Treatment of older patients with colorectal cancer: a perspective review

In a continuously aging population, the burden of colorectal cancer (CRC) is rising among older patients. Despite the fact that almost half of the cases occur in patients over 75 years, this age group is subjected to disparities regarding diagnostic and therapeutic options. So far, exclusion of older patients from randomized clinical trials has resulted in a lack of evidence-based guidelines. Nevertheless, newer data from studies specifically targeting older patients and subgroup analyses indicate that proper treatment planning and specific medical and geriatric assessment can achieve a safe and beneficial treatment result in older patients, often with similar outcomes to their younger counterparts. Resection of the primary tumour, if feasible, should be the primary goal of surgery aiming for cure, although it should be avoided under emergency conditions. Chronological age per se should not be an exclusion criterion for adjuvant or palliative chemotherapy, or targeted therapies. Careful patient selection, dose adjustments, close monitoring and early intervention in the event of side effects are essential. The benefits of treatment must be balanced with potential effects of treatment and patients’ wishes

Monitoring the Nonlinear Acoustic Behavior of Fresh Cementitious Materials during the Hardening Process Using Laser Doppler Vibrometry

A challenge in the field of material science and concrete technology is to associate material properties and behavior with changes in internal microstructure. A fundamental issue for planning, implementation, and quality control of construction projects is the fundamental understanding of the hardening process in freshly poured cement-based materials. Shortly after the mixing process, cementitious materials exhibit a substantial damping effect on ultrasonic wave propagation along with low-pulse velocity. The way a wave reflects and diffuses in the volume of a solid material can provide important information about internal heterogeneities. An important application of the wave propagation technique is the determination of layers within the material distinguished by unlike elastic properties. During the hardening process, the ultrasonic wave propagation exhibits a noticeable sensitivity at the point of phase change of the material, that is, the critical point at which the state of the suspension transforms from liquid to solid state. After that point, there is a continuous increase of pulse velocity and ultrasonic signal amplitude. The solidification point is of practical importance since at this point the load-bearing capacity of the composite material and its long-term behavior are based on the connectivity of the solid phase. This study aims to develop a nondestructive tool to monitor freshly poured cement-paste composites at early stages, during the hydration process, by means of nonlinear elastic waves. The measurement setup combined a contact ultrasonic transducer with a noncontact optical detection system, in which the principle of operation is based on the Doppler effect. This methodology enabled us to assess the amplitudes of harmonic vibrations of an acoustic wave propagating through the material with a specific fundamental frequency. This enabled the evaluation of important material properties, such as minute changes in the internal microstructure of fresh concrete during hardening, the evolution of nonlinearity parameters that relate to higher-order elastic constants of the material, as well as the ultrasonic wave velocity

Monitoring the Hydration Process in Carbon Nanotube Reinforced Cement-Based Composites Using Nonlinear Elastic Waves

There is currently an increased need for associating construction material properties and behavior with the nature of their microstructure. One of the major issues in this context is the need for understanding the curing process in freshly poured cement-based materials. This is particularly important when nanoreinforcement materials, such as carbon nanotubes, are used to enhance the mechanical behavior and multifunctionality of the final structure. The solidification point, at which the state of liquid suspension transmutes to the solid state, is of particular interest since it greatly influences the load-bearing capacity of the cement-based material and its structural behavior at the long term. The main purpose of the present work is to develop a reliable method for monitoring the hydration process during the early stages of freshly poured cementitious composites enhanced with carbon nanotubes. This methodology is based on the use of nonlinear elastic waves. To achieve this goal, a combination of contact ultrasonics with noncontact optical detection was used. The detection method for evaluating the setting process is based on the assessment of higher-harmonic amplitudes of an ultrasonic wave, with a given frequency, propagating through the cementitious material. It was observed that the material nonlinearity changes significantly during the hardening process, compared to velocity or attenuation measurements which are based on linear acoustics. These changes were more noticeable as the concentration of carbon nanotubes in the cement matrix increases, indicating that higher harmonics are more susceptible to minute microstructural changes

The Role of Continuing Perioperative Chemotherapy Post Surgery in Patients with Esophageal or Gastroesophageal Junction Adenocarcinoma: a Multicenter Cohort Study

Purpose: The aim of this cohort study was to assess the benefit that patients with lower esophageal or gastroesophageal junction (E/GEJ) adenocarcinoma receive by continuing perioperative chemotherapy post-surgery. Methods: Three hundred twelve patients underwent radical tumor surgical resection after preoperative chemotherapy. Chemotherapy was mainly ECX (epirubicin, cisplatin, capecitabine). Propensity score matching (PSM) was used to compare continuation of chemotherapy post-surgery vs. no postoperative treatment. Results: Two hundred ten patients (67.3%) had GEJ and 102 (32.7%) lower esophageal adenocarcinoma. Microscopically clear surgical margins (R0), according to the Royal College of Pathologists, were achieved in 208 patients (66.7%). In total, 225 patients (72.1%) continued perioperative chemotherapy post-surgery. PSM was used to create two patient groups, well-balanced for basic epidemiological, clinical, and histopathological characteristics. The first included 148 patients who continued perioperative chemotherapy after surgery and the second 86, who did not receive postoperative treatment. The first group had non-significantly different median time-to-relapse (TTR 22.2 vs. 25.7 months, p = 0.627), overall survival (OS 46.1 vs. 36.7 months, p = 0.199), and post-relapse survival (15.3 vs. 8.7 months, p = 0.122). Subgroup analysis showed that only patients with microscopically residual disease after surgery (R1 resection) benefited from continuation of chemotherapy post-surgery for both TTR (hazard ratio [HR] 0.556, 95% CI 0.330–0.936, p = 0.027) and OS (HR 0.530, 95% CI 0.313–0.898, p = 0.018). Conclusions: Continuation of perioperative chemotherapy post-surgery was not associated with improved outcome in patients with E/GEJ adenocarcinoma. Patients with microscopically residual disease post-surgery might receive a potential benefit from adjuvant chemotherapy