Table 1 Studies reporting clinical features of xerostomia in patients with advanced cancer

Davies et al., 2021 [17]

n = 250

Mixed cancer: gastrointestinal (32%), lung (18%), breast (14%)

Median age: 68 yr (range 36–91 yr)

Female: 58%

Oral Symptom Assessment Scale (OSAS)

Frequency: options—“rarely”, “occasionally”, “frequently”, “almost constantly”

Intensity: options—“slight”, “moderate”, “severe”, "very severe"

Distress: options—“not at all”, “a little bit”, “somewhat”, “quite a bit”, “very much”

Prevalence: 83.5%

Most common oral symptom reported

Frequency: “rarely”- 9%, “occasionally” - 18.5%, “frequently” - 39%, “almost constantly”- 33.5%

Intensity: “slight”- 23%, “moderate”- 41%, “severe"- 26.5%, "very severe"- 9.5%

Distress: “not at all”- 18%, “a little bit”- 30%, “somewhat”- 21%, “quite a bit”- 19%, “very much”- 12%

Webber et al., 2021 [18]

n = 1507

Mixed cancer: gastrointestinal (52%), urological (12%), lung (10%)

Median age: 66 yr (no range)

Female: 48%

Memorial Symptom Assessment Scale-Short form (MSAS-SF) [59]

Distress: options—“not at all”, “a little bit”, “somewhat”, “quite a bit”, “very much”

Prevalence: 70%

4^th most common symptom reported

Distress: “not at all/a little”- 40%, “somewhat”- 20%, “quite a bit/very much”- 40%

Tebidze et al., 2019 [19]

n = 50

Mixed cancer: lung (37%), urological (13%), breast (11%), gynaecological (11%)

Age range: 20–75 yr

Female: 40%

Non-validated questionnaire

Intensity: options—“slight”, “moderate”, “severe”

Prevalence: 74%

Intensity: “slight”- 19%, “moderate”- 46%, “severe”- 35%

Vigstad et al., 2019 [20]

n = 274

Mixed cancer: gastrointestinal (29.5%), lung (25%), urological (15.5%)

Median age: 69 yr (range 38–90 yr)

Female: 49%

Edmonton Symptom Assessment Scale (ESAS)—Norwegian version

Intensity: 0–10 NRS; 0 = “none”, 1–3 = “mild”, 4–6 = “moderate”, 7–10 = “pronounced”

Prevalence: 73%

Intensity: “none” - 27%, “mild” - 20%, “moderate” - 24%, “pronounced” - 29%

Van Lancker et al., 2017 [21]

n = 400

Mixed cancer: lung (23%), gynaecological (12%), gastrointestinal (10%)

Mean age: 75 yr (range 65–93 yr)

Female: 48%

Assessment Symptoms Palliative Elderly (ASPE) [60]. [ASPE appears to have been modified in this study]

Frequency: options—“rarely”, “sometimes”, “often”, “always”

“Intensity”: options—“not”, “somewhat”, “moderate”, “very serious”

Prevalence: 77%

Most common symptom reported

Frequency: “rarely”- 2%, “sometimes”- 33%, “often”- 32%, “always”- 33%

Intensity: “not” - 25%, “somewhat”- 13%, “moderate”- 25.5%, “very serious”- 36.5%

Alsirafy, 2016 [22]

n = 89

Mixed cancer: gastrointestinal (26%), central nervous system (21%), lung (14%)

Median age: 53 yr (no range)

Female: 42%

Open questioning about symptoms / non-validated questionnaire

Intensity: options—“mild”, “moderate”, “severe”

Prevalence: 57% (questionnaire)

6^th most common symptom reported

One patient reported  xerostomia on open questioning

Intensity: “mild”- 57%, “moderate”- 27.5%, “severe”- 15.5%

Mercadante et al., 2015 [23]

n = 669

Mixed cancer: gastrointestinal (38%), lung (21%), haematological (10.5%)

Mean age: 72.1 yr (SD ± 12.3 yr)

Female: 49%

Non-validated questionnaire

Intensity: 0–10 NRS; 0 = “absence of symptom”, 10 = “maximum intensity a patient can imagine”

Prevalence: 40.4%

Intensity: mean 5.4 (SD ± 2.1)

Fischer et al., 2014 [24]

n = 104

“Terminally ill cancer patients”

Mean age: 66 yr (SD ± 16.3 yr)

Female: 59%

Non-validated questionnaire

Frequency: 0–10 NRS

Intensity: 0–10 NRS; 0 = “no dry mouth”, 10 = “dry mouth as much as can be”

Prevalence: 91%

Frequency: mean 5.8 (SD ± 2.5)

Intensity: mean 5.02 (SD ± 3.07); median 6.06

Oechsle et al., 2013 [25]

n = 40

Mixed cancer: lung (30%), gastrointestinal (15%), gynaecological (15%)

Median age: 63 yr (range 37–88 yr)

Female: 55%

Memorial Symptom Assessment Scale—German version (modified)

Frequency: options—“rarely” (score = 1), “occasionally” (score = 2), “frequently” (score = 3), “almost constantly” (score = 4)

Intensity: options—“slight” (score = 1), “moderate” (score = 2), “severe” (score = 3), "very severe" (score = 4)

Distress: options—“not at all” (score = 0), “a little bit” (score = 1), “somewhat” (score = 2), “quite a bit” (score = 3), “very much” (score = 4)

Prevalence: 63%

Frequency: mean 1.55 (SD ± 1.50)

Intensity: mean 1.42 (SD ± 1.39)

Distress: mean 1.07 (SD ± 1.40)

Al-Shahri et al., 2012 [26]

n = 124

Mixed cancer: breast (27.4%), head and neck (15.3%), gastrointestinal (12.9%)

Median age: 56 yr (range 20–92 yr)

Female: 59%

Non-validated questionnaire

Intensity: 0–10 NRS; 0 = “absence”, 10 = “greatest severity”

Prevalence: 69.4%

Intensity: mean 4.5 (SD ± 2.3)

Intensity: median 5 (range 0–10)

Alt-Epping et al., 2012 [27]

n = 101

Mixed cancer: gastrointestinal (30%), lung (22%) breast (14%)

Age: < 60 yr—39.5%, ≥ 60 yr—60.5%

Female: 59.5%

Non-validated questionnaire

Intensity: 0–10 NRS; 0–1 = “quite low”, 4–5 = “moderate”, 9–10 = “quite high”

Prevalence: 82%

Intensity: 0–1 - 37.5%, 2–3 - 7%, 4–5 - 29%, 6–8 - 6%, 9–10 - 20.5%

Wilberg et al., 2012 [28]

n = 99

Mixed cancer population: gastrointestinal (21%), lung (19%), prostate (11%)

Mean age: 63.9 yr (SD ± 12.3 yr)

Female: 53.5%

Edmonton Symptom Assessment Scale—Norwegian version

Intensity: 0–10 NRS; higher scores = higher intensity

Prevalence: 78%

Intensity: mean 4.7 (SD ± 3.0)

Spichiger et al., 2011 [53]

n = 103

Mixed cancer: urological (23.5%), gastrointestinal (18.5%), lung (16.5%)

Mean age: 63 yr (range 19–89 yr)

Female: 38%

Memorial Symptom Assessment Scale (MSAS) [61]

Frequency: options–“rarely” (score = 1), “occasionally” (score = 2), “frequently” (score = 3), “almost constantly” (score = 4)

Intensity: options—“slight” (score = 1), “moderate” (score = 2), “severe” (score = 3), "very severe" (score = 4)

Distress: options—“not at all” (score = 0), “a little bit” (score = 1), “somewhat” (score = 2), “quite a bit” (score = 3), “very much” (score = 4)

Prevalence: 65% (admission)

Frequency: mean 2.66

Intensity: mean 2.44

Distress: mean 2.03

Webber et al., 2011 [54]

n = 120

Mixed cancer diagnosis: gastrointestinal (28%), breast (14%), lung (13%), urological (13%)

Median age: 61 yr (range 20–87 yr)

Female: 54%

MSAS-SF (see above)

Prevalence: 70%

Distress: “not at all”/ “a little bit”- 44%, “somewhat”- 19%, “quite a bit” / “very much”- 37%

Kirkova et al., 2010 [55]

n = 181

Mixed cancer: gastrointestinal (29.5%), lung (24%), haematological (9.5%)

Mean age: 64 yr (SD ± 13 yr)

Sex: no data

Non-validated questionnaire

Distress: options—“bothersome / distressful”, “not”

Prevalence: 66%

Distress: “bothersome / distressful” - 50%

Bovio et al., 2009 [29]

n = 143

Mixed cancer: lung (36.5%), gastrointestinal (33.5%), urological (7%)

Mean age: 68 yr (range 57–79 yr)

Female: 35%

Non-validated questionnaire (adapted from MSAS-SF)

[Xerostomia deemed present if patient was distressed “somewhat”/ “quite a bit”/ “very much”, but not “a little bit”]

Prevalence: 73%

Xerostomia associated with anorexia (p = 0.012), and dysphagia for solids (p = 0.032)

Xerostomia associated with reduced energy intake (p = 0.006)

McMillan et al., 2009 [30]

n = 275

Mixed cancer: lung (33%), gastrointestinal (25.5%), urological (12.5%)

Mean age: 72.7 yr (SD ± 11.7 yr)

Female: 45.5%

MSAS—modified version

Intensity: options—“slight” (score = 1), “moderate” (score = 2), “severe” (score = 3), "very severe" (score = 4)

Distress: options—“not at all” (score = 0), “a little bit” (score = 1), “somewhat” (score = 2), “quite a bit” (score = 3), “very much” (score = 4)

Prevalence: 71.3%

3^rd most common symptom reported

Intensity: mean 2.2 (SD ± 1.1)

Distress: mean 1.7 (SD ± 1.3)

Higher distress score associated with higher score on Clinical Epidemiological Scale – Depression (p = 0.003)

Tsai et al., 2006 [31]

n = 77

Mixed cancer: gastrointestinal (44%), lung (23.5%), gynaecological (10.5%)

Median age: 62 yr (range 16–86 yr)

Female: 61%

Non-validated questionnaire

Intensity: options–“none” (score = 0), “mild” (score = 1), “moderate” (score = 2), “severe” (score = 3),

Prevalence: 53.9% (admission)

Intensity (admission): mean 0.7 (SD ± 0.8)

Tranmer et al., 2003 [56]

n = 66

Mixed cancer: “metastatic cancer or stage IV lymphoma”

Mean age: 64.14 yr (SD ± 12.16 yr)

Female: 56%

MSAS (see above)

Prevalence: 82%

2^nd most common symptom reported

Frequency: “frequently” / “almost constantly”- 76%

Severity: “moderate” / “severe” / “very severe”- 91%

Distress: “quite a bit” / “very much”- 37%

McMillan et al., 2002 [32]

n = 178

“Patients with cancer newly admitted to hospice home care”

Mean age: 71 yr (range 37-95 yr)

Female: 40%

MSAS—modified version

Distress: options—“not at all” (score = 0), “a little bit” (score = 1), “somewhat” (score = 2), “quite a bit” (score = 3), “very much” (score = 4)

Prevalence: 78%

3^rd most common symptom reported

Distress: mean 2.5 (SD ± 1.1)

Davies et al., 2001 [2]

n = 120

Mixed cancer: “most common

cancer diagnoses were carcinoma of breast, bronchus, prostate, and large bowel”

Median age: 66 yr (range 19–89 yr)

Female: 61%

MSAS (see above)

Additional questions about “mouth discomfort”, “difficulty chewing”, and “difficulty speaking”

Prevalence: 78%

4^th most common symptom reported

Frequency: “rarely” - 4.5%; “occasionally” - 20.5%; “frequently” - 39.5%; “almost constantly” - 35.5%

Severity: “slight” - 14%; “moderate” - 36.5%; “severe” - 33.5%; “very severe” - 16%

Distress caused: “not at all” - 16%; “a little bit” - 21.5%; “somewhat” - 22,5%; “quite a bit” - 26%; “very much” - 14%

Severity of xerostomia correlated with severity of mouth discomfort (p < 0.001); difficulty speaking (p < 0.001); “change in the way food tastes” (p = 0.001); lack of appetite (p = 0.005); difficulty chewing (p = 0.01); difficulty swallowing (p = 0.01)

Oneschuk et al., 2000 [33]

n = 99

Mixed cancer: lung (28%), gastrointestinal (27%), genitourinary (18%),

Mean age: 67 yr (SD ± 12.7 yr)

Female: 58%

Non-validated questionnaire

Intensity: 0–10 NRS

Relative “importance” versus other symptoms / problems: options–“not important” (score = 1), “slight importance” (score = 2), “some importance” (score = 3), “moderate importance” (score = 4), “considerable importance” (score = 5), “very important” (score = 6), “great importance” (score = 7)

Prevalence: 88%

Intensity: mean 6.2 (SD ± 2.21)

Relative importance: mean 3.6 (SD ± 1.67)