Genitourinary Cancer

PV QA 4 - Poster Viewing Q&A 4

TU_21_3522 - A Comparison of Prospectively Collected Genitourinary and Gastrointestinal Toxicities and Dose Volume Histogram in Patients Treated with Intensity-Modulated Radiation Therapy or Non-Intensity-Modulated Post-Operative Radiation Therapy

Tuesday, October 23
2:45 PM - 4:15 PM
Location: Innovation Hub, Exhibit Hall 3

A Comparison of Prospectively Collected Genitourinary and Gastrointestinal Toxicities and Dose Volume Histogram in Patients Treated with Intensity-Modulated Radiation Therapy or Non-Intensity-Modulated Post-Operative Radiation Therapy
S. E. Nicholas1, W. Fu1, C. Hu2, Z. Cheng3, T. R. McNutt4, L. P. Cho5, T. L. DeWeese4, and A. N. Viswanathan IV5; 1Johns Hopkins University School of Medicine, Baltimore, MD, 2Johns Hopkins University School of Medicine Department of Biostatistics, Baltimore, MD, 3Johns Hopkins Medicine, Baltimore, MD, 4Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, 5Johns Hopkins Hospital, Department of Radiation Oncology and Molecular Radiation Sciences, Baltimore, MD

Purpose/Objective(s): To compare maximum genitourinary (GU) and gastrointestinal (GI) toxicities within 5 weeks of starting radiation therapy between intensity-modulated radiation therapy (IMRT) and conventional radiation therapy (non-IMRT) in post-hysterectomy patients treated for cervical or endometrial cancer. We also were interested to determine the dose volume histogram (DVH) values that predict grade 2+ toxicities.

Materials/Methods: Post-hysterectomy cervical and endometrial cancer patients treated at our institution were retrospectively analyzed for toxicity. GU and GI toxicities were collected prospectively using CTCAE version 4.0 during weekly on-treatment visits using a centralized database from week 1 to 6 of radiation therapy. DVH parameters were analyzed. Univariate analysis of toxicity, patient characteristics, and DVH parameters was performed using chi-square test and logistic regression.

Results: A total of 105 post-hysterectomy patients with stages I-IIIC2 endometrial (n=83, 79%) or IA-IIA cervical (n=22, 21%) cancer were treated from May 2003-November 2016. Ninety-one patients (87%) had on treatment visit assessments to evaluate (51 with IMRT and 40 with non-IMRT), including 55 patients (30 with IMRT and 25 with non-IMRT) with DVH parameters available. There was no difference between the two groups regarding baseline patient characteristics. Within 5 weeks of treatment, 23.5% patients in IMRT and 40% in non-IMRT had at least one grade 2+ toxicity (p=0.12). Bowel V40 and V45 were lower in the IMRT (median [Q1-Q3] 216cc [145-373]) than non IMRT (570cc [334-668]) cohorts. Among all patients, bowel V25, V30, V40 and V45 were all significantly associated with increased incidences of any grade 2+ toxicity, while bowel V5, V10, V15, V20 and V35 were not (Table 1). The medians (Q1-Q3) of bowel V45 were 199cc (80-457cc) among those had < grade 2 GI toxicity and 527cc (147-829cc) among those had 2+ GI toxicity (p=0.03). Table 1: DVH Parameters and Toxicity
Bowel DVH: Median cc (Q1-Q3cc) < Grade 2 Toxicity Grade 2+ Toxicity P Value
V5 1066 (654-1517) 1200 (826-1615) 0.5
V10 907 (588-1392) 1108 (780-1565) 0.36
V15 814 (537-1160) 1037 (680-1499) 0.2
V20 745 (475-1102) 1004 (508-1393) 0.1
V25 605 (408-897) 905 (395-1270) 0.038
V30 466 (327-727) 788 (258-1075) 0.027
V35 398 (271-615) 681 (214-966) 0.4
V40 289 (177-472) 607 (189-887) 0.009
V45 184 (78 - 388) 527 (155-800) 0.005

Conclusion: The rates of experiencing at least one grade 2 or higher toxicity were lower for patients treated with IMRT than non-IMRT. Bowel V45 was associated with Grade 2+ toxicity. IMRT was associated with a lower bowel V40 and V45 in this group of post hysterectomy patients.

Author Disclosure: S.E. Nicholas: None. W. Fu: None. Z. Cheng: None. T.R. McNutt: Research Grant; Elekta Oncology Systems, Philips Radiation Oncology Systems, Toshiba. Patent/License Fees/Copyright; Accuray-Tomotherapy, Sun Nuclear. President Elect; AAPM-MAC. T.L. DeWeese: None. A.N. Viswanathan: None.

Send Email for Sarah Nicholas


Assets

TU_21_3522 - A Comparison of Prospectively Collected Genitourinary and Gastrointestinal Toxicities and Dose Volume Histogram in Patients Treated with Intensity-Modulated Radiation Therapy or Non-Intensity-Modulated Post-Operative Radiation Therapy



Attendees who have favorited this

Please enter your access key

The asset you are trying to access is locked. Please enter your access key to unlock.

Send Email for A Comparison of Prospectively Collected Genitourinary and Gastrointestinal Toxicities and Dose Volume Histogram in Patients Treated with Intensity-Modulated Radiation Therapy or Non-Intensity-Modulated Post-Operative Radiation Therapy