Table 1.
General information from the included studies.
| First author, target disease | Patient recruitment years | Study type | LCT group compared with control | Total no. of patients | NOS score | Type of oligometastases; preceding Tx for primary dz. | Defined no. of oligomets. |
|---|---|---|---|---|---|---|---|
| He, NSCLC | 2003–2013 | R | N/A | 21 | 7 | Synchronous and metachronous; OP | ≤3, in lung |
| Iyengar, NSCLC | 2014–2016 | P | RCT | 29 | 9 | Synchronous; PR or SD after CTx | Up to six lesions (including primary) in three organs |
| Sheu, NSCLC | 1998–2012 | R | PSM, balanced except higher age | 74 | 9 | Synchronous; no PD after CTx | ≤3 |
| Yano, NSCLC | 1994–2004 | R | N/A | 93 | 7 | Metachronous; surgery | Controllable with surgery or RTx |
| Frost, NSCLC | 2000–2016 | R | PSM | 180 | 9 | Synchronous | 1–4 in one organ |
| Gomez, NSCLC | 2012–2016 | P | RCT | 49 | 9 | Synchronous and metachronous; CTx | ≤3 |
| Gray, NSCLC | 2000–2011 | R | Younger age (p = 0.027) | 66 | 7 | Synchronous | ≤4, brain alone |
| Hu, NSCLC | 2010–2016 | R | More brain mets, less lung mets. (p < 0.001) | 231 | 8 | Synchronous; TKI | ≤5 in single organ |
| Song, NSCLC | 2005–2019 | R | PSM, more peripheral location of mets. (p = 0.048) | 70 | 9 | Synchronous | ≤5 |
| Xu Q, NSCLC | 2010–2016 | R | Lower T and N stage | 90 | 7 | Synchronous; PR or SD after TKI | ≤5 |
| Ni, NSCLC | 2015–2018 | R | No significant difference | 86 | 8 | Synchronous | ≤5 |
| Shang, NSCLC (postop) | 2005–2016 | R | No significant difference except mets. location | 152 | 8 | Synchronous | ≤5 |
| Xu, SCLC (extended) | 2010–2015 | R | PSM, more weight loss patient | 44 | 9 | Synchronous | In one organ or in single RT portal |
| Bouman-Wammes, prostate | 2009–2015 | R | Higher PSA at Dx. (p = 0.015), more single mets (p = 0.003) | 63 | 7 | Metachronous; prostatectomy or RTx | ≤3 |
| Lan, prostate | 2005–2016 | R | Lower PSA (p = 0.003), cT (p < 0.001), N stage (p = 0.015), fewer bone mets (p = 0.019) | 111 | 7 | Synchronous | ≤5 |
| Ost, prostate | 2012–2015 | P | RCT | 62 | 9 | Metachronous; OP, RTx | ≤3 |
| Steuber, prostate | 1993–2014 | R | PSM | 659 | 9 | Metachronous; OP and adjuvant RTx (biochemical failure) | ≤5 |
| Parker, prostate | 2013–2016 | P | RCT | 819 | 9 | Synchronous | ≤3 (low-burden subgroup) |
| Tsumura, prostate | 2003–2013 | R | N/A | 40 | 7 | Synchronous | ≤5 |
| Giessen, colorectal | 2000–2004 | P | More N-, better PS | 253 | 7 | Synchronous and metachronous; OP (95%) | 1 (~95% of patients) |
| Ruers, colorectal | 2002–2007 | P | RCT | 119 | 9 | Synchronous and metachronous | ≤9, all resectable or ablatable |
| Ruo, colorectal | 1996–1999 | R | More comorbidity (p = 0.04), more liver only and single mets. (p = 0.02) | 230 | 7 | Synchronous | ≤3 |
| Palma, multiple | 2012–2016 | P | RCT | 99 | 9 | Metachronous; no progression after definitive Tx | ≤5 |
| Chen Y, esophagus | 2012–2015 | R | No significant difference | 461 | 8 | Synchronous | ≤3 |
| Depypere, esophagus | 2002–2015 | R | N/A | 20 | 7 | Synchronous or metachronous; NAC(R)T | 3–5 mets in single organ |
| Chen J, HCC | 2013–2016 | R | PSM | 68 | 9 | Synchronous | ≤5 in lung |
| Pan, HCC | 2004–2013 | R | PSM | 92 | 9 | Synchronous | N/A |
| Morino, bile duct | 1996–2015 | R | PSM, more ICC (p < 0.001), more local mets. location (p = 0.005) | 67 | 8 | Metachronous; R0 or R1 resection | ≤3 |
| Schulz, head and neck | 2001–2016 | R | Intentioned match | 47 | 7 | Synchronous and metachronous; OP, CTx, RT | 1 (77%), but ranged up to 10 |
| Falk, sarcoma | 2000–2012 | R | Smaller primary tumor (p = 0.04), more controlled primary (p = 0.0003), less lung mets (p = 0.006) | 281 | 7 | Synchronous and metachronous; OP 93%, R0 62% R1 23% | ≤5 |
NOS Newcastle-Ottawa Scale, NSCLC non-small cell lung cancer, SCLC small cell lung cancer, HCC hepatocellular carcinoma, R retrospective, N/A not assessable, OP operation, P prospective, RCT randomized controlled trial, PR partial remission, SD stable disease, CTx chemotherapy, PSM propensity score matching, TKI tyrosine kinase inhibitor, PSA prostate-specific antigen, RTx radiotherapy, PS performance status, NACT neoadjuvant chemotherapy, NAC(R)T neoadjuvant chemotherapy and/or radiotherapy.