This study aims to investigate the effects of Transcutaneous Electrical Nerve Stimulation (TENS) in reducing the symptoms of pain and numbness and improve the daily lives of cancer patients who have Chemotherapy-induced peripheral neuropathy (CIPN).

Chemotherapy-induced peripheral neuropathy (CIPN) results from damage or dysfunction of the peripheral nerves and is one of the most common side effects of antineoplastic chemotherapy when neurotoxic drugs are used. Pain and paresthesia symptoms are prevalent, causing chronic discomfort and loss of functional abilities whilst also interfering negatively with quality of life and the patient's autonomy. In a pilot study of patients with CIPN, there was evidence that Transcutaneous Electrical Nerve Stimulation (TENS) improved the painful symptoms of patients with CIPN. This study aims to investigate the effects of TENS in reducing the symptoms of pain and numbness and improve the daily lives of cancer patients who have CIPN.

1. Primary Objectives Evaluate the effects of TENS in the reduction of symptoms related to peripheral neuropathy due to chemotherapy treatment of a high and moderate neurotoxic potential in cancer patients.

Secondary Objectives:

• Evaluate the therapeutic response of TENS with frequency variation (FV) in symptoms of paresthesia
• Evaluate the therapeutic response of TENS with frequency variation (FV) in activities of the daily lives of patients
• Evaluate the therapeutic response of TENS with frequency variation (FV) in symptoms of neuropathic pain.
• Evaluate the factors associated with better treatment response in paresthesia, in pain and activities of daily living.

Eligibility criteria: The participants of the research will include patients with any cancer diagnosis who are being subjected to chemotherapy in either adjuvant or neoadjuvant therapy, containing in its protocol at least one chemotherapeutic drug of moderate and high neurotoxic potential.

The participants of the research will receive TENS within the following parameters: VF mode TENS with a variable frequency between 7 Hz and 65 Hz. It has a pulse width of 200 µs, this is the highest tolerable intensity while still remaining comfortable for the patient. It has an application time of 60 minutes with the highest tolerable intensity, while still remaining comfortable for the patient. The treatment will be given on the same day as the chemotherapy, and will be given from home within 3 cycles. The participants will be divided into 2 groups: Experimental Group (EG) who will be administering the active TENS and the Control Group (CG) who will be administering the placebo TENS. The evaluation of the effects will be measured through the following instruments: Classification of neuropathy by the CTCAE (Common Terminology Criteria for Adverse Events) version 4.02 2009, scale of functionality ECOG, the Questionnaire of Neurotoxicity Induced by Antineoplastics (QNIA) for the evaluation of the symptoms of CIPN, and the Analogue Visual Scale (AVS) to assess the symptoms of pain and paresthesia. The error α is estimated at 5%.

Inclusion Criteria:

• - Patients who are being subjected to chemotherapeutic treatment with drugs or association of drugs with high and moderate neurotoxic degree and who present neuropathic pain and / or peripheral sensory neuropathy grade I and II of the CTCAE scale (Appendix A).
• Patients showing symptoms of peripheral neuropathy in the first cycle of chemotherapeutic treatment with three points on the visual analogue scale of pain and paresthesia.
• Patients aged between 18 and 70 years.
• Patients without Diabetes Mellitus before and during chemotherapy treatment.
• Patients who have not undergone previous chemotherapy regimens with neurotoxic drugs.
• Patients with ECOG performance status ≤ 2 (Karnofsky ≥ 50%).
• Patients that do not have a cardiac pacemaker.
• Patients without changes in sensitivity prior to chemotherapy.
• Patients without skin lesions at the site or around the site of application of the electrodes.
• Patients without cognitive and comprehension difficulties.
• Agree to participate in the study by signing the Free and Clarified Term of Consent- FCTC

Exclusion Criteria:

• Patients who have already undergone chemotherapy previously with drugs or have had association with neurotoxic drugs which have presented neuropathic pain and/or sensory peripheral neuropathy.
• Patients who have previously had acupuncture for the treatment of neuropathic pain and/or sensory peripheral neuropathy.