The use of positron emission tomography for early detection of recurrent head and neck squamous cell carcinoma in postradiotherapy patients

Positron emission tomography (PET) has recently proved to be highly sensitive in detecting known extracranial head and neck squamous cell carcinomas when compared to computed tomography and magnetic resonance imaging (MRI). The ability of PET to detect early subclinical recurrent squamous cell malignancies in patients who received primary radiotherapy was evaluated. A new PET-MRI coregistration technique was used to determine precise anatomic tumor location, enabling directed biopsies to confirm the presence of malignancy, and to plan additional therapeutic strategies. Ten patients underwent PET evaluation with intravenous [¹⁸F]-fluorodeoxyglucose and received postradiotherapy MRI scans. In all cases, PET accurately detected the presence of recurrent disease despite negative or equivocal MRI scans and indeterminate clinical examinations. PET appears to be highly effective in detecting early recurrent head and neck squamous cell malignancies in postirradiated patients.     

The role of positron emission tomography with 18F-fluorodeoxyglucose in nodal staging of clinical and radiological N0 head and neck cancers

The objective of the study was to evaluate the impact of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) imaging on nodal staging for head and neck cancers. This was a retrospectively analyzed single institution study. The study population consisted of 36 patients with head and neck cancers who were evaluated with PET/CT and went on to neck dissection. All of them had clinically and radiographically negative neck (N₀) and each patient underwent PET/CT imaging before undergoing selective neck dissection for N₀ disease. Tissues were submitted for histopathologic examination and were oriented for the pathologist to permit correlation between the histopathologic findings and the imaging results. The sizes of the lymph nodes and the maximum standardized uptake values (SUV_max) measured from PET/CT images were compared with the histopathologic findings. All primary tumors were visualized with PET/CT. On histopathological examination, 19 patients had positive and 17 patients had negative lymph nodes. Receiver operating characteristic analyses were used to predict the optimal corrected SUV_max cutoffs; the optimal value was 2.95 for respective outcomes of lymph node involvement. This cutoff value yielded 84.2 % sensitivity and 76.5 % specificity for nodal-level staging. PET/CT proved to be accurate in 27 (75 %) patients and inaccurate in 9 (25 %) patients. PET/CT was a valuable tool to assess nodal stage of head and neck cancers, and should be considered before surgical treatment.     

Fluorodeoxyglucose imaging using a coincidence gamma camera to detect head and neck squamous cell carcinoma and response to chemotherapy

This prospective study was performed to evaluate the ability of a dual-head gamma camera with fluorine-18 fluorodeoxyglucose coincidence detection emission tomography (FDG-CDET) to detect primary tumor and cervical lymph nodes in head and neck squamous cell carcinoma (HNSCC), and to show the response of the carcinoma to chemotherapy. The findings were compared with those of physical examination, computed tomography (CT), and histopathology, before treatment in 61 patients, and after induction chemotherapy in 34 of them. Before treatment, the primary was detected in 93%, 79%, and 95% of cases on panendoscopy, CT, and FDG-CDET, respectively. After chemotherapy, 34 patients were evaluable for response of the primary tumor. Surgical resection was performed in 23 of them: agreement with histopathologic results for response to treatment was 74%, 69%, and 78% for panendoscopy, CT, and FDG-CDET, respectively. No surgical resection was performed in 11 of the 34 patients, but biopsies were performed before radiotherapy, and their rates of agreement with histopathologic results for response to treatment were 75%, 75%, and 67% on panendoscopy, CT, and FDG-CDET, respectively. For cervical lymph nodes, 245 sites were resected in 41 patients, and FDG-CDET appeared competitive with CT in detecting metastatic neck disease, especially after neoadjuvant chemotherapy; the accuracy was 93%. These results demonstrated the ability of FDG-CDET to detect primary tumors and cervical lymph nodes in HNSCC and to show its response to chemotherapy, as compared to the ability of CT and panendoscopy. It may be a complementary tool to evaluate residual disease after induction chemotherapy, although higher sensitivity would be required for FDG-CDET to be considered as a staging modality.     

Positron emission tomography in the management of unknown primary head and neck carcinoma

OBJECTIVE: To assess the role of positron emission tomography (PET) in the management of unknown primary carcinoma of the head and neck region. DESIGN AND SETTING: Prospective case series at an academic medical center. PATIENTS: Twenty-six patients with an open excisional biopsy or a fine-needle aspiration biopsy finding that confirmed squamous cell carcinoma of the cervical lymph nodes and no visible primary tumor (as determined by results of a comprehensive physical examination and computed tomography and/or magnetic resonance imaging) underwent PET. The standard evaluation consisted of a comprehensive head and neck examination that included fiberoptic laryngoscopy/nasopharyngoscopy, computed tomography and/or magnetic resonance imaging, and PET followed by panendoscopy with selected biopsies and tonsillectomy. MAIN OUTCOME MEASURES: Sensitivity, specificity, and positive and negative predictive values of PET to detect an occult primary tumor. RESULTS: The PET detected 8 occult primary tumors in 26 patients (detection rate, 30.8%). Four occult primary tumors (2 at the base of the tongue and 2 in the tonsil) were detected during routine panendoscopy with negative PET findings. The sensitivity of PET was 66.0%, with a specificity of 92.9%. The positive predictive value was 88.8%, and the negative predictive value was 76.5%. CONCLUSIONS: Positron emission tomography can be a valuable tool to identify a subset of patients with an occult primary tumor in the head and neck region. In addition, it can be used to screen for primary tumors below the clavicle. Early identification of the primary tumor may allow for more accurate tumor staging and targeted radiotherapy to minimize adverse effects and complications. A normal PET finding, however, does not eliminate the need for a careful panendoscopy with directed biopsies and tonsillectomy.     

Diagnosis and staging of head and neck cancer: a comparison of modern imaging modalities (positron emission tomography, computed tomography, color-coded duplex sonography) with panendoscopic and histopathologic findings

OBJECTIVE: To compare the clinical value of positron emission tomography (PET) using fludeoxyglucose F 18, computed tomography (CT), color-coded duplex sonography (CCDS), and panendoscopy in the detection and staging of head and neck cancer. DESIGN: Prospective nonrandomized controlled study. SETTING: Medical school. PATIENTS: Convenience sample of 50 patients with suspected primary or recurrent head and neck cancer. INTERVENTION: Biopsy, tumor surgery. MAIN OUTCOME MEASURES: Information of diagnostic procedures compared with histopathologic features. RESULTS: Both PET and panendoscopy had a sensitivity of 95% and 100% for detection of primary tumor or recurrent carcinomas, respectively. Specificity for PET and panendoscopy was 92% and 85% in primary tumors and 100% and 80% in recurrent carcinoma, respectively. Sensitivity of CCDS and CT was 74% and 68% in primary tumors and 67% and 63% in recurrent carcinomas, respectively. Specificity was 75% and 69% in primary tumors and 100% and 80% in recurrent neoplasms. When assessing neck nodes, all imaging procedures exhibited identical sensitivity (84%). Specificity was 90%, 96%, and 88% in PET, CT, and CCDS, respectively. In recurrent lymph node metastases, sensitivity was 100%, 67%, and 67% and specificity was 87%, 91%, and 87% for PET, CT, and CCDS, respectively. CONCLUSIONS: Positron emission tomography was the most reliable imaging procedure in the detection of primary tumor and recurrent carcinomas localized in the head and neck region. Owing to its limited anatomical depiction, it cannot as yet replace other diagnostic procedures in preoperative planning but does contribute valuable complementary diagnostic information. Computed tomograpy may have difficulties in identifying recurrent carcinomas. For routine diagnosis of nodal spread in the neck, CCDS is recommended. Panendoscopy is a valuable diagnostic procedure that can provide key information in cases of superficial mucosal tumor involvement. Arch Otolaryngol Head Neck Surg. 2000;126:1457-1461     

脱氧葡萄糖-正电子发射计算机断层显像对颈淋巴结转移癌的诊断价值

目的：探讨脱氧葡萄糖-正电子发射计算机断层[^18F-FDG-PET／CT（PET／CT）]融合显像对颈淋巴结转移癌的诊断价值。方法：对照颈淋巴结清扫术后病理结果,回顾性对比分析20例头颈癌患者颈部正电子发射断层（PET）、CT及PET／CT资料。结果：PET对颈淋巴结转移癌的诊断敏感性、特异性及准确度分别为92.3％、85.7％、90.0％,CT分别为77.0％、57.1％、70.0％,PET／CT分别为92.3％、100.0％、95.0％,PET／CT的诊断准确度显著高于CT（P〈0．05）、略优于PET。13例鼻咽癌放疗后患者,CT诊断正确7例,PET／CT诊断正确12例。7例N。患者颈淋巴结清扫术后病理证实4例存在颈淋巴结转移,术前PET／CT均诊断正确。结论：PET／CT融合显像对颈淋巴结转移癌的诊断价值优于单独的PET及CT,尤其对于治疗后的患者,其诊断优势更加突出,有望作为是否需行颈淋巴结清扫术的指征。     

The integrated PET/CT: technological advance in diagnostics of head and neck recurrencies and CUP?

BACKGROUND: In the last years (18)F-Fluoro-deoxy-glucose (FDG)-positron emission tomography (PET) worked satisfactorily as auxiliary method in order to show recurrency of head and neck tumors and to detect primary tumors in case of CUP especially when CT and MR imaging failed to identify the tumor accurately. The correlation of FDG hypermetabolism and anatomical structures is now provided by a new technology which is integrating PET and CT: Integrated PET/CT represents a new technical development, which combines the advantages of CT and PET. PATIENTS: In a retrospective investigation 84 non selected PET/CT studies of 83 patients with recurrent head and neck disease and CUP were critically analyzed. RESULTS: 33 cases had positive PET findings. 5 of these 33 cases showed false-positive findings. In 51 PET studies there was not found any sign of suspicious FDG hypermetabolism. CONCLUSION: Integrated PET/CT delivers substantial progress in detecting tumor localization. False positive findings have to be considered and therefore indications should be strictly limited to special cases of head and neck tumor recurrency, cases with complex anatomical sites and CUP.     

Uses and limitations of FDG positron emission tomography in patients with head and neck cancer.

OBJECTIVE: Numerous authors have reported the potential usefulness of positron emission tomography (PET). These studies have had conflicting results, at least partly owing to limited sample sizes. The objective of this study is to define not only the uses, but also the limitations of PET in patients with head and neck cancer. STUDY DESIGN: Nonrandomized, retrospective analysis of PET at an academic institution. METHODS: The authors performed 146 PET scans on 133 patients with head and neck cancer. Eighteen patients (19 PET scans) with thyroid disorders were excluded. A minimum 1 year of follow-up was available in 84 patients, who were separated into groups based on whether the PET was used to detect unknown primary cancers (n = 20), stage neck nodal and distant metastases (n = 8), monitor response to nonsurgical therapy (n = 22), or detect recurrent or residual cancers (n = 34). The results of PET were compared with results from computed tomography (CT) and magnetic resonance imaging (MRI) performed in the same patients. RESULTS: Of the unknown primary cancers, PET correctly identified 7 of 20 primary sites, giving a sensitivity of 35%. When combined with CT or MRI, the sensitivity increased to 40%. When used for detection of metastatic disease, PET demonstrated five of five nodal metastases (100%) and two of four distant metastases (50%). In evaluating the response to nonsurgical therapy, PET had a sensitivity of 50% and a specificity of 83% for detecting tumor at the primary site and a sensitivity of 86% and a specificity of 73% for detecting nodal disease. When used for evaluation of recurrent/residual disease, PET identified seven of seven cases of local recurrences/residual disease and had a specificity of 85%. PET also detected seven of seven cases of nodal disease and had a specificity of 89%. CONCLUSIONS: For staging purposes, PET is limited by its lack of anatomic detail. However, PET compares favorably with CT and MRI in detecting recurrent/residual cancers. PET imaging complements the more traditional imaging modalities (CT or MRI), especially for an unknown primary cancer.     

正电子发射计算机断层-CT融合显像在头颈肿瘤中的诊断价值

目的探讨^18氟-脱氧葡萄糖(18-nuorinenuorodeoxyducose，^18F-FDG)正电子发射计算机断层显像(positron emission tomography，PET)-CT融合显像在头颈肿瘤的原发灶诊断、复发的检测和诊断分析未知原发肿瘤转移癌中的诊断价值。方法27例已确诊头颈部原发肿瘤或转移癌，进行^18F-FDGPET-CT全身显像，并与临床资料对照。结果鼻咽癌组治疗前4例PET-CT均查出原发灶，其中2例确诊有颈淋巴结转移，与病理检查结果一致。鼻咽癌放疗后12例中4例PET-CT检查鼻咽部及颈部淋巴结均为阴性表现，符合临床和病理诊断；2例放疗后原发灶复发经病理检查证实，其中1例查出颈部淋巴结及全身多处转移经随访证实；6例鼻咽原发灶PET-CT检查阴性表现．但4例颈部显示淋巴结转移经病理检查证实，2例肺部、纵隔等有转移灶未经病理检查证实。未知原发肿瘤颈淋巴转移组4例患者PET-CT均检出原发灶，3例病理检查证实，另1例未经病理检查证实。其他头颈肿瘤组7例治疗后患者中，2例患者无复发转移表现，5例不同部位肿瘤检出原发部位复发或颈淋巴结转移，有4例经病理检查证实，1例放弃治疗未经病理检查证实。结论^18F-FDGPFT-CT将PET提供的肿瘤代谢图像和CT提供的解剖图像结合，对头颈原发肿瘤诊断，检测治疗后肿瘤复发，不明原因转移癌原发灶的诊断及远处转移灶的诊断具有较大的临床价值。     

正电子发射计算机断层-CT融合显像在头颈肿瘤中的诊断价值

目的　探讨18氟 脱氧葡萄糖 (18 fluorinefluorodeoxyglucose ,18F FDG)正电子发射计算机断层显像 (positronemissiontomography ,PET) CT融合显像在头颈肿瘤的原发灶诊断、复发的检测和诊断分析未知原发肿瘤转移癌中的诊断价值。方法　 2 7例已确诊头颈部原发肿瘤或转移癌 ,进行18F FDGPET CT全身显像 ,并与临床资料对照。结果　鼻咽癌组治疗前 4例PET CT均查出原发灶 ,其中 2例确诊有颈淋巴结转移 ,与病理检查结果一致。鼻咽癌放疗后 12例中 4例PET CT检查鼻咽部及颈部淋巴结均为阴性表现 ,符合临床和病理诊断 ;2例放疗后原发灶复发经病理检查证实 ,其中 1例查出颈部淋巴结及全身多处转移经随访证实 ;6例鼻咽原发灶PET CT检查阴性表现 ,但 4例颈部显示淋巴结转移经病理检查证实 ,2例肺部、纵隔等有转移灶未经病理检查证实。未知原发肿瘤颈淋巴转移组4例患者PET CT均检出原发灶 ,3例病理检查证实 ,另 1例未经病理检查证实。其他头颈肿瘤组 7例治疗后患者中 ,2例患者无复发转移表现 ,5例不同部位肿瘤检出原发部位复发或颈淋巴结转移 ,有 4例经病理检查证实 ,1例放弃治疗未经病理检查证实。结论　18F FDGPET CT将PET提供的肿瘤代谢图像和CT提供的解剖图像结合 ,对头颈原发肿瘤诊断 ,检测治疗后肿瘤复发     

Significance of PET and integrated PET/CT in the diagnostics of occult primary tumors

BACKGROUND: In the last years (18)F-FDG-positron-emission-tomography (PET) worked satisfactorily as helpful auxiliary method in order to verify recurrency of head and neck tumors and to detect primary tumors in case of CUP syndrome especially when CT and MR imaging failed to identify the tumor accurately. Fusion of FDG hypermetabolism in PET scan and anatomical structures is achieved by integrating positron emission tomography with CT and provides improvement also in case of CUP syndrome. This retrospective study shows 47 patients with neck metastases where PET or PET/CT helped to detect primary tumor site. PATIENTS: In a retrospective investigation 49 PET studies of 47 patients with CUP syndrome were analyzed. RESULTS: 9 cases had positive PET findings, 1 case false-positive. 5 cases were false-negative. In 40 PET studies there couldn't be found any sign of suspicious FDG hypermetabolism. CONCLUSION: PET and PET/CT deliver a certain improvement in localization of primary tumor site and therapeutical strategy.     

Predictive ability of the CT to evaluate cervical lymph nodes in head and neck tumours

ObjectiveThe aim of this study was to determine the predictive value of computed tomography (CT) i.e., its sensitivity and specificity in detecting metastatic lymph nodes of head and neck tumours. We also studied the capacity of CT in correct nodal staging.Patients and methodsA CT was performed on 95 patients diagnosed with neoplastic disease of the pharynx and/or larynx. All patients subsequently underwent cervical lymph node dissections. In the imaging study, the following parameters were considered for suspected radiological nodal involvement: lymph node diameter greater than 10 mm, lesion margins poorly defined, capsule enhancement after contrast administration and lymph nodes that, despite their size, had signs of central necrosis.ResultsIn the dissections, 70.53% resulted N+ in the histological study. The sensitivity of CT was 82.09% and the specificity, 85.71%. The CT detected positivity in 55 of the 67 histologically pathological dissections, while the CT detected negativity in 24 of the 28 dissections histologically negative. The weighted kappa index value was 0.6408, indicating limited capacity for appropriate staging of the lymph nodes.ConclusionsWhile the ability of CT to detect metastatic lymph nodes in head and neck tumours is quite acceptable, it is less so for correctly staging them. It is therefore necessary to look for other imaging tests that provide greater accuracy to avoid unnecessary elective neck dissections and to reduce morbidity and mortality from them. We must now pay attention to new imaging techniques such as PET and PET/CT.     

Palpation and CT to evaluate the cervical adenopathies in head and neck tumours

Lymphatic metastasis is an important prognostic factor in patients with head and neck squamous cell carcinomas. Diagnostic evaluation and treatment of this adenopathies is very important. We can use physical examination, computered tomography (CT), magnetic resonance, ultrasound... but none of these give us a 100% security. This study evaluates the accuracy of physical examination and CT in detecting cervical lymph nodes. 120 neck dissections were performed after palpation and CT of 72 patients with head and neck carcinoma. Sensitivity of palpation was 51.7 and specificity 96.7. CTs sensitivity was 65 and specificity 86.7. Both, physical examination and palpation have a high number of mistakes evaluating cervical nodes. N0 necks are still a problem for Head and Neck Surgeons.     

Results of pretherapeutic lymph node diagnosis in head and neck tumors. Clinical value of 18-FDG positron emission tomography (PET)

BACKGROUND: Histological studies demonstrate that there is a high percentage of occult nodal metastasis in head and neck malignomas. Patients with positive lymph nodes have a comparatively worse prognosis. A neck dissection is required in these cases. By demonstrating morphological abnormalities, imaging procedures like ultrasound, computer tomography (CT), and magnetic resonance imaging (MRI) can provide important initial informations about possible malignant alteration of the lymph nodes. Positron emission tomography (PET) allows functional metabolic imaging of a suspected tumor site. The aim of this study was a comparative evaluation of different diagnostic procedures with special emphasis on the value of PET in the pretherapeutic diagnosis of nodal spread in head and neck cancer. PATIENTS AND METHODS: Forty patients (28 male and 12 female) with a suspected malignoma in the head and neck region underwent clinical examination including palpation of the neck sides, ultrasound, CT, and PET to detect a nodal spread of the malignancy. Fifty neck dissections were performed in 28 patients. Lymph node biopsies were performed in the remaining patients. The results of the diagnostic procedures were compared to the histology and the clinical course of the patients. The mean follow-up period was 12.5 months. RESULTS: A nodal metastasis was verified in 35% of all cases. Sensitivity of all imaging procedures including PET was 82%. Palpation had a sensitivity of only 61%. Specificity was 85% for ultrasound, 94% for CT and palpation, and 87% for PET. PET produced false negative results in 13.4% of all cases. Inflammation was detected in these cases. The positive predictive value was marginally better for PET than for ultrasound (77% vs. 75%). It proved to be lower than the values for palpation (86%) and CT (88%). Negative predictive value was 90-91% for all imaging procedures. CONCLUSION: In the primary diagnosis of nodal alterations in the head and neck region, a PET scan has the same diagnostic value as ultrasound or CT. By imaging the metabolism of a suspected nodal metastasis, PET can help to improve the assessment of regions with uncertain anatomic features. To avoid false positive results, acute and chronic inflammatory alterations have to be ruled out before the PET imaging.     

Cancer of unknown primary in the head and neck: Diagnosis and treatment

Cancer of unknown primary in the head and neck is defined by the presence of cancer in one or more lymph nodes within the head and neck region, not confined to the supraclavicular region, without an identifiable primary tumor. These primary sites are increasingly being identified with the help of advanced diagnostic techniques such as endoscopy, PET/CT, the HPV test, the EBV test, evaluation of biomarkers, and pathological examination. However, the remainder of these patients fall into the category of metastatic cervical cancer of unknown primary (MCCUP). MCCUP accounts for approximately 3-5% of all head and neck squamous cell carcinomas (HNSCCs). Moreover, optimal therapy for patients with MCCUP is still controversial. The treatment options range from neck dissection alone to irradiation of the bilateral neck, with or without irradiation of plausible primary sites as well. In future, precision medicine should improve the diagnosis and methods of therapy for MCCUP patients.     

Distant lymphatic metastasis from head and neck cancer.

A predictable pattern of metastasis based on tumor histology and site of origin has been well documented for most cancers that arise in the head and neck region. The current study demonstrates that this predictable pattern of metastasis can be significantly impacted by previous therapy, resulting in unusual patterns of metastasis in patients with recurrent tumors. A retrospective case series of 5 patients with head and neck carcinomas who developed metastases to distant lymph nodes is presented. All patients underwent surgery and radiotherapy to the primary tumor and regional lymphatics at the time of their initial treatment. All of the patients developed a local recurrence less than a year before the detection of distant lymphatic metastases. Cytology or excision confirmed metastases to the axillary, inguinal, or anterior intercostal lymph nodes. All of the patients underwent aggressive surgery for attempted cure of the local recurrence shortly before the presence of distant lymphatic metastases was clinically recognized. The metastatic workup of patients with carcinomas of the head and neck frequently includes examination of the regional lymph nodes as well as chest radiography, liver function tests, and serum calcium determination. This evaluation may fail to detect metastases to distant lymph nodes in patients who present with recurrent or second primary cancers. Such patients should undergo careful examination of all major lymph node-bearing regions of the body when being evaluated for the presence of distant metastases.     

Use of 18F-Fluorodeoxyglucose Positron Emission Tomography in Patients with Rare Head and Neck Cancers

Objectives

The clinical utility of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) has been demonstrated in major head and neck cancers (HNCs) but is unclear in rare HNCs. We therefore evaluated FDG PET in the management of patients with rare HNCs.

Methods

FDG PET and CT/MRI scanning were performed at the initial staging and/or the follow-up in 24 patients with rare HNCs, 10 with melanoma, 9 with sarcoma, 3 with olfactory neuroblastomas, and 2 with basal cell carcinoma. The diagnostic accuracy of CT and FDG PET for detecting primary tumors and metastases were compared with a histopathologic reference. The association between the PET results and the clinicopathologic parameters predicting tumor invasion, histologic grade and disease-free survival (DFS), was assessed.

Results

The overall accuracies of FDG PET and CT/MRI were 92% and 79%, respectively, for detecting primary tumors and 91% and 74%, respectively, for nodal metastases, but the differences were not significant due to the small number of patients. The sensitivity and specificity of FDG PET for detecting distant metastases and second primary tumors were 100% and 87%, respectively. Follow-up FDG PET correctly diagnosed locoregional recurrence in all 12 patients, as shown by biopsy, and distant metastases in 6 patients. However, thickness of melanoma, histologic grade of sarcoma, and DFS were not associated with tumor FDG uptake.

Conclusion

FDG PET may be useful for staging, posttreatment monitoring, and detection of distant metastases and second primary tumors in patients with rare HNCs.     

Positron Emission Tomography in the Evaluation of the N0 Neck

The presence of cervical lymph node metastasis in patients with head and neck cancer is associated with an unfavorable prognosis. Reports vary as to whether various conventional radiographic studies, such as computed tomography (CT) and magnetic resonance imaging, confer an advantage over physical examination in the patient without clinical findings of cervical metastasis (N0). Positron emission tomography (PET) is a functional imaging modality that has recently been used for head and neck neoplasms. The use of PET in the evaluation of the N0-staged neck in 14 consecutive patients with squamous cell carcinoma (SCC) of the upper aerodigestive tract is reported. Seven patients (50%) undergoing 13 neck dissections had pathologic evidence of disease. PET scans were positive in five patients with pathologically confirmed cervical metastasis. PET scans were negative in seven patients (11 neck dissections) with no pathologic evidence of disease. PET scans were positive for unilateral cervical metastasis in two of three patients with involvement of a single lymph node. PET scans were positive in two of three patients with more than two lymph nodes involved. PET had an accuracy of 100% in the eight patients with SCC of the oral cavity. In patients with oropharyngeal or hypopharyngeal carcinoma PET localized cervical metastasis in two of four patients with neck metastasis. In the patient with an N0-staged neck on clinical examination, PET was found to have an overall sensitivity of 78%, specificity of 100%, positive predictive value of 100%, negative predictive value of 88%, and accuracy of 92%. CT demonstrated sensitivity of 57%, specificity of 90%, positive predictive value of 80%, negative predictive value of 75%, and accuracy of 76%. PET showed a trend in increased accuracy (P= 0.11) over CT. PET appears to be a promising diagnostic aid that may be applied when evaluating the N0-staged neck, especially for SCC of the oral cavity.     

Diagnostic sensitivity of 18fluorodeoxyglucose positron emission tomography for detecting synchronous multiple primary cancers in head and neck cancer patients

We assessed the sensitivity of positron emission tomography (PET) for detecting synchronous multiple primary cancers, particularly synchronous esophageal cancers in head and neck cancer patients. We retrospectively reviewed 230 head and neck cancer patients. All the patients routinely underwent the following examinations: urinalysis, occult blood, tumor marker detection [squamous cell carcinoma (SCC), cytokeratin fragment (CYFRA), and carcinoembryonic antigen (CEA)], esophagogastroduodenoscopy, colonoscopy (when CEA was high or occult blood was positive), abdominal ultrasonography, plain chest computed tomography (CT), and PET. Bronchoscopy was performed when CT revealed lung shadow of central region. Synchronous multiple primary cancers were detected in 42 (18.2%) patients. The diagnostic sensitivity of PET for synchronous primary cancers was as follows: esophagus, 7.6% (1/13); stomach, 25.0% (2/8); lung, 66.7% (4/6); head and neck, 75.0% (3/4); colon, 0% (0/1); kidney, 0% (0/1); and subcutaneous, 100% (1/1). The sensitivity of PET for detecting synchronous esophageal cancers is low because these are early-stage cancers (almost stage 0–I). Therefore, it is necessary to perform esophagogastroduodenoscopy for detecting synchronous esophageal cancers. PET is an important additional tool for detecting synchronous multiple primary cancers because the diagnostic sensitivity of PET in synchronous head and neck cancer and lung cancer is high. But PET has the limitation of sensitivity for synchronous multiple primary cancers because the diagnostic sensitivity of PET in synchronous esophageal cancer is very low.     

Computed tomography and ultrasonographic evaluation of metastatic cervical lymph nodes with surgicoclinicopathologic correlation

The detection of cervical lymph nodal metastasis and carotid artery invasion by metastatic lymph nodes is an important issue in the management of head and neck malignancies. This study compared the evaluation of metastasis by palpation, ultrasonography (USG) and computed tomography (CT) in patients with known head and neck malignancies. Twenty-five consecutive patients with head and neck malignancy were prospectively evaluated for the presence of cervical lymphadenopathy and carotid artery invasion. All patients underwent clinical examination (palpation), USG and CT examination. A modified CT criteria was employed which yielded acceptable results for the detection of metastatic nodes. Radical neck dissection was performed for 26 neck sides, and the results of pre-operative evaluation were confirmed by the surgical and histopathological findings. Palpation, ultrasound and CT have comparable sensitivity in the determination of metastasis involving cervical lymph nodes. Thus palpation should be employed as the primary method of assessment of secondaries in the neck. However, palpation is less sensitive than CT and USG in the detection of carotid artery involvement, hence the clinical suspicion of arterial invasion should be confirmed by either CT or USG which have similar accuracy in the detection of carotid artery invasion.