CAPP2
CAPP2 followed people with Lynch syndrome, an inherited condition that carries a very high risk of bowel cancer, for ten years after two to four years on aspirin or placebo: those who took aspirin developed about a third fewer bowel cancers, which is why daily aspirin is now offered to people with the syndrome.
Overview
CAPP2 was a double-blind randomised placebo-controlled trial in which 861 carriers of Lynch syndrome from 43 international centres were assigned to 600 mg aspirin daily or placebo, with treatment lasting a mean of 25 months, and cancer outcomes followed for at least ten years (up to 20 years through registries in England, Finland and Wales). The primary endpoint was colorectal cancer.
Over a mean of ten years, 40 of 427 aspirin participants (9 percent) developed colorectal cancer against 58 of 434 on placebo (13 percent), a hazard ratio of 0.65 by intention to treat and 0.56 among those who completed two years of treatment. Non-colorectal Lynch cancers were not significantly reduced and adverse events during treatment did not differ. The trial is the evidence for daily aspirin in Lynch syndrome on the corpus's mismatch-repair-deficient colorectal cancer page, and the CaPP3 dose-finding trial followed it.
- 9 vs 13 out of 100 reached this endpoint with Aspirin 600 mg daily compared with Placebo; 4 fewer per 100.
- On this measure the first group did worse, not better.
- Put another way, the treated group had about 35 percent lower chance of the event at any given time (hazard ratio 0.65, likely range 0.43 to 0.97).
- The treated group had about 44 percent lower chance of the event at any given time (hazard ratio 0.56).
- The absolute difference, how many more people out of 100 were helped, is not reported here.
- 509 participants across both arms completed 2 years
- Aspirin 600 mg daily: 0.6; Placebo: 1.
- This endpoint is not one of the standard survival or response measures; read it alongside the trial's primary result.
- These results apply to the people the trial enrolled: People with Lynch syndrome at 43 centres worldwide: 600 mg aspirin daily or placebo for up to four years (a resistant starch factorial arm was reported separately), with colorectal cancer as the primary endpoint over a planned ten years of follow-up. People in a different situation may not see the same effect.
Numbers are from the trial as recorded here; see the source links in the table below. This is orientation, not medical advice: ask your team how closely the trial population matches you.
861 randomised.
40 cases · 58 cases
Source509 participants across both arms completed 2 years
Source95% CI 0.39 to 0.87, p 0.0085
Source| Endpoint | Arm | n | Value | HR (95% CI) | p | Source |
|---|---|---|---|---|---|---|
| Colorectal cancer over a mean of 10 years of follow-up (intention to treat)primary | Aspirin 600 mg daily | 427 | 9% | 0.65 (0.43 to 0.97) | 0.035 | link |
| Placebo | 434 | 13% | ||||
| Colorectal cancer, per protocol (at least 2 years of treatment) | Aspirin 600 mg daily | - | 509 participants across both arms completed 2 years | 0.56 (0.34 to 0.91) | 0.019 | link |
| Placebo | - | - | ||||
| Incidence rate ratio for colorectal cancer accounting for multiple primaries (intention to treat) | Aspirin 600 mg daily | - | 0.58 | - | - | link |
| Placebo | - | 1 |
Similar pages
not linked directly; found by shared links- TrialASPREE (ASPirin in Reducing Events in the Elderly)
Shares Aspirin, Aspirin for cancer prevention and adjuvant therapy.
- IdeaGet every Lynch syndrome carrier onto the right dose of aspirin
Shares Aspirin for cancer prevention and adjuvant therapy, Mismatch-repair deficient (MSI-high) colorectal cancer.
- TrialALASCCA
Shares Aspirin, Aspirin for cancer prevention and adjuvant therapy.
- TrialAdd-Aspirin
Shares Aspirin, Aspirin for cancer prevention and adjuvant therapy.
- TermLynch syndrome
Shares Aspirin for cancer prevention and adjuvant therapy, Mismatch-repair deficient (MSI-high) colorectal cancer.
- TermMicroenvironment and inflammation: tumours as wounds that do not heal
Shares Aspirin, Aspirin for cancer prevention and adjuvant therapy.