RESUMO
PURPOSE: To examine clinical outcomes and quality of life of patients with anal squamous cell carcinoma treated with interstitial pulsed-dose-rate brachytherapy (PDR-BT) with a boost to residual tumor after external radiotherapy. MATERIAL AND METHODS: Medical records of patients receiving a brachytherapy boost after radiotherapy for anal squamous cell carcinoma in our Institute between 2008 and 2019 were retrospectively reviewed. After receiving pelvic irradiation ± concurrent chemotherapy, patients received PDR-BT boost to residual tumor, in order to deliver a minimal total dose of 60 Gy. Patients' outcomes were analyzed, with primary focus on local control, sphincter preservation, morbidity, and quality of life. RESULTS: A total of 42 patients were identified, included 24, 13, and 5 patients with I, II, and III tumor stages, respectively. Median brachytherapy (BT) dose was 20 Gy (range, 10-30 Gy). Median dose per pulse was 42 cGy (range, 37.5-50 cGy). With median follow-up of 60.4 months (range, 5.4-127.4 months), estimated local control and colostomy-free survival rates at 5 years were both 88.7% (95% CI: 67.4-96.4%). The largest axis of residual lesion after external beam radiation therapy (EBRT) and poor tumor shrinkage were associated with more frequent relapses (p = 0.02 and p = 0.007, respectively). Out of 40 patients with more than 6 months follow-up, only one experienced severe delayed toxicity (fecal incontinence). Health quality perception was very good or good in 20 of 22 (91%) patients, according to their replies of quality-of-life surveys. A total dose ≥ 63 Gy was associated with higher number of anorectal grade 1+ toxicities (n = 1.5 vs. n = 0.61, p = 0.02). CONCLUSIONS: In this cohort of 42 patients with mainly I and II tumor stages, PDR-BT boost allowed for local control in 88.7% of patients, with only one grade 3 anorectal toxicity.
RESUMO
PURPOSE: To evaluate the efficiency and potential implications of the lowest dose evaluated in the maximally exposed 2cm(3) of the bladder/dose evaluated at the International Commission for Radiation Units and Measurements (ICRU) bladder point (D2cm(3)/DICRU) ratio as surrogate to locate the D2cm(3) in patients treated with MRI-guided adaptive brachytherapy for cervical cancer. METHODS AND MATERIALS: The D2cm(3) area of the bladder was located in 69 patients, using the Digital Imaging and Communications in Medicine coordinates of its barycenter, with respect to the ICRU bladder point. The D2cm(3)/DICRU ratio was correlated with the longitudinal coordinate of the D2cm(3). Afterward, the ratio was used in a retrospective cohort of 216 patients to evaluate its impact in dose-effect analyses for late urinary incontinence. RESULTS: The mean position of the D2cm(3) was 1.73±0.98 cm cranially, 0.59±0.65 cm backwardly, and 0.02±0.89 cm to the right of the ICRU point. It was located above the ICRU point in 95.7% of the patients. Its position was lower in patients with vaginal involvement at diagnosis (p=0.03). The D2cm(3)/DICRU ratio was correlated with the position of the D2cm(3) (R²=0.716, p<10(-6)). In speculating that a ratio greater than one would predict a D2cm(3) located above the ICRU point, the sensibility, specificity, positive, and negative predictive values were 95.2%, 100%, 100%, and 66.8%, respectively. Among the retrospective cohort, 85 patients had a ratio lower than 1.1, reflecting a D2cm(3) located in the lower bladder. In these patients, analyses showed significant dose relationship with Grade 2-4 incontinence (p=0.017), whereas no correlation was demonstrated in the remaining patients. CONCLUSIONS: The D2cm(3)/DICRU ratio is a relevant surrogate to estimate the localization of the D2cm(3). Significant dose-effect correlations for incontinence were established in patients with low values for this ratio.