Browsing by Author "Jensen, Garrett L."

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    Bone Density Changes Following Radiotherapy to Vertebral Metastases
    (Springer Nature, 2021-06-03) Jensen, Garrett L.; Gaddipati, Ravi; Hammonds, Kendall P.; Morrow, Andrew; Swanson, Gregory P.; Radiation Oncology, School of Medicine
    Introduction: Patients have increasing longevity and time for bone healing following radiotherapy (RT) for treatment of bone metastases (BM). Attempts to assess the treatment response of bone metastases have been either limited or heavily subjective. Our goal was to try to quantitate cancer-involved bone changes after RT using changes in bone mineral density (BMD) from computer tomographic (CT) imaging. Methods: Retrospectively, 117 spinal metastases were identified that received RT with follow-up CT scans >9 months following CT simulation. Contoured volumes included: the metastasis (gross tumor volume; GTV); the involved vertebra (gross bone volume; GBV); a total lytic volume (Lyt); a dominant lytic volume (Domlyt); a control volume, and the nearest uninvolved, unirradiated vertebra (control bone volume; CBV). The Hounsfield-density calibration curve was used to measure the density of these volumes before and after treatment. Results: Whether using raw or control-adjusted changes, the absolute and percent change in density of the GBV, GTV, Lyt, and Domlyt volumes all significantly increased (each p<0.0001). The increase in the density of Domlyt volumes was greater than that of Lyt volumes (p=0.0465), which were greater than GTV (p=0.0065), which were greater than GBV (p<0.0001). On multivariate analysis, only the biologically effective dose (BED) dose significantly correlated with GTV density change (p=0.0175). K means clustering created groups by initial lesion size, GTV, or GBV density. A significant difference in GTV density change was not detected between any groups. Conclusion: Increases in BMD are associated with healing regardless of lesion size or initial density. A prospective study to determine whether long-term control is related to early density measurements is needed.
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    Improved Pathologic response to chemoradiation in MGMT methylated locally advanced rectal cancer
    (Elsevier, 2023-07-24) Jensen, Garrett L.; Pourfarrokh, Niloufar; Volz, Marcus; Morales, Linden L.; Walker, Kimberly; Hammonds, Kendall P.; El-Ghamry, Moataz; Wong, Lucas; Hodjat, Parsa; Castro, Eduardo; Rao, Arundhati; Jhavar, Sameer G.; Radiation Oncology, School of Medicine
    Background and purpose: With the growing interest in total neoadjuvant treatment for locally advanced rectal adenocarcinoma (LARC) there is an urgent unmet need to identify predictive markers of response to long-course neoadjuvant concurrent chemoradiotherapy (LCRT). O6-Methylguanine (O6-MG)-DNA-methyltransferase (MGMT) gene methylation has been associated in some malignancies with response to concurrent chemoradiotherapy. We attempted to find if pathologic response to LCRT was associated with MGMT promoter hypermethylation (MGMTh). Materials and methods: Patients were identified with LARC, available pre-treatment biopsy specimens, and at least 1 year of follow-up who received LCRT followed by surgical resection within 6 months. Biopsies were tested for MGMTh using a Qiagen pyrosequencing kit (Catalog number 970061). The primary outcome of LCRT responsiveness was based on tumor regression grade (TRG), with grades of 0-1 considered to have excellent response and grades of 2-3 considered to be non-responders. Secondary outcomes included overall survival (OS) and recurrence free survival (RFS). Results: Of 96 patients who met inclusion criteria, 76 had samples which produced reliable assay results. MGMTh corresponded with higher grade and age of the biopsy specimen. The percentage of responders to LCRT was higher amongst the MGMTh patients than the MGMTn patients (60.0% vs 27.5%, p value = 0.0061). MGMTh was not significantly associated with improved OS (2-year OS of 96.0% vs 98.0%, p = 0.8102) but there was a trend for improved RFS (2-year RFS of 87.6% vs 74.2%, p = 0.0903). Conclusion: Significantly greater tumor regression following LCRT was seen in MGMTh LARC. Methylation status may help identify good candidates for close observation without surgery following LCRT.
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    The cost of elective nodal coverage in prostate cancer: Late quality of life outcomes and dosimetric analysis with 0, 45 or 54 Gy to the pelvis
    (Elsevier, 2022-06-27) Jensen, Garrett L.; Jhavar, Sameer G.; Ha, Chul S.; Hammonds, Kendall P.; Swanson, Gregory P.; Radiation Oncology, School of Medicine
    Purpose: Elective pelvic lymph node radiotherapy (PLNRT) in prostate cancer is often omitted from definitive (n = 267) and post prostatectomy (n = 160) radiotherapy (RT) due to concerns regarding toxicity and efficacy. Data comparing patient-reported outcome measures (PROMs) with or without PLNRT is limited. Our long-term supposition is that PLNRT, particularly to higher doses afforded by IMRT, will decrease pelvic failure rate in select patients. We aim to establish the impact of two different PLNRT doses on long term quality of life (QOL). Methods and materials: Prostate cancer patients (n = 428) recorded baseline scores using the Expanded Prostate Cancer Index Composite (EPIC), prior to definitive or post-prostatectomy RT. PLNRT, if given, was prescribed to 45 or 54 Gy at 1.8 Gy per fraction. New EPIC scores were recorded 20-36 months after radiotherapy. Absolute change in each domain subscale and summary score was recorded, along with if these changes met minimally important difference (MID) criteria. A separate multivariate analysis (MVA) was performed for each measure. Subsequent dosimetric analysis was performed. Results: Frequency of a MID decline was significantly greater with PLNRT to 54 Gy for urinary function, incontinence, and overall. No urinary decline was correlated with PLNRT to 45 Gy. PLNRT to 54 Gy was significant for decline in urinary function, bother, irritative, incontinence, and overall score in one or both MVA models while 45 Gy was not. Postoperative status was significant for decline in urinary function, incontinence, and overall. Amongst postoperative patients, there was significantly greater decline in urinary function score in the salvage setting. Neither 54 nor 45 Gy significantly affected bowel subscale or overall score decline. Conclusions: Using conventional fractionation, adding PLNRT to 54 Gy, but not 45 Gy, correlates with worse urinary QOL, with postoperative patients experiencing a steeper decline. PLNRT had no significant impact on bowel QOL with either dose.