Late Visual and Auditory Toxicity of Radiotherapy for Nasopharyngeal Carcinoma

Radiation-Induced Retinopathy and Optic Neuropathy after Radiation Therapy for Brain, Head, and Neck Tumors: A Systematic Review

Background: Patients with brain, head, and neck tumors experience a decline in their quality of life due to radiation retinopathy and optic neuropathy. Little is known about the dose–response relationship and patient characteristics. We aimed to systematically review the prevalence of radiation retinopathy and optic neuropathy. Method: The primary outcome was the pooled prevalence of radiation retinopathy and optic neuropathy. The secondary outcome included the effect of the total radiation dose prescribed for the tumor according to the patient’s characteristics. Furthermore, we aimed to evaluate the radiation dose parameters for organs at risk of radiation retinopathy and optic neuropathy. Results: The pooled prevalence was 3.8%. No retinopathy was reported for the tumor’s prescribed dose of <50 Gy. Optic neuropathy was more prevalent for a prescribed dose of >50 Gy than <50 Gy. We observed a higher prevalence rate for retinopathy (6.0%) than optic neuropathy (2.0%). Insufficient data on the dose for organs at risk were reported. Conclusion: The prevalence of radiation retinopathy was higher compared to optic neuropathy. This review emphasizes the need for future studies considering retinopathy and optic neuropathy as primary objective parameters.

Prospective study of sensorineural hearing loss following radiotherapy for nasopharyngeal carcinoma

Objectives:

To investigate the severity and incidence of sensorineural hearing loss in patients with nasopharyngeal carcinoma treated with radiotherapy.

Methods:

Forty-two patients with nasopharyngeal carcinoma were treated with conventional radiotherapy. Audiological testing was performed to compare patients' hearing before and at varying stages after radiotherapy.

Results:

At one month post-radiation, a significant hearing threshold increase was seen only for high frequencies. At 12, 24 and 60 months post-radiation, significant threshold increases were observed at speech frequencies (4.0 and 8.0 kHz), compared with pre-radiation data. The mean values of wave I, III and V latencies and of the I–V interpeak latency intervals were not significantly altered at one month post-radiation, but were significantly prolonged at 12, 24 and 60 months post-radiation, compared with pre-radiation data.

Conclusion:

In patients with nasopharyngeal carcinoma treated with radiotherapy, the severity and incidence of radiation-induced sensorineural hearing loss increased with time, especially at high frequencies. This hearing impairment may be due to changes in the cochlea and/or the retrocochlear auditory pathway.

Helical tomotherapy of nasopharyngeal carcinoma-any advantages over conventional intensity-modulated radiotherapy?

Helical tomotherapy uses different planning algorithm and dose delivery method from the linear accelerator (linac)-based intensity-modulated radiotherapy (IMRT). This study compared the dosimetric outcomes between the tomotherapy plans and conventional linac-based IMRT plans in the treatment of nasopharyngeal carcinoma (NPC). Fifteen stage II-III cancer (American Joint Committee on Cancer) NPC patients treated by tomotherapy were conveniently recruited. Apart from the tomotherapy plans, a 7-field 6-MV photon conventional IMRT plan was computed for each patient with the same CT dataset and reference from the dose constraints and target dose prescriptions of the tomotherapy plans using the XiO treatment planning system. Average values of the dose parameters including the conformity index (CI), homogeneity index (HI), maximum and minimum doses of the target volumes, and the maximum and mean doses of the organs at risk (OAR) were compared between the two treatment methods. Better dose coverage of the planning target volume (PTV) was demonstrated in the tomotherapy plans, in which the differences in the maximum and mean doses reached statistical significance (p < 0.05). Besides, the CI of the tomotherapy plans were significantly higher than the conventional linac-based plans for the nasopharynx PTV (NP-PTV) and neck lymphatics PTV (LN-PTV) (p = 0.017 and 0.010, respectively). The HI was significantly smaller in both NP-PTV and LN-PTV (p = 0.024 and < 0.001, respectively). Among the OAR, the brain stem and spinal cord doses in the tomotherapy plans were lower than that of the conventional IMRT plans. However, the doses to the other OAR did not show significant dosimetric differences. In the treatment of nasopharyngeal carcinoma, tomotherapy plans were superior to the 7-field conventional IMRT plans in PTV dose conformity and homogeneity and the sparing of the brain stem and spinal cord. However, no significant advantages were observed for the rest of the OAR.

Choroidal neovascular membrane in radiation retinopathy

Radiation retinopathy can occur years after the initial radiotherapy of the cancers of head and neck. It generally has a fulminant course, and can cause a variety of severe retinal abnormalities. Choroidal neovascularization has been rarely reported in radiation retinopathy. In this case report, a 21-year-old boy is presented who developed fulminant radiation retinopathy and choroidal neovascular membrane 4 years after receiving radiotherapy for his nasopharyngeal carcinoma.

Nasopharyngeal carcinoma in the pediatric age group: the northern Israel (Rambam) medical center experience, 1989-2004

Nasopharyngeal carcinoma (NPC) is rare in children, accounting for less than 1% of all malignancies. Radiation therapy has been the mainstay of treatment of many years, but to improve survival, the use of chemotherapy has been advocated. This is a retrospective analysis of 13 patients less than 20 years of age treated for NPC the Rambam Medical Center during 1989 to 2004. Eight boys and five girls with a median age of 14.5 years (range 10-19) were included. Median follow up (including patients who died) was 6.15 years (range 1-15 years). Duration of symptoms was 1 to 24 months (median 5 months). Of the 13 patients, one patient had stage I, 6 had stage III, 5 had stage IV-A, and 1 had stage IV-B disease. Ten patients (77%) had undifferentiated carcinoma (WHO type III) and three patients (23%) had nonkeratinizing carcinoma (WHO type II). Most of the children received two or three courses of neoadjuvant multiagent chemotherapy consisting of cisplatin and 5-FU, followed by radiotherapy with doses in excess of 60 Gy. One child received concomitant chemoradiation. Ten of the 13 patients (77%) are alive without disease 6 years after diagnosis (range 1-15 years). One patient developed local and distant metastases 1 year after diagnosis and is currently receiving combined radiochemotherapy. Two patients died. Overall survival was 84%; event-free survival was 77%. Nine patients (69%) developed moderate to severe long-term complications. Pediatric NPC is curable by combined radiation and chemotherapy, with doses of radiation in excess of 60 Gy. Long-term follow-up is important for early detection of second malignancies as well as for radiation-induced endocrinologic deficiencies and other normal tissue complications.

Treatment of stage III-IV nasopharyngeal carcinomas by external beam irradiation and local low doses of IL-2

The therapeutic effect of intratumoural application of Interleukin-2 (IL-2) was studied in patients with stage III-IV nasopharyngeal carcinoma (NPC) that received radiotherapy. Patients with stage III-IV NPC receiving a standard treatment of 7,000 cGy external beam irradiation have a mean disease-free survival of about 1.5 years. In this paper, we describe ten of these patients who were treated with additional peritumoural and intratumoural injections with 3 x 10(4) U IL-2 on 5 days in weeks 2, 4, and 6 of the 7-weeks' irradiation period. This combined treatment group was compared with a historical group of patients treated with standard irradiation alone. Local IL-2 therapy showed a marked clinical and statistical significant improvement of disease-free survival. After 5 years, 63% of the IL-2 treated patients were disease-free versus 8% of the control patients. These results suggest that the therapeutic results of radiotherapy can be significantly improved by combining it with local IL-2 treatment. To our knowledge, this is the first clinical report showing that local IL-2 therapy is effective against an infiltrative and locally metastasizing tumour in human patients.