The incidence and predictive dosimetric parameters for nasolacrimal duct obstruction after carbon-ion radiotherapy were demonstrated in a prospective cohort. These data should help optimize carbon-ion radiotherapy treatments for patients with head and neck tumors.

Dose–volume constraints for head‐and‐neck cancer in carbon ion radiotherapy: A literature review

“…31 ARD was evaluated according to the CTCAE. The study constructed logistic regression models of grade 2-3 ARD NTCP for low-dose (5-15 Gy [RBE]), middledose (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)), and high-dose (40-50 Gy [RBE]) regions. The skin surface area irradiated with at least 40 Gy (RBE) (S40) from the high-dose group produced the NTCP model with the best performance.…”

“…Previous studies have associated various constraints with OAR complications related to the HN cancer CIRT 2,17–31 . This review provides an extensive list of constraints for HN cancer CIRT based on the Japanese RBE models.…”

Carbon-ion Radiotherapy for Inoperable Head and Neck Bone and Soft-tissue Sarcoma: Prospective Observational Study

“…Furthermore, preventing acute adverse events can also reduce the occurrence of late adverse events (14-16). Late adverse events such as osteoradionecrosis (21,22), trismus (23), nasolacrimal duct obstruction (24), tooth loss (25), brainstem necrosis (26), brain injury (27), and optic nerve injury (28) have been reported. In the future, we intend to develop a C-ion RT plan considering these dose indicators of onset; thus, the incidence of adverse events is anticipated to be reduced compared with that of the present study.…”

Carbon Ion Dose Constraints in the Head and Neck and Skull Base: Review of MedAustron Institutional Protocols

“…Eye and adnexa are other important organs that can be considered ''orphans,'' because, until now, no specific CIRT toxicity analysis has been performed and no CIRT constraints have been set, to our knowledge. The only existing formal analysis focused on lacrimal duct dose constraints [48]; however, the lacrimal duct is rarely a clinical issue because it is typically either far away from, or well into, the target volume and would never be prioritized over target coverage. At MedAustron, we have set constraints for lens, cornea, lacrimal gland, macula, and retina based on clinical judgments and extrapolation from photon experience.…”