 However, despite the fact that AS is a viable alternative, there are issues and challenges. First, although the majority of occult tumors do not progress initially, the accumulative risk of tumor progression increases with time. From an analysis of the 1479 PTMCs observed over 5 years, 212 14.3 eventually met the progression criteria such as tumor enlargement, local invasion, new lymph node metastasis or becoming clinical disease and had surgery. Therefore, with longer observation, a greater proportion of patients would end up having surgery. Second some patients tend to find it difficult to accept AS as a treatment. Even if they do initially, the wait and see approach may distress patients leading to non-compliance. To date, little is known how this may affect patients well-being and health-related quality of life HRQOL over time. Third, since there are no clinical or molecular parameters to predict which tumors are more likely to progress, patients often need life-long follow-up. However, this may be challenging because patients may move to different places. Lastly, there are now less invasive, non-surgical options available to potentially eradicate PTMCs. Image-guided thermal ablation IGTA using laser ablation or radiofrequency ablation appears promising. With technological advances, they may eventually replace surgery in the future. However, reports have so far been non-randomized, uncontrolled and short follow-up. Furthermore, despite being less-invasive, they still require a small skin incision. 