Impact of treatment planning target volumen (PTV) size on radiation induced diarrhoea following selenium supplementation in gynecologic radiation oncology - a subgroup analysis of a multicenter, phase III trial

Abstract

BackgroundIn a previous analysis (Int J Radiat Oncol Biol Phys 70:828-835,2010), we assessed whether an adjuvant supplementation with selenium (Se) improves Se status and reduces the radiation-induced side-effects of patients treated by adjuvant radiotherapy (RT) for cervical and uterine cancer. Now, a potential relation between the planning target volume (PTV) of the RT and the Se effect concerning radiation induced diarrhoea was evaluated in detail.MethodsWhole blood Se concentrations had been measured in patients with cervical (n=11) and uterine cancer (n=70) after surgical treatment, during, and at the end of RT. Patients with initial Se concentrations of less than 84 μg/l were categorized as Se-deficient and randomized before RT to receive Se (as sodium selenite) per os on the days of RT, or to receive no supplement during RT. Diarrhoea was graded according to the Common Toxicity Criteria system (CTC, Version 2a). The evaluation of the PTV of the RT was ascertained with the help of a specialised computer-assisted treatment planning software used for radiation planning procedure.ResultsA total of 81 patients had been randomized for the initial supplementation study, 39 of which received Se [selenium group, SeG] and 42 serving as controls [control group, CG]. Mean Se levels did not differ between SeG and CG upon study initiation, but were significantly higher in the SeG compared to the CG at the end of RT. The actuarial incidence of at least CTC 2 radiation induced diarrhoea in the SeG was 20.5% compared to 44.5% in the CG (p=0.04). The median PTV in both groups was 1302 ml (916–4608). With a PTV of <= 1302 ml (n=41) the actuarial incidence of at least CTC 2 diarrhoea in the SeG was 22.3% (4 of 18 patients) compared to 34.8% (8 of 23 patients) in the CG (p=0.50). In patients with a PTV of > 1302 ml (n=40) the actuarial incidence of at least CTC 2 diarrhoea in the SeG was 19.1% (4 of 21 patients) versus 52.6% (10 of 19 patients) in the CG (p=0.046).ConclusionsSe supplementation during RT was effective to improve blood Se status in Se-deficient cervical and uterine cancer patients, and reduces episodes and severity of RT-induced diarrhoea. This effect was most pronounced and significant in patients with large PTV (> 1302 ml).

Acute radiation toxicity during and after concurrent chemoradiotherapy in patients with localy advanced cervical cancer

“…Previous studies have shown that 14 to 68% of patients with abdomen or pelvic tumors are treated with curative or palliative radiotherapy 25,31 . During the treatment, the incidence of anaemia, leukopenia, cystitis, diarrhoea and neuropathy rises to 84%, which is significantly more than after completion of the treatment 29,[32][33][34][35] . Grade 3 and 4 toxicity occurs in 4 to 40% of patients and correlates with the target volume size, fractionation regimen, received dose and radiation techniques 25,35,36 .…”

Efficacy and Interaction of Antioxidant Supplements as Adjuvant Therapy in Cancer Treatment

“…None of the selected trials reported survival rates or clinical response data, but a follow-up study assessed survival 6 years after 1 trial. 101,102 The study reported that there was no significant difference in 6-year survival between groups. 102 Buntzel et al 103 and Muecke et al 101 performed RCTs for patients undergoing radiotherapy for HNC, and cervical and endometrial cancer.…”

“…101,102 The study reported that there was no significant difference in 6-year survival between groups. 102 Buntzel et al 103 and Muecke et al 101 performed RCTs for patients undergoing radiotherapy for HNC, and cervical and endometrial cancer. They concluded that selenium supplements reduced the number of episodes and the severity of radiotoxicities, such as dysphagia and diarrhea.…”

“…In addition to our 49 results, Muecke et al 102 performed a follow-up study of their 2013 report. 101 They reported that there were no differences between groups in 6-year survival rate using selenium supplementation during radiation.…”

“…100 It affects a wide range of biological processes, including energy metabolism and membrane integrity (by acting as an antioxidant), as well as protecting against DNA damage, exerting antiinflammatory effects, and regulating the production of active thyroid hormone. 100,101 Based on these capabilities, some clinical trials were performed with cancer patients during chemotherapy or radiotherapy. We found 6 results (4 chemotherapy, 2 radiotherapy) for selenium use during cancer therapy.…”