A Review on the Assessment of Radiation Induced Salivary Gland Damage After Radiotherapy

Adult stem cells are often touted as therapeutic agents in the regenerative medicine field, however data detailing both the engraftment and functional capabilities of solid tissue derived human adult epithelial stem cells is scarce. Here we show the isolation of adult human salivary gland (SG) stem/progenitor cells and demonstrate at the single cell level in vitro self-renewal and differentiation into multilineage organoids. We also show in vivo functionality, long-term engraftment, and functional restoration in a xenotransplantation model. Indeed, transplanted human salisphere-derived cells restored saliva production and greatly improved the regenerative potential of irradiated SGs. Further selection for c-Kit expression enriched for cells with enhanced regenerative potencies. Interestingly, interaction of transplanted cells with the recipient SG may also be involved in functional recovery. Thus, we show for the first time that salispheres cultured from human SGs contain stem/progenitor cells capable of self-renewal and differentiation and rescue of saliva production. Our study underpins the therapeutic promise of salisphere cell therapy for the treatment of xerostomia.

To investigate the impact of xerostomia on overall quality of life (QoL) outcome and related dimensions among head and neck cancer patients treated with primary radiotherapy. A total of 288 patients with Stage I-IV disease without distant metastases were included. Late xerostomia according to the Radiation Therapy Oncology Group (RTOG-xerostomia) and QoL (European Organization for Research and Treatment of Cancer QLC-C30) were assessed at baseline and every 6th month from 6 months to 24 months after radiotherapy. A significant association was found between RTOG-xerostomia and overall QoL outcome (effect size [ES] 0.07, p 65 years). An analysis of the impact of RTOG-xerostomia on overall QoL outcome over time showed an increase from 0.09 at 6 months to 0.22 at 24 months. With elapsing time, a worsening was found for these individual scales with increasing RTOG-xerostomia. The results of this prospective study are the first to show a significant impact of radiation-induced xerostomia on QoL. Although the incidence of Grade > or =2 RTOG-xerostomia decreases with time, its impact on QoL increases. This finding emphasizes the importance of prevention of xerostomia.