Abstract 335P
Background
SCLC grows and spreads faster than most solid tumors. Older reviews indicate that treatment time is associated with survival in LS SCLC, but little is known about the impact of time for diagnostic work-up. We analyzed patients from a randomized trial comparing high-dose with standard dose thoracic radiotherapy (TRT) to investigate whether time until treatment start or treatment time were associated with outcomes in patients who underwent PET/CT staging, selective nodal irradiation, and twice-daily TRT.
Methods
Patients received 4× platinum/etoposide chemotherapy (chemo) and were randomized to receive TRT of 60 Gy/40 fractions or 45 Gy/30 fractions. TRT was to start 21–28 days after first the chemo-course and to be completed within 22 (45 Gy) or 29 days (60 Gy).
Results
166/170 patients (97.6%) commenced TRT and were analyzed; 57.8% were women, 89.2% had PS 0–1, 83.7% stage III disease, 53.6% were in the 60 Gy group, 92.2% received 4 chemo-courses, 96.4% completed TRT and 83.7% received prophylactic cranial irradiation. Median time from symptom debut until CT scan was 60.5 days (IQR 23.5–115). Median time from CT scan until first chemo-course was 20 days (IQR 12–28.5), 65.7% of patients commenced chemo within the recommended 28 days. There were no significant associations between time from symptom debut, CT scan and first chemo-course and PFS or OS. 87.3% started TRT and 88.6% completed TRT within recommended timeframes. There was a trend towards improved PFS (p=0.093) and OS (p=0.052) among those who commenced TRT ≤28 days after the first chemo-course. Those who completed TRT within recommended timeframes had significantly longer PFS (p=0.018), but not OS (p=0.11). Patients who commenced and completed TRT within protocol timeframes had significantly longer PFS (median 18.7 vs. 8.9 months; p=0.006) and OS (median 38.0 vs. 20.1 months; p=0.013). These differences remained statistically significant in multivariable analyses adjusting for baseline characteristics.
Conclusions
In patients with LS SCLC undergoing PET/CT staging and receiving CRT with twice-daily TRT, treatment time, but not time from symptom debut or time for diagnostic work-up, was significantly associated with treatment outcomes.
Clinical trial identification
clinicaltrials.gov: NCT02041845.
Legal entity responsible for the study
Norwegian University of Science and Technology.
Funding
The Norwegian Cancer Society, The Liaison Committee for Education, Research and Innovation in Central Norway, the Nordic Cancer Union.
Disclosure
T.O. Halvorsen: Financial Interests, Personal, Invited Speaker: Takeda, AstraZeneca, Pfizer; Financial Interests, Personal, Advisory Board: Sanofi, AstraZeneca; Financial Interests, Personal, Advisory Role: Immedica; Financial Interests, Institutional, Funding: Roche, AstraZeneca, MSD. B.H. Gronberg: Financial Interests, Personal, Advisory Board, Immunotherapy: MSD; Financial Interests, Personal, Advisory Board, EGFR+ NSCLC: Janssen; Financial Interests, Personal, Advisory Board, Immunotherapy ES SCLC: Accord; Financial Interests, Personal, Advisory Board, Adboard ADRIATIC: AstraZeneca; Financial Interests, Personal, Invited Speaker, Lecture: MSD, Janssen, Pfizer, AstraZeneca, BMS, Gilead; Financial Interests, Institutional, Research Grant: Roche, AstraZeneca; Financial Interests, Personal, Invited Speaker: Eli Lilly; Non-Financial Interests, Personal, Leadership Role, Chairman: Norwegian Lung Cancer Study Group; Non-Financial Interests, Personal, Other, Member of the Rare Tumors Committee: International Association for the Study of Lung Cancer; Other, Personal, Other, Spouse is employee: Eli Lilly. All other authors have declared no conflicts of interest.