[Organ preservation for rectal cancer: What are the arguments in favor of radiotherapy?] / Préservation d'organe dans les cancers du rectum : quels arguments en faveur de la radiothérapie ?

Standard care for rectal cancers relies on both tumor (location relative to the sphincter, T and N stage, sphincter involvement) and patients characteristics. Radical surgery (total mesorectal excision) following short-course radiotherapy (RT) or standard chemo-radiotherapy, associated with induction or consolidation chemotherapy (total neoadjuvant treatment), remains the cornerstone of locally advanced rectal cancer (T3cd, T4 and/or N+) treatment. Nevertheless, for early stages, this radical resection could be avoided in favor of conservative approaches combining RT (external, contact, brachytherapy) with or without chemotherapy (concurrent, induction or consolidative), or even be limited, for good responders, to a local excision with view of organ-preservation strategies. This conservative approach could also be offered selectively to patients with complete clinical response after the induction sequence, irrespective of initial tumor characteristics. The Watch and Wait strategy relies on clinical, endoscopic and radiological evaluations, as well as sustained surveillance. Ongoing studies aim to improve response rates, either with chemotherapy intensification, or RT boost dose escalation with brachytherapy or contact-therapy.

Preparation of Long-Lived, Non-Autoionizing Circular Rydberg States of Strontium.

Alkaline earth Rydberg atoms are very promising tools for quantum technologies. Their highly excited outer electron provides them with the remarkable properties of Rydberg atoms and, notably, with a huge coupling to external fields or to other Rydberg atoms while the ionic core retains an optically active electron. However, low angular-momentum Rydberg states suffer almost immediate autoionization when the core is excited. Here, we demonstrate that strontium circular Rydberg atoms with a core excited in a 4D metastable level are impervious to autoionization over more than a few millisecond time scale. This makes it possible to trap and laser-cool Rydberg atoms. Moreover, we observe singlet to triplet transitions due to the core optical manipulations, opening the way to a microwave to optical quantum interface.

Evaluation of microscopic tumor extension in non-small-cell lung cancer for three-dimensional conformal radiotherapy planning.

PURPOSE: One of the most difficult steps of the three-dimensional conformal radiotherapy (3DCRT) is to define the clinical target volume (CTV) according to the degree of local microscopic extension (ME). In this study, we tried to quantify this ME in non-small-cell lung cancer (NSCLC). MATERIAL AND METHODS: Seventy NSCLC surgical resection specimens for which the border between tumor and adjacent lung parenchyma were examined on routine sections. This border was identified with the naked eye, outlined with a marker pen, and the value of the local ME outside of this border was measured with an eyepiece micrometer. The pattern of histologic spread was also determined. RESULTS: A total of 354 slides were examined, corresponding to 176 slides for adenocarcinoma (ADC) and 178 slides for squamous cell carcinoma (SCC). The mean value of ME was 2.69 mm for ADC and 1.48 mm for SCC (p = 0.01). The usual 5-mm margin covers 80% of the ME for ADC and 91% for SCC. To take into account 95% of the ME, a margin of 8 mm and 6 mm must be chosen for ADC and SCC, respectively. Aerogenous dissemination was the most frequent pattern observed for all groups, followed by lymphatic invasion for ADC and interstitial extension for SCC. CONCLUSION: The ME was different between ADC and SCC. The usual CTV margin of 5 mm appears inadequate to cover the ME for either group, and it must be increased to 8 mm and 6 mm for ADC and SCC, respectively, to cover 95% of the ME. This approach is obviously integrated into the overall 3DCRT procedure and with other margins.