Functional segregation of the highly conserved basic motifs within the third endoloop of the human secretin receptor

In this study, a mutagenesis-based strategy was employed to assess the roles of two highly conserved motifs (KLR and RLAR) within the third endoloop of the human secretin receptor. Block deletion of KLRT and mutation of Lys323 (K(323)I) significantly reduced cAMP accumulation, and these mutations did not affect ligand interaction and receptor number expressed on the cell surface. Thus, the KLRT region at the N terminus of the third endoloop, particularly Lys323, is important for G protein coupling. For the RLAR motif, receptors with substitutions at positions 339 and 342 from Arg to Ala (R(339, 342)A), Glu (R(339, 342)E), or Ile (R(339, 342)I) as well as block deletion of the RLAR motif were all found to be defective in both secretin-binding and cAMP production. Interestingly, a single mutation at the corresponding positions of Arg339 or Arg342 responded as the wild-type human secretin receptor in all functional assays, indicating that the presence of one Arg at either position within the RLAR motif is sufficient for a normal receptor function. Immunofluorescent staining of these mutant receptors showed that these Arg residues are responsible for surface presentation and/or receptor stability.

Examining prognostic factors and patterns of failure in nasopharyngeal carcinoma following concomitant radiotherapy and chemotherapy: impact on future clinical trials

PURPOSE

Concomitant chemotherapy and radiotherapy (CCRT), followed by adjuvant chemotherapy, has improved the outcome of nasopharyngeal carcinoma (NPC). However, the prognosis and patterns of failure after this combined-modality treatment are not yet clear. In this report, the prognostic factors and failure patterns we observed with CCRT may shed new light in the design of future trials.

METHODS AND PATIENTS

One hundred forty-nine (149) patients with newly diagnosed and histologically proven NPC were prospectively treated with CCRT followed by adjuvant chemotherapy between April 1990 and December 1997. One hundred and thirty-three (89.3%) patients had MRI of head and neck for primary evaluation before treatment. Radiotherapy was delivered either at 2 Gy per fraction per day up to 70 Gy or 1.2 Gy per fraction, 2 fractions per day, up to 74.4 Gy. Chemotherapy consisted of cisplatin and 5-fluorouracil. According to the AJCC 1997 staging system, 32 patients were in Stage II, 53 in Stage III, and 64 in Stage IV (M0).

RESULTS

Univariate analysis revealed that WHO (World Health Organization) Type II histology, T4 classification, and parapharyngeal extension were poor prognostic factors for locoregional control. Multivariate analysis revealed that T4 disease was the most important adverse factor that affects locoregional control, the risk ratio being 5.965 (p = 0.02). Univariate analysis for distant metastasis revealed that T4 and N3 classifications, serum LDH level > 410 U/L (normal range, 180-460), parapharyngeal extension, and infiltration of the clivus were significantly associated with poor prognosis. Multivariate analysis, however, revealed that T4 classification and N3 category were the only two factors that predicted distant metastasis; the risk ratios were 3.994 (p = 0.02) and 3.390 (p = 0.01), respectively. Therefore, based on the risk factor analysis, we were able to identify low-, intermediate-, and high-risk patients. Low-risk patients were those without the risk factors mentioned above. They consisted of Stage II patients with T2aN0, T1N1, and T2aN1 categories and of Stage III patients with T1N2 and T2aN2 categories. Their risk of recurrence is low (4%). Intermediate-risk patients were those with at least one univariate risk factor. They are Stage II patients with T2bN0 and T2bN1 categories and Stage III patients with T2bN2 and T3N0-2 categories. The risk of recurrence is modest (18%). High-risk patients have risk factors by multivariate analysis. They are stage T4 or N3 patients. Their risk of recurrence is high (36%).

CONCLUSION

Low-risk patients have an excellent outcome. Future trials should focus on reducing treatment-associated toxicities and complications and reevaluate the benefit of sequential adjuvant chemotherapy. The recurrence in treatment of intermediate-risk patients is modest; CCRT and adjuvant chemotherapy may be the best standard for them. Patients with T4 and N3 disease have poorer prognosis. Hyperfractionated radiotherapy may be considered for the T4 patients. Future study in these high-risk patients should also address the problem of distant spread of the disease.

Toward a theory of individual differences and leadership: understanding the motivation to lead

A broad, integrative theoretical framework for understanding the relationship between individual differences and various leader behaviors is presented; it proposes a new individual-differences construct called the motivation to lead (MTL). A large-scale study using 3 samples in different occupational and cultural contexts shows 3 factors underlying MTL, namely, affective-identity, noncalculative, and social-normative MTL. A parsimonious model of antecedents to MTL is developed through hierarchical regression modeling and is cross-validated using confirmatory latent variable modeling. MTL is shown to provide incremental validity over other predictors such as general cognitive ability, values, personality, and attitudes in the prediction of 2 behavioral measures of leadership potential. Findings are discussed with reference to the theoretical framework proposed for understanding individual differences in leader behavior.

An unusual encounter of a "cobra" in the heart: rare appearance of an Amplatzer Septal Occluder

This article presents the unusual appearance of a "cobra" due to "acute bending" of the proximal part and partial opening of the distal part of the left atrial disk of an Amplatzer Septal Occluder during the process of transcatheter closure of a secundum atrial septal defect in a 6-year-old boy. The possible reasons and method to overcome this technical problem, which resulted in successful occlusion of the atrial septal defect, are discussed.

A case series of six children with primary pulmonary hypertension

INTRODUCTION

Primary pulmonary hypertension is an uncommon but serious disease in children. Management is difficult despite recent advances in pharmacotherapy.

CLINICAL PICTURE

We reviewed patients with this condition with respect to their presenting symptoms, investigations, treatment and outcome.

TREATMENT

These children were treated with individualised combinations of oxygen, diuretics and calcium antagonists.

OUTCOME

In our follow-up of 5 children, 4 had died.

CONCLUSION

This condition is irreversible and progressive with a high mortality rate. A better understanding of, and research into, the pathogenesis would hopefully lead to the formulation of improved therapeutic strategies for this condition.

Long-term survival of nasopharyngeal carcinoma following concomitant radiotherapy and chemotherapy

PURPOSE

The purpose of this study is to demonstrate long-term survival of nasopharyngeal carcinoma treated with concomitant chemotherapy and radiotherapy (CCRT) followed by adjuvant chemotherapy.

METHODS AND PATIENTS

One hundred and seven patients with Stage III and IV (American Joint Committee on Cancer, AJCC, 1988) nasopharyngeal carcinoma (NPC) were treated with concomitant chemotherapy and radiotherapy (CCRT) followed by adjuvant chemotherapy between April 1990 and December 1997 in Koo Foundation Sun Yat-Sen Cancer Center, Taipei. The dose of radiation was 70 Gray (Gy) given in 35 fractions, 5 fractions per week. Two courses of chemotherapy, consisting of cisplatin and 5-fluorouracil, were delivered simultaneously with radiotherapy in Weeks 1 and 6 and two additional monthly courses were given after radiotherapy. According to the AJCC 1997 staging system, 32 patients had Stage II disease, 44 had Stage III, and 31 had Stage IV disease.

RESULTS

With median follow-up of 44 months, the 5-year overall survival rate in all 107 patients was 84.1%, disease-free survival rate was 74.4%, and locoregional control rate was 89.8%. The 3-year overall survival for Stage II was 100%, for Stage III it was 92.8%, and for Stage IV, 69. 4% (p = 0.0002). The 3-year disease-free survival for Stage II was 96.9%, for Stage III it was 87.7%, and for Stage IV it was 51.9% (p = 0.0001).

CONCLUSION

CCRT and adjuvant chemotherapy is effective in Taiwanese patients with advanced NPC. The prognosis of AJCC 1997 Stage II and III disease is excellent, but, for Stage IV (M0), it is relatively poor. Future strategies of therapy should focus on high-risk AJCC 1997 Stage IV (M0) cohort.

Comment on "Algebraic perturbation theory for polar fluids: A model for the dielectric constant"

Kalikmanov [Phys. Rev. E 59, 4085 (1999)] proposed a perturbation theory method to calculate the dielectric constant of dipolar hard sphere fluids using an infinitely long cylindrical container to avoid the depolarization. We demonstrate that while the method is very helpful, his theory appears to be incomplete because of the incorrect calculation of the corresponding three-body integrals. It is shown that with the correct consideration of these terms the theory is consistent with the results of earlier work in low-density limit, and at high densities the method yields the equation of Tani et al. [Mol. Phys. 48, 863 (1983)] for the dipolar hard sphere fluid dielectric constant.

Recurrent and novel mutations of GCDH gene in Chinese glutaric acidemia type I families

Glutaric acidemia type I is caused by mutations of the glutaryl-CoA dehydrogenase (GCDH) gene resulting in loss of GCDH enzyme activity. Patients present with progressive dystonia and lesions in basal ganglia. Dietary treatment, when instituted from the early neonatal period, markedly reduces dystonia and morbidity. Early diagnosis and prenatal diagnosis will be facilitated by knowledge of locally prevalent GCDH mutations. Several common GCDH mutations have been found in different ethnic groups. GCDH mutations were studied in 5 Chinese glutaric acidemia type I families. We detected two novel recurrent mutations (A219T and IVS10-2A>C) which were found in two unrelated families. An asymptomatic carrier of IVS10-2A>C was also found on screening of 120 individuals. Other mutations were identified, including two other novel (R386G & IVS3+1G>A) and two known mutations (G178R & R355H). Fibroblasts from patients carrying the novel mutations were confirmed to be deficient for GCDH activity. This is the first report of GCDH mutations describing recurrent mutations in Chinese patients. The carrier rate of IVS10-2A>C may be particularly high in Chinese.

Heart rate variability of children with mitral valve prolapse

Studies have indicated that adult patients with mitral valve prolapse (MVP) may have autonomic dysfunction. The purpose of this study was to evaluate heart rate variability (HRV) in children with MVP. Sixty-seven children with MVP (ages 6 to 18 years; 30 boys and 37 girls) were consecutively studied and subdivided into those with or without symptoms. Thirty-seven normal age-matched children (17 boys and 20 girls) were studied as controls. The patients were further divided into 4 age subgroups. HRV was measured using a 24-hour Holter electrocardiogram (ECG) system (Laser SXP Holter Analysis System, Marquette Electronics, Milwaukee, WI). The ECGs were analyzed in both time domain and frequency domain (spectral analysis). Symptomatic and asymptomatic children with MVP were combined for analysis because they were not significantly different in terms of their HRV. All time-domain indices, with the exception of SDANN (SD of the mean of RR intervals in all 5-minute segments of the 24-hour ECG), were significantly lower in children with MVP than in controls. Children with MVP showed significantly lower spectral power of the high frequency (HF) and low frequency (LF) components when compared with controls. The ratio of LF to HF (LF/HF) was significantly higher in children with MVP. Similar differences were observed in the 4 age subgroups. Sex differences in HRV were observed when girls had lower HRV compared with boys. Lower time-domain and frequency-domain indices of HRV in children with MVP are suggestive of decreased parasympathetic activity and a shift in sympathovagal balance. Various factors including differences in heart rate may contribute to sex differences in HRV.

Mutational analysis of BRCA1 and BRCA2 genes in Chinese ovarian cancer identifies 6 novel germline mutations

Germline mutations in the BRCA1 and BRCA2 genes predispose women to breast and ovarian cancer. An incidence of 5% and 3.3% respectively has been reported of BRCA1 and BRCA2 mutations in women with ovarian cancer unselected for family history. The contribution of BRCA1 and BRCA2 mutations to ovarian cancer in Chinese women is unknown. A total of 60 samples of ovarian cancer diagnosed in Chinese unselected for age or family history were analyzed for BRCA mutations using the protein truncation test. The entire coding exon of BRCA1 of 53 cases and that of exon 11 of BRCA2 of 43 cases were successfully screened. Six germline (11.3%) mutations (633C>T, 1080delT, 1129delA, 2371-2372delTG, 3976-3979delGTGA, and IVS 22+7 A>G) were detected in BRCA1. One germline mutation (3337C>T) (2.1%) was detected in BRCA2. None of these seven cases were associated with strong family history of breast and/or ovarian cancer. Five out of our six BRCA1 mutations and the one BRCA2 mutation identified are novel. Our 11.3% incidence of BRCA1 mutations in ovarian cancer found amongst Chinese with insignificant family history is apparently higher than that previously reported in other populations. It suggests that BRCA1 mutation may play a significant role in the development of sporadic ovarian cancer in Chinese women.

Posterior fossa subdural hematoma due to ruptured arteriovenous malformation

Patients with cerebellar arteriovenous malformations (AVM) commonly present to the neurosurgical department after having suffered hemorrhages. The subarachnoid space is the usual location for these often repeating episodes of bleedings. In addition, these patients can present with parenchymal hemorrhage. Acute subdural hematoma caused by a ruptured cerebellar AVM is a rare entity and is not generally recognized. The authors present a case of acute posterior fossa subdural hematoma resulting from a ruptured cerebellar AVM.

Interferon treatment for multiple sclerosis patients in Hong Kong

We report on nine patients with multiple sclerosis who had received interferon beta-1a treatment for 6 months or more. Seven patients were Chinese and two were Caucasian. Seven patients had the relapsing-remitting type of multiple sclerosis, one had the primary-progressive type, and one had the progressive-relapsing type. Among the six compliant patients with the relapsing-remitting type of disease, four had less frequent relapses after treatment. This study could not show whether or not the use of interferon beta-1a was beneficial to non-compliant patients, or patients with other types of multiple sclerosis.

Concomitant radiotherapy and chemotherapy for early-stage nasopharyngeal carcinoma

PURPOSE

Early-stage nasopharyngeal carcinoma (NPC) continues to carry a failure rate of 15% to 30% when treated with radiotherapy alone; the benefit of concomitant radiotherapy and chemotherapy (CCRT) in early-stage NPC is unclear. The purpose of this report is to describe our efforts to improve treatment outcome in early-stage NPC after CCRT.

PATIENTS AND METHODS

Of 189 newly diagnosed NPC patients without evidence of distant metastases who were treated in our institution between 1990 and 1997, 44 presented with early-stage (stage I and II) disease according to the American Joint Committee on Cancer (AJCC) 1997 NPC staging system. Twelve of these patients were treated with radiotherapy alone and 32 with CCRT. Each patient's head and neck area was evaluated by magnetic resonance imaging or computed tomography. Radiotherapy was administered at 2 Gy per fraction per day, Monday through Friday, for 35 fractions for a total dose of 70 Gy. Chemotherapy consisting of cis-diamine-dichloroplatinum and fluorouracil was delivered simultaneously with radiotherapy in weeks 1 and 6 and sequentially for two monthly cycles after radiotherapy.

RESULTS

Patients who were treated with radiotherapy alone primarily had stage I disease, whereas none of those who were treated with CCRT had stage I disease (11 of 12 patients v none of 32 patients; P =.001). The locoregional control rate at 3 years for the radiotherapy group was 91.7% (median follow-up period, 34 months) and was 100% for the CCRT group (median follow-up period, 44 months) (P =.10). The 3-year disease-free survival rate in the radiotherapy group was 91.7% and was 96.9% in the CCRT group (P =.66).

CONCLUSION

Our results reveal excellent prognosis of AJCC 1997 stage II NPC treated with CCRT. Stage II patients with a greater tumor burden treated with CCRT showed an equal disease-free survival, compared with stage I patients treated with radiotherapy alone. A prospective randomized trial is underway to confirm the role of CCRT in stage II NPC.

The feasibility of three-dimensional guglielmi detachable coil for embolisation of wide neck cerebral aneurysms

SUMMARY

The three-dimensional Guglielmi detachable coil is a modification of the conventional Guglielmi coil. It has a unique complex structure, with alternating small and large loops at 90 degrees angle to each other during deployment. The enhanced coil complexity optimizes coil purchase on the aneurysm wall, promoting coil stability within the aneurysm sac. It may be the solution of the single catheter technique in the embolisation of wide neck aneurysms.We report our early experience in the embolisation of wide neck aneurysms using these complex coils.

Safety and effectiveness of percutaneous fluoroscopic gastrostomy in cancer patients

PURPOSE

To evaluate the safety and effectiveness of percutaneous fluoroscopic gastrostomy (PFG) in cancer patients.

METHODS

We retrospectively analyzed the success rate, complication rate, and patient outcomes of PFG performed during a 15-month period in our hospital. The Cope type 10-French and 12-French self-retaining catheters were used for gastrostomy.

RESULTS

Of the 113 PFG procedures requested during the study period, 112 (99.1%) were performed successfully; one procedure was cancelled because the nasogastric tube could not be passed through the obstructed esophagus. Thirty-day follow-ups were obtained for 92.0% of the procedures. Of the patients with at least 30 days of follow-up, eight (7.8%) died, but only two deaths (1.9%) were procedure-related. Major complications, including peritonitis and severe wound infection, occurred after eight procedures (7.8%). Minor complications, including superficial wound infection, tube fracture, leakage, severe pain, mild hemorrhage, and tube migration, occurred after 23 procedures (22.3%). The severity of pneumoperitoneum was significantly associated with the frequency of complications (p < 0.05). After placement of the gastrostomy, 68% of the patients maintained or increased their initial body weight; 28% lost 10% or less of their body weight; and 4% lost more than 10% of their body weight.

CONCLUSIONS

PFG appears to be effective and relatively safe for long-term nutritional support in cancer patients.

Quantification of bacterial adhesion forces using atomic force microscopy (AFM)

This study demonstrated that atomic force microscopy (AFM) can be used to obtain high-resolution topographical images of bacteria, and to quantify the tip-cell interaction force and the surface elasticity. Results show that the adhesion force between the Si3N4 tip and the bacteria surface was in the range from -3.9 to -4.3 nN. On the other hand, the adhesion forces at the periphery of the cell-substratum contact surface ranged from -5.1 to -5.9 nN and those at the cell-cell interface ranged from -6.5 to -6.8 nN. The two latter forces were considerably greater than the former one, most likely due to the accumulation of extracellular polymer substance (EPS). Results also show that the elasticity varied on the cell surface.

Clavicle malunion

The clavicle fracture that has united with deformity or shortening may have an adverse effect on normal shoulder girdle function. We report on 4 patients in whom a malunited fracture of the clavicle was believed to be a contributing factor to shoulder girdle dysfunction. In each patient, the functional status of the involved limb was improved after corrective osteotomy at the site of deformity, realignment, and plate fixation.

Survival of a 30-week baby with congenital myotonic dystrophy initially ventilated for 55 days

In previous reports, duration of initial ventilation exceeding 1 month almost always predicts non-survival of babies with congenital myotonic dystrophy. However, a baby with this condition survived beyond infancy after 55 days' ventilation. We describe this case in detail, explain why the baby survived and highlight the importance of individualized assessment, in addition to applying general prognostic terms described in the literature.

Reversible dementia due to dural arteriovenous fistula: a simple surgical option

Dural AVMs can produce a wide variety of symptoms related to raised intracranial pressure, venous congestion, and cerebral ischaemia. We present a unique case of reversible dementia, due to venous hypertension. The cerebral ischaemia was caused by extensive bilateral arteriovenous malformations of the external carotid system, which drained into the superior sagittal and transverse sinuses and resulted in venous hypertension. Although partial occlusion by endovascular embolization and ligation procedures had some effect, only 'scalping and silastic implantation' gave satisfactory amelioration of symptoms.

Value of abdominal sonography in the assessment of children with abdominal pain

PURPOSE

We retrospectively evaluated the usefulness of sonography in the diagnostic assessment of children with abdominal pain.

METHODS

From July 1988 to October 1996, 676 children who had abdominal pain and were referred for sonography underwent abdominal and pelvic sonographic examination. Of these, 644 children had recurrent abdominal pain (RAP) and 32 children had acute or subacute abdominal pain (ASAP). The mean ages and relative risks of underlying abnormalities were calculated for children with RAP and ASAP.

RESULTS

Abdominal abnormalities were sonographically detected in 10 children with RAP (2%), a significantly lower incidence than in children with ASAP (56%, p < 0.0001), with a relative risk of 0.028 (95% CI, 0.014-0.055). In the RAP group, an underlying abnormality was more likely (p < 0.001) to be sonographically detected in children who had atypical clinical features (5 of 46%; 11%) than in those with typical clinical features (5 of 598; 1%), with a relative risk of 12.94 (95% CI, 3.90-43.30). Children with RAP were found to have hydronephrosis (3), urinary cystitis (2), duplex kidney (1), hypoplastic low-lying kidney (1), choledochal cyst (1), ovarian teratoma (1), and gross gaseous distention with fecal masses (1). Children with ASAP had urinary cystitis (4), intussusception (2), appendicitis (2), appendiceal abscess (1), perforated gut with ascites (1), gut duplication (1), thickened gut wall with fluid from severe gastroenteritis (1), gross gaseous distention with fecal masses (1), hepatosplenomegaly (1), cholecystitis (1), gross hydronephrosis (1), Wilms' tumor (1), and abdominal neuroblastoma (1).

CONCLUSIONS

Abdominal sonography is useful in children with ASAP. Although an underlying abnormality was rarely found in children with RAP, children who have RAP with atypical clinical features should have sonographic screening. If no abnormalities are found, the normal sonograms may be reassuring to parents.

Transcatheter occlusion of atrial septal defects: an initial experience with the Amplatzer septal occluder

OBJECTIVE

To discuss the initial experience with the use of a new double disc occluding device, the Amplatzer septal occluder in transcatheter occlusion of secundum atrial septal defects (ASD).

METHODS

Transvenous sizing of secundum ASD was performed in five children under general anaesthesia using transoesophageal echocardiographic and fluoroscopic guidance. An Amplatzer septal occluder equal to or minimally larger than the stretched diameter of the ASD was used for transcatheter occlusion of the defect in three suitable patients. Pulmonary balloon valvuloplasty with a 18 mm x 3 cm Mansfield balloon catheter was carried out in one patient with associated pulmonary valvar stenosis in the same procedure setting.

RESULTS

Stretched diameters of the defects in the three patients ranged from 14 to 17 mm. Devices of sizes 14, 17 and 17 were deployed through 7F and 8F sheaths, respectively. The upper and lower rims of interatrial septum were more than 8 mm in all patients. All patients had successful occlusion with complete obliteration of the atrial left to right shunting. Simultaneous pulmonary balloon valvuloplasty for the valvar stenosis reduced pressure gradient from 53 mmHg to 22 mmHg across the valve prior to septal occlusion in one patient. No intraprocedural or short-term complication was encountered.

CONCLUSIONS

The design of the Amplatzer septal occluder permits ease in loading, delivery, deployment and stable seating of the device. This initial experience shows that Amplatzer device occlusion is feasible, relatively safe and effective and appears to be a viable alternative to surgical closure of secundum atrial septal defects in properly selected patients.

Quantitative method to determine the cohesion of viscoelastic agents by dynamic aspiration

PURPOSE

To quantitatively determine the cohesion of ophthalmic viscoelastic agents using an in vitro method based on dynamic aspiration kinetics.

SETTING

Alcon Laboratories, Inc., Fort Worth, Texas, USA.

METHOD

Five viscoelastic agents were tested: Healon GV (sodium hyaluronate 1.4%); Provisc (sodium hyaluronate 1.0%); Healon (sodium hyaluronate 1.0%); Amvisc Plus (sodium hyaluronate 1.6%); Viscoat (sodium hyaluronate 3.0%-chondroitin sulfate 4.0%). Samples were placed into a tared polypropylene container using a positive displacement pipette. Calibrated vacuum was applied for 2 seconds to a polypropylene tip (inner diameter 0.5 mm) lowered into the viscoelastic sample. The quantity of viscoelastic agent remaining in the container after aspiration was determined gravimetrically. The procedure was repeated at various vacuum levels between 100 and 700 mm Hg. The percentage of viscoelastic agent aspirated was plotted against vacuum pressure. The slopes of these curves indicate the relative cohesion of the viscoelastic sample.

RESULTS

The cohesion-dispersion indices (percentage viscoelastic agent aspirated/100 mm Hg) were Healon GV (72.3) > Provisc (46.0) > Healon (31.2) = Amvisc Plus (21.4) > Viscoat (3.4).

CONCLUSION

The method provided a quantitative basis for the clinical classification of viscoelastic materials as cohesive or dispersive. The aspiration kinetics profile (curve shape), maximum rate of removal, and vacuum levels at which the bolus removal of the viscoelastic agent started (break point) were useful in characterizing the viscoelastic agents. Because the results agree with the clinical impression of cohesion/dispersion, this method may be used to predict the surgical performance of viscoelastic agents.

Prognostic features and treatment outcome in locoregionally advanced nasopharyngeal carcinoma following concurrent chemotherapy and radiotherapy

PURPOSE

Concurrent chemotherapy and radiotherapy (CCRT) are effective in treatment of locoregionally advanced nasopharyngeal carcinoma (NPC). However, the prognostic factors after CCRT have not been evaluated. We therefore attempt to evaluate factors that influence treatment outcomes following CCRT.

METHODS AND MATERIALS

Seventy-four (5 in stage III and 69 in stage IV) patients with locoregionally advanced NPC were treated with CCRT. Radiotherapy was delivered either at 2 Gray (Gy) per fraction per day up to 70 Gy or 1.2 Gy, 2 fractions per day, up to 74.4 Gy. Concurrent chemotherapy consisted of cisplatin and 5-fluorouracil. Cox proportional-hazards model was used to analyze the prognostic factors which included age, gender, pathologic type, T, N, lactate dehydrogenase (LDH), and infiltration of the clivus.

RESULTS

The primary tumor control rate at 3 years was 96.7% (95% confidence interval [CI]: 92.5-100), distant metastasis-free survival 81.1% (95% CI: 70.6-91.6), disease-free survival 77.0% (95% CI: 65.3-88.7), and overall survival 79.8% (95% CI: 69.2-90.4) with a median follow-up interval of 29 months (range 15-74 months). Cox proportional-hazards model revealed that infiltration of the clivus and serum level of LDH before treatment were the most two important factors that predict distant metastases. Infiltration of the clivus and the serum LDH level greater than 410 U/L were strongly associated with distant metastasis-free survival (p = 0.0004 and p = 0.0002, respectively). When these two risk factors were considered together, no distant metastasis was observed in 40 patients with both intact clivus and LDH < or = 410 U/L. On the contrary, 13 of the remaining 34 patients with at least one risk factor developed distant metastasis (p = 0.0001).

CONCLUSION

Our study demonstrates that CCRT can improve the primary tumor control of 96.7% and disease-free survival of 77.0% at 3-year follow-up. Distant metastasis, however, is the major cause of failure. Infiltration of the clivus by the tumor and LDH greater than 410 U/L are the two independent and useful prognostic factors in patients with locoregionally advanced NPC who were treated with CCRT. Good- and poor-risk patients can be distinguished by virtue of their having both conditions.