Lung cancer staging: the value of ipsilateral scalene lymph node biopsy performed at mediastinoscopy

The accurate preoperative staging of lung cancer remains an essential element in its proper treatment. In most centers, N3 disease contraindicates an operative approach, despite the advent of combined modality therapy. Although it is used to confirm palpable supraclavicular disease, routine scalene lymph node biopsy to stage nonpalpable disease has been abandoned.

From January 1991 to July 1995, 408 cervical mediastinoscopies were performed by a single surgeon for the staging of lung cancer. In those patients eligible for induction therapy, when N2 or N3 disease was strongly suspected or identified, ipsilateral scalene lymph node biopsy was performed through the same cervical incision using the mediastinoscope to reach the scalene fat pad.

Eighty-one patients underwent this additional staging procedure. There was minimal morbidity and no deaths. Of these 81 fully staged patients, primary tumor histology was non-small cell in 95.1%. Thirty-nine patients were staged as N2 after standard mediastinoscopy. Of these, 6 (15.4%) harbored occult nonpalpable supraclavicular lymph node disease as well. Nineteen patients were staged as N3-contralateral after standard mediastinoscopy. Of these, 13 (68.4%) had occult supraclavicular disease as well. Of all 58 patients with superior mediastinal nodal involvement identified by standard mediastinoscopy, 19 (32.8%) also harbored occult scalene lymph node disease, rendering them ineligible for our induction therapy protocols. Scalene positive primary tumors were all centrally located (visualizable by flexible bronchoscopy) (19 of 19) and were uniformly of nonsquamous origin.

We believe that this technique is a valuable extension to standard cervical mediastinoscopy and can be used in N2 or N3 staged patients with central, nonsquamous tumors before considering a combined modality therapeutic approach that includes operation. Through its use, more accurate staging before initiation of therapy and elimination of those patients who may derive no benefit from an aggressive surgical approach may be possible.