Head and neck cancer: how imaging predicts treatment outcome

Abstract

Sophisticated imaging methods, such as computed tomography, magnetic resonance imaging and positron emission tomography, play an increasingly important role in the management of head and neck cancer. Pretreatment imaging findings have predictive value for patient outcome, independently from the currently used TNM classification, and may be used to tailor treatment to the individual patient. Based on per-treatment imaging, individualised replanning during radiotherapy may ameliorate tumour control rates and reduce toxic effects to normal tissues. Early posttreatment imaging studies contain important prognostic information, and allow selection of patients for further treatment or watchful waiting.

Figure 1

Patient suffering cancer of floor of the mouth. (A) CT image (sagittal reformatting) shows primary tumor at the junction of the floor of the mouth and oral tongue (arrowheads). (B) Axial CT image. Slightly enlarged lymph node (minimal axial diameter 12 mm) in the submandibular region (arrow): suspicious for metastatic adenopathy. (C)–(E) Axial diffusion-weighted MR-images. Compared to the image (C), the signal clearly reduced in the adenopathy (arrow) on the image (D), indicating easy diffusion of water protons. The ADC-map (E) shows a relative high signal ( ). These findings are consistent with a benign adenopathy. Histological examination of the neck dissection specimen did not show tumour.

Figure 2

(A), (B) Squamous cell carcinoma of the left false vocal cord. A small infiltrating lesion is seen in the right paraglottic space (arrows). Normal true vocal cord (asterisk). Because of paraglottic space infiltration, this lesion was classified as a T3 tumour. Measured tumour volume on CT images was 0.3 ml. No evidence of disease 2 years after end of radiotherapy. (C), (D) Another patient suffering supraglottic squamous cell cancer, also centered on the false vocal cord (asterisk), but more extensively infiltrating the paraglottic space (arrows). This lesion was also classified as a T3 tumour. Tumour volume was 6.1 ml. Local failure occurred 6 months after the end of radiotherapy.

Figure 3

Patient suffering squamous cell carcinoma of the oropharynx, stage T3N2b. A base-line FDG-PET (A) shows uptake in the primary tumour (black arrow) and in regional adenopathy (black arrowhead). F-MISO-PET (B) acquired 1 day later, shows uptake in the primary tumour (white arrow) and the adenopathy (white arrowhead), indicating the presence of hypoxia. Repeat F-MISO-PET after 4 weeks of radiotherapy (C) shows loss of F-MISO uptake, suggesting tumour reoxygenation (images courtesy of Sandra Nuyts, MD, PhD).

Figure 4

Axial CT images in a patient with supraglottic cancer. (A) Pretreatment image. Enhanced soft tissue mass, arising from the right lateral border of the epiglottis, infiltrating the paraglottic fat (arrow); on lower sections, also infiltration of the preepiglottic space was seen. Small metastatic lymph node (arrowhead). The tumour was staged as T3N1. (B) Four months after the end of radiotherapy, a baseline follow-up CT study was performed. Clinically, the patient was doing well. The asymmetrical and slightly enhancing tissue infiltration in the tumour bed (arrows) is doubtful. Follow-up CT was recommended. (C) Eight months after the end of radiotherapy. The patient was now experiencing some pain and swallowing difficulties, but clinical examination did not reveal abnormal findings. On CT, the soft tissue infiltration in the supraglottis (arrows) is progressive compared to the baseline study, very suspicious for tumour recurrence. At direct laryngoscopy, an intact mucosa was found, and biopsy was negative. Because of the very worrisome findings on CT, direct laryngoscopy was repeated and deep (submucosal) tissue was sampled; histopathologic examination of this tissue confirmed the presence of cancer. Subsequently, total laryngectomy was performed.

Figure 5

Axial CT images in a patient suffering from a T3N2c tongue base squamous cell cancer. (A) Before chemoradiotherapy. Infiltrating tongue base tumour (arrowheads). Necrotic neck adenopathy (arrow); several other, bilateral adenopathies were visible on this study. (B) Follow-up study obtained 6 months after completion of therapy. Residual deformity of tongue base, but no enhancing mass is seen; the neck adenopathies disappeared. Patient is now 4 years after therapy, without evidence of disease.