A new cure model that corrects for increased risk of non-cancer death: analysis of reliability and robustness, and application to real-life data.

BACKGROUND: Non-cancer mortality in cancer patients may be higher than overall mortality in the general population due to a combination of factors, such as long-term adverse effects of treatments, and genetic, environmental or lifestyle-related factors. If so, conventional indicators may underestimate net survival and cure fraction. Our aim was to propose and evaluate a mixture cure survival model that takes into account the increased risk of non-cancer death for cancer patients. METHODS: We assessed the performance of a corrected mixture cure survival model derived from a conventional mixture cure model to estimate the cure fraction, the survival of uncured patients, and the increased risk of non-cancer death in two settings of net survival estimation, grouped life-table data and individual patients' data. We measured the model's performance in terms of bias, standard deviation of the estimates and coverage rate, using an extensive simulation study. This study included reliability assessments through violation of some of the model's assumptions. We also applied the models to colon cancer data from the FRANCIM network. RESULTS: When the assumptions were satisfied, the corrected cure model provided unbiased estimates of parameters expressing the increased risk of non-cancer death, the cure fraction, and net survival in uncured patients. No major difference was found when the model was applied to individual or grouped data. The absolute bias was < 1% for all parameters, while coverage ranged from 89 to 97%. When some of the assumptions were violated, parameter estimates appeared more robust when obtained from grouped than from individual data. As expected, the uncorrected cure model performed poorly and underestimated net survival and cure fractions in the simulation study. When applied to colon cancer real-life data, cure fractions estimated using the proposed model were higher than those in the conventional model, e.g. 5% higher in males at age 60 (57% vs. 52%). CONCLUSIONS: The present analysis supports the use of the corrected mixture cure model, with the inclusion of increased risk of non-cancer death for cancer patients to provide better estimates of indicators based on cancer survival. These are important to public health decision-making; they improve patients' awareness and facilitate their return to normal life.

Carcinoembryonic antigen kinetics predict response to first-line treatment in metastatic colorectal cancer: Analysis from PRODIGE 9 trial.

BACKGROUND: To examine the relationship between carcinoembryonic antigen (CEA) kinetics and prognosis in metastatic colorectal cancer (mCRC) patients receiving first-line chemotherapy in the PRODIGE9 trial. METHODS: Associations between monthly CEA measurements within 6 months since baseline and progression-free survival (PFS) were evaluated using a joint-latent class-mixed model. A validation set was used to test our prognosis model. Correlations between CEA trajectories (classes) and baseline characteristics were also investigated. RESULTS: Three classes were identified. Class 1 had low baseline CEA with small variations. Class 2 had high baseline CEA with a rapid decrease reaching the same CEA level at 6 months as in class 1. Class 3 had high baseline CEA with a transient decrease followed by an increase to reach, at 6 months, the same CEA level as at baseline. Six-month PFS was significantly lower in class 3 than in classes 1 and 2 (57% vs. 91% and 93% respectively; p<0.01). Class 3 was significantly associated with ECOG 2 status, a high LDH level and non-resected primary tumor. DISCUSSION: Variations in CEA kinetics correlate with prognosis in patients receiving first-line chemotherapy for mCRC. We propose here a user-friendly application to classify CEA trajectory.

Impact of G-CSF Prophylaxis on Chemotherapy Dose-Intensity, Link Between Dose-Intensity and Survival in Patients with Metastatic Pancreatic Adenocarcinoma.

BACKGROUND: In metastatic pancreatic adenocarcinoma, few data are available on the use of granulocyte-colony stimulating factor (G-CSF) prophylaxis and its impact on dose-intensity (DI), or the link between DI and progression-free survival (PFS). This study assessed the impact of G-CSF prophylaxis on the DI received by patients and the relationship between full DI and PFS according to chemotherapy regimens. PATIENTS AND METHODS: Patients from three first-line randomized phase II clinical trials were included in this retrospective cohort. G-CSF prophylaxis groups were identified and balanced according to baseline characteristics using a propensity score. Patients were classified into 2 treatment groups (FOLFIRINOX vs FOLFIRI/nab-paclitaxel (NAB)). DI was a binary variable (full/reduced). Adverse events were defined using NCI-CTCAE v4.0. RESULTS: Of the 498 patients, 154 (31%) were in "prophylaxis" group; 179 (36%) were treated by FOLFIRINOX and 319 (64%) by FOLFIRI/NAB. In FOLFIRINOX group, G-CSF prophylaxis was significantly associated with a higher rate of full DI (OR, 5.07; 95% CI, 1.52-16.90; P < .01) while in FOLFIRI/NAB group, it was significantly associated with a lower rate of full DI (OR, 0.23; 95% CI, 0.06-0.83; P = .03). Full DI was associated with a non-significant increase in PFS (FOLFIRINOX group: HR 0.83; 95% CI, 0.59-1.16; P = .27; FOLFIRI/NAB group: HR 0.84; 95% CI, 0.63-1.11; P = .22). CONCLUSION: Granulocyte-colony stimulating factor prophylaxis was associated with a higher rate of full DI with FOLFIRINOX. Full DI was associated with a non-significant increase in PFS. These results need to be confirmed prospectively.

Neoadjuvant treatment for borderline resectable pancreatic adenocarcinoma is associated with higher R0 rate compared to upfront surgery.

BACKGROUND: Neoadjuvant treatment (NAT) is debated for borderline resectable pancreatic cancer (BRPC). This retrospective study assessed the impact of NAT on R0 rate and survival for BRPC patients in comparison with upfront surgery (US). MATERIAL AND METHODS: Between 2010 and 2017 patient records for all consecutive patients treated for BRPC according to NCCN 2017 were reviewed. The endpoints analysed were R0 rate, recurrence-free-survival (RFS) and overall survival (OS). RESULTS: Seventy-nine patients were included: 63 (79.7%) patients received NAT and 16 (20.3%) were upfront operated. NAT consisted in FOLFIRINOX (median cycles: 5, range 4-8) followed by chemoradiation (n = 55, 87.3%, median dose: 54 Gy). Thirty-nine (61.9%) patients had resection. R0 rate was higher in the NAT group considering a margin clearance of 0 mm (94.9%) or 1 mm (89.7%) compared to the US group (68.8% and 43.8% respectively). In the whole population, median RFS was 12.6 [95%CI: 10.5-22.1] in the NAT group vs 7.7 [95%CI: 4.4-14] months in the US group (p < 0.01). Median OS was 29.0 [95%CI: 23.5-63.1] and 27.2 [95%CI: 11.6-38.8] months in the NAT and US groups respectively (p = 0.06). In operated patients the NAT group achieved better RFS and OS than the US group (p < 0.01 for both). In multivariate analysis NAT, surgical resection and age <65 (p < 0.01 for both) were prognostic of RFS. NAT, surgical resection and adjuvant chemotherapy were prognostic of OS (p < 0.05 for all). In operated patients (n = 55) multivariate analysis showed that N1 status was associated with decreased RFS; age < 65 and NAT were associated with a longer RFS. Receiving a NAT, an adjuvant chemotherapy and achieving a ypT0-1N0 status were associated with better OS. NAT was well tolerated with 14.3% grade ≥ 3 toxicities. CONCLUSION: NAT permitted a high R0 rate with a 0- or 1-mm clearance margin and was associated with better RFS and OS for patients with BRPC.

Predictive factors of severe early treatment-related toxicity in patients receiving first-line treatment for metastatic colorectal cancer: Pooled analysis of 2190 patients enrolled in Fédération Francophone de Cancérologie Digestive (FFCD) trials.

AIM: Few studies have explored the association between baseline characteristics and the occurrence of early toxicities in patients treated with first-line chemotherapy for metastatic colorectal cancer (mCRC). PATIENTS AND METHODS: Individual patient data of 2190 patients enrolled in 10 prospective FFCD (Fédération Francophone de Cancérologie Digestive) trials were analysed. Severe early toxicity was defined as the occurrence of grade ≥III toxicity within 3 months after initiation of chemotherapy (ET3). RESULTS: Patients received monotherapy based on 5-FU (n = 1068), a cytotoxic doublet (n = 395) or tritherapy with a cytotoxic doublet plus anti-VEGF agent or a cytotoxic triplet (n = 727). The patients received 5-FU (100%), Irinotecan (39.6%), Oxaliplatin (13.4%), Bevacizumab (29.6%) or Aflibercept (1.8%). ET3 occurred in 244 patients (22.8%) with monotherapy, 248 patients (62.8%) with doublet and 392 patients (53.9%) with tritherapy. The most frequent ET3s were related to biological abnormalities and/or gastrointestinal, general and vascular disorders. The prognostic factors for the occurrence of an ET3 in multivariate analysis were a performance status of 2 rather than 0-1 (OR 2.57; 95% CI [1.16, 5.73]; p = 0.02), tritherapy versus monotherapy (OR 2.31; 95% CI [0.84, 6.33]; p = 0.02), alkaline phosphatase > 300 UI/l (OR 3.07; 95% CI [1.79, 5.27]; p < 0.001) and non-resected primary tumour versus resection (OR 1.59; 95% CI [1.06, 2.39]; p = 0.02). Median overall survival in patients without ET3 was significantly longer than that in patients with ET3 (HR 0.87; 95% CI [0.80-0.96]; p = 0.004). CONCLUSION: ET3 is frequent whatever the treatment regimen and is associated with certain baseline characteristics. The clinical impact of ET3 on prognosis in mCRC warrants further investigation.

Flexible Modeling of Net Survival and Cure by AML Subtype and Age: A French Population-Based Study from FRANCIM.

With improvements in acute myeloid leukemia (AML) diagnosis and treatment, more patients are surviving for longer periods. A French population of 9453 AML patients aged ≥15 years diagnosed from 1995 to 2015 was studied to quantify the proportion cured (P), time to cure (TTC) and median survival of patients who are not cured (MedS). Net survival (NS) was estimated using a flexible model adjusted for age and sex in sixteen AML subtypes. When cure assumption was acceptable, the flexible cure model was used to estimate P, TTC and MedS for the uncured patients. The 5-year NS varied from 68% to 9% in men and from 77% to 11% in women in acute promyelocytic leukemia (AML-APL) and in therapy-related AML (t-AML), respectively. Major age-differenced survival was observed for patients with a diagnosis of AML with recurrent cytogenetic abnormalities. A poorer survival in younger patients was found in t-AML and AML with minimal differentiation. An atypical survival profile was found for acute myelomonocytic leukemia and AML without maturation in both sexes and for AML not otherwise specified (only for men) according to age, with a better prognosis for middle-aged compared to younger patients. Sex disparity regarding survival was observed in younger patients with t-AML diagnosed at 25 years of age (+28% at 5 years in men compared to women) and in AML with minimal differentiation (+23% at 5 years in women compared to men). All AML subtypes included an age group for which the assumption of cure was acceptable, although P varied from 90% in younger women with AML-APL to 3% in older men with acute monoblastic and monocytic leukemia. Increased P was associated with shorter TTC. A sizeable proportion of AML patients do not achieve cure, and MedS for these did not exceed 23 months. We identify AML subsets where cure assumption is negative, thus pointing to priority areas for future research efforts.

Impact of time-varying cumulative bevacizumab exposures on survival: re-analysis of data from randomized clinical trial in patients with metastatic colo-rectal cancer.

BACKGROUND: As cancer treatment, biotherapies can be as effective as chemotherapy while reducing the risk of secondary effects, so that they can be taken over longer periods than conventional chemotherapy. Thus, some trials aimed at assessing the benefit of maintaining biotherapies during chemotherapy-free intervals (CFI). For example, the recent PRODIGE9 trial assessed the effect of maintaining bevacizumab during CFI in metastatic colorectal cancer (mCRC) patients. However, its analysis was hindered by a small difference of exposure to the treatment between the randomized groups and by a large proportion of early drop outs, leading to a potentially unbalanced distribution of confounding factors among the trial completers. To address these limitations, we re-analyzed the PRODIGE9 data to assess the effects of different exposure metrics on all-cause mortality of patients with mCRC using methods originally developed for observational studies. METHODS: To account for the actual patterns of drug use by individual patients and for possible cumulative effects, we used five alternative time-varying exposure metrics: (i) cumulative dose, (ii) quantiles of the cumulative dose, (iii) standardized cumulative dose, (iv) Theoretical Blood Concentration (TBC), and (v) Weighted Cumulative Exposure (WCE). The last two metrics account for the timing of drug use. Treatment effects were estimated using adjusted Hazard Ratio from multivariable Cox proportional hazards models. RESULTS: After excluding 112 patients who died during the induction period, we analyzed data on 382 patients, among whom 320 (83.8%) died. All time-varying exposures improved substantially the model's fit to data, relative to using only the time-invariant randomization group. All exposures indicated a protective effect for higher cumulative bevacizumab doses. The best-fitting WCE and TBC models accounted for both the cumulative effects and the different impact of doses taken at different times. CONCLUSIONS: All time-varying analyses, regardless of the exposure metric used, consistently suggested protective effects of higher cumulative bevacizumab doses. However, the results may partly reflect the presence of a confusion bias. Complementing the main ITT analysis of maintenance trials with an analysis of potential cumulative effects of treatment actually taken can provide new insights, but the results must be interpreted with caution because they do not benefit from the randomization. TRIAL REGISTRATION: clinicaltrials.gov, NCT00952029 . Registered 8 August 2009.

Modeling excess hazard with time-to-cure as a parameter.

Cure models have been widely developed to estimate the cure fraction when some subjects never experience the event of interest. However, these models were rarely focused on the estimation of the time-to-cure, that is, the delay elapsed between the diagnosis and "the time from which cure is reached," an important indicator, for instance, to address the question of access to insurance or loans for subjects with personal history of cancer. We propose a new excess hazard regression model that includes the time-to-cure as a covariate-dependent parameter to be estimated. The model is written similarly to a Beta probability distribution function and is shown to be a particular case of the non-mixture cure models. Parameters are estimated through a maximum likelihood approach and simulation studies demonstrate good performance of the model. Illustrative applications to three cancer data sets are provided and some limitations as well as possible extensions of the model are discussed. The proposed model offers a simple and comprehensive way to estimate more accurately the time-to-cure.

Cancer cure for 32 cancer types: results from the EUROCARE-5 study.

BACKGROUND: Few studies have estimated the probability of being cured for cancer patients. This study aims to estimate population-based indicators of cancer cure in Europe by type, sex, age and period. METHODS: 7.2 million cancer patients (42 population-based cancer registries in 17 European countries) diagnosed at ages 15-74 years in 1990-2007 with follow-up to 2008 were selected from the EUROCARE-5 dataset. Mixture-cure models were used to estimate: (i) life expectancy of fatal cases (LEF); (ii) cure fraction (CF) as proportion of patients with same death rates as the general population; (iii) time to cure (TTC) as time to reach 5-year conditional relative survival (CRS) >95%. RESULTS: LEF ranged from 10 years for chronic lymphocytic leukaemia patients to <6 months for those with liver, pancreas, brain, gallbladder and lung cancers. It was 7.7 years for patients with prostate cancer at age 65-74 years and >5 years for women with breast cancer. The CF was 94% for testis, 87% for thyroid cancer in women and 70% in men, 86% for skin melanoma in women and 76% in men, 66% for breast, 63% for prostate and <10% for liver, lung and pancreatic cancers. TTC was <5 years for testis and thyroid cancer patients diagnosed below age 55 years, and <10 years for stomach, colorectal, corpus uteri and melanoma patients of all ages. For breast and prostate cancers, a small excess (CRS < 95%) remained for at least 15 years. CONCLUSIONS: Estimates from this analysis should help to reduce unneeded medicalization and costs. They represent an opportunity to improve patients' quality of life.