Study	No. of participants analysed	Timing of interim PET scan	Unadjusted results for interim PET
Andre 2017	Favourable: N = 371 standard arm Unfavourable: N = 583 standard arm	PET2	*PET‐negative Favourable group: N = 2 events (both relapses) in the ABVD + INRT arm, ITT 5‐year PFS rate was 99.0% (95% CI 3.8 to 66.1) Unfavourable group: N = 22 events (16 relapses and 6 deaths not related to HL), ITT 5‐year PFS rate was 92.1% (95% CI 88.0 to 94.8) *Results presented here are only for participants without interim PET adaptation (ABVD + INRT arm). Unclear how many of these participants were PET‐positive or PET‐negative. In total (all participants included in the study), there were 465 PET‐negative participants and 361 PET‐positive participants. *PET‐positive N = 41 events (36 relapses and 5 deaths not related to HL) in the ABVD + INRT arm, ITT 5‐year PFS rate was 77.4% (95% CI 70.4 to 82.9)
Casasnovas 2019	Standard arm N = 413	PET2	PET2 results (N = 398) Intention‐to‐treat analysis PET2‐negative N = 349 participants (88%), 5‐year PFS = 88.4% (95% CI 83.3 to 92) PET2‐positive N = 49 participants (12%), 5‐year PFS = 73.5% (95% CI 58.7 to 83.6) Results for entire standard arm 5‐year PFS = 86.2% (95% CI 81.6 to 89.8) 41 participants relapsed or progressed, 14 deaths Comment: Logrank test for difference between groups in the standard arm after PET2 was not reported and could not be obtained. Per‐protocol analysis N = 372 participants 5‐year PFS = 86.7% (95% CI 81.9 to 90.3) for entire arm
Gallamini 2014	260 (stages IIA ‐ IV)	PET2	PET‐negative N = 215, 12 events (progression N = 7, relapse N = 5), 3‐year PFS = 95% PET‐positive N = 45, 33 events (progression N = 27, relapse N = 6), 3‐year PFS = 28% Logrank test for difference between groups: P < 0.0001
Hutchings 2014	121 (all stages)	PET1 (N = 121) PET 2 (N = 89)	PET1 results (N = 126) PET‐negative N = 89, 5 events (relapse), 2‐year PFS = 94.1% PET‐positive N = 37, 22 events (17 primary refractory disease, 5 relapses), 2‐year PFS = 40.8% Log‐rank test for difference between groups: P < 0.01 PET1 vs. PET2 results (N = 89) Participants scanned after PET1 and 2 PET1‐negative 2‐year PFS = 98.3% PET1‐positive 2‐year PFS = 38.5% PET2‐negative 2‐year PFS = 90.2% PET2‐positive 2‐year PFS = 23.1% 14 PET1‐positive converted to a PET2‐negative (6 progressed). All PET1‐negative were also PET2‐negative.
Markova 2012	69 (advanced stages)	PET4	PET‐negative N = 51, 2 events (1 relapse and 1 death), % of PFS not reported PET‐positive N = 18, 4 events (progression or relapse), % of PFS not reported Log‐rank test for difference between groups: P = 0.016
Oki 2014	229 (all stages)	PET2	3‐year PFS rates in PET2‐negative versus PET–positive by disease subgroups Early stage favourable: 100% vs. 100% Early stage unfavourable: 91.5% vs. 56.3% (P < 0.0001) Early stage non‐bulky: 95.9% vs. 76.9% (P = 0.0018) Stage II bulky: 83.3% vs. 20% (P = 0.017) Advanced stage with IPS≤2: 77.0% vs. 30.0% (P < 0.001) Advanced stage with IPS≥3: 71.0% vs. 44.4% (P = 0.155)
Okosun 2012	23 (stages II ‐ IV)	PET2 or PET3	PET‐negative: N = 21, no events, 2‐year PFS = 100% PET‐positive: N = 2, 1 event (treatment failure), 2‐year PFS = 50% Log‐rank test for difference between groups: P = 0.0012