Pretesh Patel

Duke University, Durham, North Carolina, United States

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Publications (5)23.23 Total impact

  • No preview · Article · Dec 2015 · International journal of radiation oncology, biology, physics
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    ABSTRACT: Background: The practice of treating a solitary pulmonary nodule (SPN) suspicious for stage I non-small cell lung cancer (NSCLC) with stereotactic ablative radiotherapy (SABR) in the absence of pathology is growing. In the absence of randomized evidence, the appropriate prior probability threshold of lung cancer of when such a strategy is warranted can be informed using decision analysis. Methods: A decision tree and Markov model were constructed to evaluate the relative merits of surveillance, a PET scan-directed SABR strategy (without pathology), or a PET scan-biopsy-SABR strategy, when faced with an SPN at different prior probabilities for lung cancer. Diagnostic characteristics, as well as disease, treatment, and toxicity parameters, were extracted from the literature. Deterministic analysis and probabilistic sensitivity analyses were performed to inform the appropriate lung cancer prior probability threshold between treatment strategies. Results: In the reference case analysis, the prior probability threshold between surveillance and PET scan-biopsy-SABR was 17.0%; between PET scan-directed SABR and PET scan-biopsy-SABR, the threshold was 85.0%. The latter finding was confirmed on probabilistic sensitivity analysis (85.2%; 95% CI, 80.0% to 87.2%). This predicted lung cancer prior probability threshold was most sensitive to the diagnostic sensitivity of transthoracic biopsy (range, 77.2% to 94.0%) and the detection rate of false negatives on CT scan surveillance (range, 82.4% to 92.3%). Conclusions: This model suggests that if there are concerns about morbidity related to biopsy for an SPN, a PET scan-directed SABR strategy is warranted when the prior probability of lung cancer exceeds a point estimate of 85%.
    Full-text · Article · May 2014 · Chest
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    ABSTRACT: Stereotactic body radiotherapy (SBRT) involves the treatment of extracranial primary tumors or metastases with a few, high doses of ionizing radiation. In SBRT, tumor kill is maximized and dose to surrounding tissue is minimized, by precise and accurate delivery of multiple radiation beams to the target. This is particularly challenging, because extracranial lesions often move with respiration and are irregular in shape, requiring careful treatment planning and continual management of this motion and patient position during irradiation. This review presents the rationale, process workflow, and technology for the safe and effective administration of SBRT, as well as the indications, outcome, and limitations for this technique in the treatment of lung cancer, liver cancer, and metastatic disease. Cancer 2013;. © 2013 American Cancer Society.
    Full-text · Article · Apr 2014 · Cancer
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    ABSTRACT: Recent in vitro and in vivo evidence has suggested that statin medications may have anticancer activity. We sought to determine whether statin use was associated with improved clinical outcome in men treated with brachytherapy for prostate cancer. A database of men with prostate cancer treated with permanent Iodine-125 brachytherapy between January 1999 and February 2009 was retrospectively analyzed. Standard guidelines (i.e., American Brachytherapy Society selection criteria) were used for selecting patients for brachytherapy. Biochemical failure was defined using the Phoenix definition. From a total of 247 men with prostate adenocarcinoma treated with brachytherapy, 174 patients (70 %) were identified as using statin medications, either during initial visit or during follow-up. Median PSA follow-up was 51 months after date of implant (range 9.4-140.35). Overall biochemical failure rate was 7.3 % (18 patients). On univariate analysis, statin use was associated with significantly improved freedom from biochemical failure [hazard ratio (HR) 0.28; 95 % CI 0.10-0.72; p < 0.01 by log-rank test]. In multivariate Cox analysis performed with the variables statin use, pretreatment PSA, clinical T stage, Gleason score, and D90 or V100, statin use remained significantly associated with improved freedom from biochemical failure (HR 0.288; 95 % CI 0.086-0.886; p = 0.0299). Statin use was associated with a significant improvement in freedom from biochemical failure in this cohort of men treated with brachytherapy for prostate cancer. Further investigation into the favorable effect of statin use on brachytherapy and radiation therapy in general is warranted, including prospective trials.
    No preview · Article · Mar 2014 · World Journal of Urology
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    ABSTRACT: Ampullary carcinoma is a rare malignancy. Despite radical resection, survival rates remain low with high rates of local failure. We performed a single-institution outcomes analysis to define the role of concurrent chemoradiotherapy (CRT) in addition to surgery. A retrospective analysis was performed of all patients undergoing potentially curative pancreaticoduodenectomy for adenocarcinoma of the ampulla of Vater at Duke University Hospitals between 1976 and 2009. Time-to-event analysis was performed comparing all patients who underwent surgery alone to the cohort of patients receiving CRT in addition to surgery. Local control (LC), disease-free survival (DFS), overall survival (OS), and metastases-free survival (MFS) were estimated using the Kaplan-Meier method. A total of 137 patients with ampullary carcinoma underwent Whipple procedure. Of these, 61 patients undergoing resection received adjuvant (n = 43) or neoadjuvant (n = 18) CRT. Patients receiving chemoradiotherapy were more likely to have poorly differentiated tumors (P = .03). Of 18 patients receiving neoadjuvant therapy, 67% were downstaged on final pathology with 28% achieving pathologic complete response (pCR). With a median follow-up of 8.8 years, 3-year local control was improved in patients receiving CRT (88% vs 55%, P = .001) with trend toward 3-year DFS (66% vs 48%, P = .09) and OS (62% vs 46%, P = .074) benefit in patients receiving CRT. Long-term survival rates are low and local failure rates high following radical resection alone. Given patterns of relapse with surgery alone and local control benefit in patients receiving CRT, the use of chemoradiotherapy in selected patients should be considered.
    No preview · Article · Nov 2011 · Annals of Surgical Oncology