Outcomes after Surgery for Early Stage Breast Cancer in Women Staged With Preoperative Breast Magnetic Resonance Imaging According to Breast Tissue Density.

Purpose: To determine surgical outcomes and breast cancer disease-free survival outcomes of women with early stage breast cancer with and without use of preoperative breast MRI according to breast tissue density.

Methods: Women with early stage breast cancer diagnosed from 2004 to 2009 were classified into 2 groups: 1) those with dense and heterogeneously dense breasts (DB); 2) those with nondense breasts (NDB) (scattered fibroglandular and fatty replaced tissue). The 2 groups were reviewed to determine who underwent preoperative MRI.

Prophylactic Cranial Irradiation in Extensive Stage Small Cell Lung Cancer: Outcomes at a Comprehensive Cancer Centre.

Purpose: The role of prophylactic cranial irradiation (PCI) remains controversial in extensive stage small cell lung cancer (ES-SCLC) with the publication of 2 randomized control trials demonstrating differing outcomes in overall survival. The aim of this study is to determine the impact of PCI on survival and the development of brain metastasis while addressing the disparate use of postchemotherapy brain imaging in the aforementioned trials.

Methods And Materials: The medical records of 397 consecutive patients with ES-SCLC between Jan.

Age Bias in Time From Diagnosis Comparisons of Prostate Cancer Treatment.

Objectives: Observational studies of prostate cancer treatment have demonstrated a major survival benefit with prostatectomy; randomized trials have been less certain in this regard. This discrepancy is hypothesized to be due to the use survival calculations based on time from diagnosis (TFD), which can bias toward better survival for younger cohorts. Attained age is an alternative timescale that can mitigate this effect.

Role of fine-needle aspiration in the surgical management of pancreatic neuroendocrine tumors: utility and limitations in light of the new World Health Organization classification.

Context: Pancreatic neuroendocrine tumors (Panc-NETs) are rare and tend to get overshadowed by their more prevalent and aggressive ductal adenocarcinoma counterparts. The biological behavior of PancNETs is unpredictable, and thus management is controversial. However, the new World Health Organization classification has significantly contributed to the prognostic stratification of these patients.

Oligometastasis as a predictor for occult disease.

Oligometastasis can be defined as a state of limited metastases that is potentially amenable to ablative local therapy; the success of such therapy depends on whether or not additional occult metastases exist. A model is presented here to predict occult metastases given detectable oligometastases. Predictions were based on Bayes' theorem, in conjunction with descriptions of the statistical distributions for the sizes and numbers of hematogenous metastases.

Pancreatectomy Versus Conservative Management for Pancreatic Cancer: A Question of Lead-time Bias.

Objectives: Pancreatectomy is regarded as the only curative treatment for cancer of the pancreas. A population-based study was conducted to examine its efficacy within the general community.

Methods: Overall and cancer-specific survivals were compared between individuals treated with pancreatectomy and those managed nonsurgically.

Tweedie convergence: a mathematical basis for Taylor's power law, 1/f noise, and multifractality.

Plants and animals of a given species tend to cluster within their habitats in accordance with a power function between their mean density and the variance. This relationship, Taylor's power law, has been variously explained by ecologists in terms of animal behavior, interspecies interactions, demographic effects, etc., all without consensus.

Taylor's power law and fluctuation scaling explained by a central-limit-like convergence.

A power function relationship observed between the variance and the mean of many types of biological and physical systems has generated much debate as to its origins. This Taylor's law (or fluctuation scaling) has been recently hypothesized to result from the second law of thermodynamics and the behavior of the density of states. This hypothesis is predicated on physical quantities like free energy and an external field; the correspondence of these quantities with biological systems, though, remains unproven.

Extinction kinetics for metastatic cancer stem cells.

Purpose: Cancer Stem Cells (CSC) are hypothesised to influence tumour growth through their self-replication, cell loss, and differentiation into growth-limited cell types. A model for the random gain and loss of metastatic CSC is developed to investigate how the balance between these processes might affect metastatic efficiency, tumour involution and treatment response.

Materials And Methods: A stochastic birth-death model for metastasis was constructed for the replication and loss of CSC.

Histological subtypes of prostatic cancer: a comparative survival study.

Introduction: Variant histological subtypes of prostatic cancer occur uncommonly and are associated with poor survival, as has been ascertained through limited series and case reports. Here a population-based analysis of prostatic cancer is provided, to better analyze the survival behavior of these subtypes.

Materials And Methods: The American SEER registry was used to review prostatic cancer diagnosed from 1988 to 2003, classified according to the International Classification of Diseases for Oncology.

Dying with cancer: the influence of age, comorbidity, and cancer site.

Background: Cancer survival is influenced by age, comorbidity, and type of cancer. A population-based study was conducted to compare the interplay between age and mortality for different cancers.

Methods: This study analyzed 784,378 cases, comprising 22 of the commonest SEER cancers diagnosed between 1984 and 1993.

A population-based analysis of second primary cancers after irradiation for rectal cancer.

Objective: To investigate the possible association between pelvic irradiation for rectal cancer and subsequent second primary cancers.

Patients And Methods: A population-based analysis of 20,910 individuals with rectal cancer from the Surveillance, Epidemiology, and End Results registry, for whom follow-up times were at least 5 years, was performed. Kaplan-Meier estimates for the development of second cancers within irradiated and nonirradiated cohorts provided a comparison that accounted for censored data.

Empirically-based estimates for the burden of subclinical metastases.

Purpose: To describe the frequency distribution for the number of residual subclinical metastatic tumor cells after removal of the primary cancer.

Materials And Methods: Previously obtained autopsy, surgical pathological and laboratory data were used to characterize the size and number distributions for hematogenous and lymphatic metastases. Monte Carlo simulations were used to estimate the numbers of residual tumor cells based upon the assumption of a lognormal distribution for the sizes of metastases and Poisson, Poisson negative binomial, or negative binomial distributed numbers of metastases (corresponding to lymphatic metastases within individuals, hematogenous metastases within individuals, and lymphatic metastases within populations, respectively).

The comparative survival of renal leiomyosarcoma.

Introduction: Leiomyosarcoma of the kidney and renal pelvis is a rare tumor that, on the basis of limited data, has been ascribed a particularly poor prognosis compared to other subtypes of renal malignancy. Here the population-based Surveillance, Epidemiology, and End Results (SEER) registry is used to study the survival of renal leiomyosarcomas.

Methods: There were 95,935 cases of invasive cancer of the kidney and renal pelvis retrieved from the SEER registry to provide 112 cases of leiomyosarcoma.

Scale invariant correlations between genes and SNPs on Human chromosome 1 reveal potential evolutionary mechanisms.

The local density of gene structures and single nucleotide polymorphisms (SNPs) along human chromosomes appears inhomogeneous. In chromosome 1, the density patterns from both these elements are shown here to exhibit similar scale invariant clustering, as well as long-ranged and scale invariant auto- and cross-correlations. The local densities of these elements sites can be accurately represented by the scale invariant exponential dispersion models, a group of stochastic models that act as limiting distributions for a wide range of generalized linear models.

Lymph node-based prognostics: limitations with individualized cancer treatment.

Objectives: Clinicians will commonly individualize adjuvant cancer therapy, on the basis of the number of involved lymph nodes and other clinicopathological factors, under the assumption that despite the expected statistical variability of such data one can nonetheless garner useful information for the individual case. Here the scientific basis of this assumption will be examined.

Methods: Survival data from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program for 19,107 breast, 4,234 gastric, and 4,058 rectal cancers were studied with Kaplan-Meier estimates and Cox proportionate hazard models.

Prostatic irradiation is not associated with any measurable increase in the risk of subsequent rectal cancer.

Purpose: To investigate a putative increased risk of rectal cancer subsequent to prostatic radiotherapy.

Methods And Materials: In an analysis of the Surveillance, Epidemiology, and End Results registry, we compared men who had radiotherapy for prostatic carcinoma with those treated surgically and those treated with neither modality. Kaplan-Meier analyses for the time to failure from rectal cancer were performed between age-matched subgroups of the three cohorts.

The number distribution for involved lymph nodes in cancer.

The number of involved lymph nodes exhibits considerable heterogeneity within populations. Here, the implications of population heterogeneity are explored with respect to the kinematics of nodal metastases. Data from the National Cancer Institute's Surveillance, Epidemiology, and End Results program for 224656 breast, 12404 gastric, 18015 rectal, 4117 cervical and 2443 laryngeal cancers as well as 9118 melanomas were used to construct frequency distributions for the number of involved nodes which were then fitted to the negative binomial distribution.

Chance mechanisms affecting the burden of metastases.

Background: The burden of cancer metastases within an individual is commonly used to clinically characterize a tumor's biological behavior. Assessments like these implicitly assume that spurious effects can be discounted. Here the influence of chance on the burden of metastasis is studied to determine whether or not this assumption is valid.

Statistical kinematics of axillary nodal metastases in breast carcinoma.

The number of involved lymph nodes in individuals with breast cancer is highly variable, and of both prognostic and therapeutic importance. A statistical description for the frequency distribution of the numbers of involved nodes in an affected population could potentially reveal mechanisms of axillary metastasis, and eventually facilitate predictive models for tumor control and axillary sampling. A meta-analysis of 15 studies involving 24,757 axillary dissections was performed, including conventional dissections, sentinel node dissections and studies of occult metastases.

Large-scale genomic correlations in Arabidopsis thaliana relate to chromosomal structure.

Background: The chromosomes of the plant Arabidopsis thaliana contain various genomic elements, distributed with appreciable spatial heterogeneity. Clustering of and/or correlations between these elements presumably should reflect underlying functional or structural factors. We studied the positional density fluctuations and correlations between genes, indels, single nucleotide polymorphisms (SNPs), retrotransposons, 180 bp tandem repeats, and conserved centromeric sequences (CCSs) in Arabidopsis in order to elucidate any patterns and possible responsible factors for their genomic distributions.