Multidimensional penalized splines for survival models: illustration for net survival trend analyses.

BACKGROUND: In descriptive epidemiology, there are strong similarities between incidence and survival analyses. Because of the success of multidimensional penalized splines (MPSs) in incidence analysis, we propose in this pedagogical paper to show that MPSs are also very suitable for survival or net survival studies. METHODS: The use of MPSs is illustrated in cancer epidemiology in the context of survival trends studies that require specific statistical modelling. We focus on two examples (cervical and colon cancers) using survival data from the French cancer registries (cases 1990-2015). The dynamic of the excess mortality hazard according to time since diagnosis was modelled using an MPS of time since diagnosis, age at diagnosis and year of diagnosis. Multidimensional splines bring the flexibility necessary to capture any trend patterns while penalization ensures selecting only the complexities necessary to describe the data. RESULTS: For cervical cancer, the dynamic of the excess mortality hazard changed with the year of diagnosis in opposite ways according to age: this led to a net survival that improved in young women and worsened in older women. For colon cancer, regardless of age, excess mortality decreases with the year of diagnosis but this only concerns mortality at the start of follow-up. CONCLUSIONS: MPSs make it possible to describe the dynamic of the mortality hazard and how this dynamic changes with the year of diagnosis, or more generally with any covariates of interest: this gives essential epidemiological insights for interpreting results. We use the R package survPen to do this type of analysis.

Trends in incidence of invasive vaginal cancer in France from 1990 to 2018 and survival of recently diagnosed women - A population-based study.

OBJECTIVE: The aim of this study was to analyze trends in the incidence of vaginal cancer in France over a 28-year period and to present survival for recently-diagnosed women. METHODS: French cancer registries provided data on invasive vaginal cancers diagnosed from 1990 to 2015 and followed up through June 2018. Trends in incidence were analyzed using a Poisson model with a bidimensional penalized spline of age and year at diagnosis. Net survival analysis was restricted to recently-diagnosed cases (2010-2015) and used a novel approach based on a bidimensional penalized spline of age and time-since-diagnosis to model excess mortality hazard. RESULTS: With 162 new cases estimated in France in 2018, vaginal cancer represented 0.9 % of genital cancers in French women. In 2018, the world population age-standardized incidence rate was 0.2 per 100,000 person-years, median age at diagnosis was 75 years. The standardized incidence rate decreased significantly by 3 % per year (95 % CI, -3.8; -2.2) between 1990 and 2018 (0.4 cases per 100,000 person-year in 1990, vs 0.2 in 2018). Age-standardized net survival at 1 and 5 years after diagnosis was respectively 74 % and 45 %. CONCLUSIONS: This study confirms that vaginal cancer is still a rare malignancy in France with 5-year net survival that remains low. We observed a consistent decrease in the incidence rate between 1990 and 2018. It may be too early to attribute these trends to a positive impact of vaccination campaigns against hrHPV infection, since vaginal cancer mainly affects older women and HPV vaccination has only been available since the early 2000s, and only targets young girls.

Diverging incidence trends of oral tongue cancer compared to other head and neck cancers in young adults in France.

While head and neck cancer incidence decreased worldwide due to reduced tobacco and alcohol consumption, oral tongue cancer (OTC) incidence has been reported to be increasing in several countries. Our study examines the incidence trends of OTC in France from 1990 to 2018, globally and by age; and compares the incidence trends with the evolution of the incidence of other human papilloma virus-unrelated head and neck squamous cell carcinoma, that is, cancers of the remaining subsites of the oral cavity (RSOCC) and laryngeal cancers for the period 1990 to 2018. World age-standardized incidence rates of oral tongue cancers (C02), cancers of the remaining subsites of the oral cavity (RSOCC, C03-06) and laryngeal cancers (C32) were estimated using the French National Network of Cancer Registries for the period 1990 to 2018. Trends in national incidence rates were estimated from a mixed-effect Poisson model including age and year effects using penalized splines and a district-random effect. In women aged 30 and 40, a significant increase in OTC incidence was observed, while ROSCC showed a nonsignificant incidence decrease. In young men aged 25, a marginally significant increase of OTC incidence years was observed, while incidence rates of RSOCC significantly declined. The results suggest a tendency towards diverging incidence trends for OTC compared to RSOCC and laryngeal cancer in young adults. The observed trends may reflect changes in underlying exposures or emerging exposures not yet identified, and stress the need to further investigate the etiology of oral tongue cancers.

Multidimensional penalized splines for incidence and mortality-trend analyses and validation of national cancer-incidence estimates.

BACKGROUND: Cancer-incidence and mortality-trend analyses require appropriate statistical modelling. In countries without a nationwide cancer registry, an additional issue is estimating national incidence from local-registry data. The objectives of this study were to (i) promote the use of multidimensional penalized splines (MPS) for trend analyses; (ii) estimate the national cancer-incidence trends, using MPS, from only local-registry data; and (iii) propose a validation process of these estimates. METHODS: We used an MPS model of age and year for trend analyses in France over 1990-2015 with a projection up to 2018. Validation was performed for 22 cancer sites and relied essentially on comparison with reference estimates that used the incidence/health-care ratio over the period 2011-2015. Alternative estimates that used the incidence/mortality ratio were also used to validate the trends. RESULTS: In the validation assessment, the relative differences of the incidence estimates (2011-2015) with the reference estimates were <5% except for testis cancer in men and < 7% except for larynx cancer in women. Trends could be correctly derived since 1990 despite incomplete histories in some registries. The proposed method was applied to estimate the incidence and mortality trends of female lung cancer and prostate cancer in France. CONCLUSIONS: The validation process confirmed the validity of the national French estimates; it may be applied in other countries to help in choosing the most appropriate national estimation method according to country-specific contexts. MPS form a powerful statistical tool for trend analyses; they allow trends to vary smoothly with age and are suitable for modelling simple as well as complex trends thanks to penalization. Detailed trend analyses of lung and prostate cancers illustrated the suitability of MPS and the epidemiological interest of such analyses.

Trends in probabilities of death owing to cancer and owing to other causes in patients with colon cancer.

BACKGROUND: It is of interest to both the clinicians and patients to estimate the probability of death owing to cancer in the presence of other causes as time elapses since diagnosis. The objective of this study was to depict for patients diagnosed with colon cancer between 1990 and 2010 in France, the probability of surviving up to 10 years after diagnosis and to disentangle the probability of death owing to cancer from that of death owing to other causes. PATIENTS AND METHODS: Individuals with cancer were described, up to 10 years after diagnosis, as belonging to one of three categories: those who died owing to a cause related to cancer, those who died owing to another cause and those who survived. Net survival, crude probabilities of death related to colon cancer, death related to another cause and survival were estimated by modeling excess mortality hazard. RESULTS: In women of all ages, 5 and 10-year net survival improved over calendar time. The 10-year probability of survival decreased when age increased in both sexes. It was higher in women than in men, and this difference increased with age. Crude probabilities of death related to colon cancer decreased between 1990 and 2010 for men and women, although this was not observed in the eldest men. CONCLUSION: Crude probability of death related to colon cancer is an important indicator for patients and health policy makers. Results of cancer screening should be faced to trends in probability of death related to colorectal cancer.

Effect of Buparlisib, a Pan-Class I PI3K Inhibitor, in Refractory Follicular and Poorly Differentiated Thyroid Cancer.

BACKGROUND: Dysregulation of the phosphatidylinositol 3-kinase (PI3K) pathway is frequent in advanced follicular (FTC) and poorly differentiated thyroid (PDTC) carcinomas and has been implicated in oncogenesis and tumor progression. This study investigated the efficacy and safety of buparlisib, a pan-PI3K inhibitor in radioiodine refractory FTC and PDTC. METHODS: The primary endpoint of this open-label, multicenter, phase 2 pilot study was progression-free survival (PFS) at 6 months. The sample size was determined considering that a PFS ≤50% at 6 months would denote an absence of benefits (null hypothesis). Secondary endpoints were objective response rate, PFS at 12 months, overall survival at 6 and 12 months, and safety based on the frequency and severity of adverse events (AEs). RESULTS: Forty-three patients (19M/24 F; median age: 67 years) with metastatic, radioiodine refractory, progressive disease received buparlisib, 100 mg, daily. Histology was PDTC in 25 (58%), FTC in 17 (40%), and Hürthle cell carcinoma in 1 (2%). RAS mutation was found in 44% (12/27) and activation of the PI3K pathway in 35% (8/23) of tested tumors. The probability of PFS was 41.7% [95% confidence interval (CI) 7.7-55.5] at 6 months and 20.9% [CI 0-35.7] at 12 months, lower than the 50% expected PFS. At 6 months, 25.6% patients had stable disease, 48.8% were progressive and 25.6% had stopped treatment due to AE. The response to therapy was not influenced by age, sex, histology, or genetic alterations. The overall survivals at 6 and 12 months were 85.9% [CI 76-97] and 78.7 % [CI 67-92], respectively. The mean tumor growth rate decreased from 3.78 mm/month [CI 2.61-4.95] before treatment to 0.8 mm/month [CI -0.2-1.88] during treatment (p < 0.02). Severe grade 3-4 AEs occurred in 27 patients (63%), including hepatitis (25%), hyperglycemia (21%), mood disorders (12%), and skin toxicity (12%), with favorable outcome after temporary or permanent treatment discontinuation or dose reduction. CONCLUSIONS: Buparlisib did not result in significant efficacy in advanced FTC and PDTC. However, the decrease in tumor growth rate may suggest incomplete inhibition of oncogenic pathways and/or escape mechanisms. This should lead to evaluate combined therapy associating inhibitors of both the PI3K and mitogen-activated protein kinase pathways.

Predicting thyroid nodule malignancy at several prevalence values with a combined Bethesda-molecular test.

Investigation of thyroid nodules using fine-needle aspiration cytology (FNAC) gives indeterminate results in up to 30% of samples using the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC). We present a combined Bethesda-molecular predictor of nodule malignancy to improve the accuracy of the preoperative diagnosis of thyroid nodules. To detect a molecular signature of thyroid nodule malignancy, a molecular test was performed on FNACs from 128 thyroid nodules from prospectively included patients, collected in a tertiary center. The test relied on a transcriptomic array of 20 genes selected from a previous study. An optimal set of seven genes was identified using a logistic regression model. Comparison between the combined predictor (TBSRTC + molecular) and TBSRTC alone used the area under the ROC curve (AUC). Performance of the combined predictor was calculated according to various malignancy prevalence values and benefit-to-harm ratios (B/Hr) (favoring sensitivity or specificity). In our population (36% malignancy prevalence) and with a B/Hr of 1, the combined predictor achieved 95% specificity and 76% sensitivity. The AUC was 93.5%; higher than that of TBSRTC (P = 0.004). Among indeterminate nodules (30% malignancy prevalence), sensitivity and specificity were 52.2% and 96.2%, respectively, with a B/Hr of 1, or 95.7% and 64.2% with a B/Hr of 4 (favoring sensitivity), allowing avoidance of 64% of unnecessary surgeries at the cost of only one false-positive result. In conclusion, this predictor could improve the detection of thyroid nodule malignancy, taking into account malignancy prevalence and B/Hr, and reduce the number of unnecessary thyroidectomies.

Risk of Recurrence in Pituitary Neuroendocrine Tumors: A Prospective Study Using a Five-Tiered Classification.

Background: Most pituitary neuroendocrine tumors (PitNETs) show benign behavior, but a substantial number are invasive, recur, or resist medical treatment. Based on a retrospective case-control study, we recently proposed a classification of PitNETs of prognostic relevance. This prospective study aims to test the value of this classification in an independent patient cohort. Methods: All patients who underwent PitNET surgery from 2007 to 2012 in one single center were included. Using a grading system based on invasion on magnetic resonance imaging, immunocytochemical profile, Ki-67, mitotic index, and p53 positivity, tumors were classified. Progression-free survival of the graded tumors was calculated by the Kaplan-Meier method and compared using the log-rank test. A multivariate analysis, using a Cox regression model, was also performed. Results: In total, 365 patients had grade 1a PitNETs (51.2%), followed by grade 2a (32.3%), 2b (8.8%), and 1b tumors (7.7%). Of 213 patients with a follow-up, 42% had recurrent (n = 52) or progressive disease (n = 37) at 3.5 years. Grade was a significant predictor of progression-free survival (P < 0.001). Multivariate analysis indicated grade (P < 0.001), age (P = 0.035), and tumor type (P = 0.028) as independent predictors of recurrence and/progression. This risk was 3.72-fold higher for a grade 2b tumor compared with grade 1a tumor. Conclusions: Our data suggest that classification of PitNETs into five grades is of prognostic value to predict postoperative tumor behavior and identifies patients who have a high risk of early recurrence or progression. It therefore will allow clinicians to adapt their therapeutic strategies and stratify patients in future clinical trials.

Oversizing the tibial component in TKAs: incidence, consequences and risk factors.

PURPOSE: The incidence of anteroposterior overhang of the tibial component after TKA and its effect on clinical outcome were investigated, and the morphometric characteristics of the knees in which tibial baseplates were oversized were identified. METHOD: One hundred and fourteen consecutive TKAs were retrospectively assessed. The dimensions of the tibia were measured on a pre-operative CT scan and were compared with those of the implanted tibial component. We analysed the effect of anteroposterior and mediolateral size variations on clinical outcomes 1 year after surgery. RESULTS: An anteroposterior overhang was observed in 87 % of cases on the lateral plateau, in 88 % on the central plateau and in 25 % on the medial tibial plateau. The mean post-pre-operative size differences were 3.2 ± 2.7, 2.8 ± 2.7 and -1.6 ± 2.3 mm, respectively. (Positive value means oversizing). A mediolateral overhang of the tibial component was found in 61 % of the patients. Oversizing was significantly greater and more frequent in females. Patients oversized in the anteroposterior dimension had lower post-operative pain scores. Patients with mediolateral oversizing had decreased flexion 1 year after surgery. Anteroposterior oversizing was observed more frequently in patients with asymmetric tibial plateaus, while mediolateral oversizing was observed more frequently in patients with small tibias. CONCLUSIONS: This study demonstrates that the incidence of oversized tibial plateau components is surprisingly high and that functional outcomes are lower in the case of mediolateral or anteroposterior oversizing. The risk of oversizing could be predicted as it occurs predominantly in patients with asymmetric proximal tibia and/or small tibia. LEVEL OF EVIDENCE: IV.

A new prognostic clinicopathological classification of pituitary adenomas: a multicentric case-control study of 410 patients with 8 years post-operative follow-up.

Pituitary adenomas are currently classified by histological, immunocytochemical and numerous ultrastructural characteristics lacking unequivocal prognostic correlations. We investigated the prognostic value of a new clinicopathological classification with grades based on invasion and proliferation. This retrospective multicentric case-control study comprised 410 patients who had surgery for a pituitary tumour with long-term follow-up. Using pituitary magnetic resonance imaging for diagnosis of cavernous or sphenoid sinus invasion, immunocytochemistry, markers of the cell cycle (Ki-67, mitoses) and p53, tumours were classified according to size (micro, macro and giant), type (PRL, GH, FSH/LH, ACTH and TSH) and grade (grade 1a: non-invasive, 1b: non-invasive and proliferative, 2a: invasive, 2b: invasive and proliferative, and 3: metastatic). The association between patient status at 8-year follow-up and age, sex, and classification was evaluated by two multivariate analyses assessing disease- or recurrence/progression-free status. At 8 years after surgery, 195 patients were disease-free (controls) and 215 patients were not (cases). In 125 of the cases the tumours had recurred or progressed. Analyses of disease-free and recurrence/progression-free status revealed the significant prognostic value (p < 0.001; p < 0.05) of age, tumour type, and grade across all tumour types and for each tumour type. Invasive and proliferative tumours (grade 2b) had a poor prognosis with an increased probability of tumour persistence or progression of 25- or 12-fold, respectively, as compared to non-invasive tumours (grade 1a). This new, easy to use clinicopathological classification of pituitary endocrine tumours has demonstrated its prognostic worth by strongly predicting the probability of post-operative complete remission or tumour progression and so could help clinicians choose the best post-operative therapy.

Mediolateral oversizing influences pain, function, and flexion after TKA.

PURPOSE: Manufacturers of total knee arthroplasty (TKA) have introduced narrower femurs to improve bone-implant fit. However, few studies have reported the clinical consequences of mediolateral oversizing. Our hypothesis was that component oversizing negatively influences the results after TKA. METHODS: One hundred and twelve prospectively followed patients with 114 consecutive TKA (64 females and 50 males) were retrospectively assessed. The mean age of the patients was 72 years (range, 56 to 85 years). The dimensions of the femur and tibia were measured on a preoperative CT-scan and were compared with those of the implanted TKA. The influence of size variation on the clinical outcomes 1 year after surgery was assessed. RESULTS: Mediolateral overhang was observed in at least one area in 66 % of the femurs (84 % in females and 54 % in males) and 61 % of the tibia (81 % in females and 40 % in males). Twenty-two patients presented no overhang in any area and 16 had overhang in all studied zones. The increase in the Pain and KOOS scores were 43 ± 21 and 36 ± 18 in the patients without overhang and 31 ± 19 and 25 ± 13 in patients with overhang (p = 0.033; p = 0.032). Knee flexion was 127° ± 7 and 121° ± 11, respectively. Regression and latent class analysis showed a significant negative correlation between overall oversizing and overall outcome. CONCLUSIONS: This study confirms that oversizing may lead to worse clinical results in TKA. The clinical consequences are that surgeons should pay attention not to oversize implants during implantation nd that oversizing should be ruled out in case of so called unexplained pain. LEVEL OF EVIDENCE: IV.

Prostate cancer ablation with transrectal high-intensity focused ultrasound: assessment of tissue destruction with contrast-enhanced US.

PURPOSE: To assess contrast material-enhanced ultrasonographic (US) findings seen after high-intensity focused ultrasound (HIFU) ablation of prostate cancer and correlate the US findings with post-HIFU biopsy findings. MATERIALS AND METHODS: The study was ethics committee approved. Written informed consent was obtained from all patients. Twenty-eight patients referred for HIFU prostate cancer ablation underwent contrast-enhanced prostate US before treatment, gadolinium-enhanced magnetic resonance (MR) imaging and repeat contrast-enhanced US 1-3 days after treatment, and contrast-enhanced US-guided biopsy 30-45 days after treatment. The contrast-enhanced US enhancement patterns of the biopsy sites--assigned a score of S0 for no enhancement, S1 for mild and/or patchy enhancement, or S2 for marked enhancement--were compared with corresponding biopsy findings, which were assigned a score of B0 for necrosis and/or fibrosis without viable prostate gland tissue, B1 for vascularized tissue without viable gland tissue, or B2 for viable gland tissue (benign or malignant). Then, six additional patients underwent contrast-enhanced prostate US 15-30 minutes and 1 day after HIFU ablation, and the results of these two US examinations were compared. RESULTS: Contrast-enhanced US performed on days 1-3 and days 30-45 after HIFU ablation depicted a large devascularized zone with peripheral enhancing areas that were localized anteriorly in all 28 patients, posteriorly in nine, laterally in five, and at the apex in 20 patients. MR findings were concordant. At biopsy, viable gland tissue was found at nine (6.2%) of 146 S0 sites, 10 (34%) of 29 S1 sites, and 44 (60%) of 73 S2 sites. The odds ratios for finding viable tissue (score B1 or B2) at S1 and S2 sites as opposed to S0 sites were 21 (95% confidence interval [CI]: 6, 71) and 73 (95% CI: 22, 243), respectively (P < .0001). Contrast-enhanced US performed 15-30 minutes and 1 day after treatment in the six additional patients had similar findings. CONCLUSION: Contrast-enhanced US is a promising tool for distinguishing between ablated (devascularized) and viable (enhancing) tissue immediately after HIFU treatment.

Prognostic factors in prolactin pituitary tumors: clinical, histological, and molecular data from a series of 94 patients with a long postoperative follow-up.

CONTEXT AND OBJECTIVE: Predicting pituitary tumor behavior remains a challenge. This multiparameter investigation aimed to identify markers for recurrence and progression in prolactin tumors. DESIGN: From a cohort of patients treated for prolactin tumors by surgery, we retrospectively studied clinical data, tumor characteristics, clinical outcome, and the expression of nine genes by quantitative RT-PCR. RESULTS: This study included 94 patients (62 females and 32 men), with long postoperative follow-up periods (mean, 138 +/- 46 months); 54.3% of patients had a macro or giant adenoma. Tumors were classified into three pathological groups based on their radiological and histological characteristics (noninvasive, 61; invasive, 22; and aggressive-invasive, 11). Immediately after surgery, 60 patients (63.8%) went into remission (prolactin level normalization). Persistently elevated prolactin levels (36.2%) were associated with increasing age, male sex, high preoperative prolactin levels, large tumor size on univariate analysis, and invasion and pathological classification on univariate and multivariate (P = 8 x 10(-10) and 3 x 10(-8)) analysis. During follow-up, 19 patients (20%) had tumors that recurred or progressed under dopamine agonist treatment. Invasion and pathological classification were associated with recurrence or progression on univariate analysis. Seven genes (ADAMTS6, CRMP1, PTTG, ASK, CCNB1, AURKB, and CENPE) were associated with tumor recurrence or progression and five of these (ADAMTS6, CRMP1, ASK, CCNB1, and CENPE) were associated with the pathological classification. CONCLUSION: This study identifies both the clinical and histological factors that relate to prolactin tumor recurrence or progression. Molecular markers give additional information for prognosis of such tumors. Altogether, our results could influence the management of patients with pituitary tumors.