Local Control Of Nasopharyngeal Carcinoma Research Articles

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

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

Purpose To study the prognostic significance of primary tumor volume on local control of nasopharyngeal carcinoma. Methods and materials Between 1998 and 2001, 308 consecutive patients with nasopharyngeal carcinoma treated with radical intent were staged with MRI. On the basis of the extent of tumor infiltration outlined by a diagnostic radiologist, the gross tumor volume of the primary and involved retropharyngeal nodes (GTV-P) was delineated by a radiation oncologist for three-dimensional conformal radiotherapy to the nasopharyngeal region using the Helax-TMS Planning System. All patients were treated with 2 Gy daily to a total dose of 70 Gy in 6–7 weeks. Additionally, chemotherapy was given to 128 patients (42%). Results The median GTV-P for the whole series was 22 cm 3 (range, 1.4–218 cm 3). Although the GTV-P varied substantially within each T stage, the overall correlation between these two parameters was strongly significant ( p <0.01), with the median GTV-P 2.7 cm 3 for T1, 13.2 cm 3 for T2, 28.1 cm 3 for T3, and 65.5 cm 3 for T4. With a median follow-up of 1.9 years (range, 0.1–3.9 years), the 3-year local failure-free rate was 87%. The 3-year local failure-free rate was 97% for patients with a GTV-P <15 cm 3 compared with 82% for those with a GTV-P ≥15 cm 3 ( p <0.01). On multivariate analysis (with T stage as a covariate), GTV-P remained an independent prognostic factor for the local failure-free rate (hazard ratio, 1.01; 95% confidence interval, 1.00–1.02; p <0.01). Conclusion Our data suggested that GTV-P is a strongly significant factor for predicting local control of nasopharyngeal carcinoma. The risk of local failure was estimated to increase by 1% for every 1 cm 3 increase in primary tumor volume.

Adjuvant high-dose rate brachytherapy after chemoradiation for treatment of early T-stage nasopharyngeal carcinoma.

The local control of nasopharyngeal carcinoma after conventional radiotherapy has historically been suboptimal. Recently, investigators have reported improved outcomes for this patient population with the use of combined chemoradiotherapy. The purpose of this analysis of our prospective treatment protocol was to evaluate the additional value of high-dose rate intracavitary brachytherapy (HDRIB) on the disease response, local control, and survival. Between March 1999 and January 2001, 16 patients with newly diagnosed locally advanced (stage III and IV) nasopharyngeal carcinoma were treated prospectively at the Radiation Oncology Department of the National University Hospital of Singapore. All patients were staged according to the AJCC (1997) Staging System and had early T stages (T1 and T2). Treatments included concurrent external beam radiotherapy (EBRT) and chemotherapy as follows: 66 Gy to the primary tumor in conventional fractionation with cisplatin based concurrent chemotherapy followed by adjuvant cisplatin and 5-fluorouracil (5-FU) chemotherapy. Ten Gy of HDRIB in 2 weekly fractions were delivered after the completion of EBRT to all 16 patients. All patients were evaluable for treatment response, local control, survival, and toxicity analysis. The median follow-up for the whole group of patients was 18 months (range: 10-34 months). All patients obtained pathologic complete response at the primary site at 4 months after the completion of the treatment. At the time of this analysis, 15 (93.8%) patients are alive with no evidence of disease. One patient (6.2%) developed locoregional recurrence in the neck at 9 months, and distant metastasis at 11 months after the completion of treatment. Our experience has shown adjuvant HDRIB after concurrent chemoradiation offers encouraging disease response, local control, and survival. A prospective study is being planned to further evaluate the role of adjuvant HDRIB after concurrent chemoradiation on treatment outcome.

Prognostic factors of nasopharynx tumors investigated by MR imaging and the value of MR imaging in the newly published TNM staging

Purpose: To examine the usefulness of MR imaging for predicting local control of nasopharyngeal carcinoma (NPC) and the value of MR imaging in the newly published fifth edition of the TNM classification. Methods and Materials: We studied 29 patients with NPC with MR imaging and CT before and after treatment. Staging was done according to the fourth and newly published fifth editions of the International Union Against Cancer (UICC) staging system. The radiotherapy protocol was designed to deliver 66 to 68 Gy to the primary tumor and clinically involved nodes. Results: MR proved better than CT at identifying obliteration of the pharyngobasilar fascia, invasion of the sinus of Morgagni, through which the cartilaginous portion of the eustachian tube and the levator veli palatini muscle pass, invasion of the skull base, and metastases to lymph nodes in the carotid and retropharyngeal spaces. All seven patients without invasion of the pharyngobasilar fascia had local control. The local control rates of patients with invasion of the skull base were not good (60 to 73%). There was no apparent relationship between tumor volume determined by T1-weighted MR images and local control when the tumor volume was more than 20 cc. The newly published N staging system appears to successfully identify the high-risk group for distant metastasis as N3. In our series, four of five patients with N3 disease developed distant metastases. Conclusion: Deep infiltration of the tumor is a more important prognostic factor in NPC than tumor volume. Since the newly published T staging system requires a search for tumor invasion into soft tissue such as parapharyngeal space and bony structures, MR imaging may be indispensable for the newly published NPC staging system.

Effect of time, dose and fractionation on local control of nasopharyngeal carcinoma

Abstract To study the effect of radiation factors on local control of nasopharyngeal carcinoma, 1008 patients with similarly staged T1N0-3M0 disease (Ho's classification) were retrospectively analyzed. All patients were treated by megavoltage irradiation alone using the same technique. Four different fractionation schedules had been used sequentially during 1976–1985: with total dose ranging from 45.6 to 60 Gy and fractional dose from 2.5 to 4.2 Gy. The median overall time was 39 days (range = 38–75 days). Both for the whole series and 763 patients with nodal control, total dose was the most important radiation factor. The hazard of local failure decreased by 9% per additional Gy ( p p = 0.06). Further study is required for elucidation, as 85% of patients completed treatment within a very narrow range (38–42 days), and the possible hazard is clinically too significant to be ignored.

Effect of time, dose and fractionation on local control of nasopharyngeal carcinoma

To study the effect of radiation factors on local control of nasopharyngeal carcinoma, 1008 patients with similarly staged T1N0-3M0 disease (Ho's classification) were retrospectively analyzed. All patients were treated by megavoltage irradiation alone using the same technique. Four different fractionation schedules had been used sequentially during 1976–1985: with total dose ranging from 45.6 to 60 Gy and fractional dose from 2.5 to 4.2 Gy. The median overall time was 39 days (range = 38–75 days). Both for the whole series and 763 patients with nodal control, total dose was the most important radiation factor. The hazard of local failure decreased by 9% per additional Gy ( p < 0.01). Biological equivalents expressed in terms of Biologically Effective Dose or Nominal Standard Dose also showed strong correlation. Fractional dose had no significant impact. The effect of overall treatment time was insignificant for the whole series, but almost reached statistical significance for those with nodal control ( p = 0.06). Further study is required for elucidation, as 85% of patients completed treatment within a very narrow range (38–42 days), and the possible hazard is clinically too significant to be ignored.

Local control of nasopharyngeal carcinoma after intracavitary implant: technique and results

Local control of nasopharyngeal carcinoma after intracavitary implant: technique and results