Hypopharynx cancer

Diagnostic imaging

The disease extent is often underestimated endoscopically because of submucosal tumour spread. Such submucosal spread can be visualized by CT or MRI.

Early pyriform sinus tumours may be very subtle; images obtained during a modified Valsalva manoeuvre (while letting the patient blow against closed lips) may be helpful (Fig.1). Larger cancers appear as soft tissue masses often involving the anterior, lateral and posterior wall of the pyriform sinus. Pyriform sinus cancers have the tendency to grow anteriorly in the laryngeal paraglottic space (Fig.2). Anterolateral spread results in invasion of the thyroid cartilage. Soft tissue thickening or obliteration of the deep fat planes behind the level of the true vocal cord signifies involvement of the pyriform sinus apex. Inferior extension into the postcricoid area may occur submucosally and therefore endoscopically undetectable. Lateral extension may result in extrapharyngeal spread into the neck; the large neck vessels are then at risk of becoming involved by the primary tumour.

Cancer of the posterior hypopharyngeal wall commonly appears as a flat but often widespread mass lesion which may extend into the lower oropharynx.

Cancer originating in the postcricoid area is rare. Besides superior spread within the hypopharynx and extrapharyngeal spread, involvement of the proximal oesophagus may be seen.

These cancers may invade the prevertebral muscles; CT and MRI have a high true negative but also high false positive rate in diagnosing such posterior tumour spread.

Lymphadenopathy head and neck is often present in hypopharyngeal cancer.

Treatment

Most posterior hypopharyngeal wall lesions are treated by radiotherapy. Postcricoid cancer is treated by total laryngopharyngectomy with reconstruction, generally with a pectoralis major myocutaneous flap. If the tumour extends to the oesophagus, an oesophagectomy is also required. In cancer confined to the pyriform sinus or with minimal extension beyond it, a partial laryngopharyngectomy is feasible if the pyriform apex is not involved; this leaves the patient with a functional larynx. If the apex is involved, the risk of laryngeal invasion is high and a total laryngopharyngectomy has to be performed.

Low-volume hypopharyngeal cancer can be effectively treated by radiation therapy. As in laryngeal cancer, CT (or MRI) is helpful in selecting patients into a favourable group for radiation treatment, by providing an estimate of tumour volume. It appears that patients with bulky disease at the pyriform apex on imaging have a less favourable local outcome after radiotherapy.

RH