The effect of hematopoietic stem cell transplantation on patient-reported subjective oral dryness: a systematic review focusing on prevalence, severity and distress

Salivary flow rate, subjective oral dryness and dental caries 5 years after haematopoietic cell transplantation

BACKGROUND

The aim of this study was to describe salivary flow rate, subjective oral dryness and dental caries 5 years post haematopoietic cell transplantation (HCT).

METHODS

HCT survivors of a previous longitudinal observational cohort study in the Netherlands (the H-OME study) were invited to participate in this additional follow-up after 5 years (the HOME2 study). During the additional follow-up appointment, stimulated (SWS) and unstimulated whole saliva (UWS) was collected, participants rated subjective oral dryness on a 0 - 10 scale, and caries lesions were assessed. Furthermore, dental records, including treatments and radiographs, were requested for the 5 years preceding and the 5 years following transplantation. Paired t-tests were performed to determine changes in UWS and SWS flow rates and subjective oral dryness from pre-HCT, and to compare the number of caries-related dental treatments (restorations, endodontic treatments or extractions) before and after HCT. Hyposalivation of UWS (< 0.2 mL/min) and SWS (< 0.7 mL/min) at 3 and 12 months, was used to explore the predictive potential of hyposalivation on a high dental treatment need (> 3 treatments) over the 5 years post-HCT.

RESULTS

Five years post-HCT, 39 HCT survivors were included. The mean UWS flow rate was 0.36 mL/min (SD 0.26) and the mean SWS flow rate 1.02 (SD 0.57); survivors were diagnosed with a median of 0 dentine lesions (range 0 - 12) and 73% reported a subjective oral dryness score ≥ 1. Survivors underwent a median of 3 (range 0 - 20) dental treatments during the 5 years following transplantation. The mean difference in UWS 5 years post-HCT compared to pre-HCT was 0.03 (95% CI: -0.07 - 10.12), the mean difference for SWS was -0.18 (95% CI: -0.45 - 0.08) and for subjective oral dryness 1.2 (95% CI: 0.2 - 2.1). In the 5 years post-HCT, non-significantly more treatments were performed compared to the 5 years pre-HCT (mean difference: 0.5, 95%CI: -1.2 - 2.2). Seventy eight percent of patients with hyposalivation of SWS at 12 months had a high dental treatment need, compared with 38% with no hyposalivation.

CONCLUSIONS

Five years post-HCT, mean UWS and SWS flow rates were not significantly different from pre-HCT levels but subjective oral dryness scores were elevated.

Cancer therapy-related salivary dysfunction

Salivary gland dysfunction is a common side effect of cancer treatments. Salivary function plays key roles in critical daily activities. Consequently, changes in salivary function can profoundly impair quality of life for cancer patients. We discuss salivary gland anatomy and physiology to understand how anticancer therapies such as chemotherapy, bone marrow transplantation, immunotherapy, and radiation therapy impair salivary function. We discuss approaches to quantify xerostomia in the clinic, including the advantages and limitations of validated quality-of-life instruments and approaches to directly measuring salivary function. Current and emerging approaches to treat cancer therapy-induced dry mouth are presented using radiation-induced salivary dysfunction as a model. Limitations of current sialagogues and salivary analogues are presented. Emerging approaches, including cellular and gene therapy and novel pharmacologic approaches, are described.

Subjective Oral Dryness following Hematopoietic Cell Transplantation: A Report from the Orastem Study

Xerostomia, or subjective oral dryness, is a serious complaint after hematopoietic cell transplantation (HCT). Xerostomia is rated as one of the most bothersome symptoms by HCT recipients, negatively affecting quality of life. This substudy of the Orastem study, a prospective longitudinal, international, observational, multicenter study, aimed to describe the prevalence and severity of xerostomia following HCT. Furthermore, the effect of the conditioning regimen, type of transplantation, and oral mucosal changes related to chronic graft-versus-host disease (cGVHD) in the development of xerostomia were studied. All HCT recipients rated xerostomia on a scale of 0 to 10 before the conditioning regimen, several times early post-HCT, and at 3 months post-HCT, and only allogeneic HCT recipients also rated xerostomia at 6 and 12 months post-HCT. In addition, stimulated whole mouth saliva was collected several times. Linear regression models and longitudinal mixed-effects models were created to investigate the influence of risk indicators on xerostomia. A total of 99 autologous and 163 allogeneic HCT recipients were included from 6 study sites in Sweden, Canada, the Netherlands, and the United States. The prevalence of xerostomia was 40% before the conditioning regimen, 87% early post-HCT, and 64% at 3 months post-HCT. Complaints after autologous HCT were transient in nature, while the severity of xerostomia in allogeneic HCT recipients remained elevated at 12 months post-HCT. Compared to autologous HCT recipients, allogeneic HCT recipients experienced 1.0 point more xerostomia (95% confidence interval [CI], .1 to 2.0) early post-HCT and 1.7 points more (95% CI, .4 to 3.0) at 3 months post-HCT. Allogeneic HCT recipients receiving a high-intensity conditioning regimen experienced more xerostomia compared to those receiving a nonmyeloablative or reduced-intensity conditioning regimen. The difference was 2.0 points (95% CI, 1.1 to 2.9) early post-HCT, 1.8 points (95% CI, .3 to 3.3) after 3 months, and 1.7 points (95% CI, .0 to 3.3) after 12 months. Total body irradiation as part of the conditioning regimen and oral mucosal changes related to cGVHD did not significantly influence the severity of xerostomia. Conditioning regimen intensity was a significant risk indicator in the development of xerostomia, whereas total body irradiation was not. Allogeneic HCT recipients experienced more xerostomia than autologous HCT recipients, a difference that cannot be explained by a reduction in stimulated salivary flow rate or the development of oral mucosal changes related to cGVHD.