The effectiveness of AI-based chatbots in psycho-oncology is related to the technology's capacity to provide continuous, accessible, and tailored psychological support to the needs of cancer patients. Cancer distress as a form of psychological, emotional, social, or spiritual distress can manifest from the time of diagnosis to the stages of treatment and afterwards, and is associated with anxiety, depression, sleep disturbances, concerns about recurrence, and decreased quality of life. From a theoretical perspective, intelligent chatbots can cover a portion of patients' psychological needs by providing interactive communication, psychoeducation, identifying distress symptoms, and teaching coping strategies. These systems are able to provide content related to anxiety management, breathing and relaxation, emotion regulation, problem-solving, and treatment adaptation at the right time, based on the patient's responses, and refer the patient to a psychologist or other members of the treatment team for a specialized evaluation if warning signs are observed. Early evidence in the field of digital interventions and mental health chatbots suggests that structured interaction with these technologies can be associated with a reduction in distress and anxiety in some patients, especially when the chatbot is designed based on a valid psychological framework and is part of a comprehensive care plan. However, the severity and persistence of this effect depends on the type of cancer, the stage of treatment, individual characteristics, the level of patient participation, and the quality of system design, and chatbots cannot be considered as a substitute for specialized psychological intervention. Its most important applications include early Distress screening, daily symptom monitoring, providing short interventions, strengthening psychological self-care, and facilitating patient communication with the treatment team. In contrast, the possibility of providing an incorrect response, inadequate diagnosis of psychological crises, poor understanding of emotional nuances, confidentiality issues of health data, and the patient's over-dependence on technology are important challenges. Therefore, the effectiveness of chatbots AI should be evaluated with indicators such as reduced distress and anxiety scores, improved quality of life, increased self-efficacy, and patient satisfaction rates. It is suggested that future studies be conducted with randomized trials, diverse cancer samples, longer follow-up periods, and comparisons with usual care or standard psychological interventions. Also, the use of chatbots in psycho-oncology should be under expert supervision, based on valid protocols, and accompanied by a referral mechanism in high-risk settings. Overall, AI-powered chatbots can be used as a complementary tool in reducing some components of distress and anxiety in patients undergoing cancer treatment, but determining their definitive effectiveness and clinical status still requires quality empirical evidence and long-term evaluations.