Analysis of incidence and prognostic factors for ipsilateral breast tumour recurrence and its impact on disease-specific survival of women with node-negative breast cancer: a prospective cohort study

INTRODUCTION: This study had three aims: to establish the incidence of ipsilateral breast tumour recurrence (IBTR) in a community treatment setting, to evaluate known factors – in particular younger age (< 40 years) – predictive for local recurrence, and to assess the impact of local recurrence on disease-specific survival (DSS). METHODS: A consecutive series of 1,540 women with node-negative breast cancer, diagnosed between the ages of 18–75 years, were prospectively accrued between September 1987 and September 1999. All had undergone a resection of the primary breast cancer with clear margins, an axillary lymph node dissection with a minimum of four sampled nodes, and breast-conserving surgery (of any type). RESULTS: During the study follow-up period, 98 (6.4%) IBTRs and 117 (7.6%) deaths from or with breast cancer were observed. The median time to IBTR was 3.1 years and to death from or with disease was 4.3 years. In the multivariate Cox proportional hazards (PH) regression model for IBTR with adjuvant therapy factors, independent risk factors included age < 40 years (relative risk (RR) = 1.89, 95% confidence interval (CI) of 1.00 – 3.58), presence of intraductal disease (RR = 1.81, 95% CI = 1.15–2.85) and histological grade ('G2' or G3 versus G1: RR = 1.59, 95% CI = 0.87–2.94). In the multivariate Cox PH regression model for DSS with adjuvant therapy factors, independent risk factors included previous IBTR (RR = 2.58, 95% CI = 1.41–4.72), tumor size (1–2 cm versus < 1 cm: RR = 1.95, 95% CI = 1.05–3.64, > 2 cm versus < 1 cm: RR = 2.94, 95% CI = 1.56–5.56), progesterone receptor status (negative or equivocal versus positive or unknown: RR = 2.15, 95% CI = 1.36–3.39), lymphatic invasion (RR = 1.78, 95% CI = 1.17–2.72), and histological grade ('G2' or G3 versus G1: RR = 8.59, 95% CI = 2.09–35.36). The effects of competing risks could be ignored. CONCLUSION: The Cox PH analyses confirmed the importance of known risk factors for IBTR and DSS in a community treatment setting. This study also revealed that the early occurrence of an IBTR is associated with a relatively poor five-year survival rate

Investigation on the origin of hot electrons in laser plasma interaction at shock ignition intensities

Shock Ignition is a two-step scheme to reach Inertial Confinement Fusion, where the precompressed fuel capsule is ignited by a strong shock driven by a laser pulse at an intensity in the order of 10 16 W/cm 2 . In this report we describe the results of an experiment carried out at PALS laser facility designed to investigate the origin of hot electrons in laser-plasma interaction at intensities and plasma temperatures expected for Shock Ignition. A detailed time- and spectrally-resolved characterization of Stimulated Raman Scattering and Two Plasmon Decay instabilities, as well as of the generated hot electrons, suggest that Stimulated Raman Scattering is the dominant source of hot electrons via the damping of daughter plasma waves. The temperature dependence of laser plasma instabilities was also investigated, enabled by the use of different ablator materials, suggesting that Two Plasmon Decay is damped at earlier times for higher plasma temperatures, accompanied by an earlier ignition of SRS. The identification of the predominant hot electron source and the effect of plasma temperature on laser plasma interaction, here investigated, are extremely useful for developing the mitigation strategies for reducing the impact of hot electrons on the fuel ignition

Characterization of hot electrons generated by laser-plasma interaction at shock ignition intensities

In an experiment carried out at the Prague Asterix Laser System at laser intensities relevant to shock ignition conditions (I > 1016 W/cm2), the heating and transport of hot electrons were studied by using several complementary diagnostics, i.e., Kα time-resolved imaging, hard x-ray filtering (a bremsstrahlung cannon), and electron spectroscopy. Ablators with differing composition from low Z (parylene N) to high Z (nickel) were used in multilayer planar targets to produce plasmas with different coronal temperature and collisionality and modify the conditions of hot-electron generation. The variety of available diagnostics allowed full characterization of the population of hot electrons, retrieving their conversion efficiency, time generation and duration, temperature, and angular divergence. The obtained results are shown to be consistent with those from detailed simulations and similar inertial confinement fusion experiments. Based on the measured data, the advantages, reliability, and complementarity of the experimental diagnostics are discussed