Chapter 6 - What problem are you solving?

Abstract

In this chapter, three related problems and examples are provided to facilitate the thinking processes to solve the problems. For example, if you would like to understand the risk of metastasis to para-aortic lymph node (PALN) in cervical cancer, information on surgical staging, such as each stage or the presence or absence of lymph-node positivity on positron emission tomography, is useful in some patient groups. However, identifying the risk groups for PALN recurrence after whole-pelvic radiation therapy (WPRT) is an alternative method. Solving this problem is helpful to enable the selection of suitable patients for undergoing extended-field radiation therapy (EFRT), which is unnecessary in low-risk patients due to the risk–benefit outcome. Patients with high-to-intermediate risk who undergo EFRT may suffer from radiation-induced emesis (RIE), which can negatively impact the quality of life. Furthermore, awareness of the risk factors of RIE is important for the prevention and management of adverse outcomes. Dosimetric correlation is helpful for solving the second problem. The final problem deals with the identification of patients who have better outcomes after the detection of post-WPRT PALN recurrence. Active stringent surveillance in patients with high to intermediate risk of PALN recurrence can be helpful for the early detection of recurrence and better treatment outcomes with salvage treatment. The concepts underlying the examples discussed herein may be extrapolated for application in radiotherapy for lesions in other sites.