Nasopharyngeal carcinoma. Pattern of tumor regression after radiotherapy

Surveillance tools for detection of recurrent nasopharyngeal carcinoma: An evidence-based review and recommendations

Objective

Nasopharyngeal carcinomas (NPC) are tumors arising from epithelium of the nasopharynx. The 5-year survival rate of primary NPC is 80% with significant risks of recurrence. The objective here is to provide an evidence-based systemic review of the diagnostic value of different modalities in detecting local, regional, and distal recurrent NPC, as well as the associated costs with these modalities.

Methods

MEDLINE, EMBASE, and the Cochrane review database were queried. Two hundred and twenty-three abstracts were generated using the inclusion criteria: patients >18 years of age; histopathological reference standard; and modalities pertaining to imaging or microbiology.

Results

Twenty-four manuscripts fulfilled the inclusion criteria and 5 surveillance tools identified: endoscopy, MR, FDG-PET, Tc-99m MIBI and ²⁰¹TI SPECT, and EBV DNA.

Conclusions

For local surveillance, endoscopy is the gold standard recommendation, with increased efficacy if Narrow Band Imaging or contact endoscopy are utilized. MRI and FDG-PET is also recommended to help with local to distal spread; however, Tc-99m MIBI and ²⁰¹TI SPECT are options as well. EBV DNA is recommended as a cheap and accessible adjunct surveillance tool if an available as an option.

Posttreatment Magnetic Resonance Imaging Surveillance of Head and Neck Cancers

Treatment strategies and recommended surveillance imaging differ for head and neck cancers depending on subsite and neoplasm type, and pose confusion for referring physicians and interpreting radiologists. The superior soft tissue resolution offered by magnetic resonance imaging is most useful in the surveillance of cancers with high propensities for intraorbital, intracranial, or perineural disease spread, which most commonly include those arising from the sinonasal cavities, nasopharynx, orbits, salivary glands, and the skin. This article discusses recommended surveillance protocoling and reviews treatment approaches, common posttreatment changes, and pearls for identifying disease recurrence in a subsite-based approach.

Autoantibody Signatures as a Biomarker Panel for the Detection of Nasopharyngeal Carcinoma

OBJECTIVE

The early symptoms of nasopharyngeal carcinoma (NPC) are not obvious, and it is difficult to make early diagnosis. A case-control study was conducted to identify potential biomarkers and established a diagnosis model for nasopharyngeal carcinoma.

METHODS

Plasma samples of 131 cases of NPC and 132 cases of healthy individuals were incubated with the Ray Biotech Human Lung Cancer IgG Autoantibody Detection Array G1, and signal values were used to develop a risk prediction model for NPC diagnosis.

RESULTS

Of the 30 autoantibodies, high expression of MAGE-A4, NY-ESO-1, HuD, Survivin, IMDH2, Ubiquilin-1, IMP1, PGP9.5, IMP3, C-Myc and low expression of Cyclin B1 were potential biomarkers for NPC diagnosis (p <0.05), among which Survivin, MAGE-A4 and IMP3 shows higher AUC of 0.674, 0.652 and 0.650 respectively, the specificity of them was 89.39% (95% CI: 82.85-94.08%), 90.15% (95% CI: 83.75-94.65%) and 88.64% (81.95-93.50%).The risk probability analysis for NPC diagnosis based on the panel of Cyclin B1, NY-ESO-1, Survivin, and IMP3 displayed the best diagnosis performance with an AUC of 0.779, p (Yi = 1) = 1/(1+EXP[8.316+1.672*CyclinB1-1.152*NY-ESO-1-2.052*Survivin-0.950*IMP3]), the specificity of that was 86.36% (95% CI: 79.31-91.71%).

CONCLUSIONS

Our findings demonstrated that the panel of Cyclin B1, NY-ESO-1, Survivin, and IMP3 has a good performance in the detection of NPC, and all 11 autoantibodies may also have a certain significance for the prognosis of NPC.

Efficacy of endoscopy in assessing the local disease response in nasopharyngeal carcinoma patients after treated with intensity-modulated radiotherapy

AIM

The optimal local disease assessment after intensity-modulated radiotherapy (IMRT) for nasopharyngeal carcinoma (NPC) patients remains unclear. Our aim was to investigate the efficacy of post-IMRT endoscopies.

METHODS

The medical record of NPC patients with IMRT treatments during 2013 to 2015 was reviewed. Endoscopies and nasopharyngeal biopsies were performed at 6 weeks post-IMRT. Second biopsies were performed 4 weeks later for patients with abnormal first biopsies. Results of endoscopic assessments were correlated with histology using standard descriptive statistics.

RESULTS

A total of 262 patients were reviewed. Endoscopy showed a sensitivity, specificity, positive predictive value, and negative predictive value (NPV) of 71%, 90%, 41% and 97%, respectively. Disease remission at 6 weeks was observed in 234 patients (89.3%). Sixteen patients (6.1%) had ultimate disease remission (late responders) and 12 (4.6%) had persistent local disease.

CONCLUSION

Endoscopy had high specificity and NPV; therefore, invasive biopsy could be exempted in case of normal endoscopy.

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.

A Predictive Scoring Model for Short-Term Local Recurrent Nasopharyngeal Carcinoma Based on Magnetic Resonance Imaging

OBJECTIVE

To predict the early identification of recurrence based on magnetic resonance imaging (MRI) in nasopharyngeal cancer (NPC) patients.

METHODS

The clinical and MRI data of 215 patients with local recurrent NPC were retrospectively reviewed. Logistic regression analysis was performed to distinguish the independent risk factors for the short-term (less than 24 months) local recurrence of NPC. The predictive score model was based on the regression coefficients of significant independent variables.

RESULTS

Residual disease in the nasopharyngeal cavity (NC), masticator space invasion (MSI), skull base bone erosion (SBBE), and MRI-detected cranial nerve invasion (MDCNI) were all significant independent risk factors for the short-term recurrence of NPC (p < 0.05). The receiver operating characteristic curve showed that the total score had a maximal AUC (area under the curve) value of 0.897, with a cutoff point of 10.50. The sensitivity and specificity were 79.4% and 80.5%, respectively.

CONCLUSION

Residual lesions in NC, MSI, SBBE, and MDCNI are independent risk factors in predicting the short-term recurrence of NPC. The authors' findings suggest that patients with a score of more than 10.50 points should be hypervigilant regarding the possibility of short-term recurrence.

A retrospective study of the prognostic value of MRI-derived residual tumors at the end of intensity-modulated radiotherapy in 358 patients with locally-advanced nasopharyngeal carcinoma

Objective

To retrospectively analyze the prognostic value of magnetic resonance imaging (MRI)-derived residual tumors after intensity-modulated radiation therapy (IMRT) in the patients with locally-advanced nasopharyngeal carcinoma.

Methods

A total of 358 patients with locally-advanced nasopharyngeal carcinoma who received IMRT were classified as having residual tumors or no residual tumor based on MRI at the end of radiotherapy. The χ² test, log-rank test, Cox proportional hazards regression model and Kaplan-Meir survival curves were used to investigate the relationship of clinicopathological features and residual tumors and to assess the prognostic value of residual tumors.

Results

The 3-year overall survival (OS) rate was 73% in the residual tumor group and 90% in the no residual tumor group (HR 2.15, 95% CI 1.21-3.82,, P = 0.007); 3-year local relapse-free survival (LRFS) was 89% in the residual tumor group and 97% in the no residual tumor group (HR 4.46, 95% CI 1.61-12.38, P = 0.002); 3-year disease free survival (DFS) was 67% in the residual tumor group and 82% in the no residual tumor group (HR 2.21, 95% CI 1.40-3.48, P = 0.001). A high prescribed radiation dose (>73.92 Gy) did not increase the percentage volume of the GTVnx receiving 95% of the prescribed dose (GTVnx V95%) or improve any survival outcome.

Conclusion

The presence of a residual tumor after IMRT was a significant negative independent prognostic factor for OS, LRFS and DFS. Although IMRT have improved the distribution of radiotherapy doses into the tumors, residual tumors detected by MRI after IMRT are still associated with poor prognosis in patients with advanced nasopharyngeal carcinoma.

MR imaging prediction of local control of nasopharyngeal carcinoma treated with radiation therapy and chemotherapy

OBJECTIVE

To retrospectively evaluate the association of MRI findings with local control of nasopharyngeal carcinoma (NPC) treated with radiation therapy and chemotherapy (chemoradiotherapy).

METHODS

Pre-treatment MRIs of 101 patients (78 males and 23 females, 23-79 years of age) who had NPC treated with chemoradiotherapy were retrospectively reviewed to evaluate tumour involvement of nasopharyngeal anatomic subsites, tumour volume and MRI appearance. Local control rates were evaluated with respect to these MRI findings.

RESULTS

Univariate analysis (using the Kaplan-Meier method) showed that invasion of the skull base as determined by MRI was a significant predictor of local control. In terms of clinical characteristics, T stage and pathological subtype were significant predictors of local control. Multivariate analysis (Cox regression model) of the radiologic findings and clinical characteristics revealed that invasion of the skull base (p = 0.003) and pathological subtype (p < 0.001) were independent prognostic factors for local control.

CONCLUSION

Invasion of the skull base as determined by MRI predicts the likelihood of local failure and may be helpful in identifying a subset of patients with tumours at risk of local recurrence within 3 years after primary chemoradiotherapy.

ADVANCES IN KNOWLEDGE

It has now become common practice to use MRI for pre-treatment evaluation of patients with NPC. The potential role for MRI findings in predicting local control and prognosis in patients with NPC has implications for treatment planning.

Primary tumor regression speed after radiotherapy and its prognostic significance in nasopharyngeal carcinoma: a retrospective study

BACKGROUND

To observe the primary tumor (PT) regression speed after radiotherapy (RT) in nasopharyngeal carcinoma (NPC) and evaluate its prognostic significance.

METHODS

One hundred and eighty-eight consecutive newly diagnosed NPC patients were reviewed retrospectively. All patients underwent magnetic resonance imaging and fiberscope examination of the nasopharynx before RT, during RT when the accumulated dose was 46-50 Gy, at the end of RT, and 3-4 months after RT.

RESULTS

Of 188 patients, 40.4% had complete response of PT (CRPT), 44.7% had partial response of PT (PRPT), and 14.9% had stable disease of PT (SDPT) at the end of RT. The 5-year overall survival (OS) rates for patients with CRPT, PRPT, and SDPT at the end of RT were 84.0%, 70.7%, and 44.3%, respectively (P < 0.001, hazard ratio [HR] = 2.177, 95% confidence interval [CI] = 1.480-3.202). The 5-year failure-free survival (FFS) and distant metastasis-free survival (DMFS) rates also differed significantly (87.8% vs. 74.3% vs. 52.7%, P = 0.001, HR = 2.148, 95% CI, 1.384-3.333; 91.7% vs. 84.7% vs. 66.1%, P = 0.004, HR = 2.252, 95% CI = 1.296-3.912). The 5-year local relapse-free survival (LRFS) rates were not significantly different (95.8% vs. 86.0% vs. 81.8%, P = 0.137, HR = 1.975, 95% CI, 0.976-3.995). By multivariate analyses, the PT regression speed at the end of RT was the only independent prognostic factor of OS, FFS, and DMFS (P < 0.001, P = 0.001, and P = 0.004, respectively). The 5-year FFS rates for patients with CRPT during RT and CRPT only at the end of RT were 80.2% and 97.1%, respectively (P = 0.033). For patients with persistent PT at the end of RT, the 5-year LRFS rates of patients without and with boost irradiation were 87.1% and 84.6%, respectively (P = 0.812).

CONCLUSIONS

PT regression speed at the end of RT was an independent prognostic factor of OS, FFS, and DMFS in NPC patients. Immediate strengthening treatment may be provided to patients with poor tumor regression at the end of RT.

Quantitative analysis of plasma cell-free Epstein-Barr virus DNA in nasopharyngeal carcinoma after salvage nasopharyngectomy: A prospective study

BACKGROUND

The quantity of circulating cell-free Epstein-Barr virus (EBV) DNA in patients with nasopharyngeal carcinoma (NPC) managed by radiotherapy has prognostic relevance. We measured the copy number of EBV DNA in patients with early recurrent NPC before and after salvage nasopharyngectomy.

METHODS

Nasopharyngectomy with the maxillary swing approach was performed for 28 patients. Serum blood samples were taken prospectively before nasopharyngectomy and on postoperative day 7. Plasma cell-free EBV DNA copies were measured with a real-time quantitative polymerase chain reaction for the BamHI-W fragment of the EBV genome.

RESULTS

Cell-free EBV DNA was detected in 17 patients before nasopharyngectomy. Surgical resection reduced the copy number of EBV DNA significantly (p = .016). Negative surgical margins achieved during nasopharyngectomy is associated with a zero EBV DNA copy postoperatively (p = .022).

CONCLUSION

Cell-free EBV DNA was detected in 61% of patients with recurrent NPC, and its quantity postoperatively reflects whether the salvage nasopharyngectomy has achieved a negative surgical margin.

False positive fluorine-18 fluorodeoxy-D-glucose positron emission tomography finding caused by osteoradionecrosis in a nasopharyngeal carcinoma patient

Nasopharyngeal carcinoma (NPC) is treated by radiotherapy with or without chemotherapy. It is not uncommon to find the residual/recurrent lesion in the skull base area. For patients who had received radiotherapy, it is difficult to differentiate the skull base tumour from post-treatment change in the CT or MRI. (18)F-2-fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) provides an alternative diagnostic choice in this situation for head and neck cancer including NPC especially when there is inconclusive CT/MRI finding. This report of an NPC patient who received radiotherapy 18 months previously, describes the misdiagnosis of tumour recurrence at the skull base found in both MRI and FDG PET scan. Histopathological studies showed osteoradionecrosis of the debrided tissue and follow-up PET showed complete regression of the skull base lesion. Therefore, a false positive result in FDG PET caused by osteoradionecrosis was confirmed. To the best of our knowledge, this is the first case report in the literature.

Nasopharyngeal carcinomas: an update

Among the group of head and neck cancers, nasopharyngeal carcinomas (NPC) represent a distinct entity in terms of their epidemiology, clinical presentation, biological markers, carcinogenic risk factors, prognostic factors, treatment and outcome. Undifferentiated NPC (UCNT), the most frequent histological type, is endemic in certain regions, especially in South East Asia. The disease has also been associated with the presence of the Epstein-Barr Virus (EBV). Although NPC is a radiosensitive and chemosensitive tumour, a substantial number of patients develop local recurrence or distant metastases. For patients with locoregional advanced disease, it is well known that conventional radiotherapy is insufficient in terms of both the local control rates and distant metastases. New techniques of radiation and new combined radiotherapy and chemotherapy modalities have been evaluated in numerous clinical trials in recent years. The purpose of this article is to review the current knowledge in terms of the epidemiology, biology, prognosis, management and outcome of patients with NPC.

Detection of Recurrent or Residual Nasopharyngeal Carcinomas After Radiotherapy with Technetium-99m Tetrofosmin Single Photon Emission Computed Tomography and Comparison with Computed Tomography—A Preliminary Study

The effectiveness of technetium-99m tetrofosmin (Tc-TF) single photon emission computed tomography (SPECT) of the head and neck for detecting recurrence of nasopharyngeal carcinomas (NPC) was evaluated and compared with computed tomography (CT). Both Tc-TF SPECT and CT of the head and neck were performed in 36 NPC patients 4 months after radiotherapy. All 36 then underwent histopathological examinations of nasopharyngeal biopsies. Based on the histopathological results, the sensitivity, specificity, and accuracy of visually interpreted Tc-TF SPECT images, to differentiation of recurrent NPC from benign lesions, were 64%, 96%, and 86%, respectively. The sensitivity, specificity, and accuracy of CT for detecting recurrent NPC were 73%, 88%, and 83%, respectively. The Tc-TF SPECT has a better specificity but a lower sensitivity to differentiate benign lesions and recurrent/residual NPC when compared with CT. Combined Tc-TF SPECT and CT sensitivity and specificity were 100% and 88%, respectively. There are much better either test alone. However, further studies, including a larger NPC patient population, are warranted to determine the exact role and clinical usefulness of Tc-TF SPECT to differentiate benign lesions and recurrent/residual NPC.

Detection of Recurrent Nasopharyngeal Carcinomas After Radiotherapy with Technetium-99m Tetrofosmin Single Photon Emission Computed Tomography in Patients with Indeterminate Magnetic Resonance Imaging Findings

The aim of this study is to evaluate the effectiveness of technetium-99m tetrofosmin (Tc-99m TF) single photon emission computed tomography (SPECT) of head and neck for detecting suspected recurrence of nasopharyngeal carcinomas (NPCs) when magnetic resonance imaging (MRI) findings are indeterminate. MRI was performed 4 months after radiotherapy and 26 NPC patients with indeterminate MRI findings were included. MRI, Tc-99m TF SPECT, and biopsy were performed within 1 week. The final results were based on histopathologic findings and clinical follow-up for at least 6 months. For detecting recurrent NPC in indeterminate MRI findings, the sensitivity, specificity, and accuracy of Tc-99m TF SPECT were 92.3%, 100.0%, and 96.2%, respectively. Based on this result, we can suggest Tc-99m TF SPECT is effective to detect recurrent NPC when MRI findings are indeterminate. However, further studies including a larger NPC patient population are warranted to determine the exact role and clinical usefulness of Tc-99m TF SPECT to differentiate benign lesions and recurrent NPC when MRI findings are indeterminate.

Using thallium-201 SPECT to detect recurrent or residual nasopharyngeal carcinoma after radiotherapy in patients with indeterminate CT findings

BACKGROUND

The aim of this study is to evaluate the usefulness of thallium-201 (Tl-201) single-photon emission CT (SPECT) to detect recurrent or residual nasopharyngeal carcinomas (NPC) when CT findings are indeterminate.

METHODS

After radiotherapy, 30 NPC patients with indeterminate CT findings were included. CT, Tl-201, and biopsy were performed at least 4 months after radiotherapy and within 1 week of each other. The final results were based on histopathologic findings and clinical follow-up after at least 6 months.

RESULTS

The rates for sensitivity, specificity, and accuracy of Tl-201 SPECT in detecting recurrent or residual NPC when there were indeterminate CT findings, were 86.7%, 93.3%, and 90.0%, respectively.

CONCLUSIONS

These results suggest that Tl-201 SPECT is effective in detecting recurrent or residual NPC when CT findings are indeterminate.

Nasopharyngeal carcinoma: posttreatment changes of imaging findings

OBJECTIVE

The purpose of this study was to determine the radiologic results of nasopharyngeal carcinoma (NPC) that showed complete responses on follow-up imaging studies after radiation therapy.

MATERIALS AND METHODS

This study is a retrospective review of 23 patients (18 male, 5 female, aged 15-71 years; mean age, 48.5 years) affected with NPC, from August 1995 to July 2000, who were examined with magnetic resonance imaging or computed tomography scan before and after either radical radiotherapy or chemoradiotherapy. The median follow-up was 24.7 months and ranged from 12 to 48 months. We analyzed the primary tumors by ascertaining/measuring tumor size, depth, middle ear effusion, skull base invasion, and lymphadenopathy. The treatment responses for primary tumors were classified as either atrophy, scar (asymmetric elevation without enhancement), or normalized. The tumor response and the appearance of bone regeneration in the previous destructive part of the skull base were also recorded.

RESULTS

The 23 patients consisted of 12 superficial tumors, for whom treatment results were normalized in 10, atrophy in 1, and scar in 1 and 11 deep tumors for whom treatment results were scar in 6, normalized in 3, and atrophy in 2. Skull base invasion was detected in 6 patients, 5 of whom showed complete healing of skull base destruction after radiotherapy. However, the other patient exhibited an unusual hyperostotic change in the skull base mimicking fibrous dysplasia of the skull base.

CONCLUSIONS

The superficial tumors tended to be radiologically normalized even when they were large. However, the deep tumors mainly changed to scar after radiation therapy. On the other hand, skull base invasion could be normalized after radiotherapy.

Posttreatment imaging of the nasopharynx

Nasopharyngeal carcinoma (NPC) is the most common epithelial tumor of the nasopharynx. Radiation therapy is the mainstay of treatment while surgery or chemotherapy is used in selected patients. NPC usually regresses after 3 months of radiation therapy. Nonetheless, a residual mass may be present following treatment and this does not necessarily indicate viable tumor. Imaging studies are often used in conjunction with clinical examination following treatment. While computed tomography (CT) is widely used due to its greater availability, less expensive, and less time consuming, MR imaging is now becoming the preferred modality. MR imaging is more capable than CT for identifying mature scarring, tumor recurrence and postradiation complications. However, MR imaging cannot reliably demonstrate mucosal recurrence or differentiate tumor recurrence from postradiation tissue changes. Familiarity with the imaging findings of various posttreatment changes, tumor recurrence and postradiation complications is essential for management of NPC. Comparison with previous images or imaging-guided biopsy facilitates definitive diagnosis.

Detection of recurrent or persistent nasopharyngeal carcinomas after radiotherapy with technetium-99m methoxyisobutylisonitrile single photon emission computed tomography and computed tomography: comparison with 18-fluoro-2-deoxyglucose positron emission tomography

BACKGROUND

The diagnostic accuracy of technetium-99m methoxyisobutylisonitrile (Tc-MIBI) single photon emission computed tomography (SPECT) and computed tomography (CT) of the head and neck for differentiating recurrent or residual nasopharyngeal carcinomas (NPC) from benign lesions after radiotherapy was compared with positron emission tomography (PET) with 18-fluoro-2-deoxyglucose (FDG).

METHODS

Thirty six NPC patients underwent head and neck CT, Tc-MIBI SPECT, and FDG-PET four months after radiotherapy to differentiate recurrent or residual NPC from benign lesions. Histopathologic examinations of nasopharyngeal biopsies were performed for all 36 patients. No patients had multiple foci of NPC.

RESULTS

Based on biopsy results, the sensitivity, specificity, and accuracy of CT for differentiating recurrent or residual NPC from benign lesions were 73%, 88%, and 83%, respectively. The sensitivity, specificity, and accuracy of Tc-MIBI SPECT were 73%, 96%, and 89%, respectively. The sensitivity, specificity, and accuracy of FDG-PET were 100%, 96%, and 97%, respectively. Combination CT and Tc-MIBI SPECT for 28 NPC patients with congruent results showed the same sensitivity, specificity, and accuracy of 100%, 96%, and 96%, respectively, as FDG-PET for differentiating recurrent or residual NPC from benign lesions. In eight patients with incongruent results between CT and Tc-MIBI SPECT, FDG-PET correctly differentiated two benign lesions and six recurrent or residual NPCs.

CONCLUSIONS

In detecting recurrent or residual NPC, FDG-PET is the best tool. However, combined use of CT and Tc-MIBI SPECT can result in the same accuracy as FDG-PET.

Comparing 18-fluoro-2-deoxyglucose positron emission tomography with a combination of technetium 99m tetrofosmin single photon emission computed tomography and computed tomography to detect recurrent or persistent nasopharyngeal carcinomas after radiotherapy

BACKGROUND

The diagnostic accuracy of combined computed tomography (CT) and technetium 99m tetrofosmin (Tc-TF) single photon emission computed tomography (SPECT) of head and neck to differentiate recurrent or residual nasopharyngeal carcinomas (NPCs) from benign lesions after radiotherapy was evaluated and compared with positron emission tomography (PET) with 18-fluoro-2-deoxyglucose (FDG).

METHODS

Four months after radiotherapy, 36 patients with NPC underwent Tc-TF SPECT and CT of head and neck to differentiate recurrent or residual NPC from benign lesions. Histopathologic examinations were performed on nasopharyngeal biopsies of all 36 patients.

RESULTS

Based on the biopsy results, the sensitivity, specificity, and accuracy of Tc-TF SPECT were 64%, 96%, and 86%, respectively, for differentiation of recurrent or persistent NPC from benign lesions. For CT and FDG-PET, the sensitivity, specificity, and accuracy were 73%, 88%, and 83% and 100%, 96%, 97%, respectively. For the 27 patients with NPC whose Tc-TF SPECT and CT results were congruent, the combination of Tc-TF SPECT and CT had the same sensitivity, specificity, and accuracy (100%, 96%, and 96%) as FDG-PET. For the nine patients with NPC with incongruent Tc-TF SPECT and CT results, FDG-PET correctly differentiated two benign lesions from seven recurrent/residual NPCs.

CONCLUSIONS

Although, FDG-PET is the best tool for detecting recurrent or residual NPC, combined congruent Tc-TF SPECT and CT results achieved the same accuracy as FDG-PET. Therefore, we concluded that FDG-PET could be considered only when Tc-TF SPECT and CT give incongruent results.

Preliminary study of in vivo autofluorescence of nasopharyngeal carcinoma and normal tissue

BACKGROUND AND OBJECTIVE

In nasopharyngeal cancer, conventional white light endoscopy does not provide adequate information to detect the flat/small lesion and identify the margin of observable tumor. In the present study, we evaluate the potential of light-induced fluorescence spectroscopic imaging for the localization of cancerous nasopharyngeal tissue.

STUDY DESIGN/MATERIALS AND METHODS

We built a multiple channel spectrometer specifically for the investigation of fluorescence collected by a conventional endoscopic system. Nasopharyngeal fluorescence were measured in vivo from 27 subjects during the routine endoscopy. The biopsy specimens for histologic analysis were taken from the tissue sites where the fluorescence were measured.

RESULTS

Two algorithms to discriminate the nasopharyngeal carcinoma from normal tissue were created based on the good correlation between the tissue autofluorescence and histologic diagnosis. For the two-wavelength algorithm, carcinoma can be differentiated from normal tissue with a sensitivity and specificity of 93% and 92%, respectively. For the three-wavelength algorithm with compensation of variation of blood content in tissue, a sensitivity of 98% and specificity of 95% were achieved.

CONCLUSION

Fluorescence endoscopic imaging used with the algorithms developed in this report is an efficient method for detecting the nasopharyngeal carcinoma.

Phase I/II dose escalation study of docetaxel and carboplatin combination supported with amifostine and GM-CSF in patients with incomplete response following docetaxel chemo-radiotherapy: additional chemotherapy enhances regression of residual cancer

Taxanes have been shown to interact with anti-apoptotic proteins. In the present study we investigated whether the addition of taxane in combination with DNA damaging drugs can further enhance tumor shrinkage in cases with incomplete response to radiotherapy. Since the dose of docetaxel in combination with carboplatin is not known, the above hypothesis was tested in the context of a dose escalation phase I study. Twenty-eight patients with locally advanced chest or pelvic tumors, showing residual disease on CT scans performed 40 d following docetaxel radio-chemotherapy, were recruited in a dose escalation protocol of docetaxel/carboplatin supported with amifostine and GM-CSF. The starting dose of docetaxel was 40 mg/m2 every 2 weeks. Carboplatin dose was calculated using the Calvert formula and was escalated in cohorts of 4 patients (starting dose AUC2 every two weeks; AUC0.5 increments up to AUC3). Thereafter the docetaxel dose was increased to 50 and 60 mg/m2, while carboplatin was escalated (by AUC0.5 increments) starting from AUC3 and AUC4 respectively. Amifostine (600 mg/m2) was administered i.v. before carboplatin and GM-CSF (480 microg) was injected s.c. on days 5, 6 and 10, 11 of each cycle. Six cycles were given and response was assessed 2 weeks after the end of chemotherapy. None out of four patients treated in the 6th dose level cohort (50 mg/m2 of docetaxel and AUC4 of carboplatin every 2 weeks) showed any grade 2-4 hematologic toxicity. Mild non-hematologic toxicity such as neuropathy, leg edema, pleural effusion, pyrexia, alopecia grade 2 and hypersensitivity was observed in 4-12% of patients. Out of four patients treated in a 7th cohort (docetaxel 60 mg/m2 and carboplatin AUC4), one developed grade IV neutropenia and two developed grade 3 severe asthenia requiring treatment delay for 2 weeks. Out of 11 patients with PR following docetaxel radio-chemotherapy, 7 (63%) showed CR after docetaxel/carboplatin additional chemotherapy. Eight out of 17 patients with MR following docetaxel radio-chemotherapy showed PR (47%) and one showed CR (6%) after additional chemotherapy. High dose combined docetaxel (50 mg/m2) and carboplatin (AUC4) chemotherapy can be safely administered on a two-weekly basis if supported with amifostine and GM-CSF. Such an additional therapy may be important in patients with incomplete response after chemo-RT. Broad spectrum cytoprotection with amifostine and GM-CSF may also contribute to the reduction of incidence of neurosensory reactions and asthenia in patients treated with taxanes.

Radiation-induced expression of functional Fas ligand in EBV-positive human nasopharyngeal carcinoma cells

Ionizing radiation remains a major therapeutic tool against human cancers, especially epithelial tumors, which account for the majority of human malignancies. Although Fas and Fas-L are essential determinants of apoptosis, few data support their role in the cytotoxic effect of ionizing radiation. Epstein-Barr-virus (EBV)-positive nasopharyngeal carcinoma (NPC) were chosen to address this question owing to their known sensitivity to ionizing radiation and their constitutive expression of the Fas-receptor. We here report that, in xenografted NPC cells, Fas-L expression, which was very low in basal conditions, was dramatically increased by tumor irradiation. Both the Fas receptor and the Fas ligand were found to be functional in this model, and a high proportion of irradiated NPC cells underwent apoptosis following tumor irradiation. Induction of Fas-L expression and apoptosis were observed for doses as low as 2 Gy. These data show an increase in Fas-L expression upon irradiation exposure, and strongly suggest that, in some epithelial malignancies, Fas-mediated apoptosis can play a major role in the anti-tumor effect of ionizing radiation, in the range of doses used for therapeutic applications.

Meningeal infiltration in recurrent nasopharyngeal carcinoma

Permeative infiltration of the meninges appears to be a distinct form of recurrent nasopharyngeal carcinoma (NPC). The present report of eight patients with recurrent NPC illustrates meningeal infiltration following basal foramina extension. Seven of the eight patients (88%) showed jugular foramen involvement. Three patients had concomitant infiltration of the foramen magnum. There was one patient showing spread through the foramen lacerum. Only four (50%) of these patients had clinically detectable tumour in the nasopharynx, while the other half showed deep submucosal recurrence with endoscopically unremarkable findings. Permeative meningeal infiltration appears to be a distinct form of NPC recurrence. It is important to recognize this phenomenon so as to optimize the treatment options.

The time course of histologic remission after treatment of patients with nasopharyngeal carcinoma

BACKGROUND

The objective of this study was to define the time course of histologic remission and to evaluate the prognostic significance of delayed histologic remission of patients with nasopharyngeal carcinoma (NPC).

METHODS

Between 1986-1994, 803 patients underwent serial postradiotherapy nasopharyngeal biopsies. Patients with positive histology underwent repeated biopsies every 2 weeks until the biopsies were found to be negative or, if remission did not occur by the 12th week after radiotherapy, treatment was initiated for persistent disease. Patients with positive histology found after the fifth week but who achieved spontaneous remission before the twelfth week were considered to have delayed histologic remission. Negative histology by the sixth week was considered early histologic remission. The outcome of patients with delayed histologic remission, early histologic remission, and persistent disease were compared.

RESULTS

Six hundred and seventeen patients (76.8%) had negative histology within 12 weeks of the completion of radiotherapy and 55 (6.9%) had persistent disease at Week 12. In 131 patients (16.3%) spontaneous remission was observed in repeat biopsies after initial positive histology. With increasing time after radiotherapy, the incidence of positive histology decreased but more patients were found to have persistent disease. Patients with early and delayed histologic remission had 5-year NPC control rates of 82.4% and 76.8%, respectively (P = 0.35) versus a 40% NPC control rate among patients with persistent disease (P < 0.001). The 5-year survival rates were 75.3%, 79.4%, and 54.2%, respectively, for the 3 groups (P < 0.001).

CONCLUSIONS

A high proportion of early positive histology remitted spontaneously. Delayed histologic remission in NPC patients is not a poor prognostic factor and additional treatment is not necessary. A confirmatory biopsy at 10 weeks is recommended before the initiation of salvage treatment.

Carcinoma of the nasopharynx

Nasopharyngeal carcinoma (NPC) is an intriguing disease that shows a distinct geographical distribution with well-defined, high-risk ethnic groups. This neoplasm exhibits strong associations with the Epstein-Barr virus, dietary and genetic factors. Radiation therapy is the mainstay of treatment and imaging plays a central role in tumor mapping and radiation therapy planning. NPC provides an excellent model for the study of normal and pathological anatomy of the skull base. It also provides an excellent model in the study of consequences of radiation therapy.

MRI of nasopharyngeal carcinoma with emphasis on relationship to radiotherapy

MRI has been used increasingly in the evaluation of nasopharyngeal carcinoma (NPC) because of its good tissue contrast and multiplanar capacity. Although there are some controversies in assessing skull base invasion and cervical metastatic adenopathy, recent reports demonstrate that MRI is currently better than or as good as CT in defining the extent of NPC. During follow-up of patients with NPC after radiotherapy, MRI is also more effective than CT in demonstrating tumor recurrence and in detecting postradiation complications. However, the difficulty of using MRI to detect early mucosal recurrence and to differentiate postradiation tissue changes from local tumor recurrence should be recognized. This paper reviews the literature regarding MRI of NPC related to radiotherapy, with special emphasis on treatment planning, recurrence assessment, and complication detection.

Expression of p53 in recurrent nodal metastasis from nasopharyngeal carcinoma (NPC)

This study reports the incidence of p53 expression in 40 patients with recurrent nodal metastasis from nasopharyngeal carcinoma (NPC) and its prognostic value in this group of patients. Immunohistochemical staining using monoclonal antibody specific for human p53 protein was performed on the tumour-bearing nodes from 40 patients. The results were divided into four grades (I, negative; II, < 10% of cells positive; III, 10-50% of cells positive; and IV, > 50% of cells positive). The staining scores were correlated with histological tumour types, subsequent recurrence and survival. All patients had undergone neck irradiation. Lymph node specimens from six patients (15%) showed positive staining of nuclear p53 protein. The distribution among the different grades was: three (7.5%) for II, two (5%) for III and one (2.5%) for IV. Patients with p53-overexpressed tumours had a significantly higher number of tumour-bearing lymph nodes. There was no correlation of p53 expression with histological tumour types, second tumour recurrence and survival. Expression of p53 appears to be uncommon in patients with recurrent nodal metastases in NPC. It did not have prognostic value in this particular series of patients.

A comparative study of technetium-99m sestamibi and technetium-99m tetrofosmin single-photon tomography in the detection of nasopharyngeal carcinoma

The intention of this prospective study was to compare the diagnostic potential of technetium-99m sestamibi (MIBI) and a novel radiotracer, 99mTc-Tetrofosmin (Tetro), for the assessment of primary nasopharyngeal carcinoma (NPC) and the differentiation of residual disease from post-therapy changes. A total of 38 patients underwent MIBI and Tetro single-photon emission tomography (SPET) imaging at initial presentation (n=22) or following therapy (n=16). The findings were correlated with computed tomography or magnetic resonance imaging (MRI) on a site-by-site basis. Tumour/background (Tm/Bkg) ratios were obtained on coronal sections. Biopsy (nine patients) and/or 12- to 24-month clinical follow-up data were available in the post-therapy group. All primary disease sites were accurately detected by both imaging studies. Although there was no statistical difference between the two imaging techniques in the detection of primary disease, MIBI was superior to Tetro in the detection of regional lymph node metastases (sensitivity: 95% vs 79%). Tetro and MIBI SPET were true-positive in all patients (n=7) with proven residual/recurrent disease. In nine patients who had no evidence of residual/recurrent tumour, MRI was false-positive in five while Tetro and MIBI SPET were false-positive in two and three patients, respectively. Tm/Bkg ratios were </=1.7 in all false-positive cases except one. Tetro, MIBI and MRI had specificities of 78%, 67% and 44%, and accuracies of 87.5%, 81% and 69%, respectively. The results of Tetro and of MIBI SPET were not statistically different from one another with regard to the prediction of residual/recurrent or metastatic NPC.

Intracavitary radiotherapy boosting for nasopharynx cancer

Intracavitary radiotherapy is conceptually an attractive method of boosting dose to nasopharynx cancer whilst sparing sensitive normal tissues. A high dose rate (HDR) microselectron can be used to deliver a brachytherapy boost conveniently, safely, comfortably and effectively. Following external radiotherapy a single outpatient treatment has been given to patients using the remote afterloading system of sources placed in modified paediatric endotracheal tubes. This has been associated with good primary control and no evidence of serious morbidity in eight patients. The main limitation of this method is restriction of its utilization to small volume primary disease.

High dose rate intracavitary brachytherapy in the treatment of nasopharyngeal carcinoma

A retrospective study on 61 patients, with local persistent or recurrent nasopharyngeal carcinoma (NPC), treated during 1990-1992 with high dose rate intracavitary brachytherapy alone or combined with external irradiation, is presented. All 39 patients with persistent disease were treated solely with brachytherapy. The actuarial 3-year local failure-free survival (LFFS) rates of the persistent and recurrent groups were 82% and 45% respectively. The corresponding disease specific survival rates were 82% and 62%. Fifteen patients with recurrence received the combined modality treatment and their 3-year LFFS rate was 65%. Three out of 7 patients treated by brachytherapy could be controlled locally. The total dose given to the floor of sphenoid was an important predictor of local control. Of the 23 patients with persistent disease treated with < 17.5 Gy to this area, 6 failed locally as opposed to none of the 16 patients receiving a higher dose (p = 0.031). For those with recurrence treated by the combined modality, none of the 7 patients given >/= 57.5 Gy recurred while 5 local failures were observed among those receiving a smaller dose (p = 0.041). The general implications of these results for the treatment of NPC recurrence are discussed.

Afterloading radiotherapy for local persistence of nasopharyngeal carcinoma

71 patients suffering from local persistence of nasopharyngeal carcinoma after primary external radiotherapy were treated by afterloading intracavitary 192Ir. 66 (93.0%) had a complete response as evidenced by fibreoptic nasopharyngoscope examination and biopsy 4 weeks after the treatment. Significant prognosticators were studied by both monovariate and multivariate analysis. The early overall clinical stage at first presentation predicted a favourable survival. Local tumour control was adversely affected by advanced T-stage at first presentation, and by using a single 192Ir source, unilaterally applied to treat only one side of the nasopharynx. The intracavitary treatment was tolerated well and treatment complications were confined to the nasopharynx: chronic radiation ulceration (five patients) and diffuse telangiectasia (three patients).

Nasopharyngeal carcinoma: local control by megavoltage irradiation

This is a retrospective analysis of the long-term local control in 4128 patients with non-disseminated nasopharyngeal carcinoma treated solely by megavoltage irradiation during the years 1976-1985. The T-stage distribution according to Ho's classification was T1 37%, T2 14% and T3 49%. Different fractionation schedules had been employed at different periods, and the median dose to the primary target was equivalent to 65 Gy by time dose fractionation calculation. In 8% (344) of patients the tumour failed to regress completely after the basic course, but 89% (148/167) of those suitable for salvage with additional irradiation eventually attained complete local remission. The cumulative incidence of local failure was 24% (5% persistence, 19% recurrence). The 10-year actuarial local failure-free survival was 67%. While patients with T2 and T3a tumours achieved local control comparable to T1, those with T3c-d had the poorest control (with highest incidence of persistence and advanced recurrence). T-stage adjusted analyses suggested a significant trend of dose-response: the odds ratios for local failure were 1.16 and 1.86, respectively, when patients given 60-63 Gy and 55-59 Gy were compared with those given 64 Gy or above (p value = 0.0018). Patients treated during 1981-1985 achieved higher local failure-free survival than those treated during 1976-1980 (75% versus 70% at 5 years, p value = 0.0013). The possible attributes are studied, and ways for future optimization of treatment discussed.

CT-based radiotherapy treatment planning for cancer of the nasopharynx

We analysed 32 cases of nasopharyngeal carcinoma (NPC) treated with radiotherapy trying to define the role of CT scan during radiotherapy planning, as well as radiation treatment and the follow-up of the patients. CT scan was found to help 15 cases with low-parapharyngeal involvement and/or bone erosion. Persistent abnormal CT findings at 2 mo after the end of radiation treatment were related to a 30% local recurrence rate. This rate went up to 100% in case of skull-base destruction.

Transpalatal insertion of radioactive gold grain for the treatment of persistent and recurrent nasopharyngeal carcinoma

PURPOSE

To evaluate the efficacy of radioactive gold grain implant via the split palate approach in the control of locally recurrent or persistent nasopharyngeal carcinoma.

METHODS AND MATERIAL

Forty-three patients, 10 for persistent NPC, 28 for first relapse in the nasopharynx, and five for second relapse in the nasopharynx, were treated. The diameter of the tumors at the time of gold grain implant ranged from 0.5 to 5 cm, the number of gold grains inserted varied from 4 to 14, the median number was seven.

RESULTS

There was no significant difference in the control of the primary tumor for persistent disease (80% at 5 years), first relapse (61% at 5 years) and second relapse (80% at 3 years), p = 0.8845. The difference in survival between the three subgroups of patients, however, was highly significant (p = 0.0040). Thirty patients had CT evaluation before gold grain implant and the tumor was found confined to the nasopharynx in 21, in the remaining nine patients erosion of the sphenoid sinus or other parts of the base of skull was noted. The difference in the control between those patients with tumors confined to the nasopharynx and those patients with extranasopharyngeal extension of tumor almost reached statistical significance (81% and 44% respectively at 5 years, p = 0.0554). For the six patients who developed local recurrence after gold grain implant and were evaluable for the pattern of failure, the recurrent tumors were considered originating from another region of the nasopharynx in four, and in-field failure in the other two cases.

CONCLUSION

Radioactive gold grain implant as salvage treatment provides satisfactory control of persistent and recurrent nasopharyngeal carcinoma. The local control was better when the tumor was localized to the nasopharynx, thus underlines the importance of close follow-up for early recognition of relapse and persistent tumor. However, such patients still suffered from high incidence of regional and distant failure, the pathophysiology and management of which require further investigation.

Radiation therapy for nasopharyngeal carcinoma: histologic appearances and patterns of tumor regression

Nasopharyngeal carcinoma is a common malignancy in Hong Kong and is treated by external radiotherapy. After 6.5 weeks of radiotherapy, the nasopharynx of 100 patients was examined and biopsy specimens were taken. All patients had repeated examination and biopsies done every 2 weeks until exophytic tumor was not seen and biopsy samples were negative on more than one examination of the nasopharynx. The interval between the cessation of therapy and biopsy ranged from 1 day to 11 weeks. Twenty-three patients had atypical findings and five of these had residual tumor requiring gold grain implantation brachytherapy. We identified a number of distinct pathologic changes in the post-biopsy material. Most of these changes disappeared 8 weeks after the cessation of therapy, but the presence of residual tumor after this time was an indication for subsequent therapy. If the date of the first biopsy was delayed until 6 weeks after the completion of radiotherapy, the percentage of atypical biopsies containing residual tumor rose from 21% to 55%. The posttreatment biopsy should be performed twice, as four patients had negative biopsy findings due to sampling error.

Value of clinical follow-up for local nasopharyngeal carcinoma relapse

Three hundred seventy-nine new patients with nasopharyngeal carcinoma (NPC) were followed clinically and the physical examination, including that of the nasopharynx by indirect mirror for symptoms after treatment. At the time of analysis, with a median follow-up of 34.8 months, 47 patients had developed recurrent disease in the nasopharynx and in the immediately adjacent regions. In 31 patients the first clinical features to suggest local recurrence were progressive symptoms (group A). In another 13 patients recurrence of tumor in the nasopharynx was detected by indirect mirror examination (group B). In the remaining three patients, the diagnosis was made during investigation for neck node recurrence. The more common symptoms at diagnosis of local recurrence were headache; cranial nerve palsy involving the third, fourth, fifth, and sixth nerves; and ear and nasal symptoms. Group B patients tended to have less of these symptoms. The presence of tumor was confirmed by fiberscopic examination and biopsy in all group B patients and 14 of 31 group A patients, the tumor was submucosal in the remaining 17 group A patients. The recurrence in group B patients was diagnosed significantly earlier than the group A patients (p = 0.0294), and group A patients suffered from more invasive and extensive disease in comparison with group B patients (p = 0.0044). There were significantly less patients in group A who were amenable to curative brachytherapy (p = 0.0280). Clinical follow-up for local NPC recurrence was found to be useful. More frequent use of fiberscopic examination in the follow-up, especially for those not adequately examined by indirect mirror examination, will improve the detection rate. Cross-sectional imaging techniques and the monitoring of tumor markers may supplement clinical and fiberscopic examinations. An algorithm for diagnosing recurrent NPC and possible treatment are suggested.

Prognostic value of paranasopharyngeal extension of nasopharyngeal carcinoma on local control and short-term survival

The local tumor control of 262 patients with nasopharyngeal carcinoma (NPC) at median follow-up of 27 months was studied with reference to the paranasopharyngeal and other aspects of extranasopharyngeal extension of tumor, as well as to other possible prognostic factors. Only cranial nerve palsy, oropharyngeal involvement, and paranasopharyngeal extension of tumor were found to be significant in a multivariate analysis using Cox model for factors influencing local tumor control. Other factors and other parameters of extranasopharyngeal extension of tumor, namely, erosion of the base of skull, intracranial extension, and involvement of nasal fossa, were found not be significant. The degree of paranasopharyngeal extension in each side was correlated with scales measuring extranasopharyngeal extension of tumor in other directions (p = 0.001). Although the T stage and the paranasopharyngeal extension were individually found to be well correlated with local tumor control, the prognostic value of paranasopharyngeal extension remained significant among subgroups of patients with T3 and T4 disease (p = 0.1044 and 0.0010, respectively).

The efficacy of fiberoptic endoscopic examination and biopsy in the detection of early nasopharyngeal carcinoma

Fiberoptic endoscopic examination and biopsy of the nasopharynx was done in 130 patients as a prospective study. They all had elevated titers of antibodies against the viral capsid antigen of Epstein-Barr virus but no symptoms or signs of nasopharyngeal carcinoma. Each underwent a biopsy from six fixed sites in the nasopharynx. Of the 780 biopsy specimens taken from seven patients, 11 showed the presence of nasopharyngeal carcinoma. Techniques to improve the yields of such biopsies with fiberoptic endoscopy are discussed. The presence of tumor was unrelated to the macroscopic endoscopic findings. The highest incidence of subclinical tumor is in the pharyngeal recess.