Salvage re-irradiation in non-melanoma skin cancers: A multicenter analysis.

BACKGROUND AND PURPOSE: We conducted a multicentre real-world study to assess the outcomes of radical salvage re-irradiation for non-melanoma skin cancer (nMSC) recurrences following definitive or postoperative radiotherapy. MATERIALS AND METHODS: Data on patients treated between 2006 and 2022 with re-irradiation for nMSCs were retrospectively collected from five high-volume brachytherapy centers. The primary endpoint was local control (LC). Secondary endpoints included overall survival, progression-free survival, and adverse events (AEs). The Kaplan-Meier estimator and Cox Proportional-Hazards Model were utilised in the analysis. RESULTS: A total of 58 patients with a median age of 78.4 years with recurrences of previously irradiated nMSC in the head and neck region were included in the analysis. The majority had cutaneous basal cell carcinoma (BCC; 91.4%), and were irradiated with high-dose-rate brachytherapy (HDR-BT; 91.4%). The most common locations included the nasal region (36.2%) and external ear (18.9%). The 1-year LC was 73.1% and decreased to 41.7% at three years. The size of the re-irradiated lesion was the single independent prognostic factor in Cox analysis (per mm; HR 1.07; 95% CI 1.04-1.11; p < 0.001). Grade 3 or worse AEs were reported in 7 cases (12.1%). CONCLUSION: Re-irradiation for nMSCs, predominantly administered with brachytherapy for radiorecurrent BCC, is associated with high recurrence rates, and the risk of failure significantly increases with the size of the treated lesion. Re-irradiation could be an option for selected elderly patients with small, localised, inoperable recurrences after RT to achieve local control or defer systemic treatment; however, prospective trials are necessary to confirm its safety and efficacy.

Pre-operative high-dose-rate brachytherapy in early-stage cervical cancer: long-term single-center results.

PURPOSE: The aim of the study was to report the outcomes of pre-operative high-dose-rate brachytherapy (pHDR-BT), followed by hysterectomy in patients with early cervical cancer. MATERIAL AND METHODS: From January, 1998 to December, 2003, 113 women with IB1, IB2, and IIA1 cervical cancer (according to International Federation of Gynecology and Obstetrics [FIGO] 2018) were treated with pHDR-BT, and 6 to 8 weeks later followed by radical hysterectomy. Patients found to have positive lymph nodes, residual cervical cancer, involved parametria, or lymphovascular space invasion (LVSI) received post-operative adjuvant therapy. RESULTS: Post-operatively, 81.4% of patients had a complete response to pHDR-BT in the cervix, and 18.6% had residual cervical cancer. Failures occurred in 11/113 (9.7%) patients (all were stage IIA1), with pelvic recurrences in 5/113 (4.4%) and distant metastasis (DM) in 6/113 (5.3%). The 5- and 10-year disease-free survival (DFS) rates were 100% for IB1 and IB2, and 86.4% and 81.3% for IIA1, respectively. Lymph node involvement and/or residual cervical cancer correlated with worse DFS. Two vesicovaginal fistulas were observed (one in a patient treated only with pHDR-BT and one in a woman, who underwent adjuvant external-beam radiotherapy [EBRT]). Two rectovaginal fistulas and one case of proctitis were observed in patients treated with adjuvant EBRT. CONCLUSIONS: pHDR-BT in early cervical cancer is well-tolerated and effective in sterilizing tumor cells in the cervix. The growing number of publications in this area may help define an optimal therapeutic scheme, but randomized trials are required to determine the best candidates for this treatment modality.In our opinion, cervical cancer patients with FIGO stage IIA1 are not good candidates for pHDR-BT, and could be given this treatment only after rigorous selection, including assessment with state-of-the-art imaging, due to higher probability of treatment failure.

Advanced dose calculation algorithm in superficial brachytherapy - the impact of tissue inhomogeneity on treatment plan dosimetry.

PURPOSE: Given tissue inhomogeneity and lack of backscatter media, superficial brachytherapy necessitates more accurate dosimetry than TG-43 formalism. However, the introduction of modern model-based dose calculation algorithms into clinical practice should be carefully evaluated. The aim of this work was to compare dose distributions calculated with TG-43 and advanced collapsed cone engine (ACE) algorithms for individual multi-catheter moulds, and investigate the impact of target size and the lack of bolus to differences between plans. MATERIAL AND METHODS: Eleven treatment plans for individual mould multi-catheter high-dose-rate brachytherapy (IMM HDR) were selected for retrospective analysis. All treatment plans were initially calculated with TG-43 formula and re-calculated using ACE algorithm. Plan re-calculation with ACE was repeated for each plan in order to assess the impact of bolus. To evaluate differences between TG-43 and ACE dose distributions, dose-volume histogram (DVH) parameters for each ROI were compared. Dmax (maximal point dose), D0.1cc, and D2cc were calculated for each risk's organ (OARs) and for external contour. For clinical target volume (CTV), D98, D90, D50, CTV coverage (CTV-V100), and dose delivered to reference point were compared between the plans. RESULTS: A significantly lower values (p < 0.05) of CTV parameters were observed for treatment plans calculated with ACE algorithm comparing to TG-43. Further analysis showed that differences between CTV-V100 for ACE and TG-43 plans depended on CTV volume. Dosimetric parameters for OARs were significantly lower in ACE plans than those of TG-43. Only D2cc for external and D0.1cc for both eye lenses in ACE plans were insignificantly different comparing to TG-43 plans. CONCLUSIONS: Results show that differences between dosimetric parameters are statistically significant. However, their clinical relevance is still undetermined. Careful re-evaluation of the clinical results based on long-term research on TG-43 is necessary to safely introduce modern algorithms to clinical practice.