472P - Risk of recurrence and optimal adjuvant treatment in invasive lung adenocarcinomas manifesting as radiological part-solid nodules

Background

Radiological part-solid nodules (PSNs) containing both solid and ground-glass opacity (GGO) component has lower incidence of nodal metastasis and better prognosis than radiological solid nodules. Previous studies demonstrated that risk of recurrence in GGO-predominant PSNs (0< consolidation-to-tumor ratio ≤0.5) was negligible, while recurrence was not rare in solid- predominant PSNs (0.5< consolidation-to-tumor ratio <1). However, the detailed recurrence patterns and the role of adjuvant therapy after recurrence remained unclear in solid-predominant PSNs.

Methods

Patients with cN0 solid-predominant PSNs (0.5< consolidation-to-tumor ratio <1) undergoing surgery from 2008 to 2015 were collected. The exclusion criteria were as follows: (a) adenocarcinoma in situ or minimally invasive adenocarcinoma, (b) history of other malignancy, (c) multiple primary lesions, and (d) positive resection margin. Median follow-up time was 77.0 months. The initial recurrence site and adjuvant treatment data were collected.

Results

This study included 443 solid-predominant PSNs. Postoperative recurrence was diagnosed in 88 patients (19.9%), including 38 (8.6%) distant, 26 (5.9%) locoregional, and 24 (5.4%) combined recurrences. Lymph node metastasis (P=0.011), lymphovascular invasion (P=0.001), and larger solid component size (P=0.007) were independent predictors of postoperative recurrence. Multivariate Cox regression identified older age (P=0.014, HR=1.044) and early recurrence (P<0.001, HR=4.046) as independent predictors of decreased survival in patients who experienced recurrence. EGFR mutation and ALK rearrangement were identified in 44 (50.0%) and 3 (3.4%) patients who experienced recurrence, respectively. Tyrosine kinase inhibitors demonstrated significant advantages over chemotherapy in patients who experienced recurrence. (median overall survival: 75 vs. 52 months, P=0.004).

Conclusions

Radiological solid-predominant PSNs comprise a heterogeneous population. Active follow-up and effective adjuvant treatment is warranted in patients with risk factors of recurrence. Patients with driver mutations can greatly benefit from targeted therapy if recurrence occurs.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.