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Effect of modern, high-quality prostate intensity-modulated radiation therapy on outcome: Evidence from a community radiation oncology program.

ABSTRACT: Radiation technique for prostate cancer has continuously evolved over the past several decades. The aim of the present study was to describe the effects of implementing modern prostate intensity-modulated radiation therapy (M-IMRT) on dosimetry and outcome. Between January 2010 and April 2012, 48 consecutive patients were treated with conventional prostate IMRT (C-IMRT) to a dose of 81 Gy. Between May 2012 and April 2015, 50 consecutive patients were treated with M-IMRT to the entire prostate to a dose of 75.6-79.2 Gy, while using prostate magnetic resonance imaging fusion, dose-volume constraints prioritizing normal tissue avoidance above planning target volume coverage, and boosting any dominant intraprostatic masses to 79.2-81 Gy. Rectal Dmax, V75, V60, V65 and V50, bladder Dmax, V75, V70 and V65, and acute and late toxicities were compared between the C-IMRT and M-IMRT groups. The median follow-up for the C-IMRT and M-IMRT groups was 61 vs. 26 months, respectively (P<0.001). M-IMRT resulted in a significant reduction in median rectal Dmax, rectal V75, rectal V70, rectal V65, bladder Dmax, bladder V75, bladder V70 and bladder V65 (P<0.01 for all). There was no significant difference in rectal V50. The 2-year rate of late grade ≥2 rectal bleeding was 13% with C-IMRT vs. 3% with M-IMRT (P=0.03). The 2-year rate of late grade ≥2 genitourinary toxicity was 11% for C-IMRT vs. 5% for M-IMRT (P=0.21). There were no significant differences in acute toxicity, biochemical control or overall survival. Therefore, compared with C-IMRT, M-IMRT was associated with reduced rectal toxicity without compromising disease control.

SUBMITTER: Kao J

PROVIDER: S-EPMC5532702 | biostudies-other | 2017 Aug

REPOSITORIES: biostudies-other

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Project description:To give a preliminary report of clinical and treatment factors associated with toxicity in men receiving high-dose radiation therapy (RT) on a phase 3 dose-escalation trial.The trial was initiated with 3-dimensional conformal RT (3D-CRT) and amended after 1 year to allow intensity modulated RT (IMRT). Patients treated with 3D-CRT received 55.8 Gy to a planning target volume that included the prostate and seminal vesicles, then 23.4 Gy to prostate only. The IMRT patients were treated to the prostate and proximal seminal vesicles to 79.2 Gy. Common Toxicity Criteria, version 2.0, and Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer late morbidity scores were used for acute and late effects.Of 763 patients randomized to the 79.2-Gy arm of Radiation Therapy Oncology Group 0126 protocol, 748 were eligible and evaluable: 491 and 257 were treated with 3D-CRT and IMRT, respectively. For both bladder and rectum, the volumes receiving 65, 70, and 75 Gy were significantly lower with IMRT (all P<.0001). For grade (G) 2+ acute gastrointestinal/genitourinary (GI/GU) toxicity, both univariate and multivariate analyses showed a statistically significant decrease in G2+ acute collective GI/GU toxicity for IMRT. There were no significant differences with 3D-CRT or IMRT for acute or late G2+ or 3+ GU toxicities. Univariate analysis showed a statistically significant decrease in late G2+ GI toxicity for IMRT (P=.039). On multivariate analysis, IMRT showed a 26% reduction in G2+ late GI toxicity (P=.099). Acute G2+ toxicity was associated with late G3+ toxicity (P=.005). With dose-volume histogram data in the multivariate analysis, RT modality was not significant, whereas white race (P=.001) and rectal V70 ?15% were associated with G2+ rectal toxicity (P=.034).Intensity modulated RT is associated with a significant reduction in acute G2+ GI/GU toxicity. There is a trend for a clinically meaningful reduction in late G2+ GI toxicity with IMRT. The occurrence of acute GI toxicity and large (>15%) volumes of rectum >70 Gy are associated with late rectal toxicity.

Project description:PurposeQuality of life (QoL) outcomes play a major role in the treatment selection for prostate cancer (CaP). We evaluated the urinary QoL outcomes in men who were treated with image-guided intensity-modulated radiation therapy (IG-IMRT) for CaP.Methods and materialsWe enrolled men who were diagnosed with CaP and underwent IG-IMRT in a large urological group practice into a prospectively maintained database. The typical radiation treatment dosage to prostates and seminal vesicles was 8100 cGy in 45 fractions. Urinary QoL was self-assessed using the standardized incontinence grade and International Prostate Symptom Score (IPSS) at baseline and at each follow-up visit. We evaluated the cumulative incidence of urinary incontinence and changes in both continence and IPSS over time.ResultsOf the 3602 men who were eligible for analysis, 3086 (85.7%) had no urinary incontinence; 479 (13.3 %) had minimal incontinence (no requirement for pads), and 37 (1.0 %) had significant urinary incontinence that required the use of pads or interfered with activities of daily living, at baseline. After a median follow-up of 24 months (range: 12.0-41.0 months), these numbers were 80.6%, 17.4%, and 2.0%, respectively. Radiation therapy appeared to have a beneficial effect on some men: 54.1% of men with minimal incontinence became completely continent of urine during follow-up. Of those with significant urinary incontinence, 29.7% reported resolution and 27.0% reported improved symptoms with no requirement for pads. Of the 1276 men with moderate IPSS, the mean IPSS decreased from 12 to 9.8 at the time of the last follow-up (P < .001). Similarly, of the 233 men with severe IPSS, the mean IPSS decreased from 24 to 13 at the time of the last follow-up (P < .001).ConclusionIG-IMRT for clinically localized CaP is associated with a relatively low incidence of urinary incontinence. Although unexplained, IG-IMRT seems to improve symptoms in some men with baseline urinary incontinence and moderate-to-severe IPSS.

Project description:PurposeThis study aimed to develop a quality control framework for intensity modulated radiation therapy plan evaluations that can account for variations in patient- and treatment-specific risk factors.Methods and materialsPatient-specific risk factors, such as a patient's anatomy and tumor dose requirements, affect organs-at-risk (OARs) dose-volume histograms (DVHs), which in turn affects plan quality and can potentially cause adverse effects. Treatment-specific risk factors, such as the use of chemotherapy and surgery, are clinically relevant when evaluating radiation therapy planning criteria. A risk-adjusted control chart was developed to identify unusual plan quality after accounting for patient- and treatment-specific risk factors. In this proof of concept, 6 OAR DVH points and average monitor units serve as proxies for plan quality. Eighteen risk factors are considered for modeling quality: planning target volume (PTV) and OAR cross-sectional areas; volumes, spreads, and surface areas; minimum and centroid distances between OARs and the PTV; 6 PTV DVH points; use of chemotherapy; and surgery. A total of 69 head and neck cases were used to demonstrate the application of risk-adjusted control charts, and the results were compared with the application of conventional control charts.ResultsThe risk-adjusted control chart remains robust to interpatient variations in the studied risk factors, unlike the conventional control chart. For the brainstem, the conventional chart signaled 4 patients with unusual (out-of-control) doses to 2% brainstem volume. However, the adjusted chart did not signal any plans after accounting for their risk factors. For the spinal cord doses to 2% brainstem volume, the conventional chart signaled 2 patients, and the adjusted chart signaled a separate patient after accounting for their risk factors. Similar adjustments were observed for the other DVH points when evaluating brainstem, spinal cord, ipsilateral parotid, and average monitor units. The adjustments can be directly attributed to the patient- and treatment-specific risk factors.ConclusionsA risk-adjusted control chart was developed to evaluate plan quality, which is robust to variations in patient- and treatment-specific parameters.

Project description:BACKGROUND:Prostate cancer treatment is a significant source of morbidity and spending. Some men with prostate cancer, particularly those with significant health problems, are unlikely to benefit from treatment. OBJECTIVE:To assess relationships between financial incentives associated with urologist ownership of radiation facilities and treatment for prostate cancer. DESIGN, SETTING, AND PARTICIPANTS:A retrospective cohort of Medicare beneficiaries with prostate cancer diagnosed between 2010 and 2012. Patients were further classified by their risk of dying from noncancer causes in the 10 yr following their cancer diagnosis by using a mortality model derived from comparable patients known to be cancer-free. INTERVENTION:Urologists were categorized by their practice affiliation (single-specialty groups by size, multispecialty group) and ownership of a radiation facility. OUTCOME MEASUREMENTS AND ANALYSIS:Use of intensity-modulated radiation therapy (IMRT) and use of any treatment within 1 yr of diagnosis. Generalized estimating equations were used to adjust for patient differences. RESULTS:Among men with newly diagnosed prostate cancer, use of IMRT ranged from 24% in multispecialty groups to 37% in large urology groups (p<0.001). Patients managed in groups with IMRT ownership (n=5133) were more likely to receive IMRT than those managed by single-specialty groups without ownership (43% vs 30%, p<0.001), regardless of group size. Among patients with a very high risk (> 75%) of noncancer mortality within 10 yr of diagnosis, both IMRT use (42% vs 26%, p<0.001) and overall treatment (53% vs 44%, p<0.001) were more likely in groups with ownership than in those without, respectively. CONCLUSIONS:Urologists practicing in single-specialty groups with an ownership interest in radiation therapy are more likely to treat men with prostate cancer, including those with a high risk of noncancer mortality. PATIENT SUMMARY:We assessed treatment for prostate cancer among urologists with varying levels of financial incentives favoring intervention. Those with stronger incentives, as determined by ownership interest in a radiation facility, were more likely to treat prostate cancer, even when treatment was unlikely to provide a survival benefit to the patient.

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Effect of modern, high-quality prostate intensity-modulated radiation therapy on outcome: Evidence from a community radiation oncology program.

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