Parotid Lymph Node Metastasis Research Articles

Results of surgical treatment of lymph node metastases in patients with cutaneous squamous cell carcinoma of the head and neck

IntroductionOut of all cutaneous squamous cell carcinomas originating in the head and neck (HNCSCC), 2–4% are associated with parotid or cervical lymph node metastasis. The aim of this study is to analyse the prognostic factors of patients with HNCSCC with lymph node involvement treated surgically. Additionally, we aim to compare the prognostic capacity of the classification of these patients according to the 8th edition of the TNM, and an alternative classification proposed by O'Brien et al. Patients and methodsRetrospective review of 65 patients with HNCSCC with lymph node metastasis treated surgically during the period 2000–2020. ResultsDuring the study period we carried out 13 neck dissections and 52 parotidectomies + neck dissection in patients with lymph node metastases from a HNCSCC. The great majority of patients (89.2%) received post-operative radiotherapy. The 5 year disease-specific survival was 69.9%, and the overall survival it was 42.8%. The classification proposed by O'Brien et al., based on the parotid or cervical location of the lymph node metastases, and the size and number of the metastatic lymph nodes, had a better prognostic capacity than the TNM classification. ConclusionsThe surgical treatment of lymph node metastases in patients with HNCSCC achieved a high disease control. The classification based on the location, size and number of lymph node metastases proposed by O'Brien et al had better prognostic capacity than the TNM classification.

Resultados del tratamiento quirúrgico de las metástasis ganglionares en pacientes con carcinomas escamosos cutáneos de cabeza y cuello

IntroductionOut of all cutaneous squamous cell carcinomas originating in the head and neck (HNCSCC), 2%-4% are associated with parotid or cervical lymph node metastasis. The aim of this study is to analyse the prognostic factors of patients with HNCSCC with lymph node involvement treated surgically. Additionally, we aim to compare the prognostic capacity of the classification of these patients according to the 8th edition of the TNM, and an alternative classification proposed by O’Brien et al. Patients and methodsRetrospective review of 65 patients with HNCSCC with lymph node metastasis treated surgically during the period 2000-2020. ResultsDuring the study period we carried out 13 neck dissections and 52 parotidectomies +neck dissection in patients with lymph node metastases from a HNCSCC. The great majority of patients (89.2%) received post-operative radiotherapy. The 5year disease-specific survival was 69.9%, and the overall survival it was 42.8%. The classification proposed by O’Brien et al., based on the parotid or cervical location of the lymph node metastases, and the size and number of the metastatic lymph nodes, had a better prognostic capacity than the TNM classification. ConclusionsThe surgical treatment of lymph node metastases in patients with HNCSCC achieved a high disease control. The classification based on the location, size and number of lymph node metastases proposed by O’Brien et al. had better prognostic capacity than the TNM classification.

Clinical treatment considerations in the intensity-modulated radiotherapy era for parotid lymph node metastasis in patients with nasopharyngeal carcinoma

PurposeNo specific irradiation guidelines have been proposed for parotid lymph node (PLN) metastasis in patients with nasopharyngeal carcinoma (NPC). This study aimed to explore the dose prescription and target delineation for PLN metastasis in patients with NPC. MethodsWith the NPC database from a big-data platform, 10,685 patients with primarily diagnosed, non-distant metastatic, histologically proven NPC and treated with intensity modulated radiotherapy (IMRT) at our center from 2008 to 2019 were reviewed and those with PLN metastasis were enrolled in this study. Dosimetry parameters were collected from the dose-volume histograms (DVH). The primary endpoint was overall survival (OS). Least absolute shrinkage and selection operator regression (LASSO) was operated for variable selection. Multivariate Cox regression analysis was applied to identify the independent prognostic factors. ResultsPLN metastases were identified in 275/10685 (2.5%) patients. Of 367 positive PLN, 199 were in superficial intra-parotid, followed by 70 in deep intra-parotid, 54 in subparotid and 44 in subcutaneous pre-auricular. Better survival outcome was observed in PLN-radical IMRT group, compared with PLN-sparing group. In 190 patients received PLN-radical IMRT, multivariate analysis revealed that D95% of level VIII > 55 Gy was an independent beneficial prognostic factor for overall survival (OS), progression-free survival (PFS), distant metastasis-free survival (DMFS), and parotid relapse-free survival (PRFS). ConclusionBased on the distribution pattern of PLN metastasis in NPC and the result of dose-finding study, involving the ipsilateral level VIII into low-risk clinical target volume (CTV2) is recommended for NPC with PLN metastasis.

Association between factor of parotid lymph node and prognosis in parotid cancer

IntroductionSurvival significance of parotid lymph node (LN) factors in parotid cancer remains unclear, our goal was to assess the impact of number, size, and extranodal extension (ENE) of metastatic parotid LNs on prognosis in parotid cancer. Materials and methodsPatients with surgically treated parotid cancer were retrospectively enrolled. Primary outcome variable was recurrence-free survival (RFS) and overall survival (OS). The hazard ratios (HRs) of main predictive variables including the number, size, and ENE of positive parotid LNs on RFS and OS were analyzed using Cox model. The secondary outcome variable was ENE of metastatic parotid LN, its association with clinicopathologic variables were evaluated using Chi-square test. ResultsIn total, 453 patients (186 male and 267 female) were included. The 10-year RFS and OS rates were 73% (95%CI: 69%–77%) and 61% (95%CI: 55%–67%), respectively. In Cox model, compared none parotid LN metastasis, one metastatic parotid LN did not offer additional compromise of RFS (p = 0.224) or OS (p = 0.135), but two or more positive LNs decreased the control of RFS (HR: 2.017; 95%CI: 1.378–4.632) and OS (HR: 2.173; 95%CI: 1.367–4.275). When accounting for the number of metastatic LNs, LN size or ENE was no longer related to RFS or OS. ENE of parotid LN tended to develop if there was presence of T3/4 stage, lymphovascular invasion, high histologic grade, N2/3 stage, and three or more positive parotid LNs. ConclusionQuantitative parotid LN burden but not ENE or LN size is an important determinant of survival in patients with parotid cancer.

Metastatic parotid gland malignancy: A preliminary study in an eastern Chinese population

ObjectiveThis study aimed to determine the incidence and clinicopathological patterns of metastatic carcinoma of the parotid gland. MethodNinety patients with parotid gland metastases admitted to our hospital between January 2003 and December 2018 were included in this study. Clinical and pathological data were obtained from the medical records and follow-ups. Kaplan-Meier analysis was used to assess overall survival of patients. ResultsAmong the 90 patients, parotid gland metastases originated from the head and neck in 86 (95.6%), from non-head and neck in 4 (4.4%), from the oral cavity in 30(33.3%), and from the eyelid in 21 (23.3%). Among the 85 cases with parotid gland lymph node metastasis, 45 (52.9%) were diagnosed with extra-lymph node metastasis. The capsule of the parotid lymph nodes was thinner than that of the cervical lymph nodes (P < 0.05). Hematogenous metastases to the parotid gland (only five cases) were rare, mainly from the non-head and neck malignancies. Patients with oral squamous cell carcinoma and meibomian adenocarcinoma with parotid metastatic disease had poorer overall survival (P < 0.05). ConclusionEastern China population analysis showed that parotid gland metastases usually arise from oral squamous cell carcinoma and eyelid, but rarely from cutaneous squamous cell carcinoma. Most cases metastasize to the parotid lymph nodes via the lymphatic system and are prone to extranodal extension with little or no facial nerve involvement. These findings have important implications for the treatment of metastatic parotid malignancies.

The role of total parotidectomy in high-grade parotid malignancy: A multisurgeon retrospective review

PurposeDetermine rates of intra-parotid and neck nodal metastasis, identify risk factors for recurrence, and report outcomes in patients with primary high-grade parotid malignancy who undergo total parotidectomy and neck dissection. Materials & methodsRetrospective review of patients undergoing total parotidectomy and neck dissection for high-grade parotid malignancy between 2005 and 2015. The presence and number of parotid lymph nodes, superficial and deep, as well as cervical lymph nodes involved with metastatic disease were assessed. Risk factors associated with metastatic spread to the parotid deep lobe were identified and recurrence rates reported. Results75 patients with median follow-up time of 47 months. 35 patients (46.7%) had parotid lymph node metastasis. Seven patients (9.3%) had deep lobe nodal metastasis without metastasis to the superficial lobe nodes. Nine patients (12%) had positive intra-parotid nodes without positive cervical nodes. Cervical nodal disease was identified in 49.3% patients (37/75). Local, parotid-bed recurrence rate was 5.3% (4/75). Regional lymph node recurrence rate was also 5.3% (4/75). Rate of distant metastasis was 30.6% (23/75). The overall disease free survival rate for all patients at 2 and 5 years were 71% and 60% respectively. ConclusionParotid lymph node metastasis occurred at a similar rate to cervical lymph node metastasis (46.7% and 49.3%, respectively). Deep lobe parotid nodal metastasis occurred in nearly a quarter of patients and can occur without superficial parotid nodal metastasis. Rate of recurrence in the parotid bed, which may represent local or regional recurrence, was similar to regional cervical lymph node recurrence. Total parotidectomy and neck dissection should be considered high-grade parotid malignancy regardless of clinical nodal status.

Application of modified V-Y advancement flap for reconstruction of facial defect

Objective:To investigate the clinical effect of modified V-Y advancement flap for reconstruction of facial skin defect. Methods:Thirty-eight patients with facial skin tumors underwent individual tumor resection according to pathological type and lesion depth. Based on the defect site and size, appropriate V-Y advancement flap was designed to reconstruct the skin defect in one stage. There were 9 cases of classic subcutaneous tissue pedicle V-Y advancement flap, 24 cases of modified subcutaneous tissue pedicle V-Y advancement flap and 5 cases of perforated V-Y advancement flap in our study. Results:Among the 38 patients, 34 cases had primary healing. Two cases developed necrosis at the edge of the flap and healed after debridement. Local infection occurred in 2 cases, which healed after short-term dressing change. Postoperative mild eyelid ectropion occurred in 2 cases and oral horn displacement in 1 case. The patients were followed up for 6-36 months postoperatively, and the function and appearance recovered well. One case had local recurrence and 3 cases had parotid lymph node metastasis, which were removed again and supplemented with radiotherapy. Conclusion:The improved design of V-Y advancement flap can enlarge the scope of facial defect reconstruction, and achieve good appearance and function.

Metastasis of oral squamous cell carcinoma to the parotid lymph nodes

Parotid lymph node (PLN) metastasis greatly worsens the prognosis of patients with oral squamous cell carcinoma (OSCC) and poses a great challenge for further treatment of OSCC. The clinicopathological characteristics and treatment strategies for PLN metastasis from OSCC need to be comprehensively elucidated. A retrospective review of OSCC patients who experienced postoperative PLN metastasis in our department between 2000 and 2018 was performed in this study. A total of 47 OSCC patients with postoperative PLN metastasis were identified. PLN with metastasis were divided into three groups based on the location: parotid tail (PLN-t), superficial lobe (PLN-sl), and deep lobe (PLN-dl). Most of the patients experienced PLN metastasis within less than 12 months after the primary surgery for OSCC. Comparatively, patients with PLN-sl metastasis were more prone to have infiltration of the facial nerve. The tongue and buccal mucosa were the most frequent primary sites associated with PLN metastasis from OSCC. PLNs in the parotid tail were most commonly affected by the metastasized OSCC. Consequently, we recommend a series of strategies for the prevention and treatment of PLN metastasis for OSCC patients. In conclusion, PLNs should not be overlooked during preoperative evaluation and postoperative follow-up examinations for OSCC patients.

Parotidectomy in the management of squamous cell carcinoma of the external auditory canal.

To investigate optimal approaches for appropriate removal of the parotid gland in the management of squamous cell carcinoma (SCC) of the external auditory canal (EAC) at different tumor stages. In total, 39 patients with SCC of EAC treated at the Second Affiliated Hospital of Nanchang University between September 2003 and April 2019 were enrolled in this study. All patients underwent lateral temporal bone resection or subtotal temporal bone resection. Total parotidectomy was performed in patients with direct parotid invasion. Superficial parotidectomy was performed in patients with parotid node metastasis and patients with advanced stages without evidence of parotid involvement. The mean follow-up period was 68.7months. Local recurrences or distant metastases occurred in five patients (12.8%). The 5-year overall survival rate was 78.4%. The 5-year survival rate was 100% in early stage (T1 and T2) patients, and 58.9 and 50.0% in patients staged III and IV, respectively. Direct parotid invasion was observed in only advanced-stage patients, while parotid node metastasis was noted in both early and advanced-stage patients preoperatively. There were no significant differences (χ2 = 0.1026; p = 0.749) between different tumor primary locations. However, soft tissue or preauricular organs became vulnerable once the anterior wall was infiltrated or eroded. Parotid management is important for achieving safer and wider tumor-free margins. Total parotidectomy should be mandatory for all advanced-staged (T3 and T4) patients. An optimal decision for parotid management in early stages depends on the infiltration or erosion of the anterior wall of the EAC.

Establishment and Validation of a Nomogram for Nasopharyngeal Carcinoma Patients Concerning the Prognostic Effect of Parotid Lymph Node Metastases.

PurposeThe prognosis of nasopharyngeal carcinoma (NPC) patients with parotid lymph node (PLN) metastasis remains unclear. This study was performed to investigate the prognostic significance and optimal staging category of PLN metastasis and develop a nomogram for estimating individual risk. Materials and MethodsClinical data of 7,084 non-metastatic NPC patients were retrospectively reviewed. Overall survival (OS) was the primary endpoint. A nomogram was established based on the Cox proportional hazards regression model. The accuracy and calibration ability of this nomogram was evaluated by C-index and calibration curves with bootstrap validation. ResultTotally, 164/7,084 NPC patients (2.3%) presented with PLNs. Multivariate analyses showed that PLN metastasis was a negative prognostic factor for OS, progression-free survival (PFS), distant metastasis-free survival (DMFS), and locoregional relapse-free survival (LRFS). Patients with PLN metastasis had a worse prognosis than N3 disease. Five independent prognostic factors were included in the nomogram, which showed a C-index of 0.743. The calibration curves for probability of 3- and 5-year OS indicated satisfactory agreement between nomogram-based prediction and actual observation. All results were confirmed in the validation cohort. ConclusionNPC patient with PLN metastasis had poorer survival outcome (OS, PFS, DMFS, and LRFS) than N3 disease. We developed a nomogram to provide individual prediction of OS for patients with PLN metastasis.

Ca breast with bell’s palsy: a rare presentation

Parotid and cervical lymph nodes are subtle sites for metastasis from breast carcinoma. A 55-yearold female patient of carcinoma breast previously radically treated with chemo-radiotherapy and was on regular follow up conferred to our department with left sided bell’s palsy and a swelling in her left parotid region. Through this case, we present the expedient management of advanced breast cancer usher with the parotid gland and cervical lymph node metastasis. As we found this an intriguing case and outlandish and exceptional presentation, oncologists should be aware of the prodigious clinical course for early diagnosis and transcend treatment. Keywords: Metastasis, Modified radical mastectomy, Duct cell carcinoma.

Better outcome for parotid versus neck metastasis of head and neck cutaneous squamous cell carcinoma: a new report on reemerging data

IntroductionRegional metastases of cutaneous head and neck squamous cell carcinoma occur in approximately 5 % of cases, being the most important prognostic factor in survival, currently with no distinction between parotid and neck metastasis. ObjectiveThe purpose of this study was to evaluate the prognostic features among patients with head and neck cutaneous squamous cell carcinoma exhibiting regional metastasis. MethodsA retrospective analysis of patients with cutaneous squamous cell carcinoma who underwent parotidectomy and/or neck dissection from 2011 to 2018 at a single institution tertiary center was performed. Patient demographics, clinical, surgical and pathological information, adjuvant treatments, and outcome at last follow-up were collected. Outcomes included disease recurrence and death due to the disease. Prognostic value of clinic pathological features associated with disease-specific survival was obtained. ResultsThirty-eight cases of head and neck cutaneous squamous cell carcinoma with parotid and/or neck metastasis were identified. Overall, 18 (47.3 %) patients showed parotid metastasis alone, 12 (31.5 %) exhibited neck metastasis alone and 8 (21.0 %) had both. A primary tumor in the parotid zone (Hazard Ratio ‒ HR = 5.53; p = 0.02) was associated with improved disease-specific survival. Poorer disease-specific survival was observed in patients with higher primary tumor diameter (HR = 1.54; p = 0.002), higher depth of invasion (HR = 2.89; p = 0.02), invasion beyond the subcutaneous fat (HR = 5.05; p = 0.002), neck metastasis at first presentation (HR = 8.74; p < 0.001), number of positive lymph nodes (HR = 1.25; p = 0.004), and higher TNM stages (HR = 7.13; p = 0.009). Patients presenting with isolated parotid metastasis during all follow-ups had better disease-specific survival than those with neck metastasis or both (HR = 3.12; p = 0.02). ConclusionHead and neck cutaneous squamous cell carcinoma with parotid lymph node metastasis demonstrated better outcomes than cases with neck metastasis.

Prognosis and staging of parotid lymph node metastasis in nasopharyngeal carcinoma: An analysis in 10,126 patients

ObjectiveIn nasopharyngeal carcinoma (NPC), the staging category of parotid lymph node (PLN) metastasis is not explicitly defined, resulting in varied classifications and treatment strategies in clinical practice. This study aimed to determine the prognostic value and optimal staging category of PLN metastasis in NPC. Materials and methodsWith the NPC database from a big-data platform, 10,126 patients with primarily diagnosed, non-metastatic NPC and treated with intensity modulated radiotherapy at our center from 2009 to 2015 were analyzed in this study. ResultsIn total, 43/10126 patients (0.4%) were diagnosed with histologically verified PLN metastasis at initial diagnosis. Of these, 88.4% (38/43) had enlarged lymph nodes in level II and 34.9% (15/43) in level Ib. Compared with patients without PLN metastasis, those with PLN metastasis had higher risk of disease failure (adjusted hazard ratio [HR], 1.770), distant metastasis (HR, 1.907), and regional recurrence (HR, 3.649), with similar 3-year disease-free survival (70.0% vs. 71.1%) and distant metastasis-free survival (74.8% vs. 77.4%) with patients with N3 disease. Of note, 10/43 patients had regional recurrence: six had recurrent lymph nodes in level Ib; and four of these six patients had no identifiable level Ib lymph nodes on pretreatment imaging. ConclusionPLN metastasis was associated with high risk of distant metastasis and regional recurrence, and patients with PLN metastasis had similar outcome compared with patients with N3 disease. Regional recurrences in rare levels, such as level Ib, were common in patients with PLN metastasis at initial diagnosis.

Clinical management for T1 and T2 external auditory canal cancer

ObjectiveThe purpose of this study was to clarify the impact of superficial parotidectomy and postoperative radiotherapy (PORT) for the surgical treatment of early stage squamous cell carcinoma (SCC) in external auditory canal (EAC). Materials and methodsThirty-seven patients with T1 (n = 14) or T2 (n = 19) SCC in EAC treated between 2000 and 2016 at Kobe University Hospital were enrolled in this study. Thirty-three patients were operated with sleeve resection or lateral temporal bone resection. ResultsThe 5-year overall survival and disease-specific survival rates were 95% and 100%, respectively. Surgical margin was positive in 4 patients, who were treated by PORT and have been alive without disease. Prophylactic superficial parotidectomy was simultaneously performed at the time of initial surgery in 15 patients, in whom no lymph node (LN) metastasis was observed. Among the other 22 patients, regional recurrence in parotid LN was observed in one patient, who was successfully salvaged by total parotidectomy. Potential parotid lymph node metastasis rates of T1 and T2 SCC in EAC was 0% (0/14) and 5% (1/19) respectively. ConclusionsComplete resection without positive surgical margins is essential for the treatment of the patients with T1 and T2 ear cancers. Prophylactic superficial parotidectomy or neck dissection is not mandatory for T1 and T2 diseases, as long as precisely extent of disease is assessed preoperatively. PORT should be performed for the patients with positive surgical margins.Levels of evidence: 4.

The Value of Adjuvant Radiotherapy in Cutaneous Squamous Cell Carcinoma: A Review

Cutaneous squamous cell carcinoma (cSCC) is the second most common cancer in humans and its incidence is rising. Although surgery is the treatment of choice for cSCC, postoperative adjuvant radiotherapy has an important role in local and locorregional disease control. In this review, we analyze the value of postoperative radiotherapy in the management of high-risk cSCC (in particular, cases with perineural invasion), cSCC with positive surgical margins, and locally advanced cSCC (with parotid gland and/or lymph node metastasis).

Utilidad de la radioterapia en adyuvancia en el carcinoma epidermoide cutáneo

Cutaneous squamous cell carcinoma (cSCC) is the second most common cancer in humans and its incidence is rising. Although surgery is the treatment of choice for cSCC, postoperative adjuvant radiotherapy has an important role in local and locorregional disease control. In this review, we analyze the value of postoperative radiotherapy in the management of high-risk cSCC (in particular, cases with perineural invasion), cSCC with positive surgical margins, and locally advanced cSCC (with parotid gland and/or lymph node metastasis).

Cutaneous squamous cell carcinoma of the head and neck with parotid gland metastasis mimicking mucoepidermoid carcinoma: a potential diagnostic pitfall

We present an atypical case of cutaneous head and neck squamous cell carcinoma (cHNSCC), with parotid gland metastasis. This 56-year-old female presented with a slowly enlarging mass at the left pre-auricular region over the past year. At first, the patient described that there was only a bulging mass without apparent skin lesion or skin defect and it grew slowly. A magnetic resonance imaging (MRI) demonstrated a large lobulated lesion measuring 51 mm × 55 mm × 56 mm within the left parotid gland, which had invaded the ipsilateral masseter muscle causing displacement of the left lateral pterygoid muscle. The diagnostic radiologist made a provisional diagnosis of mucoepidermoid carcinoma (MEC) based on the finding of MRI. The patient then received left total parotidectomy with ipsilateral supraomohyoid neck dissection. The diagnosis later revised to cHNSCC with parotid lymph node metastasis based on pathological findings. cHNSCC may present solely as parotid tumor without apparent skin lesion which might also mimic primary MEC of the parotid gland.

Management of and risk factors for regional recurrence in upper lip squamous cell carcinoma

Our goal was to evaluate the risk factors for regional recurrence in upper lip squamous cell carcinoma (SCC).A total of 109 patients with upper lip SCC were retrospectively enrolled. Clinical and pathologic information was collected and analyzed.Fifteen (13.8%) patients had a regional metastasis, 2 patients had parotid node metastasis, and no local or distant metastasis was noted. There was neck level I node metastasis in 15 (100%) patients. In multivariate analysis, invasion depth and degree of differentiation were significantly associated with regional metastasis. The 5- and 10-year disease-specific survival rate was 95.4% and 80.1%, respectively.Invasion depth and degree of differentiation have reliable value for predicting regional metastasis.

Twice Operations for Parotid Metastasis of Nasopharyngeal Carcinoma Patient after Radical Intensity-Modulated Radiotherapy: A Case Report

The surgery treatment of parotid metastasis of nasopharyngeal carcinoma (NPC) after parotid-gland-sparing IMRT is rare report. We present such a case of NPC patient cT2N2M0 with parotid lymph node metastasis after parotid-gland-sparing IMRT patient who accepted the second operation after the first failure parotid section. This case reminded us that neck dissection added the whole parotid gland resection may be an appropriate method to treat this type of patients.

High-Risk Factors of Parotid Lymph Node Metastasis in Nasopharyngeal Carcinoma: A Case-Control Study

Although parotid-sparing IMRT decreased the dose distribution of parotid, parotid region recurrence has been reported. Prophylactic irradiation in parotid area would be necessary in patients with high risk of parotid lymph node metastasis (PLNM). This study was to detect the high-risk factors of PLNM in nasopharyngeal carcinoma. This was a 1:2 case-control study. All patients in this study were newly diagnosed NPC with N2-3 classification from January 2005 to December 2012. Cases were 22 sides with ipsilateral PLNM. Controls were 44 patients who were randomly selected from N2-3 disease in database. 20/1096 (1.82 %) NPC patients were found PLNM. Sum of the longest diameter for multiple lymph nodes (SLD) in level II was larger in case group than that in control group (6.0 cm vs. 3.6 cm, p = 0.003). Level II lymph node necrosis, level Va/b involvement, and rare neck areas involvement were more common in case group (p = 0.016, p = 0.034, and p < 0.001, respectively). RPN, level III, and level IV metastases showed no significant difference between the two groups. Multivariate analysis in logistic regression showed that only SLD ≥5 cm in II area (OR = 4.11, p = 0.030) and rare neck areas involvement (OR = 3.95, p = 0.045) were associated with PLNM in NPC patients. PLNM was an uncommon event in NPC patients. SLD ≥5 cm in level II and involvement in rare-neck areas may be potentially high-risk factors for PLNM. Sparing parotid in IMRT was not recommended for NPC patients with high risks of PLNM.