Table 2. Summary of studies assessing the impact of bariatric surgery in cancer risk.
| Author | Study design | Number of subjects | Overall, CA risk or rate | OAC risk or rate | CA risk by gender | Procedures |
|---|---|---|---|---|---|---|
| Sjostrom et al. (27); SOS | Prospective population-based matched cohort |
S =2,010; C =2,037; W =2,867; M =1,180 |
HR =0.67 (P=0.0009) | Melanoma, HR = ND (P=0.0055) | Women: HR =0.58 (P=0.0001) | LGB, HR =0.54 (P=0.026) - W only |
| Hematologic, HR =0.16 (P=0.015) | Men: HR =0.97 (P=0.90) | VBG, HR = 0.60 (P=0.0012) - W only | ||||
| Other origin, HR =0.40 (P=0.04) | RYGB, HR =0.54 (P=0.11) - W only | |||||
| Schauer et al. (28); Kaiser Permanente | Retrospective, matched cohort | S =22,198; C =66,427; over 80% women |
HR =0.67 (P<0.001) | HR =0.59 (P<.001) | Women: HR =0.64 (P<0.001) | RYGB (61%), SG (27.2%), LGB (5.6%) all performed |
| Colon, HR =0.59 (P=0.04) | OAC, HR =0.58 (P<0.001) | Outcomes per procedure not reported | ||||
| Endometrial, HR =0.50 (P<0.001) | Not OAC, HR =0.74 (P=0.001) | |||||
| Post-menopausal Breast, HR =0.58 (P<0.001) | Men: HR =0.79 (P=0.054) | |||||
| Pancreatic, HR =0.46 (P=0.04) | OAC, HR =0.70 (P=0.1) | |||||
| Adams et al. (29); Utah Series | Retrospective, population-based matched cohort | S =9,949; C =9,628; over 80% women | HR = 0.76 (P=0.0006); overall CA mortality, HR =0.54 (P=0.001) | HR =0.62 (P<0.0001); Endometrial, HR =0.22 (P<0.0001); OAC mortality, HR =0.54 (P=0.02) | Women: HR =0.73 (P=0.0004) | Only RYGB |
| Men: HR =1.02 (0.91) | ||||||
| Christou et al. (33); McGill University | Retrospective, matched cohort | S =1,035; C =5,746; 65.6% Women in S group and 64% in C group | RR =0.22 (P=0.001) | Breast, RR =0.17 (P=0.001) CRC, RR =0.32 (P=0.063) |
Not reported | RYGB (81.3%); VBG (18.7) Outcomes per procedure not reported |
| Ward et al. (34); US - University Health System Consortium | Retrospective cohort | 44,345 cases of Endometrial CA | N/A | Endometrial, RR =0.19 | N/A | Outcomes per procedure not reported |
| Tee et al. (35) | Meta-analysis 6 studies (2 prospective and 4 retrospective) | S=21,058; C =30,682 |
RR =0.55 (P<0.0001) | No statistically significant effect on different CA types (breast, melanoma, CRC, NHL, pancreatic) | Women: RR =0.68 (P<0.0001) | Not reported |
| Men: RR =0.99 (P=0.937) | ||||||
| Ostlund et al. (31); Swedish National Patient Register | Retrospective, population-based observational cohort | S =13,123; 77% women | SIR = 1.04 (0.93–1.17) | Breast, SIR =0.55 (0.44–0.68) | Women: SIR =0.97 (0.85–1.11) | GB, SIR =1.05 (0.87–1.27) |
| Endometrial, SIR =2.15 (1.62–2.81) | Men: SIR =1.41 (1.09–1.81) | VBG, SIR =1.05 (0.89–1.24) | ||||
| Kidney, SIR =2.68 (1.71–3.98) | RYGB, SIR =1.01 (0.70–1.42) | |||||
| CRC, SIR =2.14 (1.33–3.22) | ||||||
| Aravani et al. (32); English National Health Service | Retrospective, population-based observational cohort | S =39,747; C =962,860; 76.6% women in S; 62.9% in C | Not reported | CRC, SIR =1.26 (0.92–1.71) for S and SIR =1.12 (1.08–1.16) for C | Women: CRC, SIR =1.19 (0.79–1.74) for S and SIR =1.02 (0.97–1.08) for C | Restrictive surgery, SIR =1.41 (0.94–2.02) |
| CRC, SIR =1.47 (1.02–2.06) for S ≥50 y/o and SIR =1.11 (1.07–1.15) for C, ≥50 y/o | Men: CRC, SIR =1.41 (0.81–2.29) for S and SIR =1.21 (1.15–1.26) for C | Restrictive and malabsorptive surgery, SIR =1.05 (0.57–1.76) | ||||
| Breast, SIR =0.76 (0.62–0.92) | ||||||
| Endometrial, SIR = 2.98 (2.25–3.90) for S and SIR = 2.60 (2.48–2.73) for C | ||||||
| Kidney, SIR =3.06 (2.08–4.34) for S and SIR =1.78 (1.68–1.89) for C | ||||||
| Mackenzie et al. (36); Hospital Episode Statistics Database in England | Retrospective, population-based matched cohort | S =8,794; C =8,794; 80.3% women | Not reported | Breast, OR =0.25 (0.19–0.33) | Women: CRC, OR =2.61 (1.26–5.41) | RYGB: OR =0.16 (0.11–0.24), overall hormone-related cancers |
| Endometrial, OR =0.21 (0.13–0.35) | Men: CRC, OR =1.50 (0.53–4.23) | CRC, OR =2.63 (1.17–5.95) | ||||
| Prostate, OR =0.33 (0.17–0.76) | LGB: OR =0.34 (0.23–0.48), overall hormone-related CA | |||||
| CRC, OR =2.19 (1.21–3.96) | SG: OR =0.21 (0.07–0.61) |
SOS, Swedish Obese Study; S, study subjects; C, controls; W, women; M, men; LGB, laparoscopic gastric banding; GB, gastric banding; VBG, vertical banded gastrectomy; RYGB, Roux-en-Y gastric bypass; SG, sleeve gastrectomy; ND, not determined; CRC, colorectal cancer; RR, risk reduction; N/A, not applicable; CRC, colorectal cancer; NHL, non-Hodgkin’s lymphoma; SIR, standardized incidence ratio.