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Background: The purpose of this study is to measure the effects of stereotactic MR-guided adaptive radiotherapy (SMART) for rectal cancer patients in terms of early toxicity and pathological response. Materials and methods: For this prospective pilot study, patients diagnosed with locally advanced rectal cancer (LARC) with positive lymph node clinical staging underwent SMART on rectal lesion and mesorectum using hybrid MR-Linac (MRIdian ViewRay). Dose prescription at 80% isodose for the rectal lesion and mesorectum was 40 Gy (8 Gy/fr) and 25 Gy (5 Gy/fr), respectively, delivered on 5 days (3 fr/week). Response assessment by MRI was performed 3 weeks after SMART, then patients fit for surgery underwent total mesorectal excision. Primary endpoint was evaluation of adverse effect of radiotherapy. Secondary endpoint was pathological complete response rate. Early toxicity was graded according to the Common Terminology Criteria for Adverse Events (CTCAE v5.0). Results: From October 2020 to January 2022, twenty patients underwent rectal SMART. No grade 3-5 toxicity was recorded. Twelve patients were eligible for total mesorectal excision (TME). Mean interval between the completion of SMART and surgery was 4 weeks. Pathological downstaging occurred in all patients; rate of pathological complete response (pCR) was 17%. pCR occurred with a prolonged time to surgery (> 7 weeks). Conclusion: To our knowledge, this is the first study to use stereotactic radiotherapy for primary rectal cancer. SMART for rectal cancer is well tolerated and effective in terms of tumor regression, especially if followed by delayed surgery.
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BACKGROUND/AIM: To evaluate the outcome and toxicities in patients with locally advanced cervical cancer (LACC) treated with radiochemotherapy and intracavitary brachytherapy. PATIENTS AND METHODS: This study included 67 patients with LACC treated between 2010 and 2018. The most represented stage was FIGO IIB. The patients were treated with external beam radiotherapy (EBRT) to the pelvis and boost to the cervix and parametrials. Concomitant chemotherapy (CHT) with cisplatin (CDDP) 40 mg/mq was planned. Subsequently, the patients underwent CT-based endouterine brachytherapy (BT). The response was evaluated at 3 months with PET-CT and/or pelvic magnetic resonance imaging (MRI). Since then, the patients have been followed with clinical instrumental controls every 4 months for the first 2 years and every 6 months for the following 3 years. Local response was assessed with pelvic MRI and/or PET-CT scan at the end of intracavitary BT) according to RECIST 1.1 criteria. RESULTS: The median duration of treatment was 55 days (range=40-73 days). The prescription dose to the planning target volume (PTV) was delivered in 25 to 30 (median 28) daily fractions. The EBRT median dose to the pelvis and gross tumor volume were 50.4 Gy (range=45-56.25) and 61.6 Gy (range=45-70.4), respectively. The 1-year, 2-year, 3-year, and 5-year overall survival rates were 92.44%, 80.81%, 78.84%, and 76.45% respectively. The actuarial 1-year, 2-year, 3-year, and 5-year disease-free survival rates were 89.5%, 83.6%, 81%, and 78.2% respectively. CONCLUSION: This study analyzed acute and chronic toxicity, survival, and local control in cervical cancer patients treated with IMRT followed by CT-planned high dose rate-brachytherapy. Patients demonstrated satisfactory outcomes and incidence of acute and late toxicities.
