DNA repair inhibitors to enhance radiotherapy: Progresses and limitations

Radiotherapy is one of the most common form of treatment in oncology care. Indeed, radiotherapy proved to be very effective in treating a wide range of malignancies. Nevertheless, certain tumours are intrinsically radioresistant or may evolve to become radioresistant. Resistance to radiotherapy is often associated with dysregulated DNA damage response and repair. Recently, a number of strategies have been developed to improve radiotherapy efficacy by targeting the DNA damage response and repair pathways. Ongoing clinical trials showed the potential of some of these approaches in enhancing radiotherapy, but also highlighted the possible limitations. Here, we will describe (i) the main mechanisms involved in double-strand break repair; (ii) available strategies that target these DNA repair processes to improve radiotherapy and (iii) the clinical outcomes and challenges that have emerged so far.

Operative outcomes for wide awake local anesthesia versus regional and general anesthesia for flexor tendon repair

Operative repair of flexor tendons after traumatic injury may be performed under general anesthesia (GA), regional blocks, or a wide-awake local anesthesia no tourniquet (WALANT) technique. To our knowledge there are currently no large-scale reports evaluating outcomes of flexor tendon repair in patients where wide-awake anesthesia was utilized in comparison to regional anesthesia (RA) and general anesthesia. We performed a retrospective analysis of patients who underwent treatment for flexor tendon injuries at a tertiary referral center for hand surgery over a two-year period. A total of 151 patients were included (53 WALANT, 57 RA, and 41 GA) and a total of 251 tendons were repaired (63 WALANT, 104 RA and 84 GA). No statistically significant difference was observed in rates of tendon rupture, adhesions, infection, or hand function. Flexor tendon repair under WALANT is found to be safe and presents comparable operative and functional outcomes to more traditional anesthetic techniques. Additional advantages, including the ability to test the repair intraoperatively, patient education, and the potential for boosting theatre efficiency. Further studies, preferably utilizing a randomized trial methodology, may further elucidate the benefits and risks of WALANT versus regional and general anesthesia.

[Occupational chronic obstructive pulmonary diseases. Legal aspects and practical management]

The existence of occupational chronic obstructive pulmonary diseases (COPD) is now well established. Since 1989, several regulations have been progressively introduced, allowing compensation for some cases of occupational COPD. Following a brief review of the main occupational causes of COPD, the authors describe the present context for compensation in France and the procedures to be followed to ensure that patient's interests are supported.

[Compensation of damage in cancerology]

In a few situations, the consequences secondary to a carcinological pathology require an assessment of damages for compensatory purposes. This is particularly the case when liable parties have been found to be at cause of the disease: occupational pathologies in the case of inexcusable employer's fault, exposure to a radioactive risk, for example in the context of full compensation for damages suffered by the victims of nuclear experiments performed by France, or lastly, in the after-effects of late diagnosis. This article does not discuss the imputability of cancer pathologies to an event, but it proposes an adaptation of methods for assessing damages, in an attempt to provide full compensation for damages.

[Dural tears: Regarding a series of 100 cases]

INTRODUCTION

Dural tears are a dreaded surgical incident because they are difficult to anticipate and may lead to serious complications.

MATERIALS AND METHODS

The French College of Neurosurgery analyzed 100 cases of dural tears declared on the physicians accreditation website from the Haute Autorité de santé (Regional Health Authority). A questionnaire on drainage, type of dural repair and bed rest duration was sent to 87 French neurosurgeons.

RESULTS

Thirty-six percent of patients with dural tears had a history of previous spinal surgery and the most common cause of tear was surgical fibrosis into the operative field for 30% of cases. Sixty-four percent had no history of spinal surgery and, in 33% of cases, the dural tear occurred during a surgery for herniated disc. Drainage was proposed case by case in 76% of cases, the patient was allowed to stand up at day 1 in 48% of cases. The treatment of dural tears combined different techniques including in situ injection of biological glue in 86% of cases. The most common complication was the need of wound repair procedure in 59.5% of cases, which was complicated by meningitis in 21.5% of cases.

CONCLUSION

This study shows the lack of formal consensus about the procedure of repair, the method of drainage or the need to keep the patient bed ridden. This study highlights a relatively high frequency of dural tears, its potentially serious complications and stresses the need for prospective studies in order to define the appropriate action to undertake when faced with this type of incident.

Prediction of radiotherapy toxicity: 20 years of COPERNIC radiosensitivity diagnosis procedure

PURPOSE

Since 2004, in the frame of the care pathway, our Research Unit has replied to the demand of expertise of radiation oncologists about the individual radiosensitivity of some of their patients. This procedure, called COPERNIC, is based on a skin biopsy and the radiation-induced nucleoshuttling of the ATM protein (the RIANS model), a major actor of DNA break repair and signaling. In 2016, with the first 117COPERNIC fibroblast lines, we obtained a significant correlation between the maximum number of the nuclear ATM foci, pATMmax, and the CTCAE severity grade of the post-radiotherapy tissue reactions. In this study, we propose to verify the validity of our previous findings with a new COPERNIC data subset obtained in the 2014-2024 period.

MATERIALS AND METHODS

We applied a standard immunofluorescence technique to quiescent COPERNIC fibroblasts to assess, after 2Gy, the level of micronuclei, γH2AX and pATM foci. The 117 COPERNIC data published in 2016 were considered as the reference data subset. A new COPERNIC data subset composed of 133fibroblast cell lines was considered as the validating data subset.

RESULTS

Our data showed that spontaneous or residual micronuclei levels, and residual γH2AX foci levels cannot predict CTCAE grades. Conversely, the linear formula linking the maximal number of pATM foci and the corresponding CTCAE grade and obtained in 2016 from the reference data subset fitted well the validating data.

CONCLUSIONS

The maximal number of pATM foci appears to be one of the most reliable biomarkers for predicting post-radiotherapy radiotoxicity.

DNA repair inhibitors and radiotherapy

Radiotherapy (RT) is one of the main cancer treatments and grows in importance due to improved techniques. DNA damage caused by ionizing radiation creates DNA strand breaks that trigger an intervention of DNA repair pathways involving numerous proteins and enzymes. In recent years, we have identified DNA repair inhibitors as targets for inhibiting cellular repair systems and thus causing cell death. Combining RT with these DNA repair inhibitors appears to be a new approach for cancer treatment, but safety and real efficiency of this combination in practice is unclear. Numerous trials are underway in various diseases and initial results are promising overall, yet remain controversial.

[Damage repair in breast cancer has to evolve]

Breast damage is likely to result in compensation according to the principle of full compensation. However, breast damage, little covered in the scales usually used, requires a specific methodology. The quantification of functional prejudice must be done with regard to the age of the victim and must take into account the possible repercussions on mobility (shoulder and/or spine) as well as the psychological repercussions. Whether or not the nipple and areola are preserved should be described. Temporary aesthetic damage (before breast reconstruction) must be assessed on the basis of objective elements, its duration and quantification on a scale of 0 to 7. Permanent aesthetic damage takes into account scars, deformities, amputations and quality of the prosthesis. A new scale for evaluating permanent aesthetic damage is proposed. Sexual prejudice must take into account an impairment of the pleasure related to sexuality and its erotic function, in line with the concept of sexual health. However, even after reconstruction, the areas of quality of sexual life and sexual satisfaction often remain affected. An exploration using standardized questions from validated questionnaires such as BREAST-Q can be useful. The sequelae linked to the damage on a breast can also lead the woman to limit certain pleasure activities, in particular because of psychological discomfort or even be the cause of a loss of opportunity to carry out a family's life plan.

[Flexor tendon repair: a short story]

This short story of flexor tendon repair aims to illustrate hesitations and wanderings of this surgery. Obviously tendon repair was very early considered, but it developed and diffused rather lately. It became a routine practice only in 20th century. This was due on the one hand, in Occident, to the Galen's dogmatic interdiction, on the other hand, to the repair difficulties of this paradoxical structure. Actually tendon is made of fibroblasts and collagen (sticky substances), and then its only goal is to move. According to this necessity, whatever the used techniques are, gliding is the final purpose. Technical evolutions are illustrated by historical contributions to flexor tendon surgery of several "giants" of hand surgery.