Table 2. Overview of studies of renal cancer active surveillance cohorts. The two studies from the University of Michigan report on different samples of patients from the same database.
| Study | Country | Study type | Study period | Definition of SRM | Patient no. with SRM | Patient no. on AS (%) | % with RMB | Follow up (median) | % of AS patient with progression* | % of AS patients who had delayed intervention | Outcomes on AS |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Studies with no follow up | |||||||||||
| University of Michigan, 2012 (15) | USA | Retrospective analysis of prospectively entered SRM database | 2009–2010 | cT1 | 204 | 73/204 (36%) |
41% (30/73) | n/a | n/a | n/a | n/a |
| Fox Chase Cancer Center, Philadelphia, 2013 (16) | USA | Retrospective analysis of prospectively entered kidney tumour database | 2005–2011 | cT1 | 969 | 266/969 (26%) |
n/r | n/a | n/a | n/a | n/a |
| National Cancer Database (NCDB), 2019 (17) | USA | Retrospective sample | 2004–2015 | cT1a or pT1a | 75,691 | 6,228/75,691 (8%) | n/r | n/a | n/a | n/a | n/a |
| Studies with follow up | |||||||||||
| Cleveland Clinic, 2010 (18) | USA | Retrospective analysis of prospectively entered kidney tumour database | 2000–2006 | cT1 | 537 | 105/537 (20%) |
2.3% (13/537) | 3.9 years |
n/r | n/r | Cancer-specific mortality not significantly associated with management type (RN vs. PN vs. AS) |
| University of Toronto, 2011 (19) |
Canada (3 centres) | Prospective AS cohort | 2001–2009 | cT1 | n/a | 82 | 8.5% (7/82) |
3 years | n/a | 15% (12/82) | 1/82 developed metastases after 18 months of follow-up; 8.6% (7/82) died from other causes |
| DISSRM, 2015, (20) | USA (3 centres) | Prospective SRM registry | 2009–2014 | cT1a | 497 | 223/497 (45%) | 6.4% (32/497) | 2.1 years | 16% (36/223) | 9% (21/223) | AS was not predictive of OS or CSS at 5 years |
| DISSRM, 2020† (21) | USA | Prospective SRM registry | 2009–2019 | cT1a | 785 | 437/785 (56%) | n/r | 3.3 years | 25% (110/437) | 15% (67/437) | At 10 years: no difference in CSS between PI and AS groups, however OS was higher in PI (83%) vs. AS (58%) |
| Canada (Renal Cell Carcinoma Consortium), 2011 (22) | Canada (8 centres) | Prospective non-comparative clinical trial of AS | 2004–2009 | cT1a | n/a | 178 | 56% (99/178)—all patients asked to undergo RMB | 2.3 years | 15% (27/178) | 5% (9/178) (In addition, 16 withdrawn patients also had DI) | 2 patients progressed to metastatic disease at 5 and 12 months |
| Oxford, 2012, (23), 2020† (24) | UK | Retrospective analysis of local cancer database | 2005–2010 | cT1a solid or Bosniak IV | 208 | 76/208 (37%) | 7.5% | 9.4 years | 12% | 18% (14/76) | 7.8% developed metastatic disease. No statistically significant difference in OS and CSS between AS and RN or PN groups |
| Haifa (Bnai Zion Medical Center), 2015 (25) | Israel | Retrospective analysis of AS cohort | 2003–2013 | cT1a | n/a | 70 | 4% (3/70) | 2.8 years | 59% | 10% (7/70) | No cases of metastases |
| University of Michigan, 2016 (26) |
USA | Retrospective analysis of AS cohort | 2009–2011 | cT1a | n/a | 118 | 43% (51/118) | 2.5 years | 6.7% (8/118) | 24% (28/118) | 1 case (0.8%) of metastases; 8 deaths not related to SRM |
| Pusan National University, 2017 (27) | South Korea | Prospective AS cohort | 2010–2016 | SRM <3 cm | n/a | 37 | 32% (12/37) (mainly whilst on surveillance for rapid growth rate) | 2.3 years | 16% (6/37) | 8% (3/37) | No cases of metastases or cancer specific death |
| Tayside (Urological Cancers Network), 2017 (28) | UK | Retrospective AS cohort | 2007–2014 | SRM (solid or cystic) ≤4 cm |
n/a | 226 (Solid =158, Cystic =68) | 15.6% | 1.8 years | 46% | 19% (43/226) | 4.4% (7/158) metastasized |
| SEER, 2018 (29) | USA | Retrospective SRM cohort | 2002–2011 | cT1a | 10218 | 1978/10218 (19.4%) | n/r | n/r | n/r | n/r | CSS and OS significantly lower for AS group compared with TA and PN group; CSS similar between AS and RN groups |
| MD Anderson Cancer Center, Texas, 2019 (30) | USA | Prospective AS cohort | 2005–2016 | SRM ≤4 cm | n/a | 272 | 45% (123/272) | 4.8 years | n/r | 24% (64/272) | 9.3 years median OS; 98% 5-year CSS. Metastases and death in 4 cases after 2 years |
*Definitions of ‘progression’ differ between studies, see Table 3 for progression criteria used; †Abstract only. AS, active surveillance; CSS, cancer specific survival; DI, delayed intervention; OS, overall survival; PN, partial nephrectomy; RMB, renal mass biopsy; RN, radical nephrectomy; SRM, small renal mass; TA, thermal ablation.