Efficacy of stereotactic body radiotherapy and response prediction using artificial intelligence in oligometastatic gynaecologic cancer.

PURPOSE: We present a large real-world multicentric dataset of ovarian, uterine and cervical oligometastatic lesions treated with SBRT exploring efficacy and clinical outcomes. In addition, an exploratory machine learning analysis was performed. METHODS: A pooled analysis of gynecological oligometastases in terms of efficacy and clinical outcomes as well an exploratory machine learning model to predict the CR to SBRT were carried out. The CR rate following radiotherapy (RT) was the study main endpoint. The secondary endpoints included the 2-year actuarial LC, DMFS, PFS, and OS. RESULTS: 501 patients from 21 radiation oncology institutions with 846 gynecological metastases were analyzed, mainly ovarian (53.1%) and uterine metastases(32.1%).Multiple fraction radiotherapy was used in 762 metastases(90.1%).The most frequent schedule was 24 Gy in 3 fractions(13.4%). CR was observed in 538(63.7%) lesions. The Machine learning analysis showed a poor ability to find covariates strong enough to predict CR in the whole series. Analyzing them separately, in uterine cancer, if RT dose≥78.3Gy, the CR probability was 75.4%; if volume was <13.7 cc, the CR probability became 85.1%. In ovarian cancer, if the lesion was a lymph node, the CR probability was 71.4%; if volume was <17 cc, the CR probability rose to 78.4%. No covariate predicted the CR for cervical lesions. The overall 2-year actuarial LC was 79.2%, however it was 91.5% for CR and 52.5% for not CR lesions(p < 0.001). The overall 2-year DMFS, PFS and OS rate were 27.3%, 24.8% and 71.0%, with significant differences between CR and not CR. CONCLUSIONS: CR was substantially associated to patient outcomes in our series of gynecological cancer oligometastatic lesions. The ability to predict a CR through artificial intelligence could also drive treatment choices in the context of personalized oncology.

Definitive chemoradiation in vulvar squamous cell carcinoma: outcome and toxicity from an observational multicenter Italian study on vulvar cancer (OLDLADY 1.1).

BACKGROUND: Vulvar carcinoma is a rather uncommon gynecological malignancy affecting elderly women and the treatment of loco-regional advanced carcinoma of the vulva (LAVC) is a challenge for both gynecologic and radiation oncologists. Definitive chemoradiation (CRT) is the treatment of choice, but with disappointing results. In this multicenter study (OLDLADY-1.1), several institutions have combined their retrospective data on LAVC patients to produce a real-world dataset aimed at collecting data on efficacy and safety of CRT. METHODS: The primary study end-point was 2-year-local control (LC), secondary end-points were 2-year-metastasis free-survival (MFS), 2-year-overall survival (OS) and the rate and severity of acute and late toxicities. Participating centers were required to fill data sets including age, stage, histology, grading as well as technical/dosimetric details of CRT. Data about response, local and regional recurrence, acute and late toxicities, follow-up and outcome measures were also collected. The toxicity was a posteriori documented through the Common Terminology Criteria for Adverse Events version 5 scale. RESULTS: Retrospective analysis was performed on 65 patients with primary or recurrent LAVC treated at five different radiation oncology institutions covering 11-year time interval (February 2010-November 2021). Median age at diagnosis was 72 years (range 32-89). With a median follow-up of 19 months (range 1-114 months), 2-year actuarial LC, MFS and OS rate were 43.2%, 84.9% and 59.7%, respectively. In 29 patients (44%), CRT was temporarily stopped (median 5 days, range 1-53 days) due to toxicity. The treatment interruption was statistically significant at univariate analysis of factors predicting LC (p: 0.05) and OS rate (p: 0.011), and it was confirmed at the multivariate analysis for LC rate (p: 0.032). In terms of toxicity profile, no G4 event was recorded. Most adverse events were reported as grade 1 or 2. Only 14 acute G3 toxicities, all cutaneous, and 7 late G3 events (3 genitourinary, 3 cutaneous, and 1 vaginal stenosis) were recorded. CONCLUSION: In the context of CRT for LAVC, the present study reports encouraging results even if there is clearly room for further improvements, in terms of both treatment outcomes, toxicity and treatment interruption management.

An empirical approach to the definition of the target margins in eye radiosurgery.

INTRODUCTION: A system for stabilizing and monitoring eye movements during LINAC-based photon beam one single fraction stereotactic radiotherapy was developed at our Institution. This study aimed to describe the feasibility and the efficacy of our noninvasive optical localization system that was developed, tested, and applied in 20 patients treated for uveal melanoma. METHODS: Our system consisted of a customized thermoplastic mask to immobilize the head, a gaze fixation LED, and a digital micro-camera. The localization procedure, which required the active collaboration of the patient, served to monitor the eye movements during all phases of the treatment, starting from the planning computed tomography up to the administration of radiotherapy, and allowed the operators to suspend the procedure and to interact with the patient in case of large movements of the pupil. RESULTS: Twenty patients were treated with stereotactic radiosurgery (27 Gy in one fraction) for primary uveal melanoma. All patients showed a good tolerance to the treatment; until now, all patients were in local control during the follow up and one died for distant progression 6 months after radiosurgery. CONCLUSIONS: This study showed that this noninvasive technique, based on eye position control, is appropriate and can contribute to the success of LINAC-based stereotactic radiotherapy. A millimetric safety margin to the clinical target volume was adequate to take account for the organ movement. All patients treated till now showed a good local control; failures in the disease control were due to metastatic spread.

Photon-based high-dose single-fraction radiosurgery, an effective treatment modality for recurrent uveal melanoma.

Introduction: To evaluate and report the outcome of a patient with locally recurrent uveal melanoma (UM) previously treated with brachytherapy (BT), using a second personalized globe-sparing radiotherapy approach. Material and methods: In June 2020, a 78-year-old man arrived at our institution with diplopia and suspected uveal melanoma. At the ophthalmological evaluation (B-scan and A-scan ultrasonography) a lesion in the right eye at 6-7 hours of about 5 mm thickness, with internal lacunar areas, approximately 7 mm away from the limbus, was observed. The patient underwent ruthenium plaque BT at a total dose of 110 Gy prescribed to the apex of the tumour. At the follow-up, the lesion was under control until September 2021, but it recurred with a satellite exudative detachment in the lower and temporal sectors 7-10 hours. At the B-scan the lesion had a maximum thickness of 4.6 mm. Subsequently, in a multidisciplinary discussion, one single fraction stereotactic radiosurgery was scheduled. The prescribed dose was 27 Gy in the de-novo lesion and 24 Gy in the previously irradiated site. Stereotactic radiosurgery was performed in October 2021. Results: The time interval between the 2 treatments was 15 months. Twenty months after recurrence, local tumour control was observed, and no metastases were detected on follow-up examinations. No severe acute or late toxicity was observed due to the retreatment. Conclusions: Photon stereotactic radiotherapy is a feasible, acceptably tolerated modality, and it represents an eye-preserving treatment also for patients with recurrent UM unfit for BT.

Stereotactic body radiotherapy in oligometastatic cervical cancer (MITO-RT2/RAD study): a collaboration of MITO, AIRO GYN, and MaNGO groups.

OBJECTIVE: This retrospective, multicenter study analyzes the efficacy and safety of stereotactic body radiotherapy in a large cohort of patients with oligometastatic/persistent/recurrent cervical cancer. METHODS: A standardized data collection from several radiotherapy centers that treated patients by stereotactic body radiotherapy between March 2006 and February 2021 was set up. Clinical and stereotactic body radiotherapy parameters were collected. Objective response rate was defined as a composite of complete and partial response, while clinical benefit included objective response rate plus stable disease. Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer and Common Terminology Criteria for Adverse Events scales were used to grade toxicities. The primary endpoints were the rate of complete response to stereotactic body radiotherapy, and the 2 year actuarial local control rate on a 'per lesion' basis. The secondary end points were progression-free survival and overall survival, as well as toxicity. RESULTS: A total of 83 patients with oligometastatic/persistent/recurrent cervical cancer bearing 125 lesions treated by stereotactic body radiotherapy at 15 different centers were selected for analysis. Of the sites of metastatic disease, lymph node metastases were most common (55.2%), followed by parenchyma lesions (44.8%). Median total dose was 35 Gy (range 10-60), in five fractions (range 1-10), with a median dose/fraction of 7 Gy (range 4-26). Complete, partial, and stable response were found in 73 (58.4%), 29 (23.2%), and 16 (12.8%) lesions, respectively, reaching 94.4% of the clinical benefit rate. Forty-six (55.4%) patients had a complete response. Patients achieving complete response on a 'per lesion' basis experienced a 2 year actuarial local control rate of 89.0% versus 22.1% in lesions not achieving complete response (p<0.001). The 2 year actuarial progression-free survival rate was 42.5% in patients with complete response versus 7.8% in patients with partial response or stable or progressive disease (p=0.001). The 2 year actuarial overall survival rate was 68.9% in patients with complete response versus 44.3% in patients with partial response or stable or progressive disease (p=0.015). Fifteen patients (18.1%) had mild acute toxicity, totaling 29 side events. Late toxicity was documented in four patients (4.8%) totaling seven adverse events. CONCLUSION: Our analysis confirmed the efficacy of stereotactic body radiotherapy in oligometastatic/persistent/recurrent cervical cancer patients. The low toxicity profile encourages the wider use of stereotactic body radiotherapy in this setting.

Observational multicenter Italian study on vulvar cancer adjuvant radiotherapy (OLDLADY 1.2): a cooperation among AIRO Gyn, MITO and MaNGO groups.

BACKGROUND: Adjuvant radiotherapy (aRT) has been shown to reduce the risk of local relapse in vulvar cancer (VC). In this multicentre study (OLDLADY-1.2), several Institutions have combined their retrospective data on VC patients to produce a real-world dataset aimed at collecting data on efficacy and safety of aRT. METHODS: The primary study end-point was the 2-year-local control, secondary end-points were the 2-year-metastasis free-survival, the 2-year-overall survival and the rate and severity of acute and late toxicities. Participating centres were required to fill data sets including age, stage, tumor diameter, type of surgery, margin status, depth of invasion, histology, grading as well technical/dosimetric details of radiotherapy. Data about response, local and regional recurrence, acute and late toxicities, follow-up and outcome measures were also collected. RESULTS: One hundred eighty-one patients with invasive VC from 9 Institutions were retrospectively identified. The majority of patients were stage III (63%), grade 2 (62.4%) squamous carcinoma (97.2%). Positive nodes were observed in 117 patients (64.6%), moreover tumor diameter > 4 cm, positive/close margins and depth of invasion deeper than 5 mm were found in 59.1%, 38.6%, 58% of patients, respectively. Sixty-one patients (33.7%) received adjuvant chemoradiation, and 120 (66.3%) received radiotherapy alone. aRT was started 3 months after surgery in 50.8% of patients. Prescribed volumes and doses heterogeneity was recorded according to margin status and nodal disease. Overall, 42.5% locoregional recurrences were recorded. With a median follow-up of 27 months (range 1-179), the 2-year actuarial local control rate, metastasis free and overall survival were 68.7%, 84.5%, and 67.5%, respectively. In term of safety, aRT leads to a prevalence of acute skin toxicity with a low incidence of severe toxicities. CONCLUSIONS: In the context of aRT for VC the present study reports a broad spectrum of approaches which would deserve greater standardization in terms of doses, volumes and drugs used.

Endometrial Cancer: When Upfront Surgery Is Not an Option.

Background and Summary: The management of endometrial cancer, in an ever-older population with considerable comorbidity, remains a challenge for gynecological and radiation oncologists. Key Message: The present paper reviews literature data on treatment options for endometrial cancer patients unfit for surgery.

High-dose-rate brachytherapy for non-melanoma skin cancer using tailored custom moulds - a single-centre experience.

AIM OF THE STUDY: The aim of this retrospective study was to analyse tumour control, toxicity, and aesthetic outcome of patients affected by non-melanoma skin cancer (NMSC) treated with 192 Ir high-dose-rate (HDR)-brachytherapy (BT) at the Division of Radiotherapy, University of Pisa. MATERIAL AND METHODS: From January 2014 to December 2019 we treated 37 patients (median age 79 years; range 31-91 years) affected by NMSC, with the following histological subtypes: 62.2% basal cell carcinoma and 37.8% squamous cell carcinoma. We analysed 40 lesions with a depth ≤ 5 mm, located in 40.0% scalp, 17.5% nose, 25.0% face, and 17.5% ear, all treated with 192 Ir-based HDR-BT, using tailored custom moulds, with a median of 5 catheters (range, 1-9) spaced 1 cm apart. The most common fractionation scheme was 40 Gy in 8 daily fractions; the biological effective dose was 60 Gy. RESULTS: The median follow-up was 25 months (range, 3-70 months). The 2-year local control rate was 90%. Common terminology criteria for adverse event (CTCAE vs. 5.0) G1 toxicities were dermatitis (52%), pain (25%), and ulceration (22%). The only G2 acute toxicities were dermatitis and ulceration. The most common G1 late toxicities were fibrosis (17%), atrophy (15%), and hypopigmentation (12%). No G3 or higher acute or late toxicity was reported. Excellent cosmetic results were observed in 65.0% of the lesions; only 1 case (2.5%) reported a poor cosmetic result. CONCLUSIONS: Surface mould HDR-BT is a safe, effective, and well tolerated treatment modality for NMSC and can be considered a good alternative, especially for elderly patients who are often unfit for surgery.

A Large, Multicenter, Retrospective Study on Efficacy and Safety of Stereotactic Body Radiotherapy (SBRT) in Oligometastatic Ovarian Cancer (MITO RT1 Study): A Collaboration of MITO, AIRO GYN, and MaNGO Groups.

BACKGROUND: Recent studies have reported improvement of outcomes (progression-free survival, overall survival, and prolongation of androgen deprivation treatment-free survival) with stereotactic body radiotherapy (SBRT) in non-small cell lung cancer and prostate cancer. The aim of this retrospective, multicenter study (MITO RT-01) was to define activity and safety of SBRT in a very large, real-world data set of patients with metastatic, persistent, and recurrent ovarian cancer (MPR-OC). MATERIALS AND METHODS: The endpoints of the study were the rate of complete response (CR) to SBRT and the 24-month actuarial local control (LC) rate on "per-lesion" basis. The secondary endpoints were acute and late toxicities and the 24-month actuarial late toxicity-free survival. Objective response rate (ORR) included CR and partial response (PR). Clinical benefit (CB) included ORR and stable disease (SD). Toxicity was evaluated by the Radiation Therapy Oncology Group (RTOG) and the European Organization for Research and Treatment of Cancer (EORTC) and Common Terminology Criteria for Adverse Events (CTCAE) scales, according to center policy. Logistic and Cox regression were used for the uni- and multivariate analysis of factors predicting clinical CR and actuarial outcomes. RESULTS: CR, PR, and SD were observed in 291 (65.2%), 106 (23.8%), and 33 (7.4%) lesions, giving a rate of CB of 96.4%. Patient aged ≤60 years, planning target volume (PTV) ≤18 cm3 , lymph node disease, and biologically effective dose α/ß10 > 70 Gy were associated with higher chance of CR in the multivariate analysis. With a median follow-up of 22 months (range, 3-120), the 24-month actuarial LC rate was 81.9%. Achievement of CR and total dose >25 Gy were associated with better LC rate in the multivariate analysis. Mild toxicity was experienced in 54 (20.7%) patients; of 63 side effects, 48 were grade 1, and 15 were grade 2. The 24-month late toxicity-free survival rate was 95.1%. CONCLUSIONS: This study confirms the activity and safety of SBRT in patients with MPR-OC and identifies clinical and treatment parameters able to predict CR and LC rate. IMPLICATIONS FOR PRACTICE: This study aimed to define activity and safety of stereotactic body radiotherapy (SBRT) in a very large, real life data set of patients with metastatic, persistent, recurrent ovarian cancer (MPR-OC). Patient age <60 years, PTV <18 cm3 , lymph node disease, and biologically effective dose α/ß10 >70 Gy were associated with higher chance of complete response (CR). Achievement of CR and total dose >25 Gy were associated with better local control (LC) rate. Mild toxicity was experienced in 20.7% of patients. In conclusion, this study confirms the activity and safety of SBRT in MPR-OC patients and identifies clinical and treatment parameters able to predict CR and LC rate.

Adenoid Cystic Carcinoma of Bartholin's Gland: What Is the Best Approach?

Background and summary: Among all vulvar cancers, primary adenoid cystic carcinoma (ACC) of Bartholin's gland is a very rare tumor characterized by a slow growth, a high local aggressiveness, and a remarkable recurrence rate. Due to its rarity, treatment remains a challenge for oncologists and gynecological surgeons. Key message: The present paper reports clinical, radiological, and histological features of ACC of Bartholin's gland and reviews the literature data on the treatment options with a particular focus on the potential role of particle radiation therapy.

Patterns of Failures and Clinical Outcome of Patients with Early-Stage, High-Risk, Node-Negative Endometrial Cancer Treated with Surgery Followed by Adjuvant Platinum-Based Chemotherapy and Vaginal Brachytherapy.

OBJECTIVE: To assess the clinical outcome of patients with high-risk early-stage endometrial cancer and negative pelvic nodes who received adjuvant platinum-based chemotherapy plus vaginal brachytherapy (VBT). METHODS: This investigation assessed 80 patients who underwent hysterectomy, bilateral salpingo-oophorectomy, and pelvic lymphadenectomy for stage Ib-II, grade 2-3 endometrioid (n = 43) or stage Ia-II nonendometrioid (n = 37) endometrial cancer. RESULTS: Five-year local control rate, 5-year disease-free survival, and 5-year overall survival were 97, 87, and 97%, respectively, for endometrioid carcinoma, and 66, 50, and 72%, respectively, for nonendometrioid carcinoma. CONCLUSIONS: This retrospective study appears to show that adjuvant platinum-based chemotherapy plus VBT achieve very good results in endometrioid carcinoma. This combined treatment seems to be less effective in nonendometrioid carcinoma.

Vismodegibfor the treatment of radiation-induced basal cell carcinoma - a case report and brief literature study.

Vismodegib is playing an increasing role in the treatment of locally advanced or metastatic basal cell carcinoma (BCC) that is not a candidate for surgery or radiotherapy, and also in radiation-induced BCC. A 22-year-old man with a history of Hodgkin lymphoma, nodular sclerosis stage IIA, from October 1994 to February 1995 treated with 25 mg/m2 doxorubicin, 10 IU/m2 bleomycin, 6 mg/m2 vinblastine, and 375 mg/m2 dacarbazine for four cycles, followed byconformal beam radiotherapy (EBRT) on laterocervical, supraclavear, and mediastinal nodes up to a total dose of 30 Gy and following EBRT boost on mediastinal nodes up to a dose of 10 Gy. Subsequently, the patient underwent conformal EBRT on lomboaortic nodes up to total dose of 30 Gy at the University Hospital of Pisa until May 1995. There was no evidence of disease, until March 2012 when the patient developed severalBCCs, occurring in the field of prior radiation, treated with local excisions. No mutations of Hedgehog (Hh) pathway or other genes were found and nevoid basal cell carcinoma syndrome was not diagnosed. In February 2018, the patient began therapy with vismodegib at standard dose of 150 mgorally daily and was treated for 10 months, with low adverse events and with pathological complete response of disease until July 2019. This experience shows that there are, however very few, BCCs not associated with genetic disorders. Vismodegib seems to be an effective and safe therapeutic approach also for radiation-related BCCs, associated with relatively low toxicity.

Angiosarcomaafteradjuvantradiotherapy in high-risksquamouscell carcinoma of the vulva: a case report.

Squamous cell carcinoma of the vulva represents 3-5% of gynecological cancers. The incidence is higher in postmenopausal patients; the mean age of women with vulvar cancer is between 64 and 70 years. Radiotherapy plays an increasing role in the treatment of high-risk squamous cell carcinoma of the vulva; associated with surgery it significantly improves prognosis but is also associated with serious late side-effects, such as secondary malignancies. We describe a case of a 75-year-old woman who underwent deep total vulvectomy with inguinal-femoral lymphadenectomy for high-risk, keratinizing variant HPV-negative, squamous cell carcinoma of the vulva, followed by adjuvant concomitant chemo-radiotherapy, at the University Hospital of Pisa in February 2013. Five years later she developed a very large angiosarcoma in the right abdominal wall, at the edge of the previous radiotherapy field, and underwent radical surgery. After four months, she developed bone metastasis of angiosarcoma, also treated with surgery. This experience shows that the use of new technologies allows the delivery of high doses of radiotherapy, significantly correlated with a better prognosis, but also associated with fortunately rare morbidity, such as radiation-induced angiosarcoma. Due to the presence of long, mostly post-menopausal survivors among irradiated patients, screening for second malignancies must be developed for selected high-risk survivor groups.

Clinical Outcomes of Stereotactic Body Radiotherapy in Oligometastatic Gynecological Cancer.

OBJECTIVE: The objective of this study was to assess the role of stereotactic body radiotherapy (SBRT) in the treatment of distantly recurrent, oligometastatic gynecological cancer. METHODS: The hospital records of 45 patients with F-fluorodeoxyglucose (F-FDG) positron emission tomography positive, distantly recurrent, oligometastatic gynecological cancer were reviewed. All these patients had a number of target lesions less than 5, with largest diameter less than 6 cm. The treatment was delivered with a TrueBeam LINAC and RapidArc technique, using 10 or 6 MV FFF beams. A total of 70 lesions were treated, and lymph nodes represented the most common site of metastases, followed by lung, liver, and soft tissues. Twenty lesions were treated with one single fraction of 24 Gy and 5 lesions received 27 Gy delivered in 3 fractions, depending on the ability to fulfill adequate target coverage and safe dose/volume constraints for the organ at risk with either regimen. RESULTS: Positron emission tomography scan 3 months after SBRT showed a complete response (CR) in 45 lesions (64.3%), a partial response in 14 (20.0%), a stable disease in 5 (7.1%), and a progressive disease in 6 (8.6%). No lesions in CR after SBRT subsequently progressed. Overall acute toxicity occurred in 13 (28.9%) patients. The most common grade 1 to 2 adverse event was pain (n = 9, 20.0%), followed by nausea and vomiting (n = 5, 11.1%). No grade 3 to 4 acute toxicities occurred, and no late toxicities were observed. Patients who failed to achieve a CR had a 2.37-fold higher risk of progression and a 3.60-fold higher risk of death compared with complete responders (P = 0.04 and P = 0.03, respectively). CONCLUSIONS: Stereotactic body radiotherapy offers an effective and safe approach for selected cases of oligometastatic gynecological cancer.

Iodine Plaque Brachytherapy a Customized Conservative Approach to the Management of Medium/Large-sized Uveal Melanoma.

BACKGROUND/AIM: The objective of this study was to assess the role of iodine (125I) plaque brachytherapy in the management of uveal melanoma. PATIENTS AND METHODS: This is a retrospective study of 50 patients (median age 67 years; range=33-86 years) with uveal melanoma, treated with 125I plaque brachytherapy at the University Hospital of Pisa. Uveal melanoma was diagnosed with A-scan and B-scan standardized echography, fluorescein angiography, indocyanine green-angiography, optical coherence tomography, and/or magnetic resonance imaging. The primary outcomes assessed were local control, overall survival, disease progression, globe preservation, and metastases. Secondary outcomes were acute and late radiation adverse effects. RESULTS: Inclusion criteria comprised Eastern Cooperative Oncology Group performance status ≤2, life expectancy >6 months, and tumor thickness ≤10 mm and\or diameter ≤20 mm. All the patients were treated with 125I plaque brachytherapy, with a prescription dose of 85 Gy to the tumor apex. The 5-year rate of local control, progression-free survival, metastasis-free survival, enucleation-free survival, and overall survival were 83.0%, 81.4%, 90.3%, 83.1%, and 92.1% respectively. Twenty-four patients (48.0%) had one or more acute and late toxicities. The most common acute adverse events (CTCAE vs. 5.0) grade 1-3 were conjunctivitis and eye pain (6.0%). Regarding late events, radiation retinopathy grade 1-3 occurred in 18.0% of cases, while grade 1-3 vitreous hemorrhage in 2.5%. CONCLUSION: 125I plaque brachytherapy offers an effective and safe approach for selected cases of uveal melanoma, due to the reported satisfactory results in terms of local control, eye conservation and survival.

Machine-learning prediction of treatment response to stereotactic body radiation therapy in oligometastatic gynecological cancer: A multi-institutional study.

BACKGROUND AND PURPOSE: We aimed to develop and validate different machine-learning (ML) prediction models for the complete response of oligometastatic gynecological cancer after SBRT. MATERIAL AND METHODS: One hundred fifty-seven patients with 272 lesions from 14 different institutions and treated with SBRT with radical intent were included. Thirteen datasets including 222 lesions were combined for model training and internal validation purposes, with an 80:20 ratio. The external testing dataset was selected as the fourteenth Institution with 50 lesions. Lesions that achieved complete response (CR) were defined as responders. Prognostic clinical and dosimetric variables were selected using the LASSO algorithm. Six supervised ML models, including logistic regression (LR), classification and regression tree analysis (CART) and support vector machine (SVM) using four different kernels, were trained and tested to predict the complete response of uterine lesions after SBRT. The performance of models was assessed by receiver operating characteristic curves (ROC), area under the curve (AUC) and calibration curves. An explainable approach based on SHapley Additive exPlanations (SHAP) method was deployed to generate individual explanations of the model's decisions. RESULTS: 63.6% of lesions had a complete response and were used as ground truth for the supervised models. LASSO strongly associated complete response with three variables, namely the lesion volume (PTV), the type of lesions (lymph-nodal versus parenchymal), and the biological effective dose (BED10), that were used as input for ML modeling. In the training set, the AUCs for complete response were 0.751 (95% CI: 0.716-0.786), 0.766 (95% CI: 0.729-0.802) and 0.800 (95% CI: 0.742-0.857) for the LR, CART and SVM with a radial basis function kernel, respectively. These models achieve AUC values of 0.727 (95% CI: 0.669-0.795), 0.734 (95% CI: 0.649-0.815) and 0.771 (95% CI: 0.717-0.824) in the external testing set, demonstrating excellent generalizability. CONCLUSION: ML models enable a reliable prediction of the treatment response of oligometastatic lesions receiving SBRT. This approach may assist radiation oncologists to tailor more individualized treatment plans for oligometastatic patients.

Lymph-vascular Space Involvement and/or p53 Overexpression Correlated With the Clinical Outcome of Early-stage Endometrial Cancer Patients Treated With Adjuvant Vaginal Brachytherapy.

BACKGROUND/AIM: The majority of patients with endometrial cancer (EC) are diagnosed at an early stage and undergo primary surgery, followed by observation or adjuvant therapy according to risk factors on surgical samples. The objective of this study was to assess the correlation between a risk profile represented by the presence of substantial lymph-vascular space involvement (LVSI) and/or p53 overexpression and the clinical outcome of patients with early-stage endometrial cancer (EC) who received adjuvant vaginal brachytherapy (BT). PATIENTS AND METHODS: This investigation assessed 79 patients who underwent hysterectomy, bilateral salpingo-oophorectomy, and pelvic and/o aortic lymphadenectomy or sentinel lymph node biopsy followed by hypofractionated (HDR)-vaginal BT, using 192Ir source, for stage I-II endometrioid (n=70) or non-endometrioid (n=9) EC. Thirty-four patients (43.0%) were considered to have an unfavorable risk profile defined by the presence of substantial LVSI and /or p53 overexpression. RESULTS: Five-year disease-free survival (DFS) and five-year overall survival (OS) were 93.7% and 95%, respectively. There was a significant correlation between unfavorable risk-profile and pelvic recurrence rate (p=0.002) and distant recurrence rate (p=0.017). Patients with abnormal p53 had a higher risk of local relapse (p=0.041). Substantial LVSI was strongly associated with pelvic recurrence (p=0.001) and distant metastasis (p<0.001). CONCLUSION: The presence of substantial LVSI and/or p53 overexpression strictly correlated with poor outcome of patients with early-stage EC and should be taken into consideration for better planning adjuvant treatment in this clinical setting.

Positive p16 Immunostaining Is an Independent Prognostic Variable for Disease-free Survival and Overall Survival in Patients With Squamous Cell Carcinoma of the Vulva Treated With Radical Surgery and Inguinofemoral Lymphadenectomy: An Italian Single Center Retrospective Study.

BACKGROUND/AIM: The expression of the cyclin-dependent kinase inhibitor p16 correlates with the presence of human papillomavirus. The purpose of this investigation was to assess the prognostic relevance of p16 expression in patients with vulvar squamous cell carcinoma (VSCC) treated with radical surgery followed by adjuvant (chemo) radiation in selected cases. PATIENTS AND METHODS: Seventy-eight patients were analyzed retrospectively. RESULTS: Positive p16 immunostaining was detected in 19 (24.4%) patients. Five-year disease-free survival (DFS) and 5-year overall survival (OS) were better in p16-positive compared to p16-negative patients (83.9% versus 37.3% p=0.002 and 91.7% versus 57.6%, p=0.003, respectively). p16 expression retained prognostic relevance at multivariate analysis for both DFS and OS. CONCLUSION: p16 expression was detected in 24.4% of patients with VSCC and was found to be an independent prognostic variable for both DFS and OS.

Efficacy and Safety of Stereotactic Body Radiation Therapy in Oligometastatic Uterine Cancer (MITO-RT2/RAD): A Large, Real-World Study in Collaboration With Italian Association of Radiation Oncology, Multicenter Italian Trials in Ovarian Cancer, and Mario Negri Gynecologic Oncology Group Groups.

PURPOSE: This retrospective, multicenter study analyzes the efficacy and safety of stereotactic body radiation therapy in a large cohort of patients with oligometastatic/persistent/recurrent uterine cancer. METHODS AND MATERIALS: Clinical and radiation therapy data from several radiation therapy centers treating patients by stereotactic body radiation therapy between March 2006 and October 2021 were collected. Objective response rate was defined as complete and partial response, and clinical benefit included objective response rate plus stable disease. Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer and Common Terminology Criteria for Adverse Events scales were used to grade toxicities. Primary endpoints were the rate of complete response to stereotactic body radiation therapy, and the 2-year actuarial local control rate "per-lesion" basis. Secondary endpoints were progression-free survival and overall survival, as well as toxicity. RESULTS: In the study, 157 patients with oligometastatic/persistent/recurrent uterine cancer bearing 272 lesions treated by stereotactic body radiation therapy at 14 centers were analyzed. Lymph node metastases (137, 50.4%) were prevalent, followed by parenchyma lesions (135, 49.6%). Median total dose was 35 Gy (10-75.2), in 5 fractions (range, 1-10). Complete and partial responses were 174 (64.0%), and 54 (19.9%), respectively. Stable disease was registered in 29 (10.6%), and 15 (5.5%) lesions progressed. Type of lesion (lymph node), volume (≤13.7 cc) and total dose (BED10 >59.5 Gy) were significantly associated with a higher probability of achieving complete response. Patients achieving complete response (CR) "per-lesion" basis experienced a 2-year actuarial local control rate of 92.4% versus 33.5% in lesions not achieving complete response (NCR; P < .001). Moreover, the 2-year actuarial progression-free survival rate in patients with CR was 45.4%, and patients with NCR had a 2-year rate of 17.6% (P < .001). Finally, patients who had a CR had a 2-year overall survival rate of 82.7%, compared with 56.5% for NCR patients (P <.001). Severe acute toxicity was around 2%, including one toxic death due to gastric perforation, and severe late toxicity around 4%. CONCLUSIONS: The efficacy of stereotactic body radiation therapy in this setting was confirmed. The low toxicity profile and the high local control rate in complete responder patients encourage the wider use of this approach.

Photon-based High-dose Single-fraction Radiosurgery, an Effective Treatment Modality for Large and Posterior Uveal Melanoma.

BACKGROUND/AIM: Uveal melanoma (UM) is the most common primary intraocular malignant tumor. This malignancy is frequently treated using brachytherapy, stereotactic radiotherapy, or proton therapy. The objective of this study was to assess the role of stereotactic radiosurgery in the treatment of large and posterior UM. PATIENTS AND METHODS: From January 2014 to July 2021, we treated 65 patients (median age=71 years; range=31-89 years) affected by UM. Inclusion criteria were Eastern Cooperative Oncology Group (ECOG) performance status (PS) ≤2, life expectancy >6 months, tumor thickness >10 mm, diameter >16 mm or posterior UM. The treatment was delivered with a True Beam™ LINAC with arc modulation technique. All patients received 27 Gy in one fraction (biological effective dose ≈100 Gy, assuming an α/ß of 10). RESULTS: The median follow-up was 36 (range=3-90) months. Acute toxicities were reported in 14 patients, whereas late toxicity occurred in 45 (69.2%). Fifteen patients (23.0%) underwent enucleation: eight (12.3%) for failure of local control and seven (10.7%) for late treatment co-morbidities. The 5-year local control, and progression-free, metastasis-free, enucleation-free, and overall survival rates were 80%, 43%, 62%, 65% and 56%, respectively. In multivariate analysis, tumor dimensions significantly influenced survival [larger basal diameter: progression-free [hazard ratio (HR)=2.42] and overall (HR=2.61) survival; greater thickness: overall survival (HR=2.36)]. In multivariate analysis, patients without local control had a higher risk of distant metastasis (HR=3.25). CONCLUSION: Stereotactic radiosurgery offers an effective and safe approach for selected cases of UM due to the satisfactory results in terms of local control, eye conservation and survival.