Can post–rt neck dissection be omitted for patients with head-and-neck cancer who have a negative pet scan after definitive radiation therapy?

[Current Therapy Standards for Soft Tissue Sarcomas in the Head and Neck Area - Part 2]

In September 2021, the first version of the German S3 guideline on adult soft tissue sarcomas, version 1.0 (AWMF register number 032/044OL) was presented as part of the oncology guideline program of the DKG, German Cancer Aid and the AWMF. After the basic features of soft tissue sarcomas were presented in Part 1, Part 2 describes the specific options for surgical therapy depending on the location in the head and neck area.

Clinical significance of the post-radiotherapy 18F-fludeoxyglucose positron emission tomography response in nasopharyngeal carcinoma

Objective:

The aim of the present study was to evaluate the clinical significance of the post-radiotherapy ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET) response for detecting residual disease and predicting survival outcome in patients with nasopharyngeal cancer.

Methods:

We reviewed 143 patients with nasopharyngeal cancer who underwent ¹⁸F-FDG PET within 6 months after completion of radiotherapy between 2001 and 2012. ¹⁸F-FDG PET findings at the primary tumor (T–) and regional lymph nodes (N–) were separately assessed and considered negative [PET (–)] or positive [PET (+)] depending on the remaining focal increased uptake of ¹⁸F-FDG that was greater than that of the surrounding muscle or blood vessels. The standard of reference was histopathological confirmation or clinical/imaging follow-up. Overall survival (OS), distant metastasis-free survival (DMFS), and locoregional recurrence-free survival (LRRFS) rates were estimated from the date of the start of radiotherapy.

Results:

The median follow-up period was 73 months (range, 9–182 months). Overall, 83 and 66% of patients achieved T–PET (-) and N–PET (-) responses, and the negative-predictive values (NPVs) for T– and N– were 100 and 99%, respectively. The sensitivity, specificity, and positive-predictive value were 100, 84, and 8% for T–, and 67, 80, and 7% for N–, respectively. The 5-year OS, DMFS, and LRRFS rates were 83, 83, and 87%, respectively, and patients with N–PET (+) with SUV_max >2.5 showed significantly inferior 5-year OS and DMFS rates than patients with N–PET (-) or N–PET (+) with SUV_max ≤2.5 (44 vs 86%, p = 0.004; 36 vs 85%, p < 0.001).

Conclusion:

In patients that have received definitive (chemo)radiotherapy for nasopharyngeal cancer, ¹⁸F-FDG PET within 6 months of completion of treatment has a high NPV for predicting residual disease and is prognostic for long-term treatment outcomes. Patients with remaining focal increased uptake of ¹⁸F-FDG at lymph nodes may benefit from more aggressive treatments, and further studies are needed to validate the clinical significance of post-radiotherapy ¹⁸F-FDG PET.

Advances in knowledge:

We found that post-radiotherapy ¹⁸F-FDG PET findings have a high NPV for detecting residual disease and are a significant prognostic factor for treatment outcomes.

Detecting Residual/Recurrent Head Neck Squamous Cell Carcinomas Using PET or PET/CT: Systematic Review and Meta-analysis

OBJECTIVE

To evaluate the diagnostic accuracy of positron emission tomography (PET) and PET/computed tomography (CT) for detecting residual and/or recurrent local and regional disease and distant metastases in patients with head and neck squamous cell carcinomas (HNSCCs) following radiotherapy with or without chemotherapy.

DATA SOURCES

A systematic review with no language restrictions was conducted using PREMEDLINE, MEDLINE, EMBASE, and Google Scholar.

REVIEW METHODS

Only prospective studies with histopathological and/or clinical follow-up that assessed the diagnostic accuracy of PET and PET/CT in detecting residual and/or recurrent disease following radiotherapy with or without chemotherapy in patients with HNSCCs were included.

RESULTS

Twenty-seven studies were identified. The pooled sensitivity and specificity of PET and PET/CT for detecting residual or recurrent disease at the primary site was 86.2% and 82.3%, respectively. For residual and recurrent neck disease, the sensitivity and specificity were 72.3% and 88.3%, while for distant metastases, the values were 84.6% and 94.9%.

CONCLUSIONS

PET and PET/CT are highly accurate in detecting residual and/or recurrent HNSCC. PET/CT is more specific than PET alone. Specificity is also greater for scans performed more than 12 weeks after radiotherapy with or without chemotherapy. The authors support the use of PET/CT after 12 weeks posttreatment for the assessment of residual or recurrent disease.

Positron emission tomography-computed tomography versus positron emission tomography-magnetic resonance imaging for diagnosis of oral squamous cell carcinoma: A pilot study

Diagnostic imaging of head and neck cancer has made enormous progress during recent years. Next to morphological imaging modalities (computed tomography [CT] and magnetic resonance imaging [MRI]), there are also hybrid imaging systems that combine functional and morphological information (positron emission tomography [PET]/CT and PET/MRI). The aim of this study was to compare the diagnostic accuracy of PET/MRI in the diagnosis of head and neck cancer with other imaging modalities (MRI, CT, PET/CT). Ten patients (nine male and one female) with histologically proven oral squamous cell carcinoma participated in an 18 F-FDG-PET/CT scan and an additional 18 F-FDG PET/MRI scan prior to surgery. The morphological and functional results were compared with the histological results. Inclusion criteria were histologically proven oral squamous cell carcinoma and no prior surgical intervention, medical therapy, or local external radiation. There was no significant correlation between tumor differentiation and maximum standard uptake values. Functional imaging showed a slightly better correlation with the measurement of the maximal tumor diameter, whereas pure morphological imaging showed a better correlation with the measurement of infiltration depth. Only with PET/MRI could correct lymph node staging be reached; the other imaging tools showed false-negative or false-positive results. In conclusion, we showed in our limited patient cohort that PET/MRI is superior to the morphological imaging modalities, especially for lymph node staging.

PET imaging biomarkers in head and neck cancer

In locally advanced head and neck squamous cell carcinoma (HNSCC), the role of imaging becomes more and more critical in the management process. In this framework, molecular imaging techniques such as PET allow noninvasive assessment of a range of tumour biomarkers such as metabolism, hypoxia and proliferation, which can serve different purposes. First, in a pretreatment setting they can influence therapy selection strategies and target delineation for radiation therapy. Second, their predictive and/or prognostic value could help enhance the therapeutic ratio in the management of HNSCC. Third, treatment modification can be performed through the generation of a molecular-based heterogeneous dose distribution with dose escalation to the most resistant parts of the tumour, a concept known as dose painting. Fourth, they are increasingly becoming a tool for monitoring response to therapy. In this review, PET imaging biomarkers used in the routine management of HNSCC or under investigation are discussed.

Perineural spread in head and neck malignancies: clinical significance and evaluation with 18F-FDG PET/CT

Certain tumors of the head and neck use peripheral nerves as a direct conduit for tumor growth away from the primary site by a process known as perineural spread. Perineural spread is associated with decreased survival and a higher risk of local recurrence and metastasis. Radiologists play an important role in the assessment and management of head and neck cancer, and positron emission tomography/computed tomography (PET/CT) with 2-[fluorine 18]fluoro-2-deoxy-d-glucose (FDG) is part of the work-up and follow-up of many affected patients. Awareness of abnormal FDG uptake patterns within the head and neck is fundamental for diagnosing perineural spread. The cranial nerves most commonly affected by perineural spread are the trigeminal and facial nerves. Risk of perineural spread increases with a midface location of the tumor, male gender, increasing tumor size, recurrence after treatment, and poor histologic differentiation. Focal or linear increased FDG uptake along the V2 division of the trigeminal nerve or along the medial surface of the mandible, or asymmetric activity in the masticator space, foramen ovale, or Meckel cave should raise suspicion for perineural spread. If FDG PET/CT findings suggest perineural spread, the radiologist should look at available results of other imaging studies, especially magnetic resonance imaging, to confirm the diagnosis. Knowledge of common FDG PET/CT patterns of neoplastic involvement along the cranial nerves and potential diagnostic pitfalls is of the utmost importance for adequate staging and treatment planning.

Observation versus neck dissection for positron-emission tomography-negative lymphadenopathy after chemoradiotherapy

OBJECTIVES/HYPOTHESIS

To analyze outcomes among patients with residual positron-emission tomography (PET)-negative lymphadenopathy after chemoradiotherapy for head and neck cancer based on whether or not they underwent neck dissection.

STUDY DESIGN

Retrospective review.

METHODS

Fifty-five patients with stage III/IV squamous cell carcinoma of the head and neck were identified with residual PET-negative lymphadenopathy based on standardized uptake value of <3. All patients had been treated with chemoradiotherapy to a median dose of 70 Gy (range, 60-4 Gy).

RESULTS

With a median follow-up of 30 months (range, 6-67 months), the 3-year overall survival (85% vs. 81%, P = .57), progression-free survival (88% vs. 88%, P = .42), and local-regional control (96% vs. 100%, P = .68), did not differ between patients treated by neck dissection or observation.

CONCLUSIONS

Omission of neck dissection appears to be reasonable for patients with residual lymphadenopathy but negative PET after chemoradiotherapy for head and neck cancer.

LEVEL OF EVIDENCE

4.

Improving imaging diagnosis of persistent nodal metastases after definitive therapy for oropharyngeal carcinoma: specific signs for CT and best performance of combined criteria

BACKGROUND AND PURPOSE

Criteria for detection of persistent nodal metastases in treated oropharyngeal tumors are sensitive but nonspecific, leading to unnecessary nodal dissections. Developing specific imaging criteria for persistent nodal metastases could improve diagnosis while decreasing patient morbidity.

MATERIALS AND METHODS

Patients with oropharyngeal squamous cell carcinoma with nodal metastases treated by definitive radiation therapy and subsequent nodal dissection were retrospectively evaluated. One hundred thirty-eight patients had pre- and posttherapy contrast-enhanced CTs evaluated by radiologists blinded to the status of pathologically proved hemineck persistent nodal metastases. Composite scoring criteria for CT, combined from individual parameters, were compared with radiologists' opinions, previous multiparameter criteria, and outcome data.

RESULTS

New low-attenuation areas and a lack of size change (<20% cross sectional area) were both highly specific for persistent nodal metastases (99%; P = .0004). Extranodal disease on pretherapy imaging was moderately specific (86%; P = .001). The CSC correctly placed 29 patients in a low-risk category compared with 14 by previously reported criteria and radiologist reports. With good second-rater reliability, the CSC cutoff values stratified patients at highest risk of persistent nodal metastases, thereby improving specificity while maintaining sensitivity.

CONCLUSIONS

Comparing pre- and posttherapy examinations improves specificity by discriminating focal findings and size change compared with a single time point. The CSC can categorize the risk of persistent nodal metastases more accurately than previous CT methods. This finding has the potential to improve resource use and reduce surgical morbidity.

The role of neck dissection after radical chemoradiation for locally advanced head and neck cancer: should we move back?

Until a few decades ago neck dissection (ND) was the standard surgical approach for node-positive tumours. Nowadays patients with locally advanced head and neck cancer can be treated with definitive chemoradiation (CRT), which includes the treatment of the neck; however, results on residual viable tumour after conservative treatment are heterogeneous and depend on initial node stage and primary treatment. Many authors accept adjuvant surgery in patients with N2-3 disease. Regardless of the results of upfront CRT, even if there is no evidence of lymph node metastases, when the risk for persistent positive neck nodes exceeds 15-20%, elective ND might be indicated. However, despite the diffusion of innovative technologies and therapies, there are controversies about both response evaluation and surgical management of initially involved neck nodes after definitive CRT and organ preservation treatment. In this paper we will analyse state of art of neck evaluation after CRT and discuss the role of ND.

Current practice in management of the neck after chemoradiotherapy for patients with locally advanced oropharyngeal squamous cell carcinoma

Patients whose necks respond completely to chemoradiation are unlikely to have residual viable tumour, which questions the need for planned neck dissection. Partial responders often need further assessment. Positron emission tomography/computed tomography (PET/CT) is becoming the standard method of assessing the response of both the primary site and neck to chemoradiation. There is debate, however, about the timing of assessment, the best imaging technique, and the extent of neck dissection, and emerging evidence supports more selective procedures with their attendant reductions in morbidity. Various trials have tried to settle these controversies, but we hypothesised that current practice varies across the United Kingdom (UK), so we set out to establish what it is. A total of 219 questionnaires were sent to head and neck surgeons of varying disciplines and their oncology counterparts, which outlined a clinical picture of a patient with persistent nodal disease after chemoradiotherapy, and requested information about the respondents' preferred choice and timing of investigations in addition to the type of neck dissection, if indicated. There were noticeable variations in practice, with a tendency towards personal choice rather than a multidisciplinary approach. Although there were some items of broad agreement, there was disparity about the timing of imaging and operation. There is inconsistency in the management of the neck in these patients in the UK, which may reflect an absence of guidelines and paucity of evidence-based information. We need to unify practice to improve the care of patients.

A planned neck dissection is not necessary in all patients with N2-3 head-and-neck cancer after sequential chemoradiotherapy

PURPOSE

To assess the role of a planned neck dissection (PND) after sequential chemoradiotherapy for patients with head-and-neck cancer with N2-N3 nodal disease.

METHODS AND MATERIALS

We reviewed 90 patients with N2-N3 head-and-neck squamous cell carcinoma treated between 1991 and 2001 on two sequential chemoradiotherapy protocols. All patients received induction and concurrent chemotherapy with cisplatin and 5-fluorocuracil, with or without tirapazamine. Patients with less than a clinical complete response (cCR) in the neck proceeded to a PND after chemoradiation. The primary endpoint was nodal response. Clinical outcomes and patterns of failure were analyzed.

RESULTS

The median follow-up durations for living and all patients were 8.3 years (range, 1.5-16.3 year) and 5.4 years (range, 0.6-16.3 years), respectively. Of the 48 patients with nodal cCR whose necks were observed, 5 patients had neck failures as a component of their recurrence [neck and primary (n = 2); neck, primary, and distant (n = 1); neck only (n = 1); neck and distant (n = 1)]. Therefore, PND may have benefited only 2 patients (4%) [neck only failure (n = 1); neck and distant failure (n = 1)]. The pathologic complete response (pCR) rate for those with a clinical partial response (cPR) undergoing PND (n = 30) was 53%. The 5-year neck control rates after cCR, cPR→pCR, and cPR→pPR were 90%, 93%, and 78%, respectively (p = 0.36). The 5-year disease-free survival rates for the cCR, cPR→pCR, and cPR→pPR groups were 53%, 75%, and 42%, respectively (p = 0.04).

CONCLUSION

In our series, patients with N2-N3 neck disease achieving a cCR in the neck, PND would have benefited only 4% and, therefore, is not recommended. Patients with a cPR should be treated with PND. Residual tumor in the PND specimens was associated with poor outcomes; therefore, aggressive therapy is recommended. Studies using novel imaging modalities are needed to better assess treatment response.

Diagnostic performance of post-treatment FDG PET or FDG PET/CT imaging in head and neck cancer: a systematic review and meta-analysis

PURPOSE

Our objective was to conduct a systematic review and meta-analysis of studies assessing the diagnostic performance of (18)F-fluorodeoxyglucose positron emission tomography (FDG PET) with or without computed tomography (CT) in post-treatment response assessment and/or surveillance imaging of head and neck squamous cell carcinoma (HNSCC).

METHODS

A systematic search of the indexed medical literature was done using appropriate keywords to identify relevant studies. Metrics of diagnostic test accuracy, viz. sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were extracted from individual studies and combined using a random effects model to yield weighted mean pooled estimates with 95% confidence intervals (95% CI). The impact of timing of post-treatment scan, study quality and advancements in PET technology was explored through meta-regression.

RESULTS

A total of 51 studies involving 2,335 patients were included in the meta-analysis. The weighted mean (95% CI) pooled sensitivity, specificity, PPV and NPV of post-treatment FDG PET(CT) for the primary site was 79.9% (73.7-85.2%), 87.5% (85.2-89.5%), 58.6% (52.6-64.5%) and 95.1% (93.5-96.5%), respectively. Similar estimates for the neck were 72.7% (66.6-78.2%), 87.6% (85.7-89.3%), 52.1% (46.6-57.6%) and 94.5% (93.1-95.7%), respectively. Scans done ≥ 12 weeks after completion of definitive therapy had moderately higher diagnostic accuracy on meta-regression analysis using time as a covariate.

CONCLUSION

The overall diagnostic performance of post-treatment FDG PET(CT) for response assessment and surveillance imaging of HNSCC is good, but its PPV is somewhat suboptimal. Its NPV remains exceptionally high and a negative post-treatment scan is highly suggestive of absence of viable disease that can guide therapeutic decision-making. Timing of post-treatment imaging has a significant, though moderate impact on diagnostic accuracy.

Efficacy of fluoro-2-deoxy-D-glucose positron emission tomography to evaluate responses to concurrent chemoradiotherapy for head and neck squamous cell carcinoma

OBJECTIVE

This study evaluates the utility of fluorodeoxyglucose-positron emission tomography (FDG-PET) in patients with head and neck squamous cell carcinoma (HNSCC) who received concurrent chemoradiotherapy (CCRT).

METHODS

Sixty-five patients were recruited for this study between November 2002 and April 2007. The FDG-PET scan was performed before treatment and 4-6 weeks after treatment.

RESULTS

The mean of maximum standardized uptake value (SUVmax) before treatment at the primary tumor site was 8.1 (range, 2-22). The sensitivity of FDG-PET for the diagnosis of primary tumor site was 98%. The mean of SUVmax after treatment was 2.6 (range, 2-5). The sensitivity, specificity, and accuracy of FDG-PET for the diagnosis of primary tumor site after treatment were 100%, 40%, and 46%, respectively. The mean of SUVmax before treatment at the nodal site was 4.7 (range, 2-16). The mean of SUVmax after treatment was 2.0 (range, 2-6.7). The pre-treatment SUVmax of T2, T3, and T4 stages were significantly higher than that of the T1 stage. The N stage had no correlation in terms of the pre-treatment nodal site SUVmax.

CONCLUSION

Our results indicate that FDG-PET is a useful imaging method for evaluating the response of CCRT in patients with HNSCC. However, performing FDG-PET 4-6 weeks after treatment may be too early as it may give false-positive results due to fibrosis and scarring.

FDG PET imaging of head and neck cancers

In initial staging of head and neck cancers, the addition of FDG PET to conventional imaging improves the accuracy for cervical nodal metastases. The sensitivity of FDG PET is, however, limited in nodes <1 cm and in completely necrotic nodes. In the posttherapy setting, PET scans obtained at least 10 weeks after radiotherapy have an excellent predictive value to rule out residual disease. Due to the limited positive predictive value of FDG PET after radiation therapy, a positive PET scan needs to be confirmed before management decisions are made.

Can 18-FDG-PET during radiotherapy replace post-therapy scanning for detection/demonstration of tumor response in head-and-neck cancer?

PURPOSE

In routine practice, the tumor response in head-and-neck cancer (HNC) is assessed 3-4 months after radiotherapy (RT). We compared the results of fluorodeoxyglucose-positron emission tomography (FDG-PET) during (47 Gy) and 4 months after RT.

METHODS AND MATERIALS

In 40 patients with HNC, PET was performed before (PET1), at the end of Week 4 (47 Gy) (PET2), and 4 months after RT (PET3). Visual analysis classified patients as having a complete response (CR) or a non-CR (NCR). The sensitivity, specificity, accuracy, negative predictive value, and positive predictive value for PET2 and PET3 were determined. The 2-year overall survival (OS) rate for a CR and NCR was calculated for both response evaluation points.

RESULTS

After a median follow-up of 26 months, 10 patients had died, 6 had residual disease, and 24 remained disease free. The overall sensitivity, specificity, negative predictive value, positive predictive value, and accuracy of PET2 vs. PET3 for the detection of a CR was 28.6%, 81.8%, 31.0%, 80.0%, and 42.5% vs. 78.6%, 75.0%, 60.0%, 88.0%, and 77.5%, respectively. The 2-year OS rate determined at 47 Gy was 90.0% and 71.8% for a CR and NCR, respectively, and did not appear to be significantly different (p = .50). For the study, at 4 months, the OS was significantly better in the CR group (91.8%) than in the NCR group (49.9%; p = .0055).

CONCLUSION

The high specificity and positive predictive value for the evaluation of tumor response with PET2 and PET3 might avoid unnecessary salvage surgery in patients with a CR. In contrast to PET3, the sensitivity of PET 2 was low, and the difference in OS between the CR and NCR groups was not significantly different. Therefore, the evaluation of the tumor response with FDG-PET at 4 months after RT completion cannot be replaced by FDG-PET during RT at 47 Gy.

Squamous cell carcinoma of the head and neck: diffusion-weighted MR imaging for prediction and monitoring of treatment response

OBJECTIVE

To investigate the role of diffusion-weighted imaging (DWI) in predicting and monitoring chemoradiotherapy response in head and neck squamous cell carcinoma (HNSCC).

METHODS

Diffusion-weighted imaging was performed pre-treatment (n = 50), intra-treatment (n = 41) and post-treatment (n = 20). Apparent diffusion coefficient (ADC) values were correlated with locoregional failure (LF).

RESULTS

Locoregional failure occurred in 20/50 (40%) patients. A significant correlation was found between LF and post-treatment ADC (p = 0.02) but not pre- or intra-treatment ADC. Serial change in ADC was even more significant (p = 0.00001), using a fall in ADC early (pre- to intra-treatment) or late (intra- to post-treatment) to indicate LF, achieved 100% specificity, 80% sensitivity and 90% accuracy.

CONCLUSIONS

Single ADC measurements pre- or intra-treatment did not predict response, but ADC post-treatment was a marker for LF. Serial change in ADC was an even stronger marker, when using an early or late treatment fall in ADC to identify LF.

Revisiting the role of positron-emission tomography/computed tomography in determining the need for planned neck dissection following chemoradiation for advanced head and neck cancer

OBJECTIVES/HYPOTHESIS

Planned neck dissection following chemoradiation (CR) has been advocated in patients with head and neck squamous cell cancer (HNSCC) with advanced nodal disease and a clinical complete response to CR because of the potential for residual occult nodal disease. The utility of positron-emission tomography/computed tomography (PET-CT) in identifying occult nodal disease in this scenario is controversial.

METHODS

The medical records of all patients treated with CR for advanced HNSCC with N2 or N3 disease from December 2003 to June 2007 were reviewed. Patients with a complete clinical response were included if PET-CT performed 8 to 11 weeks after CR showed no distant disease and they underwent planned neck dissection.

RESULTS

Thirty-two patients met study criteria. PET-CT was positive for residual nodal disease in 20 patients (63%). Pathology revealed carcinoma in 10 patients (31%): six of 20 patients with positive PET-CT scans (30%) and four of 12 patients with negative PET-CT scans (33%). The sensitivity and specificity of PET-CT was 60% and 36%. Regional recurrence developed in two patients (6%) who were not successfully salvaged.

CONCLUSIONS

PET-CT performed 8 to 11 weeks after CR does not reliably predict the need for planned post-treatment neck dissection in patients with a complete clinical response following CR. Regional recurrence rates are comparable to those reported for patients observed with PET-CT, suggesting no advantage for planned neck dissection, and salvage rates were poor. These data suggest that delaying the timing of PET-CT, with surgery reserved for positive findings, is a reasonable alternative to planned neck dissection to avoid unnecessary surgery.

Outcome with neck dissection after chemoradiation for N3 head-and-neck squamous cell carcinoma

PURPOSE

To evaluate the role of neck dissection (ND) after chemoradiation therapy (CRT) for head and neck squamous cell carcinoma (HNSCC) with N3 disease.

METHODS AND MATERIALS

From March 1998 to September 2006, 70 patients with HNSCC and N3 neck disease were treated with concomitant CRT as primary therapy. Response to treatment was assessed using clinical examination and computed tomography 6 to 8 weeks posttreatment. Neck dissection was not routinely performed and considered for those with less than complete response. Of the patients, 26 (37.1%) achieved clinical complete response (cCR) after CRT. A total of 31 (44.3%) underwent ND after partial response (cPR-ND). Thirteen patients (29.5%) did not achieve cCR and did not undergo ND for the following reasons: incomplete response/progression at primary site, refusal/contraindication to surgery, metastatic progression, or death. These patients were excluded from the analysis. Outcomes were computed using Kaplan-Meier curves and were compared with log rank tests.

RESULTS

Comparing the cCR and cPR-ND groups at 2 years, the disease-free survival was respectively 62.7% and 84.9% (p = 0.048); overall survival was 63.0% and 79.4% (p = 0.26), regional relapse-free survival was 87.8% and 96.0% (p = 0.21); and distant disease-free survival was 67.1% and 92.6% (p = 0.059). In the cPR-ND group, 71.0% had no pathologic evidence of disease (PPV of 29.0%).

CONCLUSIONS

Patients with N3 disease achieving regional cPR and primary cCR who underwent ND seemed to have better outcomes than patients achieving global cCR without ND. Clinical assessment with computed tomography is not adequate for evaluating response to treatment. Because of the inherent limitations of our study, further confirmatory studies are warranted.

[Neck dissection following chemoradiation for node positive head and neck carcinomas]

The optimal timing and extent of neck dissection in the context of chemoradiation for head and neck cancer remains controversial. For some institutions, it is uncertain whether neck dissection should still be performed upfront especially for cystic nodes. For others, neck dissection can be performed after chemoradiation and can be omitted for N1 disease as long as a complete response to chemoradiation is obtained. The question is debated for N2 and N3 disease even after a complete response as the correlation between radiological and clinical assessment and pathology may not be reliable. Response rates are greater than or equal to 60% and isolated neck failures are less than or equal to 10% with current chemoradiation protocols. Some therefore consider that systematic upfront or planned neck dissection would lead to greater than or equal to 50% unnecessary neck dissections for N2-N3 disease. Positron-emission tomography (PET) scanning to assess treatment response and have shown a very high negative predictive value of greater than or equal to 95% when using a standard uptake value of 3 for patients with a negative PET at four months after the completion of therapy. These data may support the practice of observing PET-negative necks. More evidence-based data are awaited to assess the need for neck dissection on PET. Selective neck dissection based on radiological assessment and peroperative findings and not exclusively on initial nodal stage may help to limit morbidity and to improve the quality of life without increasing the risk of neck failure. Adjuvant regional radiation boosts might be discussed on an individual basis for aggressive residual nodal disease with extracapsular spread and uncertain margins but evidence is missing. Medical treatments aiming at reducing the metastatic risk especially for N3 disease are to be evaluated.

Clinical Applications of FDG PET and PET/CT in Head and Neck Cancer

18F-FDG PET plays an increasing role in diagnosis and management planning of head and neck cancer. Hybrid PET/CT has promoted the field of molecular imaging in head and neck cancer. This modality is particular relevant in the head and neck region, given the complex anatomy and variable physiologic FDG uptake patterns. The vast majority of 18F-FDG PET and PET/CT applications in head and neck cancer related to head and neck squamous cell carcinoma. Clinical applications of 18F-FDG PET and PET/CT in head and neck cancer include diagnosis of distant metastases, identification of synchronous 2nd primaries, detection of carcinoma of unknown primary and detection of residual or recurrent disease. Emerging applications are precise delineation of the tumor volume for radiation treatment planning, monitoring treatment, and providing prognostic information. The clinical role of 18F-FDG PET/CT in N0 disease is limited which is in line with findings of other imaging modalities. MRI is usually used for T staging with an intense discussion concerning the preferable imaging modality for regional lymph node staging as PET/CT, MRI, and multi-slice spiral CT are all improving rapidly. Is this review, we summarize recent literature on 18F-FDG PET and PET/CT imaging of head and neck cancer.

Positron emission tomography in surveillance of head and neck squamous cell carcinoma after definitive chemoradiotherapy

BACKGROUND

We assessed the role of (18)F-fluoro-deoxy-glucose positron emission tomography (PET) in detecting head and neck squamous cell carcinoma (HNSCC) after definitive chemoradiotherapy (CRT).

METHODS

A prospective study presented 80 PET before and after CRT for 44 patients, including 44 first-time post-CRT scans performed between 12 and 17 weeks after radiotherapy completion, as well as 10 repeated scans in the subsequent follow-up. PET interpretations were compared with clinicopathologic outcomes.

RESULTS

PET demonstrated better performance than CT in post-CRT surveillance. Considering all 54 post-CRT PET scans, sensitivity for detecting primary tumors was 100%, specificity 93%, positive predictive value (PPV) 80%, and negative predictive value (NPV) 100%. For cervical diseases, sensitivity was 100%, specificity 98%, PPV 92%, and NPV 100%. For distant metastases, sensitivity was 100%, specificity 98%, PPV 86%, and NPV 100%.

CONCLUSIONS

Negative PET readings were reliable for predicting free of HNSCC and helpful for selected patients in post-CRT surveillance.

Clinical outcome following radiotherapy and planned neck dissection in N+ head and neck cancer patients

CONCLUSIONS

This study confirms earlier findings that patients with viable tumour cells in the neck after external beam radiotherapy (EBRT) have a poor prognosis. The study also indicates that neck dissection (ND) does not change the prognosis for patients with a complete clinical response in the neck. At the moment our guidelines concerning this matter are being reviewed.

OBJECTIVES

The protocol at our institution stipulates a planned ND in patients with metastasis in the neck after EBRT regardless of the response in the neck. As the necessity for a planned ND has not been clarified we wanted to evaluate our results.

PATIENTS AND METHODS

Patients diagnosed from 1998 to 2002 with metastasis in the neck who received EBRT were evaluated for histopathological findings and clinical outcome.

RESULTS

A total of 156 patients were included. Overall survival was 62% and disease-specific survival was 76%. There was a complete response (CR) in the neck in 63 patients (40%); among these 15 had viable tumour cells in the neck. In patients not achieving CR, 40% (37/93) had viable tumour cells left in the neck. Patients with viable tumour cells in the neck after EBRT had disease-specific survival of 48% compared with 90% among patients without viable tumour cells.

Accuracy of positron emission tomography in the evaluation of patients treated with chemoradiotherapy for mucosal head and neck cancer

BACKGROUND

The aim of this study was to evaluate the accuracy of positron emission tomography (PET) in assessing the patients treated with primary chemoradiotherapy for mucosal carcinoma of the head and neck.

METHODS

A retrospective review of patients with biopsy-proven cancer of mucosal head and neck sites receiving chemoradiotherapy with curative intent was undertaken.

RESULTS

Seventy-eight patients met the study criteria. Staging PET identified unsuspected distant metastatic disease in 11% of patients. Sixty-one patients (78%) had a complete metabolic response on PET, with 17 showing residual disease. Sensitivity of PET was 82% (positive predictive value: 82%) and specificity was 95% (negative predictive value: 95%). Accuracy of PET response was significantly better than clinical assessment and conventional imaging (p < .002, p < .001, respectively).

CONCLUSION

PET has been found to be significantly better than clinical examination or conventional imaging in restaging patients after chemoradiotherapy. Patients with a complete response on posttreatment PET have a significant survival advantage and can be safely observed.

Prospective risk-adjusted [18F]Fluorodeoxyglucose positron emission tomography and computed tomography assessment of radiation response in head and neck cancer

PURPOSE

[(18)F]Fluorodeoxyglucose positron emission tomography (FDG-PET)/computed tomography (CT) imaging may improve assessment of radiation response in patients with head and neck cancer, but it is not yet known for which patients this is most useful. We conducted a prospective trial to identify patient populations likely to benefit from the addition of functional imaging to the assessment of radiotherapy response.

PATIENTS AND METHODS

Ninety-eight patients with locally advanced cancer of the oropharynx, larynx, or hypopharynx were prospectively enrolled and treated with primary radiotherapy, with or without chemotherapy. Patients underwent FDG-PET/CT and contrast-enhanced CT imaging 8 weeks after completion of treatment. Functional and anatomic imaging response was correlated with clinical and pathologic response. Imaging accuracy was then compared between imaging modalities.

RESULTS

Although postradiation maximum standard uptake values were significantly higher in nonresponders compared with responders, the positive and negative predictive values of FDG-PET/CT scanning were similar to those for CT alone in the unselected study population. Subset analyses revealed that FDG-PET/CT outperformed CT alone in response assessment for patients at high risk for treatment failure (those with human papillomavirus [HPV] -negative disease, nonoropharyngeal primaries, or history of tobacco use). No benefit to FDG-PET/CT was seen for low-risk patients lacking these features.

CONCLUSION

These data do not support the broad application of FDG-PET/CT for radiation response assessment in unselected head and neck cancer patients. However, FDG-PET/CT may be the imaging modality of choice for patients with highest risk disease, particularly those with HPV-negative tumors. Optimal timing of FDG-PET/CT imaging after radiotherapy merits further investigation.

Controversies in surgical management of the node-positive neck after chemoradiation

The addition of chemotherapy to radiation in the treatment of advanced-staged head and neck cancer has improved local-regional control and increased complete clinical and pathologic response rates in the neck. However, for those patients with residual neck disease on a posttreatment computed tomography (CT) scan, there remains significant controversy as to how to further assess the neck for the presence of a viable tumor and when to perform a neck dissection. Recently, investigators from Australia have assembled level I evidence to support the use of positron-emission tomography (PET) scanning to assess treatment response and have shown a very high negative predictive value for patients with a negative PET at 12 weeks after the completion of therapy. These data support the practice of observing PET-negative necks and intervening with neck dissection in PET-positive necks. However, not all investigators, practitioners, and patients are comfortable with delaying intervention for such a long time interval after treatment. The authors favor assessment of the neck with a CT scan at 6 weeks after the completion of chemoradiotherapy and recommend neck dissection for patients with radiographic residual disease at this time point. One rationale is that 6 weeks is an optimal window for operative intervention after acute treatment effects have subsided and before extensive fibrosis and scarring, which translates to less morbidity for the patient who is treated surgically. Another rationale is that those who develop regional recurrence can be hard to salvage surgically, and waiting an additional 6 weeks could allow for the expansion of resistant clones. The significance of this is unclear, however, because patients with residual disease are at a higher risk for local and distant as well as regional failure. Thus, further prospective studies of the role of postchemoradiotherapy PET scanning and neck dissection are needed.

Detection of locoregional recurrent head and neck cancer after (chemo)radiotherapy using modern imaging

After radiotherapy with or without chemotherapy differentiation between residual and recurrent head and neck cancer and (chemo)radiation sequelae is often difficult. Currently, most physicians aggressively pursue potential recurrences, leading to a high rate of futile invasive diagnostic, e.g. examinations under general anaesthesia with taking of biopsies, and surgical procedures, e.g. planned neck dissections, and a waste of health care resources. Therefore, diagnostic techniques which reliably select patients who should undergo these procedures are warranted. Conventional imaging techniques are not reliable enough for this purpose. Potential imaging techniques to detect residual and recurrent locoregional disease after chemoradiation are (serial) CT or MRI and FDG-PET, eventually in combination with specific response criteria or scoring systems. Diffusion MRI and PET/CT may further improve these techniques. FDG-PET may help to select patients clinically suspected of recurrent laryngeal carcinoma after radiotherapy for direct laryngoscopy under general anaesthesia. It is not yet clear whether FDG-PET can reliable avoid futile routine evaluation by examination under general anaesthesia in oral and oropharyngeal cancer and planned neck dissection when a residual mass persists in the neck after (chemo)radiation. The most reliable scoring criteria and the optimal time interval between completion of radiation and FDG-PET still has to be assessed.

Clinical utility of 18F-FDG PET/CT in assessing the neck after concurrent chemoradiotherapy for Locoregional advanced head and neck cancer

For patients with locoregional advanced head and neck squamous cell carcinoma (HNSCC), concurrent chemoradiotherapy is a widely accepted treatment, but the need for subsequent neck dissection remains controversial. We investigated the clinical utility of 18F-FDG PET/CT in this setting.

METHODS

In this Institutional Review Board (IRB)-approved and Health Insurance Portability and Accountability Act (HIPPA)-compliant retrospective study, we reviewed the records of patients with HNSCC who were treated by concurrent chemoradiation therapy between March 2002 and December 2004. Patients with lymph node metastases who underwent 18F-FDG PET/CT > or = 8 wk after the end of therapy were included. 18F-FDG PET/CT findings were validated by biopsy, histopathology of neck dissection specimens (n = 18), or clinical and imaging follow-up (median, 37 mo).

RESULTS

Sixty-five patients with a total of 84 heminecks could be evaluated. 18F-FDG PET/CT (visual analysis) detected residual nodal disease with a sensitivity of 71%, a specificity of 89%, a positive predictive value (PPV) of 38%, a negative predictive value (NPV) of 97%, and an accuracy of 88%. Twenty-nine heminecks contained residual enlarged lymph nodes (diameter, > or =1.0 cm), but viable tumor was found in only 5 of them. 18F-FDG PET/CT was true-positive in 4 and false-positive in 6 heminecks, but the NPV was high at 94%. Fifty-five heminecks contained no residual enlarged nodes, and PET/CT was true-negative in 50 of these, yielding a specificity of 96% and an NPV of 98%. Lack of residual lymphadenopathy on CT had an NPV of 96%. Finally, normal 18F-FDG PET/CT excluded residual disease at the primary site with a specificity of 95%, an NPV of 97%, and an accuracy of 92%.

CONCLUSION

In patients with HNSCC, normal 18F-FDG PET/CT after chemoradiotherapy has a high NPV and specificity for excluding residual locoregional disease. In patients without residual lymphadenopathy, neck dissection may be withheld safely. In patients with residual lymphadenopathy, a lack of abnormal 18F-FDG uptake in these nodes also excludes viable tumor with high certainty, but confirmation of these data in a prospective study may be necessary before negative 18F-FDG PET/CT may become the only, or at least most-decisive, criterion in the management of the neck after chemoradiotherapy.

Posttreatment imaging in head and neck cancer

Posttreatment imaging is done when a recurrent tumour is suspected, to confirm the presence of such a lesion and to determine its extent. The extent of a recurrent cancer is important information for determining the possibility of salvage therapy. Imaging may also be used to monitor tumour response and to try to detect recurrent or persistent disease before it becomes clinically evident, possibly with a better chance for successful salvage. This article reviews the expected imaging findings after treatment of head and neck squamous cell cancer, and how to differentiate these from persistent or recurrent cancer. The relative value of anatomical and biological imaging modalities, including newer techniques such as diffusion-weighted magnetic resonance imaging, is addressed. The imaging findings in treatment-induced complications, such as tissue necrosis, sometimes difficult to differentiate from cancer, are explained.

FDG-PET Evaluation of Response to Treatment

This article discusses evaluating response after and during therapy in various settings and for the types of cancers for which ample evidence demonstrates that PET imaging with flourodeoxyglucose provides a valuable surrogate for response to therapy. It also briefly discusses pitfalls in obtaining an optimal assessment of response and issues that need further attention for this modality to become established as an independent predictor of response to anticancer therapy.

Early assessment of clinical response to concurrent chemoradiotherapy in head and neck carcinoma using fluoro-2-deoxy-d-glucose positron emission tomography

OBJECTIVES

The aim of this study is to assess the utility of FDG-PET in the evaluation of therapeutic effects at 4 weeks after the completion of the concurrent chemoradiotherapy (CCR) in patients with head and neck squamous cell carcinoma (HNSCC).

METHODS

Thirty-one patients with previously untreated HNSCC were retrospectively investigated about FDG-PET, CT, MRI and biopsies of the carcinoma before and 4 weeks after the treatment.

RESULTS

The results of pathological examinations after CCR showed 6 residual cases and 25 ones with a pathologically complete response (pCR). The specificity of FDG-PET was 80%, although the sensitivity was limited to 67%.

CONCLUSIONS

FDG-PET has a high specificity but limited sensitivity to discriminate residual cancer from fibrosis or scar at 4 weeks after CCR. FDG-PET at 4 weeks after CCR was too early to perform because of limited sensitivity.