This is control group

experimenal group

After randomization, patients assigned to the intervention group will be informed about the study beforehand and their informed consent will be obtained. Subsequently, each patient will be given both theoretical and practical instructions on how to use the stress ball, and will be asked to practice. Patients will be given individual stress balls approximately 6 cm in diameter, of medium firmness, and made of medical-grade silicone. Patients who successfully use the stress ball will be instructed to take deep breaths, squeeze the stress ball in their hands, and exhale to release it for approximately 5-10 minutes during the port catheter change procedure. The practice will be observed by the researcher to ensure standardization. Throughout the study, all port catheter changes will be performed by the same nurse in the clinic, who is not involved in the study.

The State Anxiety Scale is a 20-item, 4-point Likert-type scale designed to determine how an individual feels at a given moment and under specific conditions. In the State Anxiety Inventory, the individual is asked to rate how they feel "right now" and choose one of the following options based on the intensity of the emotion or behavior expressed in the items: (1) "none", (2) "a little", (3) "a lot", and (4) "completely". The highest score of 4 is given for choosing "completely", and the lowest score of 1 is given for choosing "none". The lowest possible total score on the State Anxiety Scale is 20, and the highest is 80. A high score indicates a high level of anxiety, while a low score indicates a low level of anxiety.

Numerical Rating Scale The scale used to diagnose pain has numerical values between 0 and 10. The patient is asked to indicate their pain on the scale. During the evaluation, an 11-point scale was used, where "0" represents "no pain" and "10" represents "the most severe pain imaginable".