Comparable OS with once-daily or twice-daily radiotherapy in limited-stage SCLC
Patients with limited-stage small-cell lung cancer (SCLC) have comparable overall survival (OS) regardless of whether they receive a once-daily or twice-daily concurrent chemoradiotherapy regimen, demonstrated results of the CONVERT* trial.
The standard of care in patients with limited-stage SCLC is combined chemotherapy and thoracic radiotherapy, said the researchers, although the dose and fractionation of radiotherapy is controversial.
“[T]wice-daily radiotherapy should continue to be considered standard of care ... once-daily radiotherapy could be considered when delivery of twice-daily radiotherapy is impossible because of departmental logistics or patient choice,” they said.
Beginning day 22 of a cisplatin-etoposide chemotherapy regimen (4–6 cycles Q3W), 547 adults with limited-stage SCLC and ECOG status 0–2 were randomized to receive either 45 Gy radiotherapy (30 twice-daily fractions of 1.5 Gy over 19 days; n=274, median age 62 years) or 66 Gy (33 once-daily fractions of 2 Gy over 45 days; n=273, median age 63 years).
More patients on twice-daily radiotherapy received the full dose compared with those on the once-daily regimen (p<0.0001).
At a median 45 months, median OS was comparable between patients receiving radiotherapy twice-daily or once-daily (30 vs 25 months; hazard ratio [HR], 1.18, 95 percent confidence interval [CI], 0.95–1.45; p=0.14). [Lancet Oncol 2017;doi:10.1016/S1470-2045(17)30318-2]
Two-year and 5-year OS in the twice-daily vs once-daily groups were 56 percent vs 51 percent and 34 percent vs 31 percent, respectively.
Median progression-free survival (PFS) was also similar between the twice-daily and once-daily groups (15.4 vs 14.3 months; HR, 1.12, 95 percent CI, 0.92–1.38; p=0.26), be it local PFS (HR, 1.15; p=0.20) or metastatic PFS (HR, 1.13; p=0.24).
Neutropenia was the most frequent grade 3–4 adverse event (AE), affecting 74 and 65 percent of patients in the twice-daily and once-daily groups, respectively, with grade 4 neutropenia more common among patients on the twice-daily regimen (49 percent vs 38 percent; p=0.05). The incidence of most other AEs was comparable between groups.
With regards to radiotherapy toxicity, incidence of grade 3–4 oesophagitis was similar between patients in the twice-daily and once-daily groups (18 percent vs 19 percent; p=0.85), as was incidence of grade 3–4 pneumonitis (n=5 and 6, respectively; p=0.70).
There were 11 treatment-related deaths, three and eight in the twice-daily and once-daily groups, respectively.
“A further advantage of the twice-daily regime is that it halves the radiotherapy treatment time ... and reduces the number of fractions ... compared with the once-daily regimen,” said the researchers, who suggested that the chemoradiotherapy regimen could be further intensified due to lower toxicity rates.
They acknowledged that as most participants were Caucasian, the findings may not extend to other populations.