Cox proportional hazards regression in small studies of predictive biomarkers.

Predictive biomarkers are essential for personalized medicine since they select the best treatment for a specific patient. However, of all biomarkers that are evaluated, only few are eventually used in clinical practice. Many promising biomarkers may be erroneously abandoned because they are investigated in small studies using standard statistical techniques which can cause small sample bias or lack of power. The standard technique for failure time endpoints is Cox proportional hazards regression with a multiplicative interaction term between binary variables of biomarker and treatment. Properties of this model in small studies have not been evaluated so far, therefore we performed a simulation study to understand its small sample behavior. As a remedy, we applied a Firth correction to the score function of the Cox model and obtained confidence intervals (CI) using a profile likelihood (PL) approach. These methods are generally recommended for small studies of different design. Our results show that a Cox model estimates the biomarker-treatment interaction term and the treatment effect in one of the biomarker subgroups with bias, and overestimates their standard errors. Bias is however reduced and power is increased with Firth correction and PL CIs. Hence, the modified Cox model and PL CI should be used instead of a standard Cox model with Wald based CI in small studies of predictive biomarkers.

Prognostic value of histopathologic traits independent of stromal tumor-infiltrating lymphocyte levels in chemotherapy-naïve patients with triple-negative breast cancer.

BACKGROUND: In the absence of prognostic biomarkers, most patients with early-stage triple-negative breast cancer (eTNBC) are treated with combination chemotherapy. The identification of biomarkers to select patients for whom treatment de-escalation or escalation could be considered remains an unmet need. We evaluated the prognostic value of histopathologic traits in a unique cohort of young, (neo)adjuvant chemotherapy-naïve patients with early-stage (stage I or II), node-negative TNBC and long-term follow-up, in relation to stromal tumor-infiltrating lymphocytes (sTILs) for which the prognostic value was recently reported. MATERIALS AND METHODS: We studied all 485 patients with node-negative eTNBC from the population-based PARADIGM cohort which selected women aged <40 years diagnosed between 1989 and 2000. None of the patients had received (neo)adjuvant chemotherapy according to standard practice at the time. Associations between histopathologic traits and breast cancer-specific survival (BCSS) were analyzed with Cox proportional hazard models. RESULTS: With a median follow-up of 20.0 years, an independent prognostic value for BCSS was observed for lymphovascular invasion (LVI) [adjusted (adj.) hazard ratio (HR) 2.35, 95% confidence interval (CI) 1.49-3.69], fibrotic focus (adj. HR 1.61, 95% CI 1.09-2.37) and sTILs (per 10% increment adj. HR 0.75, 95% CI 0.69-0.82). In the sTILs <30% subgroup, the presence of LVI resulted in a higher cumulative incidence of breast cancer death (at 20 years, 58%; 95% CI 41% to 72%) compared with when LVI was absent (at 20 years, 32%; 95% CI 26% to 39%). In the ≥75% sTILs subgroup, the presence of LVI might be associated with poor survival (HR 11.45, 95% CI 0.71-182.36, two deaths). We confirm the lack of prognostic value of androgen receptor expression and human epidermal growth factor receptor 2 -low status. CONCLUSIONS: sTILs, LVI and fibrotic focus provide independent prognostic information in young women with node-negative eTNBC. Our results are of importance for the selection of patients for de-escalation and escalation trials.

Finite-Sample Bias of the Linear Excess Relative Risk in Cohort Studies of Computed Tomography-Related Radiation Exposure and Cancer.

The linear excess relative risk (ERR) is the most commonly reported measure of association in radiation epidemiological studies, when individual dose estimates are available. While the asymptotic properties of the ERR estimator are well understood, there is evidence of small sample bias in case-control studies of treatment-related radiation exposure and second cancer risk. Cohort studies of cancer risk after exposure to low doses of radiation from diagnostic procedures, e.g., computed tomography (CT) examinations, typically have small numbers of cases and risks are small. Therefore, understanding the properties of the estimated ERR is essential for interpretation and analysis of such studies. We present results of a simulation study that evaluates the finite-sample bias of the ERR estimated by time-to-event analyses and its confidence interval using simulated data, resembling a retrospective cohort study of radiation-related leukemia risk after CT examinations in childhood and adolescence. Furthermore, we evaluate how the Firth-corrected estimator reduces the finite-sample bias of the classical estimator. We show that the ERR is overestimated by about 30% for a cohort of about 150,000 individuals, with 42 leukemia cases observed on average. The bias is reduced for higher baseline incidence rates and for higher values of the true ERR. As the number of cases increases, the ERR is approximately unbiased. The Firth correction reduces the bias for all cohort sizes to generally around or under 5%. Epidemiological studies showing an association between radiation exposure from pediatric CT and cancer risk, unless very large, may overestimate the magnitude of the relationship, while there is no evidence of an increased chance for false-positive results. Conducting large studies, perhaps by pooling individual studies to increase the number of cases, should be a priority. If this is not possible, Firth correction should be applied to reduce small-sample bias.

A scoping review of statistical methods in studies of biomarker-related treatment heterogeneity for breast cancer.

BACKGROUND: Many scientific papers are published each year and substantial resources are spent to develop biomarker-based tests for precision oncology. However, only a handful of tests is currently used in daily clinical practice, since development is challenging. In this situation, the application of adequate statistical methods is essential, but little is known about the scope of methods used. METHODS: A PubMed search identified clinical studies among women with breast cancer comparing at least two different treatment groups, one of which chemotherapy or endocrine treatment, by levels of at least one biomarker. Studies presenting original data published in 2019 in one of 15 selected journals were eligible for this review. Clinical and statistical characteristics were extracted by three reviewers and a selection of characteristics for each study was reported. RESULTS: Of 164 studies identified by the query, 31 were eligible. Over 70 different biomarkers were evaluated. Twenty-two studies (71%) evaluated multiplicative interaction between treatment and biomarker. Twenty-eight studies (90%) evaluated either the treatment effect in biomarker subgroups or the biomarker effect in treatment subgroups. Eight studies (26%) reported results for one predictive biomarker analysis, while the majority performed multiple evaluations, either for several biomarkers, outcomes and/or subpopulations. Twenty-one studies (68%) claimed to have found significant differences in treatment effects by biomarker level. Fourteen studies (45%) mentioned that the study was not designed to evaluate treatment effect heterogeneity. CONCLUSIONS: Most studies evaluated treatment heterogeneity via separate analyses of biomarker-specific treatment effects and/or multiplicative interaction analysis. There is a need for the application of more efficient statistical methods to evaluate treatment heterogeneity in clinical studies.

Bioenergy therapies as a complementary treatment: a systematic review to evaluate the efficacy of bioenergy therapies in relieving treatment toxicities in patients with cancer.

PURPOSE: Bioenergy therapies are among the popular alternative treatment options for many diseases, including cancer. Many studies deal with the advantages and disadvantages of bioenergy therapies as an addition to established treatments such as chemotherapy, surgery, and radiation in the treatment of cancer. However, a systematic overview of this evidence is thus far lacking. For this reason, the available evidence should be reviewed and critically examined to determine what benefits the treatments have for patients. METHODS: In June 2022, a systematic search was conducted searching five electronic databases (Embase, Cochrane, PsychInfo, CINAHL and Medline) to find studies concerning the use, effectiveness and potential harm of bioenergy therapies including Reiki, Therapeutic Touch, Healing Touch and Polarity Therapy on cancer patients. RESULTS: From all 2477 search results, 21 publications with 1375 patients were included in this systematic review. The patients treated with bioenergy therapies were mainly diagnosed with breast cancer. The main outcomes measured were anxiety, depression, mood, fatigue, quality of life (QoL), comfort, well-being, neurotoxicity, pain, and nausea. The studies were predominantly of moderate quality and for the most part found no effect. In terms of QoL, pain and nausea, there were improved short-term effects of the interventions, but no long-term differences were detectable. The risk of side effects from bioenergy therapies appears to be relatively small. CONCLUSION: Considering the methodical limitations of the included studies, studies with high study quality could not find any difference between bioenergy therapies and active (placebo, massage, RRT, yoga, meditation, relaxation training, companionship, friendly visit) and passive control groups (usual care, resting, education). Only studies with a low study quality were able to show significant effects.

Long-term effects of childhood cancer treatment on hormonal and ultrasound markers of ovarian reserve.

STUDY QUESTION: Which treatment-related factors are (dose-dependently) associated with abnormal hormonal and ultrasound markers of ovarian reserve in female childhood cancer survivors (CCSs)? SUMMARY ANSWER: Cyclophosphamide, procarbazine, a composite group of 'other alkylating agents', dactinomycin, doxorubicin, mitoxantrone, spinal radiotherapy (RT), abdominal/pelvic RT and total body irradiation were multivariably associated with abnormal ovarian reserve markers, with dose-effect relationships being established for procarbazine and abdominal/pelvic RT. WHAT IS KNOWN ALREADY: Female childhood cancer survivors are at an increased risk of reduced ovarian function and reserve, but knowledge regarding the long-term effects of individual chemotherapeutic (CT) agents and radiotherapy fields and their respective doses is limited. STUDY DESIGN, SIZE, DURATION: The DCOG LATER-VEVO is a nationwide retrospective cohort study in which measurements were performed between 2008 and 2014. In total, 1749 female 5-year CCSs, diagnosed before age 18 years between 1963 and 2002 and 1201 controls were invited for the study. PARTICIPANTS/MATERIALS, SETTING, METHODS: Ovarian reserve was assessed by anti-Müllerian hormone (AMH), follicle stimulating hormone (FSH), inhibin B levels, and antral follicle counts (AFC). The study was a multicentre study including all seven Dutch Centers for Paediatric Oncology/Haematology. MAIN RESULTS AND THE ROLE OF CHANCE: In total, 564 CCs and 390 controls participated in the clinical part of the study. Overall, 7.0-17.7% of CCSs and 2.4-13.6% of controls had abnormal ovarian reserve markers. Above age 35, significantly more CCSs than controls had abnormal ovarian reserve markers (AMH: 26% vs. 4%; AFC: 20% vs. 3%; inhibin B: 42% vs. 16%). For AMH and FSH, significant differences were also found below age 35. Cyclophosphamide, procarbazine, a group of 'other alkylating agents', dactinomycin, doxorubicin, mitoxantrone, spinal RT, abdominal/pelvic RT and total body irradiation were multivariably associated with at least one abnormal ovarian reserve marker. Dose-effect relationships were established for procarbazine and abdominal/pelvic RT. LIMITATIONS, REASONS FOR CAUTION: Despite the large scale of the study, dose-effect relationships could not be investigated for all types of treatment due to a limited numbers of participants for specific analyses. WIDER IMPLICATIONS OF THE FINDINGS: This study demonstrated that the majority of CCSs do not show signs of a reduced ovarian reserve. However, specific subgroups of CCSs appear to be associated with a high risk. Our results are important for counselling CCSs and future patients regarding parenthood and fertility preservation. STUDY FUNDING/COMPETING INTERESTS: This study was funded by the Dutch Cancer Society (Grant no. VU 2006-3622) and by the Children Cancer Free Foundation (Project no. 20). Philips Health Systems Benelux supported this study by providing three ultrasound systems and concomitant analytic software. There are no competing interests. TRIAL REGISTRATION NUMBER: NTR2922 http://www.trialregister.nl/trialreg/admin/rctview.asp?TC = 2922.

Perspectives for personalized therapy for patients with multidrug-resistant tuberculosis.

According to the World Health Organization (WHO), tuberculosis is the leading cause of death attributed to a single microbial pathogen worldwide. In addition to the large number of patients affected by tuberculosis, the emergence of Mycobacterium tuberculosis drug-resistance is complicating tuberculosis control in many high-burden countries. During the past 5 years, the global number of patients identified with multidrug-resistant tuberculosis (MDR-TB), defined as bacillary resistance at least against rifampicin and isoniazid, the two most active drugs in a treatment regimen, has increased by more than 20% annually. Today we experience a historical peak in the number of patients affected by MDR-TB. The management of MDR-TB is characterized by delayed diagnosis, uncertainty of the extent of bacillary drug-resistance, imprecise standardized drug regimens and dosages, very long duration of therapy and high frequency of adverse events which all translate into a poor prognosis for many of the affected patients. Major scientific and technological advances in recent years provide new perspectives through treatment regimens tailor-made to individual needs. Where available, such personalized treatment has major implications on the treatment outcomes of patients with MDR-TB. The challenge now is to bring these adances to those patients that need them most.

Human individual radiation sensitivity and prospects for prediction.

In the past few decades, it has become increasingly evident that sensitivity to ionising radiation is variable. This is true for tissue reactions (deterministic effects) after high doses of radiation, for stochastic effects following moderate and possibly low doses, and conceivably also for non-cancer effects such as cardiovascular disease, the causal pathway(s) of which are not yet fully understood. A high sensitivity to deterministic effects is not necessarily correlated with a high sensitivity to stochastic effects. The concept of individual sensitivity to high and low doses of radiation has long been supported by data from patients with certain rare hereditary conditions. However, these syndromes only affect a small proportion of the general population. More relevant to the majority of the population is the notion that some part of the genetic contribution defining radiation sensitivity may follow a polygenic model, which predicts elevated risk resulting from the inheritance of many low-penetrance risk-modulating alleles. Can the different forms of individual radiation sensitivities be inferred from the reaction of cells exposed ex vivo to ionising radiation? Can they be inferred from analyses of individual genotypes? This paper reviews current evidence from studies of late adverse tissue reactions after radiotherapy in potentially sensitive groups, including data from functional assays, candidate gene approaches, and genome-wide association studies. It focuses on studies published in 2013 or later because a comprehensive review of earlier studies was published previously in a report by the UK Advisory Group on Ionising Radiation.

Optimal adjuvant endocrine treatment of ER+/HER2+ breast cancer patients by age at diagnosis: A population-based cohort study.

BACKGROUND: Prior randomised controlled trials on adjuvant hormonal therapy included HER2any patients; however, a differential effect of aromatase inhibitors (AIs) versus tamoxifen (TAM) may have been missed in ER+/HER2+ patients that comprise 7-15% of all breast cancer patients. In addition, a woman's hormonal microenvironment may influence sensitivity to TAM and AIs in the adjuvant setting, which changes during menopausal transition, a process that takes years. We studied the efficacy of AIs versus TAM in ER+/HER2+ breast cancer patients grouped by age at diagnosis as a proxy for menopausal status using treatment and outcome data from the nationwide population-based Netherlands Cancer Registry (NCR). PATIENTS AND METHODS: All women diagnosed between 2005 and 2007 with endocrine-treated, TanyNanyM0, ER+/HER2+ breast cancer were identified through the NCR (n = 1155). Patients were divided by age at diagnosis: premenopausal (≤45 years; n = 326), perimenopausal (4555 years; n = 525). A time-dependent variable, indicating whether AI or TAM was received for >50% of endocrine treatment duration, was applied to subdivide groups by predominant treatment received. Recurrence-free survival (RFS) and overall survival (OS) were assessed using Kaplan-Meier survival estimation and Cox regression. Hazard ratios (HRs) were adjusted for chemotherapy, trastuzumab, age at diagnosis, N-status, grade, pT-stage and ovarian ablation. RESULTS: During follow-up, 237 recurrences and 182 deaths occurred. Perimenopausal women derived significant RFS and OS benefit from AI compared with TAM, HR 0.47 (95% CI 0.25-0.91; P = 0.03) and HR 0.37 (95% CI 0.18-0.79; P = 0.01), respectively, whereas premenopausal women derived no benefit from AI compared with TAM. Treatment effects differed significantly between these age groups (interaction P = 0.03 and P = 0.02, respectively). Among postmenopausal women a small but non-significant AI benefit was observed. CONCLUSION: AI treatment, preferably without any TAM treatment, was associated with the best RFS and OS outcome in ER+/HER2+ perimenopausal breast cancer patients.

A critical evaluation of lymph node ratio in head and neck cancer.

In head and neck squamous cell carcinoma (HNSCC), the search for better prognostic factors beyond TNM-stage is ongoing. Lymph node ratio (LNR) (positive lymph nodes/total lymph nodes) is gaining interest in view of its potential prognostic significance. All HNSCC patients at the Netherlands Cancer Institute undergoing neck dissection for lymph node metastases in the neck region between 2002 and 2012 (n = 176) were included. Based on a protocol change in specimen processing, the cohort was subdivided in two distinct consecutive periods (pre and post 2007). The prognostic value of LNR, N-stage, and number of positive lymph nodes for overall survival was assessed. The mean number of examined lymph nodes after 2007 was significantly higher (42.3) than before (35.8) (p = 0.024). The higher number concerned mostly lymph nodes in level V. The mean number of positive lymph nodes before 2007 was 3.3 vs. 3.6 after 2007 (p = 0.745). By multivariate analysis of both pre- and post-2007 cohort data, two factors remained associated with an increased hazard of dying: N2 [HR 2.1 (1.1-4.1) and 2.4 (1.0-5.8)] and >3 positive lymph nodes [HR 2.0 (1.1-3.5) and 3.1 (1.4-6.9)]. Hazard ratio for LNR >7 % was not significantly different: pre 2007 at 2.2 (1.3-3.8) and post 2007 at 2.1 (1.0-4.8, p = 0.053). In this study, changes in specimen processing influenced LNR values, but not the total number of tumor positive nodes found. Therefore, in HNSCC, the number of positive nodes seems a more reliable parameter than LNR, provided a minimum number of lymph nodes are examined.

Cytoreduction and hyperthermic intraperitoneal chemotherapy: The learning curve reassessed.

BACKGROUND: CytoReductive Surgery and Hyperthermic IntraPEritoneal Chemotherapy (CRS-HIPEC) is now the preferred treatment of many peritoneal surface malignancies. In this retrospective study we aimed to analyze how several performance indicators changed during the first 100 CRS-HIPEC procedures in hospitals which recently introduced this treatment, and compare those with an experienced institution. METHODS: The first consecutive 100 CRS-HIPEC procedures of three institutions were compared to those of the pioneer hospital. The training provided by the pioneer hospital consisted of hands-on training during the first ten procedures; hereafter guidance was available on consult basis. Operation characteristics, morbidity and completeness of cytoreduction were evaluated by case sequence. Locally-estimated-scatter-plot smoothing was used to evaluate the learning curve. RESULTS: From four institutions 372 cases were included. A macroscopic complete cytoreduction was reached in 66% of the cases in the pioneer hospital and in 86% in the new hospitals (p < 0.001). Complete cytoreduction rates were higher at start off in the new institutions compared with the experienced institution and increased significantly in the first 100 procedures. The new hospitals started with lower morbidity than the experienced hospital, which did not significantly decrease during the study period. CONCLUSION: New institutions that were trained and mentored by an experienced CRS-HIPEC hospital performed better from the beginning with regard to complete cytoreduction and morbidity rate with than the experienced center. An improvement in complete cytoreduction rate during the first 100 procedures was observed in the new institutions.

Increased breast cancer risk in in vitro fertilisation treated women with a multiple pregnancy: a new hypothesis based on historical in vitro fertilisation treatment data.

BACKGROUND: Breast cancer risk is temporarily increased after a full-term pregnancy and declines thereafter, possibly due to increased levels of gonadal and placental hormones during pregnancy. Inconsistent results, however, have been reported after twin pregnancies with higher hormone levels. Among women treated with in vitro fertilisation (IVF), for whom the number of embryos available for implantation is known, we recently observed that a multiple birth after implantation of all transferred embryos is associated with higher levels of vascular endothelial growth factor (VEGF). As VEGF is involved in breast cancer progression, we studied the effects of embryo implantation and a multiple birth on breast cancer risk in a nationwide Dutch cohort of IVF-treated women. METHODS: We performed a cohort analysis among 12,589 women who had been treated with IVF between 1983 and 1995 and completed a risk factor questionnaire between 1997 and 1999. Data on IVF treatment were obtained from medical records. Breast cancer cases were ascertained through linkage with the population-based Netherlands Cancer Registry. Breast cancer risks associated with singleton and multiple births were estimated with Cox regression. FINDINGS: There were 1688 women (13.4%) with multiples, 6027 (47.9%) with singletons and 4874 (38.7%) nulliparous women. Breast cancer occurred in 317 women of whom 57 had multiples. Breast cancer risk was 1.44 times higher in mothers of multiples than in mothers of singletons (95% confidence interval (CI) 1.06-1.97). Risk was highest in women who gave birth to multiples from all embryos transferred (adjusted hazard ratio (HR) 1.86, 95% CI 1.01-3.43), and lower for those with multiples after incomplete embryo implantation (adjusted HR 1.31, 95% CI 0.76-2.25). INTERPRETATION: A woman's potential to implant all transferred embryos may be associated with breast cancer risk. Further research is needed to confirm our results and to identify the underlying biological mechanisms.

Increased stomach cancer risk following radiotherapy for testicular cancer.

BACKGROUND: Abdominal radiotherapy for testicular cancer (TC) increases risk for second stomach cancer, although data on the radiation dose-response relationship are sparse. METHODS: In a cohort of 22,269 5-year TC survivors diagnosed during 1959-1987, doses to stomach subsites were estimated for 92 patients who developed stomach cancer and 180 matched controls. Chemotherapy details were recorded. Odds ratios (ORs) were estimated using logistic regression. RESULTS: Cumulative incidence of second primary stomach cancer was 1.45% at 30 years after TC diagnosis. The TC survivors who received radiotherapy (87 (95%) cases, 151 (84%) controls) had a 5.9-fold (95% confidence interval (CI) 1.7-20.7) increased risk of stomach cancer. Risk increased with increasing stomach dose (P-trend<0.001), with an OR of 20.5 (3.7-114.3) for ⩾50.0 Gy compared with <10 Gy. Radiation-related risks remained elevated ⩾20 years after exposure (P<0.001). Risk after any chemotherapy was not elevated (OR=1.1; 95% CI 0.5-2.5; 14 cases and 23 controls). CONCLUSIONS: Radiotherapy for TC involving parts of the stomach increased gastric cancer risk for several decades, with the highest risks after stomach doses of ⩾30 Gy. Clinicians should be aware of these excesses when previously irradiated TC survivors present with gastrointestinal symptoms and when any radiotherapy is considered in newly diagnosed TC patients.

The inter-individual variability outperforms the intra-individual variability of differentially expressed proteins prior and post irradiation in lymphoblastoid cell lines.

CONTEXT: Radio-sensitivity in normal tissue is characterized by heterogeneity throughout the population and the absence of pre-diagnostic biomarkers. OBJECTIVE: We conducted a proteomic approach to search for radiation characteristic protein regulation. MATERIALS AND METHODS: Cell lines were 10 Gy irradiated and analysed by 2D-DIGE after 24 h. RESULTS were analysed intra- and inter-individually. The principal component analysis and hierarchical clustering was applied to all datasets. RESULTS: Differences in intra-individual spot abundance prior and post irradiation exactly show the separation of sample classes in two groups: sham-irradiated and irradiated. The inter-individual datasets clustered according to the cell line. The intra-individual differences on protein level after gamma-irradiation are very low, compared with the inter-individual differences among cell lines derived from the same tissue. CONCLUSION: The application of 2-D DIGE may offer a realistic chance for a better molecular characterization of radio-sensitivity and for the discovery of candidate biomarkers.

Perioperative systemic chemotherapy in peritoneal carcinomatosis of lymph node positive colorectal cancer treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy.

BACKGROUND: Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) is the preferred treatment of peritoneal carcinomatosis (PC) of colorectal carcinoma. Patients with positive lymph node status have worse survival after CRS-HIPEC, which is probably due to higher rates of systemic failure. In this study, we analysed the effect of administration and timing of systemic chemotherapy on the outcome of lymph node positive colorectal carcinoma patients treated with CRS-HIPEC. PATIENTS AND METHODS: A prospective database was reviewed to identify lymph node positive patients with PC treated with CRS-HIPEC within 1 year after primary tumour diagnosis between 2004 and 2012. Medical history of the patients was studied for the administration of perioperative systemic chemotherapy and follow-up. Outcome parameters were progression-free survival (PFS), overall survival (OS) and pattern of recurrence. RESULTS: Seventy-three patients treated with CRS-HIPEC for PC from lymph node positive colorectal carcinoma were identified. Fourteen patients received pre-CRS-HIPEC chemotherapy only, 32 patients underwent post-CRS-HIPEC chemotherapy only, 9 patients received chemotherapy both pre- and post-CRS-HIPEC and 16 patients did not receive any systemic chemotherapy. Of the 47 patients who did not receive pre-CRS-HIPEC chemotherapy, 11 (23%) did not receive any chemotherapy due to major postoperative complications. PFS and OS were significantly higher in patients who received systemic chemotherapy (PFS: median 15 versus 4 months, P = 0.024; OS: median 30 versus 14 months, P = 0.015), although this difference was attenuated after adjustment for major complications. Different chemotherapy timings did not differ significantly in either survival or recurrence patterns. CONCLUSIONS: In patients with PC from lymph node positive colorectal carcinoma, perioperative systemic chemotherapy is associated with increased OS and PFS, although this difference may be partly explained by the occurrence of major postoperative complication; with no evidence of difference in PFS, OS and systemic recurrence rate by timing of systemic chemotherapy.

The influence of nodal yield in neck dissections on lymph node ratio in head and neck cancer.

OBJECTIVES: Recent studies suggest that lymph node ratio (LNR) is a strong prognostic factor in head and neck cancer. This study aims to determine if the yield of harvested lymph nodes (LNs) influences the LNR. METHODS: The study included 522 head and neck cancer patients, undergoing 638 primary and salvage (selective) neck dissections between 2002 and 2012. Before 2007 the neck dissection specimens were macroscopically and microscopically examined by pathologists and after 2007 the macroscopic examination was performed by pathology technicians. For comparison of mean LN yields, univariate and multivariate analyses were performed. RESULTS: The mean number of LNs among 374 specimens examined by pathologists was 24 (range 0-89) vs. 32 (range 2-89) among 264 specimens examined by pathology technicians (P<.001). This caused the mean LNR in the non pre-treated patient group to drop from 11.4% to 8.7%. The counts of LNs per type of neck dissection were significantly different and increased with the number of levels involved. However, there was no linear relationship and the higher yields could be mostly ascribed to LNs in level V. The LNR varied from 8.1% to 18.4% among the different types of neck dissections. CONCLUSIONS: A significant increase in the number of harvested LNs, but a decrease in LNR was observed after introducing pathology technicians for macroscopic examination. A clear association between the extent of the dissection and the number of harvested LNs was observed. LNR appears to be strongly dependent on the harvesting protocol and the extent of the dissection.

Physical forces exerted by microbubbles on a surface in a traveling wave field.

The effect of a wave with a varying traveling component on the bubble activity as well as the physical force generated by microbubbles on a surface has been studied. The acoustic emission from a collection of bubbles is measured in a 928 kHz sound field. Particle removal tests on a surface, which actually measures the applied physical force by the bubbles on that surface, indicate a very strong dependence on the angle of incidence. In other words, when the traveling wave component is maximized, the average physical force applied by microbubbles reaches a maximum. Almost complete particle removal for 78 nm silica particles was obtained for a traveling wave, while particle removal efficiency was reduced to only a few percent when a standing wave was applied. This increase in particle removal for a traveling wave is probably caused by a decrease in bubble trapping at nodes and antinodes in a standing wave field.

CYP2C19 2 predicts substantial tamoxifen benefit in postmenopausal breast cancer patients randomized between adjuvant tamoxifen and no systemic treatment.

Estrogen catabolism is a major function of CYP2C19. The effect of CYP2C19 polymorphisms on tamoxifen sensitivity may therefore not only be mediated by a variation in tamoxifen metabolite levels but also by an effect on breast cancer risk and molecular subtype due to variation in lifelong exposure to estrogens. We determined the association between these polymorphisms and tamoxifen sensitivity in the context of a randomized trial, which allows for the discernment of prognosis from prediction. We isolated primary tumor DNA from 535 estrogen receptor-positive, stages I-III, postmenopausal breast cancer patients who had been randomized to tamoxifen (1-3 years) or no adjuvant therapy. Recurrence-free interval improvement with tamoxifen versus control was assessed according to the presence or absence of CYP2C19 2 and CYP2C19 17. Hazard ratios and interaction terms were calculated using multivariate Cox proportional hazard models, stratified for nodal status. Tamoxifen benefit was not significantly affected by CYP2C19 17. Patients with at least one CYP2C19 2 allele derived significantly more benefit from tamoxifen (HR 0.26; p = 0.001) than patients without a CYP2C19 2 allele (HR 0.68; p = 0.18) (p for interaction 0.04). In control patients, CYP2C19 2 was an adverse prognostic factor. In conclusion, breast cancer patients carrying at least one CYP2C19 2 allele have an adverse prognosis in the absence of adjuvant systemic treatment, which can be substantially improved by adjuvant tamoxifen treatment.