Table 1 Acupuncture treatment details based on the STRICTA checklist [11]

1a) Style of acupuncture

 - electro-acupuncture

1b) Reasoning for treatment provided, based on historical context, literature sources, and/or consensus methods, with references where appropriate

 - electro-acupuncture treatment based on the theory of TCM, literature sources, and clinical experience in acupuncture and CINV, such as references [16] and [17].

1c) Extent to which treatment was varied

 - The treatment was not varied.

2a) Number of needle insertions per subject per session (mean and range where relevant)

 - From 2 to 3.

2b) Names (or location if no standard name) of points used (uni/bilateral)

 - Four points used: ST36 (bilateral); PC6 (bilateral) ;CV12(unilateral); CV13 (unilateral).

2c) Depth of insertion, based on a specified unit of measurement, or on a particular tissue level

 - PC6: 0.5 body-inches; ST36: 1-1.5 body-inches; CV12 and CV13: 1-1.5 body-inches.

2d) Response sought (e.g., de qi or muscle twitch response)

 - ‘De qi’ sensation will be achieved by lifting and thrusting combined with twirling and rotating the needles.

2e) Needle stimulation (e.g., manual, electrical)

 - Electrical stimulation: the frequency is 2/10 Hz, and the intensity of stimulation is adjusted according to the patient’s tolerance (maximum of 10 mA).

2f) Needle retention time

 - Thirty minutes

2g) Needle type (diameter, length, and manufacturer or material)

 - A disposable stainless steel acupuncture needle, 0.25mm × 40 mm (Huatuo, Suzhou Medical Co. Ltd., Jiangsu, China).

3a) Number of treatment sessions

 - Four treatment sessions in acupuncture groups.

3b) Frequency and duration of treatment sessions

 - Once daily for 4 days, 30 minutes for each session.

4a) Details of other interventions administered to the acupuncture group (e.g., moxibustion, cupping, herbs, exercises, lifestyle advice)

 - No other interventions.

4b) Setting and context of treatment, including instructions to practitioners, and information and explanations to patients

 - University hospitals.

 - Participants will be informed about acupuncture treatment in the study as follows: “In this study, eletroacupuncture for CINV will be used based on traditional Chinese medicine.”

5) Description of participating acupuncturists (qualification or professional affiliation, years in acupuncture practice, other relevant experience)

 - The participating acupuncturists have all majored in acupuncture, have an acupuncture degree, and are qualified doctors of Tradition Chinese Medicine. All have at least 3 years of experience, and will have been trained in the standard operating procedure of electro-acupuncture on CINV. Thus, they are able to provide identical acupuncture treatment in accordance with a pre-defined protocol.

6a) Rationale for the control or comparator in the context of the research question, with sources that justify this choice

 - The control group is supplied with standard antiemetic alone, so as to provide patients with conventional treatment for CINV.

6b) Precise description of the control or comparator. If sham acupuncture or any other type of acupuncture-like control is used, provide details as for items 1 to 3 above.

 - Participants in the control group will not receive acupuncture treatment.