Volumetric analysis of tumor extent in nasopharyngeal carcinoma and correlation with treatment outcome

Region-based nasopharyngeal carcinoma lesion segmentation from MRI using clustering- and classification-based methods with learning

In clinical diagnosis of nasopharyngeal carcinoma (NPC) lesion, clinicians are often required to delineate boundaries of NPC on a number of tumor-bearing magnetic resonance images, which is a tedious and time-consuming procedure highly depending on expertise and experience of clinicians. Computer-aided tumor segmentation methods (either contour-based or region-based) are necessary to alleviate clinicians' workload. For contour-based methods, a minimal user interaction to draw an initial contour inside or outside the tumor lesion for further curve evolution to match the tumor boundary is preferred, but parameters within most of these methods require manual adjustment, which is technically burdensome for clinicians without specific knowledge. Therefore, segmentation methods with a minimal user interaction as well as automatic parameters adjustment are often favored in clinical practice. In this paper, two region-based methods with parameters learning are introduced for NPC segmentation. Two hundred fifty-three MRI slices containing NPC lesion are utilized for evaluating the performance of the two methods, as well as being compared with other similar region-based tumor segmentation methods. Experimental results demonstrate the superiority of adopting learning in the two introduced methods. Also, they achieve comparable segmentation performance from a statistical point of view.

Relationships between Tumor Volume and Lymphatic Metastasis and Prognosis in Early Oral Tongue Cancer

Objectives

Although T stage is an important prognostic tool for oral tongue cancer, it fails to define the depth of invasion and true three-dimensional volume of primary tumors. The purpose of this paper is to determine the relations between tumor volume and lymph node metastasis and survival in early oral tongue cancer.

Methods

Forty-seven patients with T1-2 tongue cancer were included. Tumor volumes were measured by the computerized segmentation of T2-weighted magnetic resonance imaging.

Results

The overall average tumor volume was 27.7 cm³ (range, 1.4 to 60.1 cm³). A significant positive correlation was found between tumor volume and pathological T stage, depth of invasion, and cervical lymph node metastasis (P<0.001, P<0.001, and P=0.002, respectively). When the tumor volume exceeded 20 cm³, the cervical metastasis rate increased to 69.2%. The overall 5-year disease specific survival rate was 80%. There was a statistically significant association between large tumor volume (≥20 cm³) and the 5-year disease-specific survival (P=0.046).

Conclusion

Tumor volume larger than 20 cm³ was associated with greater risk cervical lymph node metastasis and poor 5-year disease-specific survival rate in early oral tongue cancer patients.

Prognostic value of tumor volume for patients with nasopharyngeal carcinoma treated with concurrent chemotherapy and intensity-modulated radiotherapy

PURPOSE

We aimed to analyze prognostic factors in patients with nasopharyngeal carcinoma (NPC) treated with concurrent chemotherapy and intensity-modulated radiotherapy (IMRT); in addition, we aimed to elucidate the value of primary gross tumor volume (GTVp) in predicting prognosis of patients.

METHODS

Between February 2001 and December 2008, 321 patients with NPC treated with concurrent chemotherapy and IMRT were analyzed retrospectively. GTVp was calculated from treatment planning computed tomography scans. A receiver operating characteristics (ROC) curve was used to determine the best cutoff point of GTVp.

RESULTS

The 5-year local failure-free survival (LFFS), distant metastasis-free survival (DMFS), disease-free survival (DFS), and overall survival (OS) for NPC patients were 93.8, 80.1, 73.0, and 83.7 %, respectively. Univariate and multivariate analyses indicated that GTVp had exhibited a statistically significant correlation with LFFS, DMFS, DFS, and OS (P < 0.05, all), whereas T classification was not an independent prognostic factor. According to ROC curve analysis, 49 and 19 mL were determined as the cutoff points of GTVp for local control and distant metastasis, respectively. Based on this, 321 patients were divided into three volume subgroups. LFFS, DMFS, DFS, and OS demonstrated significant differences among patients in different volume subgroups (P < 0.001, all) and were superior to T classification for predicting prognosis of NPC patients.

CONCLUSIONS

Primary gross tumor volume is an independent prognostic factor in local control, distant metastasis, disease-free survival, and overall survival in NPC. An adjusted TNM staging system that includes GTVp as a quantitative indicator to evaluate prognosis is warranted.

Volumetric stratification of cT4 stage head and neck cancer

BACKGROUND

Locoregionally advanced stage head and neck cancer (HNC) is known for unfavorable outcome with only ~ 40-50% 3-year overall survival (OS). Clinical T4 stage includes a wide range of tumor burden. The lack of further nonsurgical subgrouping of cT4 stage makes intercenter outcome of irradiated cohorts difficult. Aim of this analysis was to further stratify cT4 stage HNC using volumetric staging.

MATERIAL AND METHODS

Between January 2002 and January 2013, a total of 201 cT4 stage squamous cell cancer (SCC) HNC patients referred to our center for curative definitive radiation were consecutively irradiated. Radiation was performed using modulated techniques. Total gross tumor volumes (tGTV: primary+nodal tumor volume) of all patients have retrospectively been stratified using a prospectively evaluated volumetric staging system which bases on 3 cut-offs (15/70/130 ml), translating into 4 prognostic subgroups [V1: 1-15 ml (n=15), V2: 16-70 ml (108), V3: 71-130 ml (62), V4: >130 ml (16)]. OS, disease-free survival (DFS), locoregional control (LRC), and distant metastasis-free survival (DMFS) rates were calculated.

RESULTS

The mean/median follow-up was 31/23 months (range 1-116 months). The 3-year OS, DFS, LRC, and DMFS rates of the entire cohort were 63, 44, 48, and 77%, respectively. Volumetric staging revealed its potential to prognostically statistically significantly divide the cT4 cohort into 4 volume subgroups (V1/2/3/4): OS: 90%/72%/58%/18%; DFS: 83%/50%/39%/10%; LRC: 81%/53%/47%/15%; DMFS: 93%/90%/70%/41%, all p<0.0001.

CONCLUSION

Volumetric staging allowed a highly statistically significant stratification of cT4 HNC stages into prognostic subgroups, which offers the chance of better intercenter comparability of irradiated advanced stage HNC cohorts.

Tumor volume is an independent prognostic indicator of local control in nasopharyngeal carcinoma patients treated with intensity-modulated radiotherapy

Background

To retrospectively analyze whether primary tumor volume and primary nodal volume could be considered independent prognostic factors for nasopharyngeal carcinoma treated with intensity-modulated radiation therapy.

Methods

Three hundred sixty-three consecutive nasopharyngeal carcinoma (NPC) patients who were stage I-IVa+b and treated with intensity-modulated radiotherapy (IMRT) in our center from October 2003 to October 2005 were analyzed retrospectively. The predictive ability of gender, age, T and N stage, combined chemotherapy, primary tumor and nodal volume for the 5-year local control (LC), distant-metastasis free survival (DMFS) and overall survival (OS) rate were investigated. Primary tumor and nodal volume were measured based on registration of magnetic resonance imaging (MRI) with contrast-enhanced computed tomography (CT) images. The Kaplan–Meier method was used for survival analysis, the log-rank test was used for univariate analyses and the Cox proportional hazard model was used for multivariate prognostic analyses.

Results

The mean value of primary tumor and nodal volume were 31.5 ml and 9.7 ml. The primary tumor and nodal volume were respectively divided into four groups for analysis (primary tumor volume: TV1≤20 ml, 20<TV2≤30 ml, 30<TV3≤40 ml, TV4>40 ml; primay nodal volume: NV1≤5 ml, 5<NV2≤10 ml, 10<NV3≤20 ml, NV4>20 ml). In univariate analysis, the 5-year LC and DMFS rate for TV4 was significantly decreased compared to the other groups (LC: p<0.001, DMFS: p=0.001), the 5-year OS rate for TV3 and TV4 were significantly decreased compared to other two subgroups (p=0.002) and the 5-year regional control (RC), DMFS and OS rate for NV3 and NV4 were significantly less than NV1 and NV2 (RC: p=0.002, DMFS: p=0.01, OS: p=0.014). Multivariate analysis showed that TV>40 ml was an adverse prognostic factor for the 5-year local regional control (LRC) rate (RR 2.454, p=0.002). Primary nodal volume had no statistical significance in predicting 5-year LRC, DMFS and OS rate in multivariate analysis.

Conclusions

Primary tumor volume could predict LRC rate of NPC patients, and the primary tumor volume of 40 ml may be the cut-off. Primary nodal volume may have predictive significance, but more data are needed. These factors should be considered in the TNM staging system of NPC for better estimates of prognosis.

Staging of nasopharyngeal carcinoma--the past, the present and the future

This article reviews the evolution of the International Union Against Cancer/American Joint Committee on Cancer staging system for nasopharyngeal carcinoma. With the increasing availability of newer imaging methods, more sophisticated radiotherapy techniques and rapidly evolving molecular assays, we also examine newer clinical features that might have impact on staging. A new version of the staging system taking into account of some of these factors is also proposed.

Tumor volume reduction rate measured during adaptive definitive radiation therapy as a potential prognosticator of locoregional control in patients with oropharyngeal cancer

BACKGROUND

The purpose of this study was to evaluate the prognostic significance of the tumor volume reduction rate (TVRR) measured during adaptive definitive radiation therapy (RT) in patients with oropharyngeal cancer.

METHODS

We reviewed the RT records of 59 patients with oropharyngeal cancer who were treated with definitive RT with or without concurrent chemotherapy between January 2006 and October 2010. Adaptive replanning was performed in all patients during RT. The pre-RT and mid-RT gross tumor volumes (GTVs) of the primary and the metastatic lymph nodes were measured and analyzed for their possible impacts on locoregional control.

RESULTS

After the median follow-up period of 41.3 months (range, 9.3-73.5 months) for survivors, there were 10 treatment failures (8 locoregional recurrences and 2 distant metastases). The locoregional control rate at 3 years in all the patients was 84.1%. The mean pre-RT and mid-RT total GTVs were 27.5 cm(3) (±17.9 cm(3) ) and 16.9 cm(3) (±12.1 cm(3) ), and the mean GTV reduction rate was 37.9% (±22.6%), respectively. The patients who achieved locoregional control had a higher TVRR than those with locoregional failure (p = .010), and those with the TVRR >35% achieved significantly higher locoregional control at 3 years (94.4% vs 72.4%; p = .018). On multivariate analysis when adjusted with other clinical prognostic factors, the TVRR was found to be a significant factor affecting the locoregional control (hazard ratio = 0.136; 95% confidence interval = 0.022-0.852; p = .033).

CONCLUSION

The TVRR measured during adaptive RT proved a significant prognosticator on locoregional disease control in patients with oropharyngeal cancer, based on which a few therapeutic modifications may be considered.

Prognostic significance of maximum primary tumor diameter in nasopharyngeal carcinoma

Background

To evaluate the prognostic value of maximum primary tumor diameter (MPTD) in nasopharyngeal carcinoma (NPC).

Methods

Three hundred and thirty-three consecutive, newly-diagnosed NPC patients were retrospectively reviewed. Kaplan-Meier analysis and the log-rank test were used to estimate overall survival (OS), failure-free survival (FFS), distant metastasis-free survival (DMFS) and local relapse-free survival (LRFS). Cox proportional hazards regression analysis was used to assess the prognostic value of MPTD.

Results

Median follow-up was 66 months (range, 2–82 months). Median MPTD in stage T1, T2, T3 and T4 was 27.9, 37.5, 45.0 and 61.3 mm, respectively. The proportion of T1 patients with a MPTD ≤ 30 mm was 62.3%; 72% and 62.9% of T2 and T3 patients had a MPTD > 30–50 mm, and 83.5% of T4 patients had a MPTD > 50 mm. For patients with a MPTD ≤ 30 mm, > 30–50 mm and > 50 mm, the 5-year OS, FFS, DMFS and LRFS rates were 85.2%, 74.2% and 56.3% (P < 0.001); 87%, 80.7% and 62.8% (P < 0.001); 88.7%, 86.4% and 72.5% (P = 0.003); and 98.2%, 93.2% and 86.3% (P = 0.012), respectively. In multivariate analysis, MPTD was a prognostic factor for OS, FFS and DMFS, and the only independent prognostic factor for LRFS. For T3-T4 patients with a MPTD ≤ 50 mm and > 50 mm, the 5-year OS, FFS and DMFS rates were 70.4% vs. 58.4% (P = 0.010), 77.5% vs. 65.2% (P = 0.013) and 83.6% vs. 73.6% (P = 0.047), respectively. In patients with a MPTD ≤ 30 mm, 5-year LRFS in T1, T2, T3 and T4 was 100%, 100%, 88.9% and 100% (P = 0.172).

Conclusions

Our data suggest that MPTD is an independent prognostic factor in NPC, and incorporation of MPTD might lead to a further refinement of T staging.

Plasma uric acid and tumor volume are highly predictive of outcome in nasopharyngeal carcinoma patients receiving intensity modulated radiotherapy

Background

The combined predictive value of plasma uric acid and primary tumor volume in nasopharyngeal carcinoma (NPC) patients receiving intensity modulated radiation therapy (IMRT) has not yet been determined.

Methods

In this retrospective study, plasma uric acid level was measured after treatment in 130 histologically-proven NPC patients treated with IMRT. Tumor volume was calculated from treatment planning CT scans. Overall (OS), progression-free (PFS) and distant metastasis-free (DMFS) survival were compared using Kaplan-Meier analysis and the log rank test, and Cox multivariate and univariate regression models were created.

Results

Patients with a small tumor volume (<27 mL) had a significantly better DMFS, PFS and OS than patients with a large tumor volume. Patients with a high post-treatment plasma uric acid level (>301 μmol/L) had a better DMFS, PFS and OS than patients with a low post-treatment plasma uric acid level. Patients with a small tumor volume and high post-treatment plasma uric acid level had a favorable prognosis compared to patients with a large tumor volume and low post-treatment plasma uric acid level (7-year overall OS, 100% vs. 48.7%, P <0.001 and PFS, 100% vs. 69.5%, P <0.001).

Conclusions

Post-treatment plasma uric acid level and pre-treatment tumor volume have predictive value for outcome in NPC patients receiving IMRT. NPC patients with a large tumor volume and low post-treatment plasma uric acid level may benefit from additional aggressive treatment after IMRT.

Correlation between nasopharyngeal carcinoma tumor volume and the 2002 International Union Against Cancer tumor classification system

BACKGROUND

The correlation between primary tumor volume and nasopharyngeal carcinoma (NPC) UICC 2002 T classification, N classification and distant metastasis after radiation therapy was discussed to provide further evidence for the inclusion of tumor volume into the TNM classification staging system.

METHODS

Between February 2001 and December 2008, 666 patients with NPC treated with intensity-modulated radiation therapy (IMRT) were analyzed retrospectively. Primary gross tumor volume was calculated from treatment planning computed tomography scans. The Kruskal-Wallis and Mann-Whitney tests were used for comparison of continuous variables and the chi-square test was used for categorical variables. A logistic regression model was used for multivariate analysis.

RESULTS

Median primary tumor volume of the 666 patients was 20.35 ml (range, 0.44 - 192.63 ml), and it gradually increased with T classification. Statistically significant differences in tumor volume were observed between patients with different T classifications (p < 0.001). The cervical lymph node metastasis rate was 64.7% (430/666); the differences in primary tumor volume between patients with or without lymph node metastasis were statistically significant (p < 0.001). Posttreatment distant metastasis occurred in 100 NPC patients, and the five-year distant metastasis-free survival was 84.2%. Univariate and multivariate analyses showed that N classification (p < 0.001) and tumor volume (p = 0.007) were the main factors influencing distant metastasis.

CONCLUSION

Tumor volume was correlated with T classification, cervical lymph node mestastasis and distant metastasis after radiation therapy in nasopharyngeal carcinoma, suggesting that tumor volume should be included into the TNM staging system.

Different approaches to volume assessment of lymph nodes in computer tomography scans of head and neck squamous cell carcinoma in comparison with a real gold standard

BACKGROUND

Volume assessment in head and neck squamous cell carcinoma (HNSCC) is becoming a more and more clinical important parameter, especially in treatment planning and response control. Various authors showed a significant impact of tumour volume on treatment outcome and local control. Regarding the increasing impact of induction chemotherapy and primary chemoradiation on HNSCC, the need for an adequate measuring tool to judge treatment response becomes obvious. This study was performed to compare the momentary 'gold standard', the diameter-based approach, and tumour volume assessment in HNSCC with approaches based on segmentation algorithms in computer tomography (CT) scans.

METHODS

CT scans were taken as part of the standardized staging investigations. Using these image data, 30 lymph nodes were defined and segmented. The segmentations were carried out with the newly developed software called 'NeckSegmenter'. After obtaining informed consent from the patient, neck dissection was performed and the excised lymph nodes underwent analysis of their true volume. The datasets were compared with each other and put in correlation with the segmented volumes.

RESULTS

Pearson's correlation index showed a higher correlation of the segmented volumes (r = 0.7979) with the true volumes than the results generated via diameter-based equation (r = 0.7974). Furthermore, the diameter-generated volumes show clearly too high volumes at 130% (confidence interval: 107.7-156.7%). The volumes generated with the segmentation are at 89.18% (confidence interval: 73.52-108.16%).

CONCLUSION

The data show a higher reliability for volumes estimated by the segmentation-based approach than the widely used diameter-based approach.

Prognostic significance of tumor volume in patients with nasopharyngeal carcinoma undergoing intensity-modulated radiation therapy

BACKGROUND

This study was undertaken to analyze the correlation between primary gross tumor volume (GTVp) and prognosis in patients with nasopharyngeal carcinoma (NPC) undergoing intensity-modulated radiation therapy (IMRT).

METHODS

Between February 2001 and December 2006, 305 patients with NPC treated with IMRT were analyzed retrospectively. GTVp was calculated from treatment planning CT scans.

RESULTS

Univariate and multivariate analyses indicated that GTVp had a statistically significant correlation to local control, distant metastasis, and overall survival in patients with NPC, whereas T classification was not an independent prognostic factor. Among patients classified with N0-1 and N2-3, there were significant differences in the rates of distant metastasis between those with GTVp smaller and larger than 25 mL (p < .001 and p = .002, respectively).

CONCLUSIONS

GTVp is highly significant in evaluating local control, distant metastasis, and overall survival of patients with NPC treated with IMRT. Therefore, it is recommended that GTVp be included in the new TNM classification system.

Prognostic impact of standardized uptake value of F-18 FDG PET/CT in nasopharyngeal carcinoma

PURPOSE

We evaluated the use of metabolic parameters of F-18 fluorodeoxyglucose positron emission tomography (FDG PET) for the assessment of the primary tumor and nodal metastasis in predicting survival in nasopharyngeal carcinoma (NPC) patients.

MATERIALS AND METHODS

The F-18 FDG PET/CT (computed tomography) scans of 46 consecutive newly diagnosed NPC patients were retrospectively reviewed. Maximal standardized uptake value (SUVmax) corrected for lean body mass of primary tumor (pSUVmax) and highest SUVmax of cervical lymph nodes (nSUVmax) were recorded. The association of FDG uptake and 2-year disease-free survival (DFS) was examined.

RESULTS

Significantly better DFS was found in patients with pSUVmax <7.5 and nSUVmax <6.5 (P = 0.042 and P = 0.019, respectively). In multivariate analysis, both pSUVmax and nSUVmax were significant independent predictors of DFS.

CONCLUSIONS

The SUVmax of the primary tumor and nodal metastasis are useful parameters for predicting DFS in NPC patients.

Natural course and tumor doubling time of nasopharyngeal carcinoma. A study of 15 patients

Nasopharyngeal carcinoma (NPC) is a non-lymphomatous carcinoma that develops in the epithelial lining of the nasopharynx. The knowledge of natural course of tumor progression has been based on anatomical model without clinical correlation. This study is the first to describe and analyze the natural progression of NPC based on clinical information and calculate the tumor growth rate of NPC. Fifteen NPC patients who refused treatment after initial work-up and then subsequent re-presentation at a later time were recruited during the period from January 2003 to August 2009. Clinical data were analyzed and CT scans were used to calculate the tumor volumes. The time interval between the first planning CT image and the subsequent planning CT image was used to calculate the rate of tumor growth in this group of patients. The tumor volume doubling time can be calculated by using the formula DT=tln2/(lnV2-lnV1), where t is the time interval between measurements and V(2) and V(1) are the tumor volumes at the end and beginning of the time interval, respectively. Cranial nerves palsies such as diplopia and systemic upset were the most common reason for re-presentation and the consent for treatment. The median growth rate was 1.63mm(3) per day and the median tumor doubling time was 279days. This study is the first report in the literature looking at the natural progression of nasopharyngeal carcinoma (NPC) based on clinical information. The current study showed that NPC has a propensity to grow superiorly to involve the skull base rather than laterally or anteriorly. Although the tumor growth rate was very variable, the median natural NPC growth rate was 1.63mm(3)/day.

Intensity-modulated radiation therapy in oropharyngeal carcinoma: effect of tumor volume on clinical outcomes

PURPOSE

To analyze the effect of primary gross tumor volume (pGTV) and nodal gross tumor volume (nGTV) on treatment outcomes in patients treated with definitive intensity-modulated radiation therapy (IMRT) for oropharyngeal cancer (OPC).

METHODS AND MATERIALS

Between September 1998 and April 2009, a total of 442 patients with squamous cell carcinoma of the oropharynx were treated with IMRT with curative intent at our center. Thirty patients treated postoperatively and 2 additional patients who started treatment more than 6 months after diagnosis were excluded. A total of 340 patients with restorable treatment plans were included in this present study. The majority of the patients underwent concurrent platinum-based chemotherapy. The pGTV and nGTV were calculated using the original clinical treatment plans. Cox proportional hazards models and log-rank tests were used to evaluate the correlation between tumor volumes and overall survival (OS), and competing risks analysis tools were used to evaluate the correlation between local failure (LF), regional failure (RF), distant metastatic failure (DMF) vs. tumor volumes with death as a competing risk.

RESULTS

Median follow-up among surviving patients was 34 months (range, 5-67). The 2-year cumulative incidence of LF, RF and DF in this cohort of patients was 6.1%, 5.2%, and 12.2%, respectively. The 2-year OS rate was 88.6%. Univariate analysis determined pGTV and T-stage correlated with LF (p < 0.0001 and p = 0.004, respectively), whereas nGTV was not associated with RF. On multivariate analysis, pGTV and N-stage were independent risk factors for overall survival (p = 0.0003 and p = 0.0073, respectively) and distant control (p = 0.0008 and p = 0.002, respectively).

CONCLUSIONS

In this cohort of patients with OPC treated with IMRT, pGTV was found to be associated with overall survival, local failure, and distant metastatic failure.

Prognostic significance of tumor volume in nasopharyngeal carcinoma

OBJECTIVE

To investigate the prognostic significance of primary and residual tumor volume in nasopharyngeal carcinoma.

METHODS

56 patients were included in the study. Diameters of tumors were measured from CT and MR film hardcopies. Diameter-based measurements were computed as an ellipsoid (V=4/3·π·d1·d2·d3) to calculate diameter-based volume. It was investigated whether primary tumor volume provided prognostic information about local regional recurrence free survival (LRRFS), disease free survival (DFS), distant metastasis free survival (DMFS) and overall survival (OS) by monovariant and multivariant analysis. Kaplan-Meier survival analysis method and log-rank test were used to estimate survival analysis (95% confidence interval). Cox regression test was used for two variant and multivariant survival analysis. Statistical Package for Social Sciences (SSSP) 10.0 for Windows programme was used for data analysis.

RESULTS

In the multivariate analysis, in the patients with tumor volume more than 60ml, local regional recurrence more frequently developed. The relationship between tumor volume and local regional recurrence was found significant (p=0.053). In the monovariate analysis, primary tumor volume was found to be a significant predictive value on DFS and DMFS. In the patients with tumor volume below 20ml, DFS was 60%, whereas in the patients with tumor volume above 60ml, DFS was 0% (p=0.007). The prevalence were 68% and 0% in the patients group that had tumor volume below 30ml and above 60ml respectively. DMSF ratios in the patients with primary tumor volume below 20ml and above 60ml were 86.67% and 33.3% respectively. The residual tumor volume (RTV) at first control after treatment was found to be a significant prognostic factor on LRRFS (p=0.03).

CONCLUSION

The foundation of new T staging systems that consists of PTV that was found as an independent prognostic factor alone in multivariate statistical analysis may precede better prediction of prognosis and more appropriate treatment of patients having different prognostic factors. RTV in the first control after treatment was a significant prognostic factor on LRRFS.

Future of the TNM classification and staging system in head and neck cancer

Staging systems for cancer, including the most universally used TNM classification system, have been based almost exclusively on anatomic information. However, the question arises whether staging systems should be based on this information alone. Other parameters have been identified that should be considered for inclusion in classification systems like the TNM. This is all the more important, as a shift toward nonsurgical treatments for head and neck cancer has been made over the years. For these treatment modalities tumor/biologic characteristics next to anatomic information may be particularly important for treatment choice and outcome. The shortcomings of the current TNM classification system will be discussed, along with suggestions for improvement and expansion of the TNM system based on tumor, patient, and environment-related factors. Further improvement of the TNM classification is expected to result in better treatment choices, outcome and prognostication of patients with head and neck cancer.

Salvage surgery for neck residue or recurrence of nasopharyngeal carcinoma: a 10-year experience

BACKGROUND

To assess the outcome of and determine prognostic factors for neck residue or recurrence of nasopharyngeal carcinoma (NPC) in patients treated with a salvage neck dissection.

MATERIALS AND METHODS

Over a 10-year period (from January 1998 through December 2007) in a tertiary hospital, we systematically reviewed the clinical charts of 355 patients with NPC who were diagnosed with neck residue or recurrence of nasopharyngeal carcinoma, after radical definitive radiotherapy with or without chemotherapy.

RESULTS

The group with recurrent nodal disease consisted of 285 patients (80.3%), while the group with residual nodal disease included 70 patients (19.7%). There were no patients died of the surgery complications. Overall survival (OS), disease-free survival (DFS), and disease-specific survival (DSS) were 54.11, 35.01, and 55.59%, respectively, at 3-year, and 26.03, 22.65, and 27.84%, respectively, at 5-year. The local control rate in the neck was 70.92% at 3 years and 60.98% at 5 years. For all the 3 survival outcomes (OS, DFS, and DSS) and the local control rate of disease in the neck, there were significant differences between the "residue group" and "recurrence group."

CONCLUSIONS

Radical neck dissection is proven to be safe and effective in the treatment of the neck failure. Our study has demonstrated that it may be possible to choose the selective lymph node dissection for patients of the residue group.

Impact of intracranial extension on survival in stage IV nasopharyngeal carcinoma: identification of a subset of patients with better prognosis

OBJECTIVE

T-stage is an imperfect prognostic indicator for patients with nasopharyngeal carcinoma. We evaluated the effect of extent of intracranial involvement on survival after conventional radiotherapy in patients with Stage T4 nasopharyngeal carcinoma.

METHODS

We conducted a retrospective analysis of the results of computed tomography, magnetic resonance imaging and treatment outcomes in 84 consecutive patients with Stage T4 nasopharyngeal carcinoma during the period September 1993 to December 2002 in Taiwan. The patients were subcategorized into those who had limited intracranial involvement (primary nasopharyngeal tumors with involvement of the unilateral cavernous sinus or the parasellar region only) or extensive involvement (extension of the tumors to the bilateral cavernous sinus or the parasellar region, into the orbit and the ethmoid sinus anteriorly, or to the prepontine region and the posterior cranial fossa).

RESULTS

Extensive intracranial involvement was found in 51.2% of the patients. Among these patients, the 5-year rate of overall survival after conventional radiotherapy was only 3.4%. In contrast, the 5-year survival among patients with limited intracranial involvement was 42.9%. This difference was significant (P < 0.001). In the multivariate analysis, extensive intracranial involvement, advanced age and a nodal status of N3 correlated with poor overall survival (all P < 0.05).

CONCLUSIONS

Among patients with T4 nasopharyngeal carcinoma, better treatment outcomes were associated with limited intracranial involvement. We conclude that a subdivision of Stage T4 nasopharyngeal carcinoma disease based on the extent of intracranial involvement would provide better prognostic information.

Validation of bidimensional measurement in nasopharyngeal carcinoma

BACKGROUND

Our previous study showed a close relationship between computed tomography (CT)-derived bidimensional measurement of primary tumor and retropharyngeal nodes (BDMprn) and gross tumor volume of primary tumor and retropharyngeal nodes (GTVprn) in nasopharyngeal carcinoma (NPC) and better prognosis for NPC patients with smaller BDMprn. In this study, we report the results on of a study to validate the use of BDM in a separate cohort of NPC patients.

METHODS

We retrospectively reviewed 103 newly diagnosed NPC cases who were treated with radiotherapy/concurrent chemoradiotherapy (CCRT) or CCRT with adjuvant chemotherapy from 2002 to 2009. We used magnetic resonance imaging (MRI) to measure BDMprn. We calculated overall survival, recurrence-free and distant metastasis-free survival curves and set a BDMprn cut off point to categorize patients into a high- or low-risk group. We then used Cox proportional hazard model to evaluate the prognostic influence of BDMprn after correcting age, gender and chemotherapy status.

RESULTS

After adjusting for age, gender, and chemotherapy status, BDMprn remained an independent prognostic factor for distant metastasis [Hazard ratio (HR) = 1.046; P = 0.042] and overall survival (HR = 1.012; P = 0.012). Patients with BDMprn < 15 cm2 had a greater 3-year overall survival rate than those with BDMprn > or = 15 cm2 (92.3% vs. 73.7%; P = 0.009). They also had a greater 3-year distant metastasis-free survival (94% vs.75%; P = 0.034).

CONCLUSION

The predictive ability of BDMprn was validated in a separate NPC cohort. A BDMprn of 15 cm2 can be used to separate NPC patients into high- and low-risk groups and predict survival rates and metastasis potential. It can, therefore, be used as a reference to design clinical trials, predict prognosis, and make treatment decisions.

Treatment response assessment of head and neck cancers on CT using computerized volume analysis

BACKGROUND AND PURPOSE

Head and neck cancer can cause substantial morbidity and mortality. Our aim was to evaluate the potential usefulness of a computerized system for segmenting lesions in head and neck CT scans and for estimation of volume change of head and neck malignant tumors in response to treatment.

MATERIALS AND METHODS

CT scans from a pretreatment examination and a post 1-cycle chemotherapy examination of 34 patients with 34 head and neck primary-site cancers were collected. The computerized system was developed in our laboratory. It performs 3D segmentation on the basis of a level-set model and uses as input an approximate bounding box for the lesion of interest. The 34 tumors included tongue, tonsil, vallecula, supraglottic, epiglottic, and hard palate carcinomas. As a reference standard, 1 radiologist outlined full 3D contours for each of the 34 primary tumors for both the pre- and posttreatment scans and a second radiologist verified the contours.

RESULTS

The correlation between the automatic and manual estimates for both the pre- to post-treatment volume change and the percentage volume change for the 34 primary-site tumors was 0.95, with an average error of -2.4 ± 8.5% by automatic segmentation. There was no substantial difference and specific trend in the automatic segmentation accuracy for the different types of primary head and neck tumors, indicating that the computerized segmentation performs relatively robustly for this application.

CONCLUSIONS

The tumor size change in response to treatment can be accurately estimated by the computerized segmentation system relative to radiologists' manual estimations for different types of head and neck tumors.

Head and neck cancers on CT: preliminary study of treatment response assessment based on computerized volume analysis

OBJECTIVE

The objective of our study was to investigate the feasibility of computerized segmentation of lesions on head and neck CT scans and evaluate its potential for estimating changes in tumor volume in response to treatment of head and neck cancers.

MATERIALS AND METHODS

Twenty-six CT scans were retrospectively collected from the files of 13 patients with 35 head and neck lesions. The CT scans were obtained from an examination performed before treatment (pretreatment scan) and an examination performed after one cycle of chemotherapy (posttreatment scan). Thirteen lesions were primary site cancers and 22 were metastatic lymph nodes. An experienced radiologist (radiologist 1) marked the 35 lesions and outlined each lesion's 2D contour on the best slice on both the pre- and posttreatment scans. Full 3D contours were also manually extracted for the 13 primary tumors. Another experienced radiologist (radiologist 2) verified and modified, if necessary, all manually drawn 2D and 3D contours. An in-house-developed computerized system performed 3D segmentation based on a level set model.

RESULTS

The computer-estimated change in tumor volume and percentage change in tumor volume between the pre- and posttreatment scans achieved a high correlation (intraclass correlation coefficient [ICC] = 0.98 and 0.98, respectively) with the estimates from manual segmentation for the 13 primary tumors. The average error in estimating the percentage change in tumor volume by automatic segmentation relative to the radiologists' average error was -1.5% +/- 5.4% (SD). For the 35 lesions, the ICC between the automatic and manual estimates of change in pre- to posttreatment tumor area was 0.93 and of percentage change in pre- to posttreatment tumor area was 0.85. The average error in estimating the percentage change in tumor area by automatic segmentation was -3.2% +/- 15.3%.

CONCLUSION

Preliminary results indicate that this computerized segmentation system can reliably estimate changes in tumor size on CT scans relative to radiologists' manual segmentation. This information can be used to calculate changes in tumor size on pre- and posttreatment scans to assess response to treatment.

Current management strategy of nasopharyngeal carcinoma

Nasopharyngeal carcinoma is an unique head and neck cancer. It is common among the southern Chinese and is closely associated with the Epstein Barr virus (EBV). To diagnose the disease in its early stage is infrequent as the symptoms are usually trivial and patients only present in late stages. Testing the blood for elevated EBV DNA has now become a screening test for the high risk group of patients, aiming to diagnose the disease in its early stages. Imaging studies, positron emission tomography scans in addition to clinical examination provide information on the extent of the disease. The confirmation of the disease still depends on endoscopic examination and biopsy. Radiotherapy with or without chemotherapy has been the primary treatment modality. The application of intensity modulated radiotherapy and the use of concomitant chemoradiation have improved the control of nasopharyngeal carcinoma together with the reduction of long term side effects. The early detection of residual or recurrence tumor in the neck or at the primary site has allowed delivery of salvage treatment. The choice of the optimal surgical salvage, either for neck disease or primary tumor depends on the extent of the residual or recurrent disease. The outcome of these patients have improved with the application of the appropriate surgical salvage.

Clinical application of tumor volume in advanced nasopharyngeal carcinoma to predict outcome

BACKGROUND

Current staging systems have limited ability to adjust optimal therapy in advanced nasopharyngeal carcinoma (NPC). This study aimed to delineate the correlation between tumor volume, treatment outcome and chemotherapy cycles in advanced NPC.

METHODS

A retrospective review of 110 patients with stage III-IV NPC was performed. All patients were treated first with neoadjuvant chemotherapy, then concurrent chemoradiation, and followed by adjuvant chemotherapy as being the definitive therapy. Gross tumor volume of primary tumor plus retropharyngeal nodes (GTVprn) was calculated to be an index of treatment outcome.

RESULTS

GTVprn had a close relationship with survival and recurrence in advanced NPC. Large GTVprn (> or =13 ml) was associated with a significantly poorer local control, lower distant metastasis-free rate, and poorer survival. In patients with GTVprn > or =13 ml, overall survival was better after > or =4 cycles of chemotherapy than after less than 4 cycles.

CONCLUSIONS

The incorporation of GTVprn can provide more information to adjust treatment strategy.

Pretreatment prognostic factors of survival in patients with locally advanced nonmetastatic squamous cell carcinoma of the head and neck treated with radiation therapy with or without concurrent chemotherapy

BACKGROUND

Identification of pretreatment prognostic factors influencing overall survival (OS) in locally advanced squamous cell carcinoma of the head and neck is an important issue in head and neck oncology.

METHODS

A total of 289 patients were treated with standard fraction or hyperfractionated radiation therapy with or without concurrent low-dose daily chemotherapy.

RESULTS

Gender (P = 0.43) and age (P = 0.26) did not influence OS whereas Karnofsky Performance Status (KPS) (P < 0.0001), T stage (P < 0.0001), and N stage (P < 0.0001) did. Stage grouping was another factor that influenced OS (P < 0.001). Patients with larynx and nasopharynx fared better than those with other primaries (P = 0.0153). Finally, treatment significantly influenced OS. Multivariate analysis showed that KPS, T and N stage, and treatment were independent prognosticators of OS.

CONCLUSIONS

KPS, T and N stage, and treatment are independent prognosticators of OS in patients with locally advanced squamous cell carcinoma of the head and neck treated with radiation therapy with or without concurrent low-dose daily chemotherapy.

Volumetric staging (VS) is superior to TNM and AJCC staging in predicting outcome of head and neck cancer treated with IMRT

The UICC classification (TNM) represents the validated standard tool to describe tumor extent and includes prognostic information on the probability of disease control. The American Joint Committee on Cancer (AJCC) stage grouping is based on the evaluation of treatment and outcome. Gross tumor volume (GTV) might be more relevant than pure description (TNM) or stage grouping as prognostic factor for local control in head and neck cancer (HNC). Based on the observation of GTV-correlated outcome in our initial HNC patient cohort treated with IMRT, we tested the hypothesis that the GTV is the most reliable predictive tool in HNC outcome. A GTV based volumetric staging system (VS) was introduced, using two volumetric cut-off values (15 and 70 cm3). VS, TNM, and AJCC stages were assessed and correlated with outcome following primary radiation in 172 HNC patients. Analyses were based on Kaplan-Meier survival curves. VS proved to be superior to the TNM/AJCC in predicting outcome. In addition, VS enabled to stratify high- and low-risk patients in advanced TN stages. GTV represented the most important prognostic indicator in HNC treated with IMRT and is recommended to be considered for therapeutic decisions and estimation of outcome.

Ki-67 and p53 correlation prognostic value in squamous cell carcinomas of the oral cavity and tongue

Epidermoid carcinomas represent from 90% to 95% of oral cavity malignant neoplasias, making up 13,470 cases/year.

Aims

To correlate p53 and Ki-67 expressions in mouth and tongue carcinomas with lymph node status, gender, histological grade, tumor volume and pathological stage.

Materials and Methods

We carried out a retrospective study of 28 cases of mouth and tongue epidermoid carcinomas. They were submitted to immunohistochemical study in order to check the expression of p53 and Ki-67 antibodies and statistically compare them in terms of lymph node status, gender, histological grade, tumor volume and pathological staging.

Results

The individually analyzed p53 proved to have statistical significance (p < 0.05) when compared to tumor volume (p=0.029). Despite a strong tendency, the p53/tumor volume relation was not significant. When p53 + Ki67 were analyzed, tumor volume had p < 0.05 (p = 0.029).

Discussion

Literature shows that the expression of p53 and Ki-67 is related to the presence of metastasis to lymph nodes and a worse prognosis.

Conclusion

In oral cavity and tongue epidermoid carcinomas, p53 and Ki-67 are related to larger tumors, metastasis to lymph nodes and very likely to a worse prognosis.

Concurrent chemoradiotherapy with adjuvant chemotherapy for high-risk nasopharyngeal carcinoma

OBJECTIVES

To evaluate the impact of invasion of the prevertebral or parapharyngeal spaces and large tumor volume on treatment outcomes in patients with nasopharyngeal carcinoma (NPC).

METHODS

A total of 105 patients with newly diagnosed NPC were enrolled in this study. TNM stage and presence of invasion of the prevertebral or parapharyngeal spaces were recorded. All patients received a total dose of 70-75 Gy.

RESULTS

After controlling for age, sex, and chemotherapy status, invasion of the prevertebral or parapharyngeal spaces and large primary tumor volume produced a significantly increased hazard ratio for distant metastasis and recurrence. We defined patients with two or more such prognostic factors as high-risk patients, in whom the 3-year metastasis-free survival rate, with and without adjuvant chemotherapy, was 100% and 69.6%, respectively (P=0.02). Their 3-year recurrence-free survival rate, with and without adjuvant chemotherapy, was 93.3% and 70.2% (P=0.09). This benefit was not observed in low-risk NPC patients.

CONCLUSION

NPC patients with any two or more of the factors, involvement of the prevertebral space, large primary tumor volume, or advanced parapharyngeal space invasion, had more recurrence and poor survival rates and benefited from concurrent chemoradiotherapy followed by adjuvant chemotherapy.

ITAC volume assessment through a Gaussian hidden Markov random field model-based algorithm

In this paper, a semi-automatic segmentation method for volume assessment of Intestinal-type adenocarcinoma (ITAC) is presented and validated. The method is based on a Gaussian hidden Markov random field (GHMRF) model that represents an advanced version of a finite Gaussian mixture (FGM) model as it encodes spatial information through the mutual influences of neighboring sites. To fit the GHMRF model an expectation maximization (EM) algorithm is used. We applied the method to a magnetic resonance data sets (each of them composed by T1-weighted, Contrast Enhanced T1-weighted and T2-weighted images) for a total of 49 tumor-contained slices. We tested GHMRF performances with respect to FGM by both a numerical and a clinical evaluation. Results show that the proposed method has a higher accuracy in quantifying lesion area than FGM and it can be applied in the evaluation of tumor response to therapy.

Primary tumor volume of nasopharyngeal carcinoma: significance for recurrence and survival

BACKGROUND

Primary tumor volume (PTV) is known to be a significant prognostic factor in malignant tumor. There have been several studies of nasopharyngeal carcinoma (NPC) relating tumor volume to treatment outcome. Our study was designed to evaluate the effect of PTV on treatment outcomes in NPC treated with radiotherapy (RT)/concurrent chemoradiotherapy (CCRT) or CCRT with adjuvant chemotherapy.

METHODS

We retrospectively reviewed 100 cases with newly diagnosed NPC who were treated with RT/CCRT or CCRT with adjuvant chemotherapy from 2002 to 2006. Magnetic resonance imaging-derived PTV was calculated using the summation-of-area technique. Kaplan-Meier plots and the log-rank test were used to estimate tumor recurrence (locoregional, distant, or both) and overall survival. Cox proportional hazards regression analysis was used to assess the prognostic impact of PTV.

RESULTS

The median PTV was 12.94 mL. PTV remained an independent prognostic factor for distant metastasis (hazard ratio [HR], 1.04; p=0.03), for any relapse (HR, 1.04; p=0.02), and for overall survival (HR, 1.09; p<0.001) in multivariate analysis. In the large tumor volume group (PTV>15 mL), patients' metastasis-free survival rates, with and without adjuvant chemotherapy, were 100% and 68.3%, respectively (p=0.002). Their 3-year recurrence-free survival rates, with and without adjuvant chemotherapy, were 94.1% and 69.6%, respectively (p=0.006). In the small tumor volume group (PTV <or= 15 mL), this phenomenon was not observed.

CONCLUSION

PTV had a close relationship with survival rates and recurrence rates in patients with NPC. The large tumor volume group (PTV>15 mL) was associated with more recurrence and poor survival rate, and it was suggested that these high-risk patients should benefit from CCRT followed by adjuvant chemotherapy.

Prognostic impact of primary tumor volume in patients with nasopharyngeal carcinoma treated by definitive radiation therapy

OBJECTIVES/HYPOTHESIS

Tumor burden has been confirmed as one of the important indicators in disease control after treatment for various types of malignancies. This report aims to document the value of the primary tumor volume of nasopharyngeal carcinoma [gross tumor volume of the primary site (GTV-P)] in predicting the treatment outcome after high-dose definitive radiation therapy.

STUDY DESIGN

A total of 154 patients with nasopharyngeal carcinoma were prospectively treated with accelerated hyperfractionated radiotherapy alone to a total dose of 78 Gy/60 fractions/6 weeks (biological effective dose = 88.2 Gy).

METHODS

Patients were assessed for local control, disease-free survival and distant failure free survival. The GTV-P was calculated by summation of area technique after delineation of the primary tumor contours on computed tomography images.

RESULTS

The median GTV-P was 14.5 mL for T1, 23.3 mL for T2, 35.8 mL for T3, and 50.9 mL for T4 diseases (P < .05). With a median follow-up of 61 months, the 5-year local failure-free rate, disease-free survival and distant failure-free survival rates were 89.4% versus 48.9% (P = .002), 56.6% versus 0% (P = .001), and 66.9% versus 16.5% (P = .0001), respectively, for patients whose GTV-P were < or =60 mL and >60 mL. Multivariate analysis revealed that GTV-P is an independent prognostic factorfor local control (hazard ratio = 3.568, P = .035). There fore, the GTV-P was significantly associated with the treatment outcome after high-dose radiation delivered in accelerated hyperfractionated schedule for nasopharyngeal cancer patients.

CONCLUSIONS

Tumor volume is a reliable indicator for supplementing the T classification of the Tumor, Node, Metastasis staging system for predicting local control after definite radiation therapy.

Prognostic influence of parapharyngeal extension in nasopharyngeal carcinoma

CONCLUSIONS

Advanced parapharyngeal tumor involvement in nasopharyngeal carcinoma (NPC) had significant predictive value associated with poorer treatment outcome. Further subclassification of parapharyngeal invasion may be considered in the TNM staging system.

OBJECTIVES

We conducted a retrospective study to elucidate the effect of parapharyngeal extension on treatment outcomes in patients with NPC who were treated with radiotherapy or concurrent chemoradiotherapy (CCRT).

PATIENTS AND METHODS

A total of 99 patients with newly diagnosed NPC were enrolled in this study. The parapharyngeal space invasion examined by CT scan was identified and graded according to Sham and Choy's classification. Potentially significant parameters were analyzed by both univariate and multivariate methods using SPSS software.

RESULTS

The overall survival, recurrence-free survival, locoregional control survival and distant metastasis-free survival rates were affected by the presence of parapharyngeal space involvement (p<0.0001, p<0.0001, p<0.0001, p=0.002, respectively). In multivariate analysis accounting for all previously known prognostic factors, parapharyngeal invasion was associated with increased risk for any recurrence, locoregional recurrence, distant metastasis, and overall survival. After adjusting with TNM classification, parapharyngeal invasion was still an independent prognostic factor in NPC.

Nasopharyngeal carcinoma

Imaging plays an important role in the staging of nasopharyngeal carcinoma. Accurate staging is necessary, as the treatment is directly dependent on stage. Clinical examination provides information on mucosal involvement but is unable to determine the deep extension or the presence of skull base invasion or intracranial spread. The intent of this manuscript is to provide information of the specific imaging findings that will directly affect the stage and treatment of nasopharyngeal carcinoma as well as post-treatment complications.

Extraction of metastatic lymph nodes from MR images using two deformable model-based approaches

We presented and evaluated two deformable model-based approaches, region plus contour deformation (RPCD), and level sets to extract metastatic cervical nodal lesions from pretreatment T2-weighted magnetic resonance images. The RPCD method first uses a region deformation to achieve a rough boundary of the target node from a manually drawn initial contour, based on signal statistics. After that, an active contour deformation is employed to drive the rough boundary to the real node-normal tissue interface. Differently, the level sets move a manually drawn initial contour toward the desired nodal boundary under the control of the evolvement speed function, which is influenced by image gradient force. The two methods were tested by extracting 33 metastatic cervical nodes from 18 nasopharyngeal carcinoma patients. Experiments on a basis of pixel matching to reference standard showed that RPCD and level sets achieved averaged percentage matching at 82-84% and 87-88%, respectively. In addition, both methods had significantly lower interoperator variances than the manual tracing method. It was suggested these two methods could be useful tools for the evaluation of metastatic nodal volume as an indicator of classification and treatment response, or be alternatives for the delineation of metastatic nodal lesions in radiation treatment planning.

Primary tumor volume of nasopharyngeal carcinoma: significance for survival

OBJECTIVES

To elucidate the effect of primary tumor volume (PTV) on treatment outcomes in patients with nasopharyngeal carcinoma (NPC) who were treated with radiotherapy or concurrent chemoradiotherapy. The TNM staging system developed by American Joint Committee of Cancer (AJCC) is universally used and accepted but its prediction of prognosis in NPC receives a lot of challenge. Primary tumor volume had been reported to have close relationship with prognosis of head and neck cancer. We may predict prognosis of NPC with PTV.

METHODS

From 1999 to 2006, 91 patients with newly diagnosed NPC who were treated with radiotherapy or CCRT were enrolled in the study. Computed tomography-derived or magnetic resonance-derived primary tumor volume was calculated. The correlation between AJCC disease stage, primary tumor volume and disease-specific survival were analyzed. Multivariate analyses using the Cox proportional hazard model was performed.

RESULTS

The median primary tumor volume for the whole series was 11.39 ml (range 1.25-166.58 ml). The median primary tumor volume was 2.69 ml in T1 disease, 10.14 ml in T2 disease, 15.41 ml in T3 disease, and 26.69 ml in T4 disease. Hazard ratio increased with tumor volume, ranging from 5.91 (95% confidence interval (95% CI) 1.13-26.43) for tumor volumes between 20 ml and 40 ml, and 15.72 (95% CI, 3.82-61.05) for tumor volumes >40 ml. With both tumor volume and T classification in the same Cox regression model, only tumor volume remained statistically significant in the prognosis of NPC.

CONCLUSION

Primary tumor volume has closer relationship with survival rates of patients with NPC. Calculation of primary tumor volume may be further considered to improve the current staging system.

Primary tumor volume calculation as a predictive factor of prognosis in nasopharyngeal carcinoma

CONCLUSIONS

Primary tumor volume (PTV) has a close relationship with survival rates of patients with nasopharyngeal carcinoma (NPC) who were treated with concurrent chemoradiotherapy (CCRT) or radiotherapy. Besides the current AJCC staging system, measurement of PTV may be needed to predict prognosis of NPC and adjust treatment strategy.

OBJECTIVES

We conducted a retrospective study to elucidate the effect of PTV on treatment outcomes in patients with NPC who were treated with CCRT or radiotherapy.

PATIENTS AND METHODS

A total of 66 patients with newly diagnosed NPC were enrolled in this study. Computed tomography (CT)-derived or magnetic resonance imaging (MRI)-derived PTV was calculated. The correlation between AJCC disease stage, PTV, and disease-specific survival was analyzed. Correlations between different prognostic factors were assessed using a Cox regression model.

RESULTS

The median PTV for the whole series was 12.01 ml (range 1.25-166.58 ml). The median PTV was 3.45 ml in T1 disease, 7.96 ml in T2 disease, 17.95 ml in T3 disease, and 64.73 ml in T4 disease. Disease stage and T stage carried no prognostic significance (p=0.25 and p =0.30, respectively). Four categories of PTV (<12.5 ml, 12.5-25 ml, 25-50 ml and >50 ml) had prognostic significance (p=0.02). Survival analysis demonstrated a significant difference in overall survival with larger tumor volume (risk ratio 5.447; p=0.044).

Outcome of Fractionated Stereotactic Radiotherapy for 90 Patients With Locally Persistent and Recurrent Nasopharyngeal Carcinoma

PURPOSE

Local recurrence remains one of the major causes of failure in nasopharyngeal carcinoma (NPC). Stereotactic radiosurgery and fractionated stereotactic radiation therapy (FSRT) have recently evolved as a salvage option of NPC. This study was conducted to review the treatment outcome after FSRT for NPC.

METHODS AND MATERIALS

Between September 1999 and December 2005, 90 patients with persistent (Group 1: n = 34, relapse within 6 months of RT) or recurrent (Group 2: n = 56, relapse beyond 6 months) NPC received FSRT using multiple noncoplanar arcs of 8-MV photon to the target. Median FSRT dose was 18 Gy in three fractions (Group 1) or 48 Gy in six fractions (Group 2). Median follow-up was 20.3 months.

RESULTS

Complete response rate after FSRT was 66% for Group 1 and 63% for Group 2. One-, 2-, and 3-year disease-specific survival (DSS) and progression-free survival (PFS) rates for all patients were 82.6%, 74.8%, 57.5%, and 72.9%, 60.4%, 54.5%, respectively. Three-year local failure-free survival, DSS, and PFS rates were 89.4%, 80.7%, and 72.3% for Group 1, and 75.1%, 45.9%, and 42.9% for Group 2, respectively. Multivariate analysis showed that recurrent disease and large tumor volume were independent factors that predicted poorer DSS and PFS. Seventeen patients developed late complications, including 2 with fatal hemorrhage.

CONCLUSIONS

Our results indicate that FSRT is effective for patients with persistent and recurrent NPC. Compared with reported results of radiosurgery, FSRT provides satisfactory tumor control and survival with a lower risk of complications and it may be a better treatment for local failures of NPC.

Stereotactic Radiosurgery Versus Gold Grain Implantation in Salvaging Local Failures of Nasopharyngeal Carcinoma

BACKGROUND

Limited local failure of nasopharyngeal carcinoma (NPC) can often be salvaged by reirradiation using different techniques. Both gold grain implantation (GGI) and stereotactic radiosurgery (SRS) have been used as salvage treatment of NPC but the relative efficacy of these two treatments is not known.

METHODS AND MATERIALS

A total of 74 patients with local NPC failure were included in this retrospective analysis. Of these patients, 37 underwent SRS (median dose, 12.5 Gy) and 37 split-palatal GGI at a dose of 60 Gy. The two groups were individually matched for prognostic factors, except for tumor volume. The median follow-up was 42 months.

RESULTS

Local control was better in the GGI group. The 3-year local failure-free rate was 77.9% for the GGI group compared with 68.3% for the SRS group. However, the difference was not statistically significant (p = 0.098). In the subgroup with a tumor volume of <or=5 cm3, the 3-year local failure-free rates were similar, with 79.3% in the GGI group and 72.4% in the SRS group. Neuroendocrine complications were more common in the SRS group, and headache and fistula were more common in the GGI group.

CONCLUSION

Stereotactic radiosurgery and GGI are both effective salvage treatment for NPC. In patients with limited local failure, both yielded comparable high tumor control rates.

Tumour volume measurement in head and neck cancer

Tumour volume is a significant prognostic factor in the treatment of malignant head and neck tumours. Studies of laryngeal and pharyngeal tumours have shown tumour volume to be an important predictor for tumour recurrence. Some studies (for instance nasopharyngeal carcinoma) have shown through multivariate modelling that tumour volume is a dominant covariate that overwhelms T stage, N stage and stage group. The results of these studies have prompted several investigators to suggest the inclusion of tumour volume as an additional prognostic factor in future revisions of the TNM staging system. This paper briefly reviews the TNM system as a staging tool, the measurement of tumour volume and how tumour volume could possibly be incorporated in the system or used as an additional prognostic factor.

Nasopharyngeal Cancers: Which Method Should be Used to Measure these Irregularly Shaped Tumors on Cross-Sectional Imaging?

PURPOSE

To determine whether the standard techniques of measuring tumor size and change in size after treatment could be applied to the measurement of nasopharyngeal cancers, which are often irregular in shape.

METHODS AND MATERIALS

The standard measurements of bidimensional (BDM) (World Health Organization criteria) and unidimensional (UDM) (Response Evaluation Criteria in Solid Tumors [RECIST] criteria), together with the maximum depth of the tumor perpendicular to the pharyngeal wall (DM), were acquired from axial magnetic resonance images of primary nasopharyngeal carcinoma in 44 patients at diagnosis and in 29 of these patients after treatment. Tumor volume measurements (VM), acquired from the summation of areas from the axial magnetic resonance images, were used as the reference standard.

RESULTS

There was a significant association between VM and BDM with respect to tumor size at diagnosis (p = 0.002), absolute change in tumor size after treatment (p < 0.001), and percentage change in tumor size after treatment (p = 0.044), but not between VM and UDM. There was also a significant association between VM and DM with respect to percentage change in tumor size after treatment (p = <0.0001) but not absolute change (p = 0.222).

CONCLUSION

When using simple measurements to assess irregularly shaped nasopharyngeal cancers, the BDM should be used to measure size at diagnosis and the BDM and percentage change in size with treatment. Unidimensional measurement does not reflect size or change in size, and therefore the RECIST criteria may not be applicable to all tumor shapes. The use of DM requires further evaluation.

SIGNIFICANCE OF TUMOUR VOLUME MEASUREMENTS IN TONGUE CANCER: A NOVEL ROLE IN STAGING

BACKGROUND

Tongue cancers are staged by the American Joint Committee on Cancer and the Union Internationale Contre le Cancer TNM staging systems. Cancer, however, evolves in a 3-D plane. Hence, using the largest tumour diameter will not reflect total cancer volume. We aim to evaluate the use of tongue cancer tumour volume (Tv) as a prognostic predictor of disease recurrence and survival.

METHODS

The study is a retrospective analysis of patients in Singapore General Hospital who underwent complete resection for histologically proven tongue carcinoma from 2000 to 2002. The Tv was measured on staging T(2)-weighted magnetic resonance imaging datasets by semiautomated methods.

RESULTS

Seventeen patients with a median follow-up duration of 57.9 months were studied. A wide range of volumes was noted in each T stage. The median time to relapse was 8.6 months for those with Tv > or = 13 cc but was not achieved for those with Tv < 13 cc. The hazard ratio comparing Tv > or = 13 cc versus <13 cc is 9.02 (95% confidence interval (CI) 1.70-47.94, P = 0.014). Of the seven deaths reported, five patients had Tv > or = 13 cc. The median overall survival was 15.8 months for those with Tv > or = 13 cc but was not achieved for those with Tv < 13 cc. The hazards of death for Tv > or = 13 cc was 3.91 times that of Tv < 13 cc (95% CI 0.86-17.86, P = 0.078).

CONCLUSION

Tongue cancer Tv measurement allows a more refined and accurate assessment of tumour status. This can be a possible prognostic indicator and be used in a novel staging method for the future.