Neural Networks Classification for Breast Cancer Analysis Paquita Putri 1, Intan Nurma Yulita 2 {paquitaputri0701@yahoo.com 1 , intan.nurma@unpad.ac.id 2 } Department of Computer Science, Padjadjaran University, Sumedang 45363, Indonesia 1,2 Abstract. Cancer is caused by a lump from a collection of cells that grows and attacks the surrounding tissue. Most breast lumps are benign, but benign breast lumps can increase the risk of developing breast cancer. Early detection can provide better handling. The diagnosis of breast cancer by a doctor is done by analyzing several factors. To help the doctor in diagnosing the data efficiently, this study implemented machine learning. The diagnosis was based on the features of digital image computation in the process of fine-needle aspiration (FNA) of a breast mass. The data came from 569 patients. The study used the neural networks classification method with multilayer perceptron algorithms. The results were obtained that the use of neural networks gave higher accuracy if it compared it in the ZeroR method. Their accuracies were 95.96%, and 62.74%, respectively. Keywords: Breast Cancer, Neural Networks, ZeroR, Multilayer Perceptron 1 Introduction Breast cancer is a type of cancer that has a high mortality rate [1]. This cancer is the most common cancer in women throughout the world and also the second most common overall [2]. This cancer is a disease in which breast cells grow out of control and attack the surrounding tissue. These cells usually form tumors that can be seen on x-ray results and felt as a lump [3]. In 2012, nearly 1.7 million cases of new breast cancer were diagnosed [4]. Cancer starts with a tumor. A tumor is a collection of abnormal cells that form lumps and grow. Tumors grow and behave differently, depending on their nature; malignant (cancer) or benign (non- cancerous) [5]. Most breast lumps are benign and not cancerous (malignant tumors). Non- cancerous breast tumors are abnormal growths, but do not spread outside the breast and are not life-threatening. But some benign breast lumps can increase the risk of developing breast cancer. Tumors are said to be malignant (cancer) if cells can grow to attack surrounding tissue or spread (metastasize) to areas of the body. Breast cancer generally attacks women, but men can also get breast cancer [6]. Malignant tumors are cells that can grow attacking the surrounding tissue while benign tumors are cells that grow but can be operated to remove the tumor without damaging the surrounding tissue [7]. The term breast cancer refers to malignant tumors that have developed in cells in the breast. It is important for everyone to check for a lump in the breast to find out whether the lump is cancerous or not so preventive measures can be taken [8]. When detected in the initial stages, there is a 30% chance that cancer can be treated effectively, but the delay in detecting will make treatment more difficult [9]. In order to optimize cancer prevention and control MSCEIS 2019, October 12, Bandung, Indonesia Copyright © 2020 EAI DOI 10.4108/eai.12-10-2019.2296520