Role of endoscopic ultrasound for pre-intervention evaluation in early esophageal cancer.

BACKGROUND: Endoscopic ultrasound (EUS) stands as an accurate imaging modality for esophageal cancer staging, however utilization of EUS in early-stage cancer management remains controversial. Identification of non-applicability of endoscopic interventions with deep muscular invasion with EUS in pre-intervention evaluation of early-stage esophageal cancer is compared to endoscopic and histologic indicators. AIM: To display the role of EUS in pre-intervention early esophageal cancer staging and how the index endoscopic features of invasive esophageal malignancy compare for prediction of depth of invasion and cancer management. METHODS: This was a retrospective study of patients who underwent pre-resection EUS after a diagnosis of esophageal cancer at a tertiary medical center from 2012 to 2022. Patient clinical data, initial esophagogastroduodenoscopy/biopsy, EUS, and final resection pathology reports were abstracted, and statistical analysis was conducted to assess the role of EUS in management decisions. RESULTS: Forty nine patients were identified for this study. EUS T stage was concordant with histological T stage in 75.5% of patients. In determining submucosal involvement (T1a vs T1b), EUS had a specificity of 85.0%, sensitivity of 53.9%, and accuracy of 72.7%. Endoscopic features of tumor size > 2 cm and the presence of esophageal ulceration were significantly associated with deep invasion of cancer on histology. EUS affected management from endoscopic mucosal resection/submucosal dissection to esophagectomy in 23.5% of patients without esophageal ulceration and 6.9% of patients with tumor size < 2 cm. In patients without both endoscopic findings, EUS identified deeper cancer and changed management in 4.8% (1/20) of cases. CONCLUSION: EUS was reasonably specific in ruling out submucosal invasion but had relatively poor sensitivity. Data validated endoscopic indicators suggested superficial cancers in the group with a tumor size < 2 cm and the lack of esophageal ulceration. In patients with these findings, EUS rarely identified a deep cancer that warranted a change in management.

Dose-response with stereotactic body radiotherapy for prostate cancer: A multi-institutional analysis of prostate-specific antigen kinetics and biochemical control.

BACKGROUND AND PURPOSE: The optimal dose for prostate stereotactic body radiotherapy (SBRT) is still unknown. This study evaluated the dose-response relationships for prostate-specific antigen (PSA) decay and biochemical recurrence (BCR) among 4 SBRT dose regimens. MATERIALS AND METHODS: In 1908 men with low-risk (50.0%), favorable intermediate-risk (30.9%), and unfavorable intermediate-risk (19.1%) prostate cancer treated with prostate SBRT across 8 institutions from 2003 to 2018, we examined 4 regimens (35 Gy/5 fractions [35/5, n = 265, 13.4%], 36.25 Gy/5 fractions [36.25/5, n = 711, 37.3%], 40 Gy/5 fractions [40/5, n = 684, 35.8%], and 38 Gy/4 fractions [38/4, n = 257, 13.5%]). Between dose groups, we compared PSA decay slope, nadir PSA (nPSA), achievement of nPSA ≤0.2 and ≤0.5 ng/mL, and BCR-free survival (BCRFS). RESULTS: Median follow-up was 72.3 months. Median nPSA was 0.01 ng/mL for 38/4, and 0.17-0.20 ng/mL for 5-fraction regimens (p < 0.0001). The 38/4 cohort demonstrated the steepest PSA decay slope and greater odds of nPSA ≤0.2 ng/mL (both p < 0.0001 vs. all other regimens). BCR occurred in 6.25%, 6.75%, 3.95%, and 8.95% of men treated with 35/5, 36.25/5, 40/5, and 38/4, respectively (p = 0.12), with the highest BCRFS after 40/5 (vs. 35/5 hazard ratio [HR] 0.49, p = 0.026; vs. 36.25/5 HR 0.42, p = 0.0005; vs. 38/4 HR 0.55, p = 0.037) including the entirety of follow-up, but not for 5-year BCRFS (≥93% for all regimens, p ≥ 0.21). CONCLUSION: Dose-escalation was associated with greater prostate ablation and PSA decay. Dose-escalation to 40/5, but not beyond, was associated with improved BCRFS. Biochemical control remains excellent, and prospective studies will provide clarity on the benefit of dose-escalation.

Prostate bed and organ-at-risk deformation: Prospective volumetric and dosimetric data from a phase II trial of stereotactic body radiotherapy after radical prostatectomy.

PURPOSE: Stereotactic body radiotherapy (SBRT) in the post-prostatectomy setting is investigational. A major concern is the deformable prostate bed clinical target volume (CTV) and the closely juxtaposed organs-at-risk (OARs). We report a volumetric and dosimetric analysis of kilovoltage cone-beam CT (CBCT) data from the first 18 patients enrolled on a phase II trial of post-prostatectomy SBRT. With instructions on bladder filling and rectal preparation, we hypothesized acceptable CTV coverage while minimal overdosing to OARs could be achieved. METHODS: All patients received 5 fractions of 6-6.8 Gy to the prostate bed. CBCT were taken prior to and halfway through each fraction. CTV and OARs were contoured for each CBCT. Changes in inter- and intra-fraction volume and dose were calculated. Relative changes in CTV V95%, bladder V32.5 Gy, and rectal V32.5 Gy and V27.5 Gy were evaluated. RESULTS: Interfraction CTV volume remained stable, with median change +5.69% (IQR -1.73% to +9.84%). CTV V95% exhibited median change -0.74% (IQR -9.15% to -0.07%). Volumetric and dosimetric changes were minor from interfraction rotation and intrafraction motion. CTV V95% was ≥93% in 13 of 18 (72%) patients; in the remaining five, median change was -14.09% (IQR -16.64% to -13.56%). Interfraction CTV volume change was significantly larger among patients with CTV V95% <93% (+25.04% vs. +2.85%, p = 0.002). CONCLUSIONS: With specific bladder and rectum filling protocols, CTV underdosing and overdosing to bladder and rectum are avoided in majority of patients. Changes in CTV shape may account for the underdosing that may be observed.