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Background: Local recurrence of rectal cancer (LRRC) previously treated with radiotherapy is associated with a poor prognosis. Historically, the integration of radiotherapy (RT) with surgery has improved the likelihood of complete resections (R0) and, consequently, enhanced survival. Unfortunately, many LRRC cases are not amenable to surgical intervention. The inclusion of chemotherapy (CHT) alongside advanced RT techniques including proton and carbon ion RT (CIRT) and stereotactic body radiation therapy (SBRT), has generated new treatment options. Therefore, there is a need for improved stratification of LRRC patients to enhance treatment outcomes. The RETRY is an integrated trial with the primary aim to explore if combining CHT with RT in all available modalities can enhance local control (LC) in LRRC patients, consequently improving survival. Methods: Experts from Italian centers specializing in rectal cancer and LRRC management collaborated to design a prospective multicenter observational study within the AIRO group for gastrointestinal malignancies. Eligible participants are adult LRRC patients who previously had pelvic RT, meet specific criteria, and are affiliated with the participating Italian centers. Specific criteria must be met for CIRT referral. A total of 88 patients will be enrolled over three years. The primary objective is to determine the 3-year LC rate. Secondary outcomes include assessing survival, quality of life, and R0 resection rates in surgery cases. A minimum dose of 40 Gy, conventional fractionation with concomitant fluoropyrimidine—with/without oxaliplatin-based CHT (CRT) is prescribed in neoadjuvant setting. Alternatively, the dose will vary from 35 to 40 Gy in 5 fractions based on clinical judgment, by SBRT. Both proton and photon therapies will be evaluated in these approaches. Surgery will be considered if deemed operable. In inoperable cases, CIRT with a dose of 40–60 Gy relative biological effectiveness (RBE) will be administered with a daily dose fraction ranging between 3 and 4.8 Gy RBE. Discussion: The RETRY trial aims to investigate the combined effects of RT and CHT and when feasible the addition of surgery, to determine whether this comprehensive approach can result in improved survival and quality of life for LRRC patients. Trial registration number ClinicalTrials.gov (No. NCT05984576). [ABSTRACT FROM AUTHOR]

Abstract Background Locally recurrent rectal cancer (LRRC) after surgery or external beam radiotherapy (EBRT) is a serious challenge for which no standard treatment is defined. In the present study, we investigated the feasibility of computed tomography (CT)-guided radioactive 125I seed (RIS) implantation assisted with three-dimensional printing non-coplanar template (3D-PNCT) in LRRC patients who previously received surgery or EBRT. Methods Sixty-six patients with LRRC treated by CT-guided RIS implantation in our institute from December 2015 to May 2019 were included. The treatment procedure included: preoperative CT localization, planning design, the printing of 3D individualized template, CT-guided RIS implantation assisted with 3D-PNCT, and postoperative dose evaluation. Therapeutic outcomes including local control (LC) and overall survival (OS) were retrospectively evaluated, as well as side effects. Results All the patients had previously received surgery or EBRT. The median follow-up time was 12.2 (range, 2.5–35.9) months. The median radioactive activity of a single RIS was 0.6 (range, 0.43–0.72) mCi. The median number of RIS was 60, ranging from 10 to 175. The dosimetric parameters included D90 (140.7 ± 33.1) Gy, D100 (90.3 ± 138.6) Gy, and V100 (91.0 ± 13.3) %. Pain relief was achieved in 85.1% (40/47) of patients. Besides, 9.1% (6/66) of patients had severe side effects (≥grade 3), including perianal skin ulcer in 1 case, fistula, radiation proctitis, and intestinal obstruction each in two cases. Median OS time was 14.7 (95% confidence interval (CI): 13.0–16.3) months, and median LC time was 12.2 (95% CI: 9.1–15.2) months. Univariate analysis revealed that when D90 > 130 Gy or D100 > 55 Gy or V100 > 90%, the LC time was remarkably prolonged. However, none of the parameters significantly affected OS. Conclusions CT-guided RIS implantation assisted with 3D-PNCT is an effective and safe salvage treatment strategy for patients with LRRC after EBRT or surgery. D90, D100, and V100 can be used as prognostic predictors. Trial registration NCT03890926 .

Background: Locally recurrent rectal cancer (LRRC) after surgery or external beam radiotherapy (EBRT) is a serious challenge for which no standard treatment is defined. In the present study, we investigated the feasibility of computed tomography (CT)-guided radioactive 125I seed (RIS) implantation assisted with three-dimensional printing non-coplanar template (3D-PNCT) in LRRC patients who previously received surgery or EBRT.Methods: Sixty-six patients with LRRC treated by CT-guided RIS implantation in our institute from December 2015 to May 2019 were included. The treatment procedure included: preoperative CT localization, planning design, the printing of 3D individualized template, CT-guided RIS implantation assisted with 3D-PNCT, and postoperative dose evaluation. Therapeutic outcomes including local control (LC) and overall survival (OS) were retrospectively evaluated, as well as side effects.Results: All the patients had previously received surgery or EBRT. The median follow-up time was 12.2 (range, 2.5-35.9) months. The median radioactive activity of a single RIS was 0.6 (range, 0.43-0.72) mCi. The median number of RIS was 60, ranging from 10 to 175. The dosimetric parameters included D90 (140.7 ± 33.1) Gy, D100 (90.3 ± 138.6) Gy, and V100 (91.0 ± 13.3) %. Pain relief was achieved in 85.1% (40/47) of patients. Besides, 9.1% (6/66) of patients had severe side effects (≥grade 3), including perianal skin ulcer in 1 case, fistula, radiation proctitis, and intestinal obstruction each in two cases. Median OS time was 14.7 (95% confidence interval (CI): 13.0-16.3) months, and median LC time was 12.2 (95% CI: 9.1-15.2) months. Univariate analysis revealed that when D90 > 130 Gy or D100 > 55 Gy or V100 > 90%, the LC time was remarkably prolonged. However, none of the parameters significantly affected OS.Conclusions: CT-guided RIS implantation assisted with 3D-PNCT is an effective and safe salvage treatment strategy for patients with LRRC after EBRT or surgery. D90, D100, and V100 can be used as prognostic predictors.Trial Registration: NCT03890926 . [ABSTRACT FROM AUTHOR]