Nasopharyngeal carcinoma: posttreatment changes of imaging findings

The evolution of bone marrow signal changes at the skull base in nasopharyngeal carcinoma patients treated with radiation therapy

BACKGROUND

Clival infiltration is frequently seen in nasopharyngeal carcinoma (NPC) and the resultant bone marrow signal changes (BMSC) can persist even after complete tumor response to the radiation therapy (RT). The differentiation of those residual BMSC from recurrent/persistent disease may be challenging. We performed serial analysis of the clival BMSC after RT, to define an expected temporal evolution of those signal changes during the follow-up.

MATERIALS AND METHODS

Serial MRI studies of 50 NPC patients (with or without initial clival infiltration) who had undergone RT were retrospectively examined. Abnormal clival BMSC and contrast enhancement (CE) were evaluated on each follow-up scan. Duration of BMSC/CE was correlated with the degree of baseline clival involvement (BCID), RT dose, and primary mass volume (PMV).

RESULTS

Clival BMSC persisted without any evidence of recurrence, for a mean of 66.5 (max. 137) months (with accompanying CE for up to 125 months) in 26 patients with clival infiltration at diagnosis. Duration of BMSC and CE showed statistical correlations with PMW (p < 0.05), but not with RT dose or BCID. The rate of recurrence in clivus was 14%. New clival lesions that occurred within the first 12 months after RT (in six patients) did not develop recurrence suggesting radiation osteitis (12%).

CONCLUSION

After RT, residual clival medullary signal change/enhancement is seen in most NPC patients and can persist even years without recurrence.

Clinical value of a plasma Epstein-Barr virus DNA assay in the diagnosis of recurrent or metastatic nasopharyngeal carcinoma: a meta-analysis

BACKGROUND

To evaluate the diagnostic value of Epstein-Barr virus (EBV) DNA in nasopharyngeal carcinoma (NPC) patients with locoregional or distant recurrence.

METHODS

Articles related to the diagnosis of recurrent or metastatic NPC by the detection of EBV DNA in plasma or serum were retrieved from different databases. Sensitivity, specificity, summary receiver operating characteristic (SROC) curves, and likelihood ratios were pooled to assess the diagnostic value of individual diagnostic tests.

RESULTS

This meta-analysis pooled 25 eligible studies including 2496 patients with NPC. The sensitivity, specificity, positive likelihood ratio (+LR), and negative likelihood ratio (-LR) of EBV DNA in the diagnosis of NPC were 0.858 (95% confidence interval (CI): 0.801-0.901), 0.890 (95% CI: 0.866-0.909), 7.782 (95% CI: 6.423-9.429) and 0.159 (95% CI: 0.112-0.226), respectively. The diagnostic odds ratio (DOR) was 48.865 (95% CI: 31.903-74.845). The SROC for EBV DNA detection was 0.93 (95% CI: 0.90-0.95).

CONCLUSION

The detection of EBV DNA for the diagnosis of recurrent or metastatic NPC has good sensitivity and specificity and might be helpful in monitoring recurrent or metastatic NPC.

Choanal Stenosis: An Unusual Late Complication of Radiation Therapy for Nasopharyngeal Carcinoma

Background

Choanal stenosis, usually a congenital anomaly in children, recently has been recognized as a late complication of radiation therapy (RT) for nasopharyngeal carcinoma (NPC).

Methods

We described the clinical history, preoperative evaluation, surgical management, and postoperative course of a case of acquired choanal stenosis after RT.

Results

The patient, a 39-year-old woman, presented with a history of NPC 16 years before presentation that had been successfully treated with RT. On presentation, the patient complained of decreased nasal airflow. Bilateral choanal stenosis was confirmed per rigid nasal endoscopy. Transnasal endoscopic repair with mitomycin application was performed, and nasal stents were left in place for 6 weeks. Postoperative endoscopic examination showed patent choanae and a patent nasopharynx without stenosis. The patient continues to have good airflow 20 months postoperatively.

Conclusion

Choanal stenosis can occur as an unusual complication of RT for NPC secondary to postradiation fibrosis. This is the first report of such a complication in the West.

MRI signal changes in the skull base bone after endoscopic nasopharyngectomy for recurrent NPC: a serial study of 9 patients

PURPOSE

This study was focused on the serial changes in magnetic resonance images (MRI) of the skull-base bone that occur after endoscopic nasopharyngectomy in patients with local recurrent nasopharyngeal carcinoma (rNPC).

MATERIALS AND METHODS

Nine patients with histologically proven rNPC were enrolled in this study. Two experienced radiologists independently reviewed all presurgical and postsurgical MR images for each patient.

RESULTS

At 36 sites on the skull base, the MRI signal underwent a change after surgery, which took the form of a heterogeneous pattern of hypointense regions with moderate contrast enhancement on T1WI. The onset of changes ranged between 2 weeks and 3 months after surgery. For 21 of the sites, the changes subsided over the course of follow-up, while in 6 they remained stable. At 9 sites, the alteration MRI signal became more pronounced with time. Changes were more common on the homolateral side of the skull base with respect to the recurrent tumor (P<0.05). The skull-base bone adjacent to the resection boundary had a higher incidence of signal change than nonadjacent areas (P<0.05).

CONCLUSIONS

MRI changes in the skull base bone, having a number of distinguishing characteristics, appear to be a common sequel to endoscopic nasopharyngectomy for rNPC.

[Post-radiation choanal stenosis]

OBJECTIVE

Description of a rare complication of radiation therapy for nasopharyngeal carcinomas and the therapeutic value of surgical endoscopic desobstruction.

CASE REPORT

A choanal stenosis observed in an 8-year-old boy, 3 years after radiation therapy and chemotherapy for a voluminous nasopharyngeal carcinoma. No initial involvement of the nasal fossa was observed. Concomitant relapse was excluded after clinical and histological examination.

RESULTS

A good functional result was achieved after the choana was unblocked in videoendoscopic surgery. After 9 months of follow-up, the breathing and odor functions remained intact.

CONCLUSION

Choanal stenosis is a rare complication of radiotherapy for nasopharyngeal carcinoma. Relapse should be excluded with biopsies beyond the stenosis. Treatment is based on endoscopic surgery.