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

The prognostic significance of race in nasopharyngeal carcinoma by histological subtype

BACKGROUND

Race has been shown to have variable prognostic importance in nasopharyngeal carcinoma (NPC). However, previous studies are limited by a lack of comprehensive treatment, epidemiologic, and comorbidity data.

METHODS

This was a retrospective cohort study utilizing the National Cancer Database from 2004 to 2016. Multivariable Cox proportional hazards regressions were used to calculate adjusted hazard ratios (aHR) for overall survival.

RESULTS

A cohort of 9995 patients met inclusion and exclusion criteria. Race, insurance, comorbidity, treatment, stage, age, and histology were independent prognosticators. Among patients with keratinizing NPC, Asians and Hispanics had superior survival (aHR 0.58 [95% confidence interval (CI) 0.48-0.69], aHR 0.76 [95% CI 0.61-0.96]) compared to white patients. Among patients with non-keratinizing differentiated NPC, Asians and black patients had improved survival (aHR 0.71 [95% CI 0.56-0.91], aHR 0.72 [95% CI 0.54-0.95]) compared to white patients. Race was not prognostic in non-keratinizing undifferentiated NPC.

CONCLUSION

The prognostic significance of race varies across histological subtypes of NPC.

Comparison of efficacy and safety of three induction chemotherapy regimens with gemcitabine plus cisplatin (GP), cisplatin plus fluorouracil (PF) and cisplatin plus capecitabine (PX) for locoregionally advanced previously untreated nasopharyngeal carcinoma: A pooled analysis of two prospective studies

PURPOSE

We compared, in this pooled analysis, the differences in efficacy and safety between three induction chemotherapy regimens including gemcitabine plus cisplatin (GP), cisplatin plus fluorouracil (PF) and cisplatin plus capecitabine (PX) in patients recruited into our two prospective studies for previously untreated locoregionally advanced nasopharyngeal carcinoma (NPC).

METHODS

GP, PF or PX followed by radical concurrent chemoradiotherapy was given to patients with previously untreated locoregionally advanced (stage III to IVA) NPC prospectively recruited into our two prospective studies. The study endpoints included progression-free survival (PFS) and overall survival (OS), locoregional recurrence-free survival (LRFS), distant metastasis-free survival (DMFS), cancer-specific survival (CSS), and major acute and late treatment-related toxicities (grade ≥ 3).

RESULTS

From 2006 to 2016, 278 patients were enrolled (84, 94 and 100 patients in GP, PF and PX group respectively). After a median follow-up of 80 months, the 3-year PFS, OS, LRFS, DMFS and CSS of the whole population were 78.7%, 88.1%, 84.9%, 80.9% and 89.8%, respectively. There were no significant differences in prespecified survival endpoints among GP, PF and PX in both stage III and stage IVA patients. GP had lower incidences of severe (grade ≥ 3) anemia and diarrhea in stage III patients, as well as severe anemia, dehydration, renal impairment and vomiting in stage IVA patients. The incidences of grade ≥ 3 late toxicities were similar among these 3 induction regimens.

CONCLUSION

GP had similar efficacy and potentially fewer treatment-related complications compared with PF and PX as induction chemotherapy for previously untreated locoregionally advanced NPC.

A Nomogram for the Prognosis of Nasopharyngeal Carcinoma with MR Imaging-Detected Tumor Residue at the End of Intensity-Modulated Radiotherapy

Objective

This study set out to institute an effective nomogram to predict the prognosis of nasopharyngeal carcinoma (NPC) using magnetic resonance imaging (MRI)-detected residual tumor at the end of intensity-modulated radiotherapy (IMRT).

Background

This study retrospectively analyzed the prognostic factors of NPC using MRI-detected residual tumor at the end of IMRT, in order to individualize the treatment of patients with poor prognosis as early as possible.

Methods

Overall, 162 NPC patients with local or regional residual tumor at the end of IMRT were retrospectively analyzed. Based on multivariate Cox regression analysis using the backward stepwise method, a nomogram was generated to predict the prognosis of these patients. Identification, calibration, clinical applicability and reproducibility were evaluated by C-index, time-dependent AUC, calibration curve and bootstrap verification. According to the best cut-off value of total score of prognoses calculated by X-tile software, all patients were separated into either low-risk or high-risk group.

Results

The nomogram identified age, chemotherapy, N stage, lymph nodes necrosis are significant predictors of prognosis. The AUC of the prediction model is 0.754, and the consistency index is 0.724 (95% confidence interval is 0.659–0.788). The model has good discrimination ability. Through bootstrapping test, the consistency index, corrected slope was 0.723, 0.861, respectively. The calibration slope of predicting 3-year and 5-year overall survival was 1.006 and 1.071, respectively. The calibration curve showed satisfactory calibration effect and good net benefit. The best cut-off value of total score of prognoses calculated by X-tile software was 149.1. Kaplan–Meier survival curve showed that OS and DMFS in the high-risk group were substantially reduced compared to those in the low-risk group.

Conclusion

We constructed and validated a new nomogram to help clinicians understand the prognosis of NPC patients with residue at the end of IMRT. With an estimate of the individual risk, clinicians can start treatment decisions as early as possible for high-risk patients with poor prognosis.

Prognostication of serial post-intensity-modulated radiation therapy undetectable plasma EBV DNA for nasopharyngeal carcinoma

Plasma Epstein-Barr virus (EBV) DNA titers have been used to monitor treatment response and provide prognostic information on survival for nasopharyngeal carcinoma (NPC). However, the long-term prognostic role of pretreatment and posttreatment titers after radical contemporaneous radiation therapy remains uncertain. We recruited 260 evaluable patients with non-metastatic NPC treated with radical intensity-modulated radiation therapy (IMRT) with or without adjunct chemotherapy. Plasma EBV DNA titers at baseline and then 8 weeks and 6 months after IMRT were measured. Cox regression models were employed to identify interaction between post-IMRT 8^th week and 6^th month undetectable titers and 3-year survival endpoints. Concordance indices (Ct) from time-dependent receiver-operating characteristics (TDROC) were compared between patients with post-IMRT undetectable and those with detectable titers. After a median follow-up duration of 3.4 years (range 1.4-4.6 years), patients with post-IMRT 8^th week and 6^th month undetectable plasma EBV DNA titers enjoyed longer 3-year survival endpoints than those who had detectable titers at the same time points. Post-IMRT 8^th week, and more significantly, post-IMRT 6^th month undetectable plasma EBV DNA were the only significant prognostic factors of 3-year survival endpoints. Ct values for all 3-year survival endpoints for both post-IMRT 8^th week and 6^th month undetectable plasma EBV DNA were significantly higher in those with stage IVA–IVB diseases compared to stage I-III counterparts. Early post-IMRT undetectable plasma EBV DNA titers were prognostic of 3-year survival endpoints in patients with non-metastatic NPC. Intensified treatment should be further explored for patients with persistently detectable titers after IMRT.

Virus-associated neoplasms of the nasopharynx and sinonasal tract: diagnostic problems

A significant fraction of nasopharyngeal and sinonasal tumors are associated with Epstein-Barr virus (EBV) or human papillomavirus (HPV). Nasopharyngeal carcinoma (NPC) and extranodal NK/T-cell lymphoma harbor EBV in practically all cases, although a small proportion of cases of the former harbor HPV. Sinonasal inverted papillomas harbor HPV in about 25% of cases. Sinonasal squamous cell carcinomas harbor transcriptionally active HPV in about 20% of cases, and limited data suggest that this subset has a better prognosis than the HPV-negative subset. This review addresses the diagnostic issues of the EBV-associated tumors. Difficulties in diagnosis of NPC may be encountered when there are prominent crush artifacts, many admixed lymphoid cells masking the neoplastic cells, or numerous interspersed granulomas, whereas benign cellular components (epithelial crypts and germinal centers) and reactive lymphoid hyperplasia can potentially be mistaken for NPC. Immunostaining for pan-cytokeratin and/or in situ hybridization for EBER can help in confirming or refuting a diagnosis of NPC. The main diagnostic problem of extranodal NK/T-cell lymphoma is recognition of the neoplastic nature of those examples predominated by small cells or showing a mixture of cells. The identification of a destructive infiltrate (dense expansile infiltrate; angiocentric growth) and definite cytologic atypia (clear cells; many medium-sized cells) would favor a diagnosis of lymphoma, which can be supported by immunohistochemistry (most commonly CD3+, CD5-, CD56+) and in situ hybridization for EBER. In conclusion, among nasopharyngeal and sinonasal neoplasms, demonstration of EBV may aid in diagnosis, particularly NPC and extranodal NK/T-cell lymphoma. Demonstration of HPV does not have a role yet in diagnosis, although this may change in the future.

Racial and Ethnic Disparities in Nasopharyngeal Cancer Survival in the United States: A SEER Study

Objective

To determine whether patient race and ethnicity affect nasopharyngeal cancer survival.

Study Design

Retrospective database analysis.

Setting

National Cancer Institute’s SEER database (Surveillance, Epidemiology, and End Results), 1988-2010.

Subjects and Methods

Nasopharyngeal carcinoma cases were extracted according to site codes and histology recode–broad groupings. The cohort of 5427 patients was used to calculate disease-specific survival in regard to race and ethnicity. Extracted data were further analyzed through direct comparisons and multivariable Cox regression models controlling for patient, tumor, and treatment characteristics.

Results

Unadjusted survival curves for all nasopharyngeal carcinomas considered together showed a statistically significant better disease-specific survival for the African American race ( P = .02) and Asian ethnicity ( P = .01) relative to Caucasian patients. The survival advantage for both these groups was eliminated after controlling for the age and sex of the patients.

Conclusion

African American and Asian patients with nasopharyngeal cancer have better disease-specific survival as compared with Caucasian patients, while Hispanic ethnicity has no effect relative to Caucasians. This disparity is accounted for by diagnosis at an older age in Caucasian patients but remains poorly explained in regard to Hispanic patients.

Role of Computed Tomography Imaging in Predicting Response of Nasopharyngeal Carcinoma to Definitive Radiation Therapy

PURPOSE

The purpose of this study was to investigate the role of posttreatment computed tomography (CT) scans in assessing response of nasopharyngeal carcinoma (NPC) to definitive radiotherapy.

MATERIAL AND METHODS

Between March 1999 and October 2003, a total of 132 consecutive patients with newly diagnosed NPC were studied. Sixty-one patients with AJCC stage I or II NPC were treated with radiation only; 71 patients with stage III or IV disease but no evidence of distant metastasis were treated with concurrent chemoradiotherapy. All patients received CT scans of the head and neck, nasopharyngoscopy, and biopsies of primary sites at 4 to 6 months after completion of radiotherapy. Clinical response of the primary tumor as determined by comparison of pre- and posttreatment CT scans was correlated to pathology results.

RESULTS

The median follow-up time for all patients was 25 months (range, 9-40 months). Radiologic progression was seen in five patients, stable disease in 18 patients, and radiographic partial (rPR) and complete responses (rCR) were seen in 67 and 42 patients, respectively, at 4 to 6 months of follow up. Biopsies of the nasopharynx were positive in six patients. For patients with rCR, two patients (4.8%) had positive biopsies. Four patients with residual disease (rPR, stable, or progressive disease) after treatment had positive biopsies. The positive and negative predictive values, sensitivity, and specificity of CT scans in evaluating the NPC response to radiotherapy were 0.04, 0.95, 0.67, and 0.32, respectively.

CONCLUSIONS

Pathologic CR for nasopharyngeal carcinoma is usually evident at 4 to 6 months after definitive radiotherapy; however, there is no correlation between pathologic and radiographic response. Although longer follow up is required to define the relationship between radiographic and pathologic responses with respect to disease control, we find CT scan at 4 to 6 months after radiotherapy to be neither sensitive nor specific in predicting the response of primary NPC to radiotherapy.

Effectiveness of brachytherapy and fractionated stereotactic radiotherapy boost for persistent nasopharyngeal carcinoma

BACKGROUND

Nasopharyngeal carcinoma (NPC) with local persistence after primary radiotherapy carries a high risk of treatment failure. We compared the effectiveness of brachytherapy and a fractionated stereotactic radiotherapy (SRT) boost in improving tumor control.

METHODS

We retrospectively reviewed the records of 755 patients with NPC treated from 1994 to 2001. Fifty-two patients (7%) had persistent local disease, but seven of them were unsuitable for radiotherapy boost. Overall, 24 patients received brachytherapy boost at a median dose of 20 Gy, and 21 patients received an SRT boost at a median dose of 15 Gy.

RESULTS

Despite the radiotherapy boost, the overall 3-year local failure-free control rate was still significantly lower for patients with persistent disease than for the rest (71% vs 86%, p < .01). Only the SRT subgroup achieved a local failure-free control rate close to that of the complete responders (82% vs 86%, p = .71).

CONCLUSIONS

SRT boost is more effective in reverting the poor prognostic influence of local persistent disease.

Nasopharyngeal carcinoma: treatments and outcomes in the 20th century

Nasopharyngeal carcinoma (NPC), although rare in Europe and North America, is not uncommon in parts of Asia such as southern China and Hong Kong. Consequently, very few oncologists in the Western world have extensive experience in treating this neoplasm. Treatment using external beam therapy and/or brachytherapy evolved greatly during the 20th century and is still evolving, particularly with the use of adjunctive chemotherapy regimes. Diagnosis of NPC has also improved with the availability of CT and MRI. This worldwide review is divided into historical, transitional and modern eras, with the latter concerning 1971-2000. Currently, the most controversial aspects of NPC are recommendations for treatment of recurrent disease and the role of chemotherapy in the overall framework of treatment. Comparison of results from different centres is not possible without an understanding of the various staging systems that are, and have been, used; a comparison is given in this review. In the future, early diagnosis, adequate radiation dose to the primary with boost to bulky disease, and regular follow-up with biopsy of any suspicious residual or recurrent disease, are likely to become key issues to improve outcome. Also, apart from direct/indirect nasopharyngoscopy, the role of follow-up CT needs to be studied for early detection of residual or recurrent disease. More clinical trials on chemo-radiation are also required, in order to study optimum doses and agents.

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.

Nasopharyngeal carcinoma in situ in nasopharyngeal carcinoma

AIMS

To assess the presence of carcinoma in situ (CIS) in patients with nasopharyngeal carcinoma (NPC) and to see if the number of biopsy sites facilitates detection of CIS.

METHODS

Formalin fixed, paraffin wax embedded biopsy specimens (n = 285) from 187 patients with NPC in 1987 were studied for the presence of CIS as well as for the histological assessment of the subtype of CIS.

RESULTS

Fifteen (8.0%) patients had CIS, representing 8.3% of all new patients with NPC and 11.6% of patients with persistent disease or relapse. CIS was undifferentiated or poorly differentiated, no cases of well differentiated squamous cell CIS were identified. There was no significant difference in the incidence of CIS when multiple endoscopic biopsy specimens were taken rather than single forceps biopsy specimens.

CONCLUSIONS

CIS can only be identified in a few patients with NPC largely because of late presentation with advanced disease at the time of diagnosis and the focal nature of the dysplastic process. The presence of dysplasia in relapses of NPC suggests that these tumours may be second growths rather than regrowths of a primary tumour.