Table 1.

Characteristics of studies that evaluated cancer therapy-related dysgeusia.

Ref. n.	Study Design	Aim (s)	Participants (N)	Assessment Tool (s)	Cancer Treatments	Key Findings
[9]	Prospective	Prevalence	75 Prostate cancer	Survey regarding the taste and smell of food, appetite, and nausea.	CT and/or HT (regimen not specified)	TAs: 17%; SAs: 8%. TAs most frequent in patients treated with denosumab (35.0% vs. 10.9%, OR = 4.40, p = 0.020) or docetaxel (41.7% vs. 12.7%, OR = 4.91, p = 0.022). Poor taste of food associated with poor appetite and ≥10% weight loss.
[29]	Prospective	Self-reported TSDs based on the type of CT treatment. Impact of CT on the severity of the TSDs.	151	Questionnaire structured in three sections: eating habits; sensory changes (taste/smell changes and thermal sensitivity); and other clinical disorders (nausea, vomiting, dry mouth, mucositis, and dysphagia).	CT (regimen, Paclitaxel, oxaliplatin, docetaxel, carboplatin, anthracyclines, cisplatin, irinotecan, 5-FU, vinorelbine)	TAs: 76%. SAs: 45%. TAs in patients treated with anthracyclines, paclitaxel, carboplatin, and docet-axel. Cisplatin and 5-FU are the CT resulting in the lowest complaints. Xerostomia is strongly associated with bad taste in mouth (OR = 5.96; CI = 2.37–14.94; p value = 0.000) and taste loss (OR = 5.96; CI = 2.37–14.94; p value = 0.000).
[30]	Cross-sectional	Prevalence, severity and self-reported characteristics of TAs induced by CT. TAs across CT regimes.	243	Validated TA Scale Self-reported TAs duration CiTAS.	CT (regimen: FOLFOX, paclitaxel, docetaxel, cisplatin, pemetrexed, FEC, EC, FOLFIRI, Gemcitabina, TJ, TPF, Gemcarbo, Cisgem, Gemox)	TAs ranged from 51–86%. 43% of participants complained of TAs with the start of Ct and 75% reported TAs within the fourth week of treatment. TAs in patients treated with gemcitabine, cisplatin plus pemetrexed and epirubi-cin plus cyclophospha-mide (EC). Low levels of TAs were found among participants receiving GEMCARBO and CISGEM. 55% of participants reported some difficulties in tasting food. Tasting saltiness was the most affected ability.
[31]	Prospective	Incidence of TAs	41 BC	Not validated Questionnaire, filter paper disk method, CTCAE v. 4.0.	CT (regimen: Epirubicin, cyclophosphamide)	TA on the 4th day after CT was 53%. TAs decreased to about 9% immediately before new cycles. Age and body surface area influenced Tas.
[32]	Prospective	Prevalence TAs across CT regimes.	109 BC, gynecological	Validated TAs scale.	CT (regimen, Gemcitabina, epirubicin, docetaxel, capecitabine, epirubicin/docetaxel)	TAs was 76.1%. The highest TAs with epiru-bicin, docetaxel, capecita-bine. Lowest TAs with gem-citabine.
[33]	Prospective	To provide new data about TSDs.	33 head/neck	Sniffin’ Sticks test (Determination of threshold, discrimination, and identification, TDI).	CT (regimen: Cisplatin, carboplatin, 5-FU, docetaxel)	In normosmic or hyposmic, the mean decrease in TDI-score was significant lower during the second cycle. Age (>55 years) and smokers had a significant (negative) impact.
[34]	Prospective	Prevalence of dysgeusia.	31 males 15 females (9 did not undergo CT)	Salt-impregnated taste strips with 6 concentrations of Sodium chloride.	CT (regimen: 5-FU, platinum, Tx)	TAs in 38.8%. 48% in 5-FU or its oral analogues. 55.6% of patients receiving oral 5-FU analogues. Patients aged ≥70 years also tended to experience dysgeusia (75%).
[35]	Prospective	Effect of cisplatin CT on odor perception.	15 bronchial cancer patients and 15 control subjects	European Test of Olfactory Capabilities (ETOC).	CT (regimen: cisplatin)	Odor detection and odor identification abilities were not influenced by the administration of cisplatin, a decrease in pleasantness was observed only for food odors, and not for non-food odors.
[36]	Cross-sectional	TAs characteristics	100	Taste recognition thresholds (TRTs) via a taste disc kit PRO-CTCAE CiTAS.	CT (regimen: Tx based)	TAs in 59%. DTX associated with a higher prevalence of more severe and longer TAs than PTX or nab-PTX regimens. Significantly elevated taste recognition thresholds (hypogeusia) for sweet, sour, and bitter tastes in the taste alteration group receiving nab-paclitaxel (p = 0.022, 0.020, and 0.039, respectively). Docetaxel, previous CT, dry mouth, and peripheral neuropathy were significantly associated with Tas.
[37]	Observational	Prevalence and clinical therapeutic risk factors.	7425	CTCAE v5.0	CT (not specified)	TAs in 19.0%; 15.0% grade 1 dysgeusia and 6.0% grade 2. CT duration (p < 0.001), female sex (p < 0.001), location of the primary tumor in the uterus (p = 0.008), head and neck (p = 0.012), and testicles (p = 0.011), and use of ifosfamide (p = 0.009), docetaxel (p = 0.001), paclitaxel (p < 0.001), pertuzumab (p = 0.005), bevacizumab (p < 0.001), and dacarbazine (p = 0.002) independently increased the risk of dysgeusia.
[38]	Mixed methods	To investigate whether mycotoxic and/or neurotoxic drugs compromise olfactory performance.	44	Sniffin’ Sticks test (Determination of threshold, discrimination, and identification, TDI).	CT (regimen: Oxaliplatin, 5-FU, capecitabine, gemcitabine, carboplatin, cisplatin, doxorubicin, liposomal doxorubicin, taxanes)	TDI scores were significantly lower after chemotherapy in all age groups. Patients older than 50 years were more susceptible to olfactory toxicity.
[39]	Case control	Changes in the perception of tastes.	43	Taste strips	CT (regimen: platinum based)	Salty and sour were the most affected tastes in the study group (p = 0.001 and 0.05).
[40]	Observational	Changes in the detection (DT) and recognition (RT) thresholds of umami, sweet, and bitter tastes.	40 (NSCLC)	Rinsing technique. Not validated Questionnaire	CT (regimen: Cisplatin, paclitaxel)	TAs 34% after treatment. 42% reported a bitter taste in the mouth. 57% reported dry mouth. 35% reported food being tasteless, and 12% reported food having an unpleasant taste.
[41]	Qualitative	Patient and carer descriptions, experiences and consequences of taste and flavor changes.	10 patients 4 carers	Semi-structured interviews	Ct (regimen: Oxaliplatin)	TAs were apparent by the third CT cycle. Worse symptoms in the 5–7 days immediately post CT infusion, relief toward the end of a CT cycle. Full resolution of symp-toms by 6–8 weeks fol-lowing the completion of oxaliplatin treatment. Most common oral sensations: ‘metallic’ or a ‘slick’ or ‘coating’ in the mouth.

Abbreviations. CT: chemotherapy; HT: hormone therapy; 5-FU: 5-fluorouracil; TAs: taste alterations; FOLFOX: folinic acid, fluorouracil, oxaliplatin; FEC: epirubicin, fluorouracil, cyclophosphamide; EC: epirubicin, cyclophosphamide; FOLFIRI: folinic acid, fluorouracil, irinotecan; TA: taste alteration; TJ: carboplatin, paclitaxel; TPF: docetaxel, cisplatin, fluorouracil; GEMCARBO: gemcitabine, carboplatin; GEMOX: gemcitabine, oxaliplatin; CISGEM: cisplatin, gemcitabine; BC: breast cancer; CTCAE: Common Terminology Criteria for Adverse Events; Tx: taxane; CiTAS: Chemotherapy induced Taste Alteration Scale; PRO-CTCAE: patient-reported outcome; DTX: docetaxel; PTX: paclitaxel; nab-PTX: nab-paclitaxel; NSCLC: non-small cell lung cancer.