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

doi:10.1016/S0360-3016(03)01625-0

International Journal of Radiation OncologyBiologyPhysics

Volume 58, Issue 3, March 2004, Pages 694-697

https://doi.org/10.1016/S0360-3016(03)01625-0 Get rights and content

Abstract

Purpose

A prospective, single institution study was conducted to evaluate the role of positron emission tomography with fluoro-deoxyglucose (FDG) before and after definitive radiation therapy for patients with head-and-neck cancer. Correlation with CT or MRI imaging and pathologic findings at the time of planned neck dissection was made.

Methods and materials

Twelve patients with AJCC Stages III-IV cancer of the head and neck received CT or MRI and PET imaging before treatment with definitive radiation therapy. One month after completion of treatment, repeat CT or MRI and PET imaging was obtained. All images were reviewed independently by radiologists who were blind to the results of the other modality. Patients then underwent planned neck dissection. Pathologic correlation with posttreatment scans allowed calculation of the sensitivity, specificity, negative predictive value, and the positive predictive value for both CT/MRI and PET.

Results

Comparison of CT/MRI to PET obtained before definitive RT revealed both primary tumor and nodal disease were detected by both modalities in all cases where primary tumor was known. After RT, comparison of CT/MRI imaging to findings of neck dissection revealed a sensitivity of 90%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 50%. Comparison of PET imaging with pathologic findings demonstrated sensitivity of 45%, specificity of 100%, positive predictive value of 100%, and a negative predictive value of 14%.

Conclusions

In this small series of patients, the presence of a positive PET 1 month after RT accurately indicated the presence of residual disease in all cases; however, a negative PET indicated absence of disease in only 14%. Further investigation is warranted before FDG-PET should be used to determine whether post-RT neck dissection should be omitted.

Introduction

Definitive radiation therapy (RT) is frequently used for locally advanced head-and-neck cancers. After treatment of such patients, there is controversy regarding the role of post-RT neck dissection. Some physicians routinely perform a neck dissection in all patients who present with large or multiple involved neck nodes after RT (1). Others suggest that, if adenopathy resolves clinically and radiographically after RT, a neck dissection may be omitted (2). Positron emission tomography with fluoro-deoxyglucose (FDG) potentially represents a noninvasive method to improve detection of residual nodal metastases.

A single-institution study was undertaken to evaluate the role of positron emission tomography (PET) scans with FDG before radiation and 1 month after definitive radiation therapy. PET with FDG demonstrates increased activity in tissues that have increased metabolic activity such as tumor tissue. This noninvasive imaging technique has the potential to evaluate response to therapy and to distinguish viable tumor from normal tissue changes after radiation therapy. This information could be used as a guide for determining further interventions.

The objectives of this study were to obtain computed tomography (CT)/magnetic resonance imaging (MRI) and PET imaging of patients before definitive RT and 1 month after completion and correlate the imaging to pathologic findings at the time of planned neck dissection. This information was then used to assess the usefulness of PET in the evaluation of these patients.

Section snippets

Methods and materials

Between 1992 and 1994, 12 patients with head-and-neck cancers were identified who had enrolled in a prospective trial at the Comprehensive Cancer Center of Wake Forest University Baptist Medical Center in Winston-Salem, NC. The clinical protocol was approved by the Clinical Research Practices Committee, and all patients signed informed consent before PET scans were obtained and before RT.

Patients enrolled in this study had American Joint Committee on Cancer Stages III-IV squamous cell carcinoma

Results

Seven patients have died of either progressive disease or other processes by 60 months postradiation therapy. Three patients were lost to follow up after 5 years and 2 patients are alive but both have developed second primary cancers (prostate and lung carcinoma).

PET scans performed before definitive RT identified the primary site and nodal disease in all cases, with the exception of 2 patients with an unknown primary. This correlated with CT/MRI imaging, which also detected primary and nodal

Discussion

It has been previously reported in several series that PET accurately detects primary head-and-neck cancers 4, 5, 6. In this study, all 10 primary lesions were detected with the pretreatment PET scan. Both modalities, however, failed to identify the site for 2 patients with an unknown primary. Lowe et al. have reported a 92% detection rate for early-stage larynx cancer (4). Wong et al. demonstrated 100% detection for 31 patients with primary head-and-neck cancers (5). Finally, Paulus et al.

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Citation Excerpt :
Some studies have suggested that ultrasound-guided assessments or plain computed tomography (CT) may be adequate.5,6 More recent publications, however, have favoured positron emission tomography and computed tomography (PET/CT), and these are becoming standard for the assessment of the response of the primary site and neck to chemoradiotherapy.7,8 There is also debate about the timing of assessment, and some authors have suggest that 6–8 weeks is adequate for PET/CT with little risk of misinterpretation.2
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
2012, International Journal of Radiation Oncology Biology Physics
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.
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.
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).
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.

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

Abstract

Purpose

Methods and materials

Results

Conclusions

Introduction

Section snippets

Methods and materials

Results

Discussion

Eur J Cancer

Planned neck dissection after definitive radiotherapy for squamous cell carcinoma of the head and neck

Head Neck

Neck surgery in patients with primary oropharyngeal cancer treated by radiotherapy

Head Neck

Positron emission tomography of patient with head and neck carcinoma before and after high dose irradiation

Cancer

Primary and recurrent early stage laryngeal cancerpreliminary results of 2-

Radiology

A prospective study of PET-FDG imaging for the assessment of head and neck squamous cell carcinoma

Clin Otolaryngol

18FDG-PET for the assessment of primary head and neck tumorsClinical, computed tomography, and histopathological correlation in 38 patients

Laryngoscope

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