Papers of the Week

Chronic pain secondary to treatment in cancer survivors without tumor evidence is not unusual. Its management often requires specific approaches that are different from those applied for cancer patients with advanced disease and short life expectancy. Some studies have described clinical benefit with ozone therapy (OT) in the management of pain and side effects secondary to cancer treatment. We present our preliminary experience with OT in the management of refractory pelvic pain syndromes secondary to cancer treatment. Case series. Six cancer patients (without tumor evidence) who had been treated previously with radiotherapy, chemotherapy, or endoscopic procedures and were suffering persistent or severe pelvic pain (median 14 months) received OT using ozone-oxygen gas mixture insufflation as a complementary therapy in addition to their scheduled conventional treatment. All cases, except one, showed clinically relevant pain improvement. Visual analog scale score with the standard treatment was 7.8 ± 2.1 before OT, 4.3 ± 3.4 ( = 0.049) after one month, 3.3 ± 3.7 ( = 0.024) after two months, and 2.8 ± 3.8 ( = 0.020) after three months of OT. The median value of "pain symptom" according to the U.S. National Cancer Institute Common Terminology Criteria for Adverse Events v. 5.0 showed a decrease from 3 (range: 2-3) to 1 (range: 0-3) ( = 0.046). Following unsuccessful conventional treatments, OT provided significant benefit in our patients with refractory pelvic pain secondary to cancer treatment. These results merit further evaluation in blinded, randomized clinical trials.