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Bowel cancer grows from a polyp over years, so removing the polyp prevents it. This roadmap follows the evidence from that discovery through the stool tests and scopes that built the screening programmes, the operation that changed rectal cancer, the chemotherapy and antibody era, immunotherapy that dissolves some tumours without surgery, and the unexplained rise in young adults, to 2032.
Colorectal cancer is the cancer with the best-understood natural history. Vogelstein and Fearon's 172 tumours (1988) showed that it accumulates mutations as an adenoma grows, and the National Polyp Study (2012) showed that cutting the adenoma out halves the death rate two decades later. That logic built the screening programmes: the Nottingham (1996), Funen (1996) and Minnesota (1993) stool-blood trials, the UK flexible sigmoidoscopy trial (2010, 17-year follow-up 2017) and finally NordICC (2022), the first randomised trial of colonoscopy itself, whose modest 18 percent reduction in incidence turned on the fact that only 42 percent of those invited came.
Treatment moved on two tracks. In the rectum the change was surgical: Heald's total mesorectal excision (1982) cut pelvic recurrence from a quarter of patients to a few percent, and the Swedish (1997), Dutch TME (2001) and MRC CR07 (2009) trials settled that radiotherapy before the operation buys local control rather than survival. In the colon the change was chemical: fluorouracil with levamisole (1990), oxaliplatin added in MOSAIC (2004), then a long de-escalation as QUASAR (2007) measured how small the stage II benefit is, the IDEA collaboration (2018) halved the duration for lower-risk stage III disease and FOxTROT (2023) moved six weeks of it before the operation.
The metastatic era began with bevacizumab (2004) and cetuximab (CRYSTAL, 2009), and immediately produced the field's first negative predictive biomarker: the EGFR antibodies work only when RAS is normal (PRIME's extended testing, 2013) and, as the pooled analysis of six trials showed (2017), only when the primary tumour is on the left. Refractory lines arrived with regorafenib (2013), trifluridine-tipiracil (2015), the combination with bevacizumab (SUNLIGHT, 2023) and fruquintinib (2023), each measured in weeks.
Then the disease split in two. Le's 41 patients (2015) showed that mismatch repair-deficient tumours respond to PD-1 blockade and proficient ones do not, KEYNOTE-177 (2020) made immunotherapy the first-line standard for that 5 percent, CheckMate 8HW (2024) added the CTLA-4 antibody, NICHE-2 (2024) produced 68 percent pathological complete responses before surgery and Cercek's dostarlimab series (2022, 2025) made surgery unnecessary in every mismatch repair-deficient rectal cancer treated. BRAF V600E disease got a targeted doublet (BEACON, 2019) and then a first-line triplet, HER2 got three regimens, KRAS G12C got sotorasib with panitumumab (2023). Circulating tumour DNA became the first reliable measure of residual disease in a solid tumour (Tie 2016), and DYNAMIC (2022) used it to halve chemotherapy in stage II without losing recurrence-free survival.
What has not been solved: 95 percent of metastatic disease is microsatellite stable and still ignores immunotherapy, screening uptake rather than test performance sets what programmes achieve, and incidence in people under 50 is rising by about 3 percent a year in the United States and by 1.6 to 7.9 percent a year across Europe for reasons nobody can name, with colibactin-producing gut bacteria the strongest current lead.
Vogelstein, Fearon and colleagues looked for four genetic changes in 172 colorectal specimens spanning adenoma to carcinoma (1988) and found they accumulated in step with clinical progression: ras mutations in 58 percent of adenomas over 1 cm but 9 percent of those under 1 cm, chromosome 18 deletions in 73 percent of carcinomas against 11 to 13 percent of early adenomas, chromosome 17p loss almost only in carcinomas. Fearon and Vogelstein set the model out in Cell in 1990. If cancer grows out of a polyp over years, then screening can prevent it rather than merely bring diagnosis forward, and the Minnesota trial (1993) had already shown that annual stool-blood testing cut colorectal cancer deaths by a third.
Every screening programme rests on this paper: if cancer arrives through a polyp that takes years to progress, then finding and removing polyps prevents cancer rather than merely catching it early.
One term page on OnCo cites this paper by its DOI; this record gives the citation a page of its own so a reader can follow it without leaving OnCo. Read the abstract above alongside the citing page listed under Related; the record was created automatically from the Europe PMC entry and its figures have not been checked by hand.
A cheap home stool test, repeated yearly or every two years and followed by colonoscopy when positive, prevents bowel cancer deaths. This is what national bowel screening programmes do today, with FIT replacing the older guaiac test.
Heald, Husband and Ryall found tumour deposits in the fatty envelope around the rectum centimetres below the tumour and began removing the whole envelope intact: 50 curative operations followed two years with no pelvic or staple-line recurrence (1982). The randomised trials then asked what radiotherapy adds on top. The Swedish Rectal Cancer Trial (1997, 1,168 patients) cut five-year local recurrence from 27 to 11 percent and improved survival from 48 to 58 percent, but against surgery that was not standardised. The Dutch TME trial (2001, 1,861 patients) repeated the question against quality-controlled total mesorectal excision: local recurrence fell from 8.2 to 2.4 percent at two years and survival did not change at all. MRC CR07 (2009, 1,350 patients) settled the timing, cutting local recurrence by 61 percent when everyone had short-course radiotherapy before surgery rather than selective chemoradiotherapy after it. Sauer's German trial (2004) made the same case for long-course chemoradiotherapy.
Moertel's 1,296 patients (1990) showed that a year of fluorouracil with levamisole cut recurrence by 41 percent and death by 33 percent in node-positive colon cancer, the first adjuvant standard in the disease. MOSAIC (2004, 2,246 patients) added oxaliplatin and raised three-year disease-free survival from 72.9 to 78.2 percent, at the price of grade 3 sensory neuropathy in 12.4 percent during treatment. QUASAR (2007, 3,239 patients, 91 percent node-negative) then measured what chemotherapy is worth when the nodes are clear: a relative risk of death of 0.82, which the authors translated into an absolute survival gain of 3.6 percent. That number is why stage II treatment has been a conversation rather than a rule ever since, and why a blood test that could pick out the 3.6 percent was worth building.
Nottingham (1996, 152,850 people) and Funen (1996, 61,933) confirmed Minnesota in Europe: biennial stool-blood testing cut colorectal cancer mortality by 15 and 18 percent, with 40 percent of the Nottingham screening group never completing a single test. The National Polyp Study's 23-year follow-up (2012) showed that removing adenomas halved colorectal cancer deaths against the general population, and the UK flexible sigmoidoscopy trial showed one look at the left colon at 55 to 64 cut incidence 23 percent and mortality 31 percent (2010), still holding at 17 years (2017). Then NordICC (2022) randomised invitations to colonoscopy itself in 84,585 people and got an 18 percent reduction in ten-year incidence, because only 42 percent attended. Kaminski (2010) had already shown that who does the colonoscopy matters: endoscopists finding adenomas in under 20 percent of people left their patients around ten times more likely to develop an interval cancer. Multitarget stool DNA (2014) found 92 percent of cancers against 74 percent for the faecal immunochemical test, but only 42 percent of advanced precancerous lesions and with lower specificity.
Hurwitz (2004) put bevacizumab into first-line chemotherapy and CRYSTAL (2009, 1,198 patients) put cetuximab into FOLFIRI, with a progression-free survival hazard ratio of 0.85 overall and 0.68 in KRAS wild-type tumours: the first negative predictive biomarker in the disease. PRIME's extended RAS analysis (2013) found that a further 17 percent of apparently eligible patients carried KRAS or NRAS mutations outside exon 2 and did worse on the antibody, so testing widened to all of KRAS and NRAS exons 2, 3 and 4. Then FIRE-3 (2014) and CALGB/SWOG 80405 (2017) compared the two antibodies head to head and disagreed: 28.7 against 25.0 months favouring cetuximab in Germany, 30.0 against 29.0 months and no difference in North America. Pooling 2,159 patients across six trials (Arnold 2017) reconciled them: the EGFR antibody helps on the left (overall survival hazard ratio 0.75) and not at all on the right (1.12), interaction p<0.001. PARADIGM confirmed it prospectively in 2022. For patients who need a response and cannot have an EGFR antibody, TRIBE (2015) showed the three-drug FOLFOXIRI backbone with bevacizumab reaches 29.8 months.
The Cancer Genome Atlas read 276 colorectal tumours (2012) and found colon and rectal cancers genomically alike once the hypermutated 16 percent were set aside: three-quarters of those were microsatellite unstable with MLH1 silencing and a quarter carried mismatch-repair or POLE mutations. Twenty-four genes were significantly mutated, and the network flagged amplifications of ERBB2, which is where every HER2 trial in this disease begins. Guinney's consensus molecular subtypes (2015) then sorted expression profiles into four groups, CMS1 immune, CMS2 canonical, CMS3 metabolic and CMS4 mesenchymal, giving the field a shared vocabulary for why right-sided and left-sided tumours behave differently and why stromal tumours resist.
CORRECT (2013, 760 patients) gave regorafenib a median survival of 6.4 against 5.0 months with hand-foot skin reaction in 17 percent; RECOURSE (2015, 800 patients) gave trifluridine-tipiracil 7.1 against 5.3 months; SUNLIGHT (2023, 492 patients) added bevacizumab to the tablet and reached 10.8 against 7.5 months, the largest gain the refractory setting has seen; FRESCO-2 (2023, 691 patients) added fruquintinib at 7.4 against 4.8 months. In the curative setting the movement went the other way. The IDEA collaboration pooled six trials and 12,834 patients (2018): three months of CAPOX was non-inferior to six in T1-T3 N1 disease (83.1 against 83.3 percent three-year disease-free survival) while six months of FOLFOX stayed standard for T4 or N2 disease. FOxTROT (2023, 1,053 patients) moved six weeks of chemotherapy before the operation and cut two-year residual or recurrent disease from 21.5 to 16.9 percent with more complete resections.
Le's 41 patients (2015) gave a 40 percent response in mismatch repair-deficient colorectal cancer and 0 percent in proficient disease, with 1,782 somatic mutations per tumour against 73; the 12-tumour expansion (2017) produced the first tumour-agnostic approval. KEYNOTE-177 (2020, 307 patients) made pembrolizumab the first-line standard for metastatic mismatch repair-deficient disease (16.5 against 8.2 months progression-free, grade 3 toxicity 22 against 66 percent) and reported 77.5 months median survival at five years. CheckMate 8HW (2024) took 24-month progression-free survival to 72 percent against 14 percent with chemotherapy. In curable disease NICHE-2 (2024) gave four weeks of nivolumab and one dose of ipilimumab before surgery and found 68 percent pathological complete responses with no relapses at three years, and ATOMIC (2025) halved recurrence by adding a year of atezolizumab to adjuvant FOLFOX. Then Cercek removed the operation altogether: every mismatch repair-deficient rectal cancer treated with six months of dostarlimab had a clinical complete response (2022, 2025), with 82 of 103 patients across both cohorts avoiding surgery and two-year recurrence-free survival of 92 percent.
BRAF V600E disease had a median survival of 13.4 months in TRIBE's molecular analysis and four to six months after first-line failure. BEACON CRC (2019, 665 patients) blocked BRAF and EGFR together and reached 9.0 against 5.4 months with the triplet and 8.4 months with the doublet; BREAKWATER later moved encorafenib and cetuximab into first line with chemotherapy and doubled survival to 30.3 against 15.1 months. HER2 took a different route: HERACLES (2016) screened 914 patients to find 48 amplified and treated 27, with a 30 percent response to trastuzumab and lapatinib; DESTINY-CRC01 (2021) gave trastuzumab deruxtecan a 45.3 percent response with two deaths from interstitial lung disease; MOUNTAINEER (2023) gave tucatinib and trastuzumab a 38.1 percent response and the first United States approval of a HER2 regimen in this disease. CodeBreaK 300 (2023) showed that a KRAS G12C inhibitor needs an EGFR antibody beside it: 5.6 against 2.2 months progression-free with sotorasib plus panitumumab.
Tie's 230 stage II patients (2016) showed circulating tumour DNA after surgery carried a hazard ratio of 18 for recurrence, the first reliable measure of minimal residual disease in a solid tumour. DYNAMIC (2022, 455 patients) turned it into a randomised strategy: chemotherapy fell from 28 to 15 percent of patients with two-year recurrence-free survival of 93.5 against 92.4 percent, non-inferior. GALAXY, the observational arm of CIRCULATE-Japan (2023, 1,039 patients), found a hazard ratio of 10.0 for recurrence at four weeks after surgery and showed the test picks out who benefits from adjuvant chemotherapy (hazard ratio 6.59). What no trial has shown is the other half: that escalating treatment for a positive result improves anything, which is what CIRCULATE-US and the European CIRCULATE trials are built to answer.
Habr-Gama simply watched the patients whose rectal cancers vanished after chemoradiotherapy: 71 of 265, with ten-year overall survival of 97.7 percent across the series (2004). Total neoadjuvant therapy made that outcome plannable. RAPIDO (2021, 920 patients) cut three-year disease-related treatment failure from 30.4 to 23.7 percent by moving all the chemotherapy in front of surgery after one week of radiotherapy; PRODIGE 23 (2021, 461 patients) raised three-year disease-free survival from 69 to 76 percent with FOLFIRINOX before chemoradiotherapy and halved the serious adverse events of adjuvant treatment; OPRA (2022, 324 patients) planned watch and wait from the start and kept the rectum in 53 percent of the consolidation-chemotherapy group with no apparent cost in disease-free survival. Elsewhere surgery held its ground the hard way: Verwaal (2003) established cytoreduction with heated intraperitoneal chemotherapy for peritoneal disease at 22.3 against 12.6 months, and PRODIGE 7 (2021) then removed the heated chemotherapy and found the survival unchanged at 41.7 against 41.2 months, so the benefit had always been the operation. CHALLENGE (2025, 889 patients) showed a three-year structured exercise programme after adjuvant chemotherapy improved disease-free survival with a hazard ratio of 0.72.
Siegel's age-period-cohort analysis of 490,305 United States cases (2017) showed the rise in young adults is a birth-cohort effect: someone born around 1990 has double the colon cancer risk and quadruple the rectal cancer risk of someone born around 1950, and the proportion of rectal cancers diagnosed under 55 doubled from 14.6 to 29.2 percent in 23 years. Vuik found the same pattern across 20 European countries and 143.7 million people (2019), with incidence rising 7.9 percent a year in 20 to 29-year-olds. By 2023 one in five new United States cases was in someone under 55, and 60 percent of cases were advanced at diagnosis against 52 percent in the mid-2000s, the stage shift screening had bought going into reverse. The United States lowered the screening start age to 45 in 2021. The strongest mechanistic lead came in 2025, when 981 genomes from 11 countries showed the colibactin signatures SBS88 and ID18 are 3.3 times more common in cancers diagnosed before 40 than after 70, are imprinted early in tumour development and account for about a quarter of APC driver indels where they are present.
The immunotherapy question moves into curable disease: AZUR-1 (dostarlimab alone for untreated mismatch repair-deficient rectal cancer, 154 participants, actual; active, not recruiting) has a primary completion date of 2 November 2026, and its randomised sibling in colon cancer (perioperative dostarlimab for T4N0 or stage III mismatch repair-deficient disease, 892 estimated participants; recruiting) of 19 March 2029; the NICHE platform runs to 1 March 2032. The ctDNA question moves from prognosis to strategy: CIRCULATE-US (NRG-GI008, 1,912 estimated participants; recruiting) has a primary completion date of 10 March 2029 and the French CIRCULATE (PRODIGE 70, 1,980 estimated participants; recruiting) of March 2032, while COBRA (NRG-GI005, 635 participants, actual) completes on 21 June 2026. HER2 moves first line with MOUNTAINEER-03 (400 estimated participants; recruiting), primary completion 31 December 2027, and BREAKWATER completes on 28 December 2027. Microsatellite stable disease has its first randomised test of Fc-enhanced CTLA-4 blockade (botensilimab and balstilimab, 234 participants, actual; active, not recruiting), primary completion September 2027. Screening's own long game continues: NordICC, with 95,000 participants actual, has a primary completion date of June 2026 and a study completion date of July 2036, which is when the 15-year mortality answer arrives.
Four things no trial on this page has fixed. First, uptake: NordICC's 18 percent reduction in incidence is what a health system gets when 42 percent of invitations are accepted, and Nottingham's 40 percent who never returned a kit are the same problem thirty years earlier. Second, capacity and quality: every positive stool test needs a colonoscopy, and Kaminski showed a tenfold difference in interval cancer risk between endoscopists at either end of the adenoma detection distribution. Third, the microsatellite stable majority: 95 percent of metastatic colorectal cancer responds to none of the immunotherapy on this page, and the best signal so far is a 17 percent response rate in a single-arm phase 1. Fourth, who gets treated at all: organ preservation, peritoneal surgery and total neoadjuvant therapy each require an MRI service, a specialist multidisciplinary team and a high-volume centre, and the trials that established them enrolled fit patients under 75.
Colonoscopy screening works, but the effect a health system gets is the effect of the invitation, not of the procedure; uptake, not test performance, is the binding constraint, and this is the trial that made that argument unavoidable.
The paper that made the adenoma detection rate the central quality measure of every screening endoscopy service, and the reason endoscopist-level auditing is a condition of accreditation.
The first credible response signal in microsatellite stable colorectal cancer, and the reason the field's attention has moved to Fc engineering and to excluding patients with active liver metastases, in whom responses are rare.
Complete cytoreductive surgery with modern systemic chemotherapy gives a median survival over 40 months in selected patients with peritoneal metastases, and the heated intraperitoneal oxaliplatin adds only late complications.
Every era's records, trial outcomes and papers, and every watch item, as JSON.
Readouts, decisions and registry completion dates ahead. Each date is quoted from its source, not inferred; a missing date means no source states one.
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For mismatch repair-deficient rectal cancer, six months of a single antibody now replaces chemotherapy, radiotherapy and an operation, and the same appears to be true for early-stage mismatch repair-deficient cancers of other organs.
If a childhood exposure to colibactin-producing Escherichia coli writes APC mutations into the colon decades before a tumour appears, then the rise in early-onset bowel cancer may be preventable by something done in childhood rather than by screening alone.
NICHE-2 shows that a month of immunotherapy before surgery can effectively cure locally advanced dMMR colon cancer, where chemotherapy after surgery has limited benefit. It is changing guidelines towards neoadjuvant checkpoint blockade for this group and raises the question of whether surgery can be omitted altogether, as in dMMR rectal cancer. Whether the same applies to MMR-proficient tumours is being tested but is not established.
Patients with rectal cancer whose tumour is mismatch-repair deficient (about 5-10% of rectal cancers) can now be offered immunotherapy alone with the realistic expectation of avoiding surgery, radiotherapy and a permanent stoma. This requires mismatch repair testing on the diagnostic biopsy, close endoscopic and MRI surveillance, and treatment in an experienced centre. It does not apply to the 90% of rectal cancers that are mismatch-repair proficient.
Colonoscopy screening works, but the effect a health system gets is the effect of the invitation, not of the procedure; uptake, not test performance, is the binding constraint, and this is the trial that made that argument unavoidable.
De-escalation guided by a blood test is now proven in stage II colon cancer, and is the template for the stage III and rectal trials that follow; the unsolved half is what to do for the positives, whose recurrence-free survival remains the worst in the trial even after chemotherapy.
Organ preservation became a plan rather than an accident: consolidation chemotherapy after chemoradiotherapy gives the best chance of keeping the rectum, and salvage surgery after regrowth does not appear to cost survival.
First-line chemotherapy-free treatment for mismatch repair-deficient metastatic colorectal cancer, approved in June 2020; the five-year follow-up published in 2024 reported median overall survival of 77.5 months despite 62 percent crossover.
Shares Sidedness (left vs right colon), Panitumumab, Cetuximab, BRAF and the tags colorectal, gi.
Shares Sidedness (left vs right colon), KRAS G12C-mutant colorectal cancer, BRAF V600E-mutant colorectal cancer, BRAF and the tags colorectal, gi.
Shares Consensus molecular subtypes (CMS1-4), Colonoscopy, BRAF V600E-mutant colorectal cancer, Colorectal cancer screening (colonoscopy, FIT, stool DNA, blood) and the tags colorectal, gi.
Shares Consensus molecular subtypes (CMS1-4), Colonoscopy, Wnt / β-catenin, Colorectal cancer screening (colonoscopy, FIT, stool DNA, blood) and the tags colorectal, gi.
Shares Consensus molecular subtypes (CMS1-4), Sidedness (left vs right colon), Lynch syndrome, BRAF V600E-mutant colorectal cancer and the tags colorectal, gi.
Shares Consensus molecular subtypes (CMS1-4), Microsatellite instability (MSI-H) / mismatch repair deficiency (dMMR), Mismatch-repair deficient (MSI-high) colorectal cancer, Minimal / molecular residual disease (MRD) and the tags colorectal, gi.
Shares Total neoadjuvant therapy (TNT, rectal cancer), Total mesorectal excision (TME), Clinical complete response (cCR), Organ preservation (watch-and-wait, bladder-sparing, larynx preservation) and the tags colorectal, gi.
Shares Panitumumab, Irinotecan (and liposomal irinotecan), FOLFIRI (5-FU, leucovorin, irinotecan), CAPOX (capecitabine, oxaliplatin) and the tags colorectal, gi.