Seventy patients with the hypopharyngeal cancer who underwent pharyngolaryngoeso-phagectomy with bilateral neck dissection between 1978 and 1990 were examined retrospectively to compare TN and pTN in these patients and clarify the clinical pathology of the hypopharyngeal cancer.
Among the 70 cases of hypopharyngeal cancer, there were 46 cases of piriformis sinus cancer (PSC) and 24 cases of postcricoid cancer (PCC). The pathological diagnosis of all these cases was squamous cell carcinoma (SCC).
The following results were obtained:
1. Invasion of the thyroid gland was seen in 8 cases of PCC (33.3%) and 6 cases of PSC (13.0%). The thyroid gland can be preserved in PSC, whereas its removal is indicated in PCC.
2. Twenty-nine cases of N0 necks proved to be pN0-2b in 27 cases (93.1%) which may be controlled by homolateral neck dissection, and pN2c in 2 cases (6.9%), which requires bilateral neck dissection. On the other hand, 29 cases of N1-2b necks which represent one-sided neck metastasis were pN0-2b in 15 cases (51.7%) and pN2c in 14 cases (48.3%). These results demonstrate that N0 necks can, in the majority of cases, be controlled by homolateral neck dissection alone but that N1-2b necks require bilateral neck dissection.
3. Occult neck metastases were observed in PCC more often than in PSC, because paratracheal metastases of PCC were difficult to expose before surgery.
4. Pathological neck metastases of both PSC and PCC were most commonly situated in the superior and middle internal jugular nodes. Paratracheal metastases of PCC was found pathologically in 10 cases (41.7%). Paratracheal nodes must be dissected meticulously during the resection of PCC.
5. Seven of 69 pathologically confirmed cases were poorly differentiated SCC, 6 were PSC and one was PCC. Six of 7 cases of poorly differentiated SCC were pN positive.
Poorly differentiated SCC was more frequently found in PSC and apt to metastasize to neck nodes. Neck dissection should be performed for this type of cancer.
