Implantation of tissue expander prior to irradiation in the era of intensity modulated radiotherapy: impact on the management of patients with pelvic digestive cancers.

PURPOSE: Before the introduction of intensity-modulated radiation therapy (IMRT), few teams used to implant a pelvic tissue expander to keep the bowel away from the radiation field, so as to reduce the risk of acute and late enteritis. However, this unexpected surgery could impact patient's overall treatment and may be no more necessary in the era of modern radiotherapy. MATERIAL AND METHODS: This is a retrospective cross-sectional study including 13 patients who underwent tissue expander implantation before radiotherapy or chemoradiotherapy for rectal or anal carcinoma between November 2008 and March 2019. First, we aim to show that IMRT could sometimes be insufficient to respect dosimetric constraints, and then we aim to report the impact of tissue expander implantation on the global strategy of care of patients with anal and rectal cancers. RESULTS: Seventy-seven percent of the included patients were treated for anal neoplasms, while the remaining 23% had locally advanced rectal cancer. The median follow-up since implantation of the expander was 51 months [3.7-115]. Three patients recurred. One patient developed grade III toxicity related to the implantation of a tissue expander. The delay between diagnosis and the start of irradiation was significantly prolonged (median of 3 months), requiring unusual induction chemotherapy. CONCLUSION: Implantation of tissue expander prior to chemoradiotherapy should be considered, even in the era of IMRT, when irradiated peritoneal cavity volume (V15Gy-V45Gy) far exceeds usual dose constraints. However, it impacts the global strategy of care by delaying the start of irradiation, by introducing induction chemotherapy, and rarely by causing post-operative complications.

The predictive value of treatment response using FDG PET performed on day 21 of chemoradiotherapy in patients with oesophageal squamous cell carcinoma. A prospective, multicentre study (RTEP3).

PURPOSE: FDG PET has been suggested to have predictive value in the prognosis of oesophageal carcinoma. However, the retrospective studies reported in the literature have shown discordant results. Additionally, only four studies have evaluated FDG PET during chemoradiotherapy (CRT) in patients with different histological lesions. The purpose of this study was to investigate the predictive value of FDG PET performed early during CRT (on day 21) in a population of patients with oesophageal squamous cell carcinoma. METHODS: Included in this prospective study were 57 patients with a histological diagnosis of squamous cell carcinoma of the oesophagus. Of these 57 patients, 48 (84%) were evaluated (aged 63 ± 11 years; 44 men, 4 women). Each patient underwent FDG PET (4.5 MBq/kg) before CRT, according to the Herskovic protocol (t0; PET1) and on day 21 ± 3 from the start of CRT (d21; PET2). The response assessment included a clinical examination, CT scan or FDG PET and histological analysis 3 months and 1 year after PET1. The patients were classified as showing a complete response (CR) or a noncomplete response. A quantitative analysis was carried out for PET1 and PET2 using the following parameters: SUVmax, SUVmean (with SUVmean40 as the 3-D volume at an SUVmax threshold of 40% and SUVmeanp as that defined by a physician), tumour volume (TV, with TV40 defined as the TV at 40% of SUVmax, and TVp as that defined by a physician); and the total lesion glycolysis (TLG, SUVmean × TV, with TLG40 defined as the TLG at 40% of SUVmax, and TLGp as that defined by a physician). The differences in responses at 3 months and 1 year between PET1 (t0) and PET2 (d21) were assessed in terms of variations in SUV, TV and TLG using a repeated measures of variance (ANOVA). RESULTS: SUVmax, SUVmean and TLG decreased significantly between PET1 (t0) and PET2 (d21; p < 0.0001). The TV significantly decreased only when assessed as TVp (p = 0.02); TV40 did not decrease significantly. With respect to the predictive value of PET1, only TV40_1 and TVp_1 values, and therefore TLG40_1 and TLGp_1, but not the SUV values, were significantly lower in patients with CR at 3 months. SUVmax1, TVp_1 and TLGp_1 were significantly lower in patients with CR at 1 year. With respect to the predictive value of PET2, only TV40_2 and TVp_2 values, and therefore TLG40_2 and TLGp_2, but not the SUV values, were significantly lower in patients with CR at 3 months. None of the PET2 parameters had significant value in predicting patient outcome at 1 year. The changes in SUVmax, TV40, TVp, TLG40 and TLGp between PET1 and PET2 had no relationship to patient outcome at 3 months or 1 year. CONCLUSION: This prospective, multicentre study performed in a selected population of patients with oesophageal squamous cell cancer demonstrates that the parameters derived from baseline PET1 are good predictors of response to CRT. Specifically, a high TV and TLG are associated with a poor response to CRT at 3 months and 1 year, and a high SUVmax is associated with a poor response to CRT at 1 year. FDG PET performed during CRT on day 21 appears to have less clinical relevance. However, patients with a large functional TV on day 21 of CRT have a poor clinical outcome (ClinicalTrials.gov NCT 00934505).