Cancer is a progressive disease characterized by the uncontrolled cell growth and its metastasis to other part of the body. It is multifactorial disease and one of the leading causes of death worldwide. Based on its progression and complexity, cancers are categorized into four stages, referred to as stage I, II, III, and IV. Unfortunately, approximately 80% of cancer patients are diagnosed in the advanced stages. Therefore, early detection is the main difficulty for cancer diagnosis, and a single test is insufficient. Thus, a holistic strategy that includes physical, pathological, radiographic, and laboratory investigations for tumor biomarkers is necessary for early cancer diagnosis. It necessitates the interdisciplinary collaboration among radiologists, pathologists, and clinicians to expedite these diagnostic processes and arrive at a definitive diagnosis and rational treatment strategy. The search for new tumor biomarkers is still ongoing, and traditional methods are being improved in response to demand by utilizing the most recent technological advancements, such as MRI, SPECT, and immunohistochemistry. Even with the tremendous advances in our understanding of its molecular properties, cancer remains a challenging disease for patients, researchers, and doctors due to its complicated and adaptive nature. Early detection, predicting aggressiveness, metastasis, and recurrence, assessing tumor margins during surgery, monitoring tumor growth and treatment resistance, and differentiating between preneoplastic and neoplastic lesions are some of the challenges in managing cancer. In the current chapter, we provide a comprehensive review on the conventional methods and technologies used for the screening and diagnosis of common tumors. Further, we also put forth the challenges in the early diagnosis of cancer.