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A. Foster

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    P1.03 - Poster Session/ Treatment of Locoregional Disease – NSCLC (ID 212)

    • Event: WCLC 2015
    • Type: Poster
    • Track: Treatment of Locoregional Disease – NSCLC
    • Presentations: 1
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      P1.03-004 - Occult Primary Non-Small Cell Lung Cancer with Mediastinal Lymph Node Involvement (ID 1573)

      09:30 - 17:00  |  Author(s): A. Foster

      • Abstract
      • Slides

      Non-small cell lung cancer (NSCLC) involving mediastinal lymph nodes without an identifiable primary tumor is a rare presentation. While definitive surgery or radiotherapy with or without concurrent chemotherapy is typically recommended, little is known about the treatment outcomes. As such, we reviewed our institutional experience to determine if subsequent development of lung tumors is common and whether prognosis is comparable to stage III NSCLC in general.

      This study was an IRB-approved retrospective review of an institutional NSCLC database. Twenty-six patients with biopsy-proven NSCLC involving mediastinal lymph nodes with no identifiable lung primary lesion and no evidence of distant metastases treated with curative intent between 1995-2013 were identified. PET-CT staging was performed in 25 of 26 patients. All followup was calculated from date of diagnosis.

      The median followup was 44 months. The median age at diagnosis was 60 years (range 51-81) among the 18 males (69%) and 8 females (31%). N2 and N3 disease were each present in 13 (50%) patients, respectively. Histologies included adenocarcinoma in 12 (46%), squamous cell carcinoma in 10 (38%), NSCLC not otherwise specified in 3 (12%), and large cell lung carcinoma in 1 (4%). Eleven patients underwent EGFR mutation analysis, with no sensitizing mutations identified. All patients had a smoking history (median 35 pack-years). Four (15%) patients underwent complete surgical resection, of whom 3 underwent induction chemotherapy and 1 was treated with surgery alone. One of the four patients underwent post-operative radiation therapy to 54 Gy. Twenty-two (85%) patients were treated with definitive radiation therapy including sequential chemotherapy and radiation in 8 (mean RT dose = 70 Gy), concurrent chemoradiation in 10 (mean RT dose = 60 Gy), neoadjuvant chemotherapy followed by concurrent chemoradiation in 3 (mean RT dose = 66 Gy), and radiation alone in 1 (treated to 60 Gy). The median overall survival was 78.1 months with actuarial 2- and 5-year survival rates of 78% and 67%, respectively. Five patients developed intrathoracic failure at a median of 19.8 months. One patient had an isolated lung failure at 13.6 years, but this likely represents a secondary primary and not tumor recurrence. Two patients had isolated mediastinal lymph node failures at 18.1 and 19.8 months and 2 patients initially had a mediastinal lymph node recurrence at 0.2 and 3.4 years, but subsequently failed in the lung at 8.5 and 3.6 years respectively. The actuarial 2- and 5-year intrathoracic control rates were 85.7% and 78.6%. Nine patients developed metastatic disease at a median of 16.5 months. The 2- and 5-year actuarial freedom from distant metastases was 70.9% and 59.1%. Among patients receiving definitive radiation, there was no difference between those receiving concurrent chemotherapy and those who did not.

      To our knowledge, this is the largest reported series of occult primary NSCLC involving mediastinal nodes. Definitive local therapy, including radiotherapy and surgery, was associated with very favorable locoregional control and survival, particularly compared with expected outcomes for stage III NSCLC.

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