Multi-Institutional Dosimetric Evaluation of Modern Day Stereotactic Radiosurgery (SRS) Treatment Options for Multiple Brain Metastases.

Purpose/Objectives: There are several popular treatment options currently available for stereotactic radiosurgery (SRS) of multiple brain metastases: 60Co sources and cone collimators around a spherical geometry (GammaKnife), multi-aperture dynamic conformal arcs on a linac (BrainLab Elements™ v1.5), and volumetric arc therapy on a linac (VMAT) calculated with either the conventional optimizer or with the Varian HyperArc™ solution. This study aimed to dosimetrically compare and evaluate the differences among these treatment options in terms of dose conformity to the tumor as well as dose sparing to the surrounding normal tissues. Methods and Materials: Sixteen patients and a total of 112 metastases were analyzed. Five plans were generated per patient: GammaKnife, Elements, HyperArc-VMAT, and two Manual-VMAT plans to evaluate different treatment planning styles. Manual-VMAT plans were generated by different institutions according to their own clinical planning standards. The following dosimetric parameters were extracted: RTOG and Paddick conformity indices, gradient index, total volume of brain receiving 12Gy, 6Gy, and 3Gy, and maximum doses to surrounding organs. The Wilcoxon signed rank test was applied to evaluate statistically significant differences (p \u3c 0.05). Results: For targets ≤ 1 cm, GammaKnife, HyperArc-VMAT and both Manual-VMAT plans achieved comparable conformity indices, all superior to Elements. However, GammaKnife resulted in the lowest gradient indices at these target sizes. HyperArc-VMAT performed similarly to GammaKnife for V12Gy parameters. For targets ≥ 1 cm, HyperArc-VMAT and Manual-VMAT plans resulted in superior conformity vs. GammaKnife and Elements. All SRS plans achieved clinically acceptable organs-at-risk dose constraints. Beam-on times were significantly longer for GammaKnife. Manual-VMATA and Elements resulted in shorter delivery times relative to Manual-VMATB and HyperArc-VMAT. Conclusion: The study revealed that Manual-VMAT and HyperArc-VMAT are capable of achieving similar low dose brain spillage and conformity as GammaKnife, while significantly minimizing beam-on time. For targets smaller than 1 cm in diameter, GammaKnife still resulted in superior gradient indices. The quality of the two sets of Manual-VMAT plans varied greatly based on planner and optimization constraint settings, whereas HyperArc-VMAT performed dosimetrically superior to the two Manual-VMAT plans

A Multi-Institutional Analysis of Adjuvant Chemotherapy and Radiation Sequence in Women With Stage IIIC Endometrial Cancer

PURPOSE: Our purpose was to evaluate the effect of sequence and type of adjuvant therapy for patients with stage IIIC endometrial carcinoma (EC) on outcomes. METHODS AND MATERIALS: In a multi-institutional retrospective cohort study, patients with stage IIIC EC who had surgical staging and received both adjuvant chemotherapy and radiation therapy (RT) were included. Adjuvant treatment regimens were classified as adjuvant chemotherapy followed by sequential RT (upfront chemo), which was predominant sequence; RT with concurrent chemotherapy followed by chemotherapy (concurrent); systemic chemotherapy before and after RT (sandwich); adjuvant RT followed by chemotherapy (upfront RT); or chemotherapy concurrent with vaginal cuff brachytherapy alone (chemo-brachy). Overall survival (OS) and recurrence-free survival (RFS) rates were estimated by the Kaplan-Meier method. RESULTS: A total of 686 eligible patients were included with a median follow-up of 45.3 months. The estimated 5-year OS and RFS rates were 74% and 66%, respectively. The sequence and type of adjuvant therapy were not correlated with OS or RFS (adjusted P = .68 and .84, respectively). On multivariate analysis, black race, nonendometrioid histology, grade 3 tumor, stage IIIC2, and presence of adnexal and cervical involvement were associated with worse OS and RFS (all P \u3c .05). Regardless of the sequence of treatment, the most common site of first recurrence was distant metastasis (20.1%). Vaginal only, pelvic only, and paraortic lymph node (PALN) recurrences occurred in 11 (1.6%),15 (2.2 %), and 43 (6.3 %) patients, respectively. Brachytherapy alone was associated with a higher rate of PALN recurrence (15%) compared with external beam radiation therapy (5%) P \u3c .0001. CONCLUSIONS: The sequence and type of combined adjuvant therapy did not affect OS or RFS rates. Brachytherapy alone was associated with a higher rate of PALN recurrence, emphasizing the role of nodal radiation for stage IIIC EC. The vast proportion of recurrences were distant despite systemic chemotherapy, highlighting the need for novel regimens

Incidence of clinical lymphedema in breast cancer patients treated with adjuvant proton-based radiotherapy

Background: The purpose of this study was to evaluate the incidence of clinical lymphedema following adjuvant proton-based radiotherapy (RT) in breast cancer (BC) patients. Materials and methods: We performed a retrospective review of our institutional database to identify BC patients treated with adjuvant proton-based RT. Patients receiving re-irradiation for a BC recurrence or those with a history of ipsilateral chest wall radiation were excluded. Clinical lymphedema was determined by documentation in the chart at baseline and during follow-up. Results: We identified 28 patients treated with adjuvant proton-based RT who met the study criteria. Median age at diagnosis was 45 (range, 24–75). Eleven patients (39%) underwent mastectomy, and fourteen (50%) underwent axillary lymph node dissection (ALND). Median number of LNs removed was 6 (range, 1–28). Nineteen patients (68%) received neoadjuvant chemotherapy. Median whole breast/chest wall dose delivered was 50 Gy (range, 44–54.0 Gy). Target volumes included the axillary and supraclavicular lymph nodes in all patients and internal mammary lymph nodes in 27 (96%) patients. Mean dose to the axilla was 49.7 Gy, and mean dose to 95% of the axillary volume (D95) was 46.3 Gy (94% of prescription dose). Mean dose to supraclavicular (SCV) volume was 47.7 Gy, and D95 was 44.1 Gy (91% of prescription dose). Grade 3 dermatitis occurred in 14% of patients. Five patients (18%) had clinical lymphedema, 4 from the ALND subset (n = 14). Conclusions: The incidence of clinical lymphedema after proton-based RT is comparable to rates reported with photon-based RT with comprehensive nodal coverage

Comparison of kV Orthogonal Radiographs and kV-Cone-Beam Computed Tomography Image-Guided Radiotherapy Methods With and Without Implanted Fiducials in Prostate Cancer

Introductio

Does prophylactic para-aortic lymphatic irradiation improve outcomes in women with stage IIIC1 endometrial carcinoma? A multi-institutional pooled analysis

PURPOSE: To evaluate the impact of prophylactic PALN RT on clinical outcomes in patients with FIGO 2018 stage IIIC1 EC. MATERIALS/METHODS: A multi-institutional retrospective study included patients with FIGO 2018 stage IIIC1 EC status post surgical staging, lymph node assessment followed by adjuvant chemotherapy and radiotherapy using various sequencing regimens. Overall survival (OS) and recurrence-free survival (RFS) rates were estimated by Kaplan-Meier method. Univariable and multivariable analysis were performed by Cox proportional hazard models for RFS/OS. In addition, propensity score matching were used to estimate the effect of the radiation field extent on survival outcomes. RESULTS: A total of 378 patients were included with a median follow-up of 45.8 months. Pelvic RT was delivered to 286 patients while 92 patients received pelvic and PALN RT. The estimated OS and RFS rates at 5 years for the entire cohort were 80% and 69%, respectively. There was no difference in the 5-year OS (77% vs. 87%, p=0.47) and RFS rates (67% vs. 70%, p=0.78) between patients treated with pelvic RT and those with pelvic and prophylactic PALN RT, respectively. After propensity score matching, the estimated Hazard Ratios (HR) of prophylactic PALN RT vs. pelvic RT were 1.50 (95% CI = (0.71, 3.19), p-value = 0.28) for OS and 1.24 (95% CI = (0.64, 2.42), p-value = 0.51) for RFS suggesting that prophylactic PALN RT does not improve survival outcomes. Distant recurrence was the most common site of first recurrence, and the extent of RT field was not associated with the site of first recurrence (P=0.79). CONCLUSIONS: Prophylactic PALN RT was not significantly associated with improved survival outcomes in stage IIIC1 EC. Distant metastases remain the most site of failure despite routine use of systemic chemotherapy, new therapeutic approaches are necessary to optimize the outcomes for women with stage IIIC1 EC