{'fraction_non_alphanumeric': 0.026386645126548196, 'fraction_numerical': 0.011308562197092083, 'mean_word_length': 4.955128205128205, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Recurrence rates after selective neck dissection in the N0 irradiated neck.

OBJECTIVES
To define patterns of subclinical metastases in irradiated N0 necks with recurrent or persistent primary site disease and to determine the regional control rate when selective neck dissection (SND) is used in this setting.


PATIENTS AND INTERVENTION
Individuals included were previously treated for head and neck squamous cell carcinoma with primary radiation therapy or chemoradiotherapy. All had recurrent or persistent disease at the primary site, with no clinical or radiographic evidence of nodal disease. The patients underwent surgical treatment of the primary site along with site-specific SND and were required to undergo at least 1 year of follow-up. Subsequent recurrence at the primary site disqualified the patient from further evaluation.


MAIN OUTCOME MEASURE
Regional tumor control.


RESULTS
Forty-three patients meeting the inclusion criteria underwent 59 SNDs (levels dissected: I-IV [n = 22], II-IV [n = 34], and I-III [n = 3]). Sixteen specimens were positive for nodal disease. The charts of 26 patients, who underwent a total of 35 SNDs, were available for review after 1 year (none of the patients involved died of disease in the neck). There were no neck recurrences (mean follow-up, 25 months; median, 21 months). All patients with more than 2 occult nodal metastases experienced primary site recurrence or distant metastases.


CONCLUSIONS
In this small cohort, SND in previously irradiated patients with recurrent primary disease but clinically negative necks has resulted in excellent tumor control in the neck. The usual patterns of nodal spread do not appear to be significantly altered with primary site recurrence after radiation therapy. The presence of more than 2 positive nodes in the neck specimen correlates with poor prognosis.