Background. Accurate assessment of irradiated neck in squamous cell carcinoma of the head and neck (HNSCC) is essential. Fine-needle aspiration cytology is often performed for suspicious lesions but it is limited by its low negative predictive value (NPV). We postulated that F-18 fluorodeoxyglucose (FDG) positron emission tomography combined with computed tomography (PET/CT) can overcome this limitation by its high NPV value and allow for a more accurate assessment of irradiated neck in HNSCC. Methods. Fifty-four HNSCC patients were included for the study. They all received previous irradiation to the neck. Clinical characteristics, details of radiotherapy, PET/CT results, follow-up findings, and final histological diagnosis were analyzed. Results. The sensitivity, specificity, positive predictive value (PPV), and NPV were 95.8%, 96.7%, 95.8%, and 96.7%, respectively. Age, sex, radiation dose, interval between PET/CT and radiotherapy completion, nature of radiotherapy, and use of second course of radiotherapy were not found to affect diagnostic accuracy of PET/CT. A new algorithm for investigation of masses in irradiated neck is proposed. Conclusions. PET/CT is an effective diagnostic tool and has a complementary role to FNAC in the management of irradiated neck in head and neck cancers, particularly in cases where suspicious lesions were identified but FNAC showed negative results. 1. Background Radiotherapy is frequently employed in the management of head and neck squamous cell carcinoma (HNSCC). Locoregionally advanced tumours are frequently given adjuvant radiotherapy with or without chemotherapy to improve locoregional control. Definitive radiation is also given for organ preservation and to avoid operative morbidity. Accurate assessment of irradiated neck is essential in management of HNSCC. Unfortunately, radiation-associated fibrosis of skin and subcutaneous tissue can easily mask underlying lesions on clinical examination. Various modalities of imaging were used to detect residual or recurrent neck diseases. However, anatomical distortion caused by radiotherapy (and often together with surgery) renders that the assessment of disease status by imaging alone is difficult. Ideally, when a suspicious lesion is identified clinically or radiologically, tissue biopsy should be sampled from suspicious lesions. In reality, however, they are often limited by inaccessibility and/or potential morbidity associated, especially in irradiated necks. Thus, fine-needle aspiration cytology (FNAC) is often performed instead. However, we have recently shown that
References
[1]
R. Chiu-Lung Chan and J. Y. Chan, “Effect of previous radiotherapy on cervical lymph node fine-needle aspiration cytology diagnostic accuracy in head and neck cancers,” Laryngoscope, vol. 122, no. 8, pp. 1779–1781, 2012.
[2]
G. Weber, “Enzymology of cancer cells (first of two parts),” The New England Journal of Medicine, vol. 296, no. 9, pp. 486–493, 1977.
[3]
Y. Makimoto, S. Yamamoto, H. Takano et al., “Lymphadenopathy in the mesenteric pedicle of the free jejunal flap: reactive lymphadenopathy, not metastatic,” Journal of Computer Assisted Tomography, vol. 30, no. 1, pp. 65–67, 2006.
[4]
A. M. Peterson, C. C. Meltzer, E. J. Evanson, J. C. Flickinger, and D. Kondziolka, “MR imaging response of brain metastases after gamma knife stereotactic radiosurgery,” Radiology, vol. 211, no. 3, pp. 807–814, 1999.
[5]
D. Mak, J. Corry, E. Lau, D. Rischin, and R. J. Hicks, “Role of FDG-PET/CT in staging and follow-up of head and neck squamous cell carcinoma,” Quarterly Journal of Nuclear Medicine and Molecular Imaging, vol. 55, no. 5, pp. 487–499, 2011.
[6]
Y. Abe, T. Matsuzawa, and T. Fujiwara, “Assessment of radiotherapeutic effects on experimental tumors using 18F-2-fluoro-2-deoxy-D-glucose,” European Journal of Nuclear Medicine, vol. 12, no. 7, pp. 325–328, 1986.
[7]
W. L. Wong, E. B. Chevretton, M. McGurk, et al., “A prospective study of PET-FDG imaging for the assessment of head and neck squamous cell carcinoma,” Clinical Otolaryngology and Allied Sciences, vol. 22, no. 3, pp. 209–214, 1997.
[8]
C. Laubenbacher, D. Saumweber, C. Wagner-Manslau et al., “Comparison of fluorine-18-fluorodeoxyglucose PET, MRI and endoscopy for staging head and neck squamous-cell carcinomas,” Journal of Nuclear Medicine, vol. 36, no. 10, pp. 1747–1757, 1995.
[9]
V. J. Lowe, J. H. Boyd, F. R. Dunphy et al., “Surveillance for recurrent head and neck cancer using positron emission tomography,” Journal of Clinical Oncology, vol. 18, no. 3, pp. 651–658, 2000.
[10]
R. J. Wong, D. T. Lin, H. Sch？der et al., “Diagnostic and prognostic value of [18F]fluorodeoxyglucose positron emission tomography for recurrent head and neck squamous cell carcinoma,” Journal of Clinical Oncology, vol. 20, no. 20, pp. 4199–4208, 2002.
[11]
C. S. Hollenbeak, V. J. Lowe, and B. C. Stack Jr., “The cost-effectiveness of fluorodeoxyglucose 18-F positron emission tomography in the N0 neck,” Cancer, vol. 92, no. 9, pp. 2341–2348, 2001.
[12]
P. E. Valk, T. R. Pounds, R. D. Tesar, D. M. Hopkins, and M. K. Haseman, “Cost-effectiveness of PET imaging in clinical oncology,” Nuclear Medicine and Biology, vol. 23, no. 6, pp. 737–743, 1996.
[13]
C. A. Uyl-de Groot, A. Senft, R. de Bree, C. R. Leemans, and O. S. Hoekstra, “Chest CT and whole-body 18F-FDG PET are cost-effective in screening for distant metastases in head and neck cancer patients,” Journal of Nuclear Medicine, vol. 51, no. 2, pp. 176–182, 2010.
[14]
A. C. G. van Hooren, J. Brouwer, R. de Bree, O. S. Hoekstra, C. R. Leemans, and C. A. Uyl-de Groot, “The cost-effectiveness of 18FDG-PET in selecting patients with suspicion of recurrent laryngeal carcinoma after radiotherapy for direct laryngoscopy,” European Archives of Oto-Rhino-Laryngology, vol. 266, no. 9, pp. 1441–1448, 2009.
