When undergoing oncology treatment such as radio and chemo therapy, there are a variety of factors which contribute to how patients feel day to day.
Chemotherapy and radiotherapy treatments are relatively common procedures used to treat a wide variety of cancers including, but not limited to breast, colon, prostate, lung and skin cancer. Both treatments use anti-cancer drugs (chemotherapy) and x-rays (radiotherapy) to destroy unwanted cancer cells, but as a secondary effect also ‘normal cells’. Although chemotherapy and radiotherapy are effective, as both treatments damage normal cells it can cause side effects.
Common side effects include[1]:
For some patients these chemotherapy and radiotherapy side effects subside in a few days, however the severity of side effects can be very uncomfortable. For others, side effects may continue on for a substantial amount of time. Generally once treatment has ceased, unwanted effects settle down[2].
References
[1] Cancer Australia. Side effects of chemotherapy canceraustralia.gov.au
[2] Cancer Council (2018, August) Managing chemotherapy side effects cancercouncil.com.au/cancer-information/cancer-treatment/chemotherapy/side-effects/

Prostate cancer is the second most commonly diagnosed cancer in males[1].
References:
[1] Healthed Email to Medical Doctors "PSA Curly Cases and the Emergence of MRI" 23/9/19