The effect of P53 expression and smoking/alcohol in P16(+) and P16(-) oropharyngeal carcinoma and risk classification: the Turkish Society of Radiation Oncology Head & Neck Study Group 01-002

OBJECTIVE

The aim of this study is to categorize the risk groups of patients with oropharyngeal carcinoma (OPC) according to p16 and p53 status, smoking/alcohol consumption history, and other prognostic factors.

STUDY DESIGN

The immunostaining of p16 and p53 of 290 patients was retrospectively evaluated. The history of smoking/alcohol consumption of each patient was noted. p16 and p53 staining patterns were reviewed. The results were compared with demographic findings and prognostic factors. Risk groups have been classified for the p16 status of patients.

RESULTS

The median follow-up was 47 months (range 6-240). Five-year disease-free survival (DFS) rates for patients with p16 (+) and (-) were 76% and 36%, and overall survival rates were 83% vs 40%, respectively (HR = 0.34 [0.21-0.57], P < .0001), HR = 0.22 [0.12-0.40] P < .0001, respectively). p16(-), p53(+), heavy smoking/alcohol consumption, performance status; advanced T and N stages in patients with p16(-), and continuing smoking/alcohol consumption after treatment were found to be unfavorable risk factors. Five-year overall survival rates were 95%, 78%, and 36% for low, intermediate, and high-risk groups, respectively.

CONCLUSIONS

The results of our study have shown that p16 negativity in patients with oropharyngeal cancer was found to be an important prognostic factor, especially for those with lower p53 expression and not smoking/consuming alcohol.

Profiling of circRNA expressions in radiation-treated head and neck cancer cells and the potential role of circPVT1

OBJECTIVE

Radiotherapy is an indispensable treatment modality for head and neck cancers (HNCs). Due to their stable structure, circular RNAs (circRNA) have been implicated as potential biomarkers for clinical use in cancers. The purpose of this study was profiling the circRNA in radiation-treated head and neck cancer cells to identify potential differentially expressed circRNAs.

DESIGN

The effects of radiation on the expression level of circRNAs were investigated in HNCs cells, compared to healthy cell lines. To predict the potential role of circRNAs in HNC patients, tissue expression levels, survival analyses of circRNAs, and circRNA-miRNA network were evaluated using TCGA/CPTAC datasets. Based on expression level in irradiated cells, circPVT1 (plasmacytoma variant translocation 1) was further investigated by sequence analysis.

RESULTS

The study revealed the characterization of differentially expressed circRNAs in cancer cells and that irradiation made significant changes in the expression of circRNAs. These findings suggest that certain circRNAs, especially circPVT1, may be potential biomarkers to monitor radiotherapy effects in patients with HNCs.

CONCLUSIONS

CircRNAs may be promising molecules for improving and understanding radiotherapy efficacy in HNCs.

Radiation-Induced Ocular Surface Disorders and Retinopathy: Ocular Structures and Radiation Dose-Volume Effect

Purpose

This study aimed to evaluate the radiation-induced adverse effects on ocular structures in head and neck cancer patients and investigate the radiation dose-volume effects on the cornea, lacrimal gland, retina, optic nerve and chiasm.

Materials and Methods

A total of 38 eyes of 19 patients were included in this prospective, cohort study. All patients underwent complete ophthalmological examination in addition to contrast sensitivity, visual field and visual evoked potentials (VEP) tests. Ophthalmological examinations and psychophysical tests were performed in 6th, 12th, 18th, 24th months and in the last visit. The relationship between the ophthalmologic findings, and the radiation doses below and above the cut-off values was evaluated.

Results

Contrast sensitivity decrease and visual field deterioration were observed in 42% of the patients in the last visit (median 26 months) whereas a prolonged latency and decreased amplitude of P100 wave in VEP was observed in 58% and 33% of the eyes, respectively at 24th month. Totally 16 patients (84.2%) developed dry eye disease and eight of them received radiotherapy below tolerance doses and had mild to moderate dry eye findings. Radiation-induced retinopathy was observed in three of the eyes in eight patients who received radiation above tolerance dose.

Conclusion

Head and neck cancers treated with radiotherapy, resulted in various ophthalmic complications. All patients who are treating with radiotherapy should be evaluated by an ophthalmologist in terms of anterior and posterior segment damage, even if the radiation dose is below the tolerance limit.

Radiation-Associated Chronic Dysphagia Assessment by Flexible Endoscopic Evaluation of Swallowing (FEES) in Head and Neck Cancer Patients: Swallowing-Related Structures and Radiation Dose-Volume Effect

PURPOSE

We aimed to restore dose-volume parameters of swallowing-related structures (SRSs) by evaluating long-term swallowing dysfunctions after radiotherapy (RT) in head and neck cancer patients (HNCPs).

MATERIALS AND METHODS

Head and neck cancer patients whose pharyngeal region was involved in RT portal and treated with definitive RT/chemoradiotherapy (CRT) were included in the analyses. Patients underwent objective swallowing assessment by flexible endoscopic evaluation of swallowing (FEES). Volumes of SRSs that received 55 Gy (V₅₅) (mean dose [D_mean]) were evaluated according to the dose-volume histograms of each patient. For every SRS, optimal dose-volume cut-off values were determined by receiver operating characteristic curve analysis.

RESULTS

Fifty-five patients at a median 20 months (range, 12-26 months) after their treatments were evaluated. There was a strong negative correlation between FEES scores and dose-volume parameters of SRS ( r ⩽ -0.5, P < .0001). According to our results, middle pharyngeal constrictor (MPC) and inferior pharyngeal constrictor (IPC) had a D_mean > 57 Gy, base of tongue (BOT) D_mean > 50 Gy, supraglottic larynx (SGL) and glottic larynx (GL) D_mean > 55 Gy, and cervical esophagus (CE) D_mean > 45 Gy. MPC V₅₅ > 70%, IPC V₅₅ > 50%, BOT V₅₅ > 65%, CE V₅₅ > 40%, and SGL and GL V₅₅ > 50% were significant predictors for dysphagia.

CONCLUSION

It was found that dysphagia correlates strongly with dose-volume parameters of SRSs. IPC, SGL, and CE were found to be structures significantly associated with dysphagia.

Evaluation of the Radiation Dose-Volume Effects of Optic Nerves and Chiasm by Psychophysical, Electrophysiologic Tests, and Optical Coherence Tomography in Nasopharyngeal Carcinoma

PURPOSE

To evaluate the radiation dose-volume effects of optic nerves and chiasm by visual psychophysical, electrophysiologic tests, and optical coherence tomography in patients with locally advanced nasopharyngeal carcinoma.

MATERIALS AND METHODS

A series of visual tests including visual acuity, visual field, contrast sensitivity, visual evoked potential, and optical coherence tomography were administered to 20 patients with locally advanced (T3-T4) nasopharyngeal carcinoma who were treated with definitive chemoradiotherapy. Volume that received 55 Gy (V55), mean dose (Dmean), highest dose to 5% of the volume (D5), and maximum dose (Dmax) for optic nerves and chiasm were evaluated for each patient. Cutoff values were identified as V55: 50%, Dmean: 50 Gy, D5: 55 Gy, and Dmax: 60 Gy. The effects of radiation dose-volume on ophthalmologic tests were evaluated.

RESULTS

Ophthalmological evaluation revealed optic neuropathy with simultaneous retinopathy in 6 eyes of 4 patients and radiation retinopathy alone in both eyes of 1 patient. Regarding radiation dose-volume effects of the optic nerve, significant detrimental effect of all parameters was observed on visual acuity. Visual field and contrast sensitivity were affected significantly with V55 ≥ 50% and Dmean ≥ 50 Gy. Visual evoked potential latency was affected significantly with Dmean ≥ 50 Gy, D5 ≥ 55 Gy, and Dmax ≥ 60 Gy. For the chiasm, significant detrimental effect of all parameters was observed on visual acuity as well. Retinal nerve fiber layer thickness and visual evoked potential amplitude were not affected by any of the dose-volume parameters neither optic nerves nor chiasm.

CONCLUSION

The volume receiving the threshold dose, mean dose, and 5% of the volume receiving the maximum dose are important parameters besides maximum dose to optic nerves and chiasm. A comprehensive ophthalmological evaluation including visual field, contrast sensitivity, visual evoked potential latency, and amplitude should be performed for these patients. Visual evoked potential latency is an objective predictor of vision loss before the onset of clinical signs.