Streamlining clinical research: an ESMO awareness call to improve sponsoring and monitoring of clinical trials.

BACKGROUND: During recent years, the burden of bureaucracy in clinical research has increased dramatically, adversely impacting the activity of investigators and clinical research teams. Although compliance with the Declaration of Helsinki, the guidelines for Good Clinical Practice (GCP), and other applicable regulations remains unquestionable, their overinterpretation and substitution by the internal operating procedures of sponsors and Contract Research Organizations (CROs) have increased the administrative burden. A survey conducted by the European Society for Medical Oncology (ESMO) Clinical Research Observatory (ECRO) among 940 investigators confirmed that they considered that the administrative burden in clinical research is excessive; that administrative procedures could be reduced without affecting the safety and the rights of the patients and the quality of the data; and that bureaucracy represents an obstacle for clinical research. METHODS: A panel of physicians with extensive experience in clinical research, composed by members of the ECRO and the ESMO Scientific Medical and Public Policy divisions, analyzed clinical trial procedures related to administrative workflow, pharmacovigilance, and medical care. RESULTS: The panel identified situations that generate debate between investigators and sponsors/CROs and selected real clinical scenarios that exemplify such situations. The panel discussed and proposed specific recommendations for those situations, based on GCP. CONCLUSIONS: This initiative aspires to streamline clinical research procedures and to become a platform for discussion among all clinical trial stakeholders, with the aim of promoting the sustainability of clinical research and the care of cancer patients.

Pooled safety analysis from phase III studies of trifluridine/tipiracil in patients with metastatic gastric or gastroesophageal junction cancer and metastatic colorectal cancer.

BACKGROUND: Trifluridine/tipiracil (FTD/TPI) showed clinical benefit, including improved survival and manageable safety in previously treated patients with metastatic colorectal (mCRC) or gastric/gastroesophageal junction (mGC/GEJC) cancer in the phase III RECOURSE and TAGS trials, respectively. A pooled analysis was conducted to further characterize FTD/TPI safety, including management of haematologic toxicities and use in patients with renal or hepatic impairment. PATIENTS AND METHODS: Adults with ≥2 prior regimens for advanced mGC/GEJC or mCRC were randomized (2 : 1) to FTD/TPI [35 mg/m2 twice daily days 1-5 and 8-12 (28-day cycle); same dosage in both trials] or placebo plus best supportive care. Adverse events (AEs) were summarized in the safety population (patients who received ≥1 dose) and analysed by renal/hepatic function. RESULTS: TAGS and RECOURSE included 335 and 533 FTD/TPI-treated and 168 and 265 placebo-treated patients, respectively. Overall safety of FTD/TPI was similar in TAGS and RECOURSE. Haematologic (neutropenia, anaemia) and gastrointestinal (nausea, diarrhoea) AEs were most commonly observed. Laboratory-assessed grade 3-4 neutropenia occurred in 37% (TAGS)/38% (RECOURSE) of FTD/TPI-treated patients (median onset: 29 days/55 days), and 96% (TAGS)/97% (RECOURSE) of cases resolved regardless of renal/hepatic function. Supportive medications for neutropenia were received by 17% (TAGS) and 9% (RECOURSE); febrile neutropenia was reported in 2% and 4%, respectively. Overall grade ≥3 AEs were more frequent in patients with moderate renal impairment [81% (TAGS); 85% (RECOURSE)] versus normal renal function (74%; 67%); anaemia and neutropenia were more common in patients with renal impairment. FTD/TPI safety (including haematologic AEs) was consistent across patients with normal and mildly impaired hepatic function. CONCLUSIONS: These results support FTD/TPI as a well-tolerated treatment in patients with mGC/GEJC or mCRC, with a consistent safety profile. Safety was largely similar in patients with normal or mildly impaired renal/hepatic function; however, patients with renal impairment should be monitored for haematologic toxicities.

Quality of life with encorafenib plus cetuximab with or without binimetinib treatment in patients with BRAF V600E-mutant metastatic colorectal cancer: patient-reported outcomes from BEACON CRC.

BACKGROUND: In the BEACON CRC study (NCT02928224), encorafenib plus cetuximab with binimetinib {9.3 versus 5.9 months; hazard ratio (HR) [95% confidence interval (CI)]: 0.60 [0.47-0.75]} or without binimetinib [9.3 versus 5.9 months; HR (95% CI): 0.61 (0.48-0.77)] significantly improved overall survival (OS) compared with the previous standard of care (control) in patients with BRAF V600E metastatic colorectal cancer (mCRC). Quality of life (QoL) was a secondary endpoint, assessed using validated instruments. PATIENTS AND METHODS: BEACON CRC was a randomized, open-label, phase III study comparing encorafenib plus cetuximab with or without binimetinib and the investigator's choice of irinotecan plus cetuximab or FOLFIRI plus cetuximab (chemotherapy control) in patients with previously treated BRAF V600E mCRC. Patient-reported QoL assessments included the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC) and Functional Assessment of Cancer Therapy-Colorectal (FACT-C). The primary outcome for these tools was time to definitive 10% deterioration. RESULTS: Encorafenib plus cetuximab, both with and without binimetinib, was associated with longer median times to definitive 10% deterioration versus the control group in the EORTC Global Health Status scale [HR (95% CI): 0.65 (0.52-0.80) versus 0.61 (0.49-0.75), respectively] and the FACT-C functional well-being subscale [HR (95% CI): 0.62 (0.50-0.76) versus 0.58 (0.47-0.72), respectively]. Consistent results were observed across all subscales of the EORTC and FACT-C instruments. QoL was generally maintained during treatment for the global EORTC and FACT-C scales. CONCLUSIONS: In addition to improving OS, encorafenib plus cetuximab with or without binimetinib delays QoL decline in previously treated patients with BRAF V600E-mutant mCRC.

Trifluridine/tipiracil versus placebo for third or later lines of treatment in metastatic gastric cancer: an exploratory subgroup analysis from the TAGS study.

BACKGROUND: Metastatic gastric cancer and cancer of the esophagogastric junction (GC/EGJ) is an aggressive disease with poor prognosis. In the TAGS study, trifluridine/tipiracil (FTD/TPI) improved overall survival (OS) compared with placebo in heavily pre-treated patients. This unplanned, exploratory subgroup analysis of the TAGS study aimed to clarify outcomes when FTD/TPI was used as third-line (3L) treatment and fourth- or later-line (4L+) treatment. PATIENTS AND METHODS: Patients were divided into a 3L group (126 and 64 in FTD/TPI and placebo arms, respectively) and 4L+ group (211 and 106 in FTD/TPI and placebo arms, respectively). Endpoints included OS, progression-free survival (PFS), time to Eastern Cooperative Oncology Group performance status (ECOG PS) deterioration to ≥2, and safety. RESULTS: Baseline characteristics were generally well balanced between FTD/TPI and placebo for 3L and 4L+ treatment. Median OS (mOS) for FTD/TPI versus placebo was: 6.8 versus 3.2 months {hazard ratio (HR) [95% confidence interval (CI)] = 0.68 (0.47-0.97), P = 0.0318} in the 3L group; and 5.2 versus 3.7 months [0.73 (0.55-0.95), P = 0.0192] in the 4L+ group. Median PFS for FTD/TPI versus placebo was 3.1 versus 1.9 months [0.54 (0.38-0.77), P = 0.0004] in the 3L group; and 1.9 versus 1.8 months [0.57 (0.44-0.74), P < 0.0001] in the 4L+ group. Time to deterioration of ECOG PS to ≥2 for FTD/TPI versus placebo was 4.8 versus 2.0 months [HR (95% CI) = 0.60 (0.42-0.86), P = 0.0049] in the 3L group; and 4.0 versus 2.5 months [0.75 (0.57-0.98), P = 0.0329] in the 4L+ group. The safety of FTD/TPI was consistent in all subgroups. CONCLUSIONS: This analysis confirms the efficacy and safety of FTD/TPI in patients with GC/EGJ in third and later lines with a survival benefit that seems slightly superior in 3L treatment. When FTD/TPI is taken in 3L as recommended in the international guidelines, physicians can expect to provide patients with an mOS of 6.8 months.

A systematic review and meta-analysis of PD-1/PD-L1 inhibitors in specific patient subgroups with advanced gastro-oesophageal junction and gastric adenocarcinoma.

BACKGROUND: immune checkpoint inhibitors(ICIs) have shown contradictory results in patients with advanced gastro-oesophageal junction/gastric cancer(GOJ/GC). AIM: to identify specific patient subgroups that would derive survival benefit from ICIs. METHODS: a subgroup meta-analysis of randomised clinical trials(RCTs) was carried out. RESULTS: four phase-III-RCTs were identified with data on the following variables: primary location(Gastric vs GOJ); age(≤ 65 vs >65); gender(male vs female); ECOG PS(0 vs 1); ethnicity (Asian vs non-Asian), histology(intestinal vs diffuse), PD-L1 expression(≥ 1% vs < 1%). PD-L1 positivity was significantly associated with survival benefit from ICIs (HR: 0.82, p 0.047), with a significant interaction between PD-L1 expression and ICI efficacy (interaction HR: 1.41, p 0.02). Numerically, the second most relevant interaction was ICI efficacy and gender, with ICI being more effective in males. CONCLUSION: The PD-L1 positive patient subgroup derives significant survival benefit from ICI in GOJ/GC, however other predictors are eagerly needed to further refine patient selection.

Phase I, first-in-human study of futibatinib, a highly selective, irreversible FGFR1-4 inhibitor in patients with advanced solid tumors.

BACKGROUND: Futibatinib is an oral, irreversible, highly selective fibroblast growth factor receptor (FGFR)1-4 inhibitor with potent preclinical activity against tumors harboring FGFR aberrations. This first-in-human, phase I dose-escalation trial (NCT02052778) evaluates the safety and pharmacokinetics/pharmacodynamics of futibatinib in advanced solid tumors. PATIENTS AND METHODS: Following a standard 3+3 dose-escalation design, eligible patients with advanced solid tumors refractory to standard therapies received 8-200 mg futibatinib three times a week (t.i.w.) or 4-24 mg once daily (q.d.). RESULTS: A total of 86 patients were enrolled in the nine t.i.w. (n = 42) and five q.d. cohorts (n = 44); 71 patients (83%) had tumors harboring FGF/FGFR aberrations. Three of nine patients in the 24-mg q.d. cohort experienced dose-limiting toxicities, including grade 3 increases in alanine transaminase, aspartate transaminase, and blood bilirubin (n = 1 each). The maximum tolerated dose (MTD) was determined to be 20 mg q.d.; no MTD was defined for the t.i.w. schedule. Across cohorts (n = 86), the most common treatment-emergent adverse events (TEAEs) were hyperphosphatemia (59%), diarrhea (37%), and constipation (34%); 48% experienced grade 3 TEAEs. TEAEs led to dose interruptions, dose reductions, and treatment discontinuations in 55%, 14%, and 3% of patients, respectively. Pharmacokinetics were dose proportional across all q.d. doses but not all t.i.w. doses evaluated, with saturation observed between 80 and 200 mg t.i.w. Serum phosphorus increased dose dependently with futibatinib on both schedules, but a stronger exposure-response relationship was observed with q.d. dosing, supporting 20 mg q.d. as the recommended phase II dose (RP2D). Overall, partial responses were observed in five patients [FGFR2 fusion-positive intrahepatic cholangiocarcinoma (n = 3) and FGFR1-mutant primary brain tumor (n = 2)], and stable disease in 41 (48%). CONCLUSIONS: Futibatinib treatment resulted in manageable safety, pharmacodynamic activity, and preliminary responses in patients with advanced solid tumors. The results of this phase I dose-escalation trial support 20 mg q.d. futibatinib as the RP2D. CLINICAL TRIAL REGISTRATION: FOENIX-101 (ClinicalTrials.gov, NCT02052778).

An extended phase Ib study of epertinib, an orally active reversible dual EGFR/HER2 tyrosine kinase inhibitor, in patients with solid tumours.

BACKGROUND: Dose-escalation of epertinib (S-222611), a new potent oral EGFR/HER2 inhibitor, has established a recommended daily dose of 800 mg in patients with solid tumours. In this study, we have recruited a larger number of patients to assess further the safety, tolerability, pharmacokinetics (PKs) and antitumour activity. PATIENTS AND METHODS: Patients with solid tumours expressing EGFR or HER2 received a single dose of epertinib at 800 mg on Day 1 to assess PK over 7 days, followed by continuous once-daily dosing from Day 8. RESULTS: We treated 76 patients with breast (n = 27), upper gastrointestinal (GI; n = 30), head and neck (n = 12) or renal cancers (n = 7). Epertinib was well-tolerated with mostly grade I and II adverse events (AEs). The most frequent AE was diarrhoea, which was generally manageable with loperamide. The objective response rate (ORR) in patients with heavily pretreated breast and upper GI cancers was 16.0% (4 PRs) and 8.3% (1CR, 1PR), respectively. All six responding patients had HER2-positive tumours; the ORR for HER2-positive breast and upper GI cancer populations was 19.0% and 20.0%. Partial response in the brain disease of one breast cancer patient lasted 7.5 months. CONCLUSION: Once-daily dosing of epertinib at 800 mg was well-tolerated and demonstrated promising antitumour activity in patients with heavily pretreated HER2-positive breast and upper GI cancer, including those with brain metastases. EUDRACT NUMBER: 2009-017817-31.

Towards an optimal treatment algorithm for metastatic pancreatic ductal adenocarcinoma (PDA).

Chemotherapy remains the mainstay of treatment for advanced pancreatic ductal adenocarcinoma (pda). Two randomized trials have demonstrated superiority of the combination regimens folfirinox (5-fluorouracil, leucovorin, oxaliplatin, and irinotecan) and gemcitabine plus nab-paclitaxel over gemcitabine monotherapy as a first-line treatment in adequately fit subjects. Selected pda patients progressing to first-line therapy can receive secondline treatment with moderate clinical benefit. Nevertheless, the optimal algorithm and the role of combination therapy in second-line are still unclear. Published second-line pda clinical trials enrolled patients progressing to gemcitabine-based therapies in use before the approval of nab-paclitaxel and folfirinox. The evolving scenario in second-line may affect the choice of the first-line treatment. For example, nanoliposomal irinotecan plus 5-fluouracil and leucovorin is a novel second-line option which will be suitable only for patients progressing to gemcitabine-based therapy. Therefore, clinical judgement and appropriate patient selection remain key elements in treatment decision. In this review, we aim to illustrate currently available options and define a possible algorithm to guide treatment choice. Future clinical trials taking into account sequential treatment as a new paradigm in pda will help define a standard algorithm.

Biological and predictive role of ERCC1 polymorphisms in cancer.

Excision repair cross-complementation group 1 (ERCC1) is a key component in DNA repair mechanisms and may influence the tumor DNA-targeting effect of the chemotherapeutic agent oxaliplatin. Germline ERCC1 polymorphisms may alter the protein expression and published data on their predictive and prognostic value have so far been contradictory. In the present article we review available evidence on the clinical role and utility of ERCC1 polymorphisms and, in the absence of a 'perfect' trial, what we call the 'sliding doors' trial, we present the data of ERCC1 genotyping in our local patient population. We found a useful predictive value for oxaliplatin-induced risk of anemia.

A phase I, pharmacokinetic and pharmacodynamic study of GSK2256098, a focal adhesion kinase inhibitor, in patients with advanced solid tumors.

BACKGROUND: Focal adhesion kinase (FAK) is important in cancer growth, survival, invasion, and migration. The purpose of this study was to determine the maximum tolerated dose (MTD), safety, pharmacokinetics (PK), and pharmacodynamics (PD) of the FAK inhibitor, GSK2256098, in cancer patients. PATIENTS AND METHODS: The dose of GSK2256098 was escalated, in cohorts of patients with advanced cancer, from 80 to 1500 mg, oral twice daily (BID), until the MTD was determined. Serial blood samples were obtained from all patients, and the PK was determined. Paired tumor biopsies were obtained in select patients, and the level of phospho-FAK (pFAK) was determined. RESULTS: Sixty-two patients (39 males, 23 females; median age 61 y.o., range 21-84) received GSK2256098. Dose-limiting toxicities of grade 2 proteinuria (1000 mg BID), grade 2 fatigue, nausea, vomiting (1250 mg BID), and grade 3 asthenia and grade 2 fatigue (1500 mg BID) were reported with the MTD identified as 1000 mg BID. The most frequent adverse events (AEs) were nausea (76%), diarrhea (65%), vomiting (58%), and decreased appetite (47%) with the majority of AEs being grades 1-2. The PK was generally dose proportional with a geometric mean elimination half-life range of 4-9 h. At the 750, 1000, and 1500 mg BID dose levels evaluated, the pFAK, Y397 autophosphorylation site, was reduced by ∼80% from baseline. Minor responses were observed in a patient with melanoma (-26%) and three patients with mesothelioma (-13%, -15%, and -17%). In the 29 patients with recurrent mesothelioma, the median progression-free survival was 12 weeks with 95% CI 9.1, 23.4 weeks (23.4 weeks merlin negative, n = 14; 11.4 weeks merlin positive, n = 9; 10.9 weeks merlin status unknown, n = 6). CONCLUSIONS: GSK2256098 has an acceptable safety profile, has evidence of target engagement at doses at or below the MTD, and has clinical activity in patients with mesothelioma, particularly those with merlin loss.

Systematic evaluation of pembrolizumab dosing in patients with advanced non-small-cell lung cancer.

BACKGROUND: In the phase I KEYNOTE-001 study, pembrolizumab demonstrated durable antitumor activity in patients with advanced non-small-cell lung cancer (NSCLC). We sought to characterize the relationship between pembrolizumab dose, exposure, and response to define an effective dose for these patients. PATIENTS AND METHODS: Patients received pembrolizumab 2 mg/kg every 3 weeks (Q3W) (n = 55), 10 mg/kg Q3W (n = 238), or 10 mg/kg Q2W (n = 156). Response (RECIST v1.1) was assessed every 9 weeks. The relationship between the estimated pembrolizumab area under the concentration-time curve at steady state over 6 weeks (AUCss-6weeks) and the longitudinal change in tumor size (sum of longest diameters) was analyzed by regression and non-linear mixed effects modeling. This model was simultaneously fit to all tumor size data, then used to simulate response rates, normalizing the trial data across dose for prognostic covariates (tumor PD-L1 expression and EGFR mutation status). The exposure-safety relationship was assessed by logistic regression of pembrolizumab AUCss-6weeks versus occurrence of adverse events (AEs) of interest based on their immune etiology. RESULTS: Overall response rates were 15% [95% confidence interval (CI) 7%-28%] at 2 mg/kg Q3W, 25% (18%-33%) at 10 mg/kg Q3W, and 21% (95% CI 14%-30%) at 10 mg/kg Q2W. Regression analyses of percentage change from baseline in tumor size versus AUCss-6weeks indicated a flat relationship (regression slope P > 0.05). Simulations showed the exposure-response relationship to be similarly flat, thus indicating that the lowest evaluated dose of 2 mg/kg Q3W to likely be at or near the efficacy plateau. Exposure-safety analysis showed the AE incidence to be similar among the clinically tested doses. CONCLUSIONS: No significant exposure dependency on efficacy or safety was identified for pembrolizumab across doses of 2-10 mg/kg. These results support the use of a 2 mg/kg Q3W dosage in patients with previously treated, advanced NSCLC. CLINICALTRIALSGOV REGISTRY: NCT01295827.

Prediction of early death among patients enrolled in phase I trials: development and validation of a new model based on platelet count and albumin.

BACKGROUND: Selecting patients with 'sufficient life expectancy' for Phase I oncology trials remains challenging. The Royal Marsden Hospital Score (RMS) previously identified high-risk patients as those with ≥ 2 of the following: albumin <35 g l(-1); LDH > upper limit of normal; >2 metastatic sites. This study developed an alternative prognostic model, and compared its performance with that of the RMS. METHODS: The primary end point was the 90-day mortality rate. The new model was developed from the same database as RMS, but it used Chi-squared Automatic Interaction Detection (CHAID). The ROC characteristics of both methods were then validated in an independent database of 324 patients enrolled in European Organization on Research and Treatment of Cancer Phase I trials of cytotoxic agents between 2000 and 2009. RESULTS: The CHAID method identified high-risk patients as those with albumin <33 g l(-1) or ≥ 33 g l(-1), but platelet counts ≥ 400.000 mm(-3). In the validation data set, the rates of correctly classified patients were 0.79 vs 0.67 for the CHAID model and RMS, respectively. The negative predictive values (NPV) were similar for the CHAID model and RMS. CONCLUSION: The CHAID model and RMS provided a similarly high level of NPV, but the CHAID model gave a better accuracy in the validation set. Both CHAID model and RMS may improve the screening process in phase I trials.

A phase I dose escalation study of AT9283, a small molecule inhibitor of aurora kinases, in patients with advanced solid malignancies.

BACKGROUND: AT9283 is an inhibitor of aurora kinases A and B with antitumor activity in preclinical models. This a First in Human phase I study assessed the safety, tolerability, pharmacokinetic and pharmacodynamic properties and preliminary efficacy of AT9283. PATIENTS AND METHODS: Patients with advanced tumors received AT9283 as a continuous central venous infusion over 3 days in cohorts of three to six patients starting at 1.5 mg/m(2)/day (equivalent to 4.5 mg/m(2)/72 h). The oral bioavailability of AT9283 was assessed in a cohort of seven patients. Pharmacodynamic analysis of biomarkers included phosphorylation of histone H3 on serine 10, proliferating cell nuclear antigen, Ki67, M30 and M65 in skin and plasma. RESULTS: Forty patients were included in all analyses. AT9283 was generally well tolerated with main toxic effects of reversible dose-related myelosuppression, gastrointestinal disturbance, fatigue and alopecia. The dose-limiting toxicity of AT9283 was grade 3 febrile neutropenia in two patients at 36 mg/m(2)/72 h and the maximum tolerated dose (MTD) was established at 27 mg/m(2)/72 h. Systemic exposure was dose proportional. The mean oral bioavailability of a 0.9 mg/m(2) dose was 29.4% (range 11.2%-36.7%). Pharmacodynamic analyses indicated antiproliferative and apoptotic activity of AT9283. Four patients with esophageal, non-small-cell lung cancer (n = 2) and colorectal cancer demonstrated RECIST stable disease ≥ 6 months. CONCLUSION: AT9283 was well tolerated up to the MTD of 27 mg/m(2)/72 h. AT9283 is currently assessed in phase II trials.

Targeting BRAF for patients with melanoma.

The prognosis of patients with metastatic melanoma is poor and not influenced by systemic therapy with cytotoxic drugs. New targeted agents directed against the RAS-RAF-MEK-ERK pathway show promising activity in early clinical development and particular interest is focused on selective inhibitors of mutant BRAF, which is present in one half of the cases of metastatic melanoma. The majority of patients on early trials of these drugs develop secondary resistance and subsequent disease progression and it is, therefore, critical to understand the underlying escape mechanisms leading to resistance.

The insulin-like growth factor-I receptor inhibitor figitumumab (CP-751,871) in combination with docetaxel in patients with advanced solid tumours: results of a phase Ib dose-escalation, open-label study.

BACKGROUND: This phase Ib trial assessed safety, tolerability, and maximum tolerated dose (MTD) of figitumumab (CP-751,871), a fully human monoclonal antibody targeting the insulin-like growth factor type 1 receptor (IGF-IR), in combination with docetaxel. METHODS: Patients with advanced solid tumours were treated with escalating dose levels of figitumumab plus 75 mg m(-2) docetaxel every 21 days. Safety, efficacy, pharmacokinetics (PKs), and biomarker responses were evaluated. RESULTS: In 46 patients, no dose-limiting toxicities were attributable to the treatment combination. Grade 3 and 4 toxicities included neutropaenia (n=28), febrile neutropaenia (n=11), fatigue (n=10), leukopaenia (n=7), diarrhoea (n=5), hyperglycaemia, lymphopaenia, cellulitis, DVT, and pain (all n=1). The MTD was not reached. Four partial responses were observed; 12 patients had disease stabilisation of > or =6 months. Pharmacokinetic and biomarker analyses showed a dose-dependent increase in plasma exposure, and complete sIGF-IR downregulation at doses of >or =3 mg kg(-1). Pharmacokinetics of docetaxel in combination was similar to when given alone. Out of 18 castration-resistant prostate cancer patients, 10 (56%) had > or =5 circulating tumour cells (CTCs) per 7.5 ml of blood at baseline: 6 out of 10 (60%) had a decline from > or =5 to <5 CTCs and 9 out of 10 (90%) had a > or =30% decline in CTCs after therapy. CONCLUSIONS: Figitumumab and docetaxel in combination are well tolerated. Further evaluation is warranted.

Second primary colorectal cancers (SPCRCs): experiences from a large Australian Cancer Registry.

BACKGROUND: We examined the rate of second primary colorectal cancer (SPCRC) in a cohort of 29 471 patients first diagnosed with colorectal cancer (CRC) from 1987 to 1996, in New South Wales (NSW), Australia. METHODS: The 5-year age group, date and site of first and subsequent CRC diagnoses as well as death dates were obtained from the NSW Central Cancer Registry. The time to SPCRC and standardised incidence ratios (SIRs) were generated. RESULTS: Six hundred and sixty patients (2.1%) developed SPCRCs and the cumulative incidence at 18 years was 5.5%, 95% confidence interval (CI) 4.9% to 6.3%. The risk of SPCRC was increased in patients with a CRC history compared with the general population (SIR = 1.5, 95% CI 1.4-1.6) and inversely related to age at first diagnosis (30-49 years, SIR = 5.1, 95% CI 3.6-7.1 versus >/=80 years, SIR = 1.1, 95% CI 0.9-1.4). The excess absolute risk of SPCRC was greater for females aged 50-69 years at first diagnosis than for males in the same age group. SPCRC was also increased in individuals with right-sided first primaries (SIR = 2.0, 95% CI 1.6-2.4). CONCLUSIONS: The SPCRC rate was increased during the first 5 years after first diagnosis but remained increased for up to 10 years in females, in patients with right-sided cancers and in patients <60 years at first diagnosis. These findings support active surveillance up to 10 years in these risk groups.