Is there a place for optimizing thoracic radiotherapy in limited-stage small cell lung cancer after twenty years?

Table 1 Key studies of thoracic radiotherapy in limited-stage small cell lung cancer

Ref.	Patient (n)	PET	ENI	PCI	RT technique	RT timing	Dose	Chemotherapy scheme	PFS	2-yr survival	Median OS (mo)	Higher grade 3-5 adverse event
Intergroup 0096 (1999)	BID 211, OD 206	0%,0%	No	Allowed	2D (100%)	W1	45 Gy/1.5 Gy/30 F/3 wk, 45 Gy/1.8 Gy/25F/5 wk	EP: W 1, 4, 7, 10	29% 2 yr, 24% 2 yr (P = 0.10)	47%,41%	23, 19 (P = 0.04a)	Esophagitis (55% vs 37%a)
Grønberg et al[7] (2016)	BID 73, OD 84	0%,0%	No	84%,82%	3D (100%)	W4	45 Gy/1.5 Gy/30F/3 wk, 42 Gy/2.8 Gy/15F/3 wk	EP: W 1, 4, 7, 10	49% 1 yr, 45% 1 yr (P = 0.93)	52%,42%	25.1,18.8 (P = 0.61)	None
CONVERT trial (2017)	BID 274, OD 273	57%, 57%	No	84%,81%	IMRT (16%), IMRT (17%)	W4	45 Gy/1.5 Gy/30F/3 wk, 66 Gy/2.0 Gy/33F/7 wk	EP: W 1, 4, 7, 10, 13, 16	15.4 mo, 14.3 mo (P = 0.26)	56%,51%	30, 25 (P = 0.14)	Neutropenia (49% vs 38%a)
Grønberg et al[9] (2020)	BID 76, BID 84	?, ?	?	82.9%, 84.5%	?, ?	W1	45Gy/1.5Gy/30F/3W, 60Gy/1.5Gy/40F/4W	EP: W 1, 4, 7, 10	14.4 mo, 19.9 mo, (P = 0.025a)	46%,70%	22.9, 41.6 (P = 0.02a)	Neutropenia (21% vs 36%a)
CALGB 306101	BID 365, OD 365		Yes	Allowed	?	W1	45 Gy/1.5 Gy/30F/3 wk, 70 Gy/2 Gy/35F/7 wk	EP o ECb: W, 4, 7, 10	Secondary endpoint		Primary endpoint	Secondary endpoint

¹Active, not recruiting. Estimated Primary Completion Data June/2023.

^aP statistically significant. BID: Twice-daily; OD: Once-daily; Gy: Grays; EP: Etoposide/cisplatin; ECb: Etoposide/carboplatin; F: Fractions; PCI: Prophylactic cranial irradiation; ENI: Elective nodal irradiation; RT: Radiotherapy; PFS: Progression-free survival; OS: Overall survival.