Management of radiotherapy-induced skin reactions

Repurposing of FDA approved kinase inhibitor bosutinib for mitigation of radiation induced damage via inhibition of JNK pathway

Radiotherapy is a common modality for cancer treatment. However, it is often associated with normal tissue toxicity in 20-80% of the patients. Radioprotectors can improve the outcome of radiotherapy by selectively protecting normal cells against radiation toxicity. In the present study, compound libraries containing 54 kinase inhibitors and 80 FDA-approved drugs were screened for radioprotection of lymphocytes using high throughput cell analysis. A second-generation FDA-approved kinase inhibitor, bosutinib, was identified as a potential radioprotector for normal cells. The radioprotective efficacy of bosutinib was evinced from a reduction in radiation induced DNA damage, caspase-3 activation, DNA fragmentation and apoptosis. Oral administration of bosutinib protected mice against whole body irradiation (WBI) induced morbidity and mortality. Bosutinib also reduced radiation induced bone-marrow aplasia and hematopoietic damage in mice exposed to 4 Gy and 6 Gy dose of WBI. Mechanistic studies revealed that the radioprotective action of bosutinib involved interaction with cellular thiols and modulation of JNK pathway. The addition of glutathione and N-acetyl cysteine significantly reduced the radioprotective efficacy of bosutinib. Moreover, bosutinib did not protect cancer cells against radiation induced toxicity. On the contrary, bosutinib per se exhibited anticancer activity against human cancer cell lines. The results highlight possible use of bosutinib as a repurposable radioprotective agent for mitigation of radiation toxicity in cancer patients undergoing radiotherapy.

Adipose-Derived Stem Cells Therapy for Radiation-Induced Skin Injury

BACKGROUND

Radiation-induced skin injuries have been treated with different medical therapies and have shown diverse outcomes. We aim to evaluate the effect of adipose-derived stem cells (ADSCs) therapy on radiation-induced skin injury.

METHODS

We performed a review by querying PubMed, Ovid MEDLINE, and EMBASE databases from inception to April 2020 following Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. The MeSH terms "adipose-derived stem cells," "wound healing," "radiation," and synonyms in combinations determined our search strategy. Experimental peer-reviewed articles describing the protocol and comparing the results with controls were included. Non-English studies were excluded.

RESULTS

Our search recorded a total of 137 articles. Only 8 studies met our inclusion criteria and were included in this review. Five studies evaluated the use of ADSC alone, whereas the others evaluated the efficacy of ADSC seeded in scaffolds. Adipose-derived stem cell-based therapies, either alone or seeded in scaffolds, were shown to improve wound healing in most studies when compared with controls.

CONCLUSIONS

There is evidence supporting the positive benefits from ADSC-based therapies in radiation-induced skin injury. However, further studies are needed to standardize the method of ADSC extraction, radiation-induced skin injury experimental model, and increase the time of follow-up to evaluate the results accurately.

Evaluation of skin reactions during proton beam radiotherapy - Patient-reported versus clinician-reported

BACKGROUND

Skin reaction is a common side-effect of radiotherapy and often only assessed as clinician-reported outcome (CRO). The aim was to examine and compare patient-reported outcome (PRO) of skin reactions with CRO for signs of acute skin reactions for patients with primary brain tumour receiving proton beam radiotherapy (PBT). A further aim was to explore patients' experiences of the skin reactions.

METHODS

Acute skin reactions were assessed one week after start of treatment, mid-treatment and end of treatment among 253 patients with primary brain tumour who underwent PBT. PRO skin reactions were assessed with the RSAS and CRO according to the RTOG scale. Fleiss' kappa was performed to measure the inter-rater agreement of the assessments of skin reactions.

RESULTS

The results showed a discrepancy between PRO and CRO acute skin reactions. Radiation dose was associated with increased skin reactions, but no correlations were seen for age, gender, education, occupation, other treatment or smoking. There was a poor agreement between patients and clinicians (κ = -0.016) one week after the start of PBT, poor (κ = -0.045) to (κ = 0.396) moderate agreement at mid treatment and poor (κ = -0.010) to (κ = 0.296) moderate agreement at end of treatment. Generally, patients' symptom distress toward skin reactions was low at all time points.

CONCLUSION

The poor agreement between PRO and CRO shows that the patient needs to be involved in assessments of skin reactions for a more complete understanding of skin reactions due to PBT. This may also improve patient experience regarding involvement in their own care.