Session Item

The standard treatment for limited-disease small-cell lung cancer (LD-SCLC) is platinum-based chemotherapy concurrent with hyperfractionated radiotherapy (RT) followed by prophylactic cranial irradiation. Despite treatment with curative intent, locoregional as well as metastatic relapse are frequent, and associated with a poor survival.

The aim of this study was to investigate pattern of failure and survival for different disease stages in LD-SCLC patients with regard to potential benefits of individualized treatment regimes.

This retrospective study included 168 consecutive patients (86 men and 82 women) with LD-SCLC treated from 2012 to 2019. Median [range] age was 67 years [40-83] at diagnosis and performance status (PS) was 0-1 (85%), 2 (14%) and 3 (1%). Disease stage was I/II (15%), IIIa (30%), IIIb/IIIc (55%). Chemotherapy consisted of 1-4 cycles of cis/carboplatin on day 1 and intravenous etoposide on day 1-3 every 3 weeks. The tumor and pathological lymph nodes received 45 Gy/30F/10w. Delineation and treatment planning were based on a planning PET/4D-CT scan. Patients were set up based on daily conebeam CT.



The patients were split into two groups, stage Ib+II+IIIa (group A) and stage IIIb+IIIc (group B). Kaplan-Meier curves were plotted for OS and compared using log-rank test. Overall survival (OS) was defined as the time from RT start until death. First failure was characterized as either loco-regional (LR), distant metastasis (M), simultaneous (LR+M) or death with no evidence of disease (DNED). The first site of failure in groups A and B was shown as cumulative incidences in stacked plots.

Of all patients, 99% received chemotherapy, 88% concurrent with RT. With a Median follow-up of 54 months, the median overall survival (mOS) was 22.3 months for the entire group with a 2-year survival rate of 47.6 %. mOS was significantly longer in Group A (27.5 months, 2-year survival rate 57 %) than in Group B (20.3 months, 2-year survival rate 40%), p=0.018, see figure 1. At two years, the risk of isolated loco-regional failure is only slightly higher in group A (13 %) compared to group B (9%), see figure 2, while both isolated M and simultaneous LR+M are lower in group A (16% and 13%) compared to group B (27% and 27%). DNED are similar in the two groups (13% and 11%). After the first six months, 24% of patients in group B presented with metastatic disease compared to 8% in group A.

OS and pattern of failure differ between the two groups. Patients with more advanced disease (stage IIIb or IIIc) have a higher risk for metastatic disease and for simultaneous failures than patients with less advanced disease (stage I-IIIa), while isolated locoregional recurrences were more frequent for lower stage disease. These differences in pattern of failure should be considered in future trials.