ACR Appropriateness Criteria ® on External Beam Radiation Therapy Treatment Planning for Clinically Localized Prostate Cancer

Preliminary toxicity analysis of 3-dimensional conformal radiation therapy versus intensity modulated radiation therapy on the high-dose arm of the Radiation Therapy Oncology Group 0126 prostate cancer trial

PURPOSE

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.

METHODS AND MATERIALS

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.

RESULTS

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).

CONCLUSIONS

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.

Practice-based evidence to evidence-based practice: building the National Radiation Oncology Registry

The National Radiation Oncology Registry (NROR), sponsored by the Radiation Oncology Institute and the American Society for Radiation Oncology, is designed to collect standardized information on cancer care delivery among patients treated with radiotherapy in the United States and will focus on patients with prostate cancer. Stakeholders were engaged through a forum that emphasized the need for patient-centered outcomes, minimal data burden, and maximal connectivity to existing registries and databases. An electronic infrastructure is under development to provide connectivity across radiation oncology and hospital information systems. The NROR Gateway features automatic abstraction as well as aggregation of treatment and outcome data. The prostate cancer data dictionary provides standardized elements in four domains: facility, physician, patient, and treatment. The pilot phase will consist of clinical centers chosen to provide a representative mix of radiation treatment modalities, facility types, population-based settings, and regional locations. The initial set of radiation practice metrics includes physician board certification and maintenance, ordering of staging scans, active surveillance discussion, dose prescriptions for low-risk/high-risk disease, radiation fields for low-risk/high-risk disease, image-guided radiation therapy use, androgen deprivation therapy use, post-brachytherapy implant computed tomography dosimetry, collection of toxicity assessments, and longitudinal patient follow-up. The NROR pilot study will provide the framework for expansion to a nationwide electronic registry for radiation oncology.

SEOM clinical guidelines for treatment of prostate cancer

Prostate cancer (PC) is the most common cancer in men. Many patients have prolonged survival and die of other diseases, so treatment decisions are often influenced by age and coexisting comorbidities. The main procedure to diagnose PC is an ultrasound-guided core needle biopsy, which is indicated when a digital rectal examination (DRE) finds nodularity or when PSA is >10 ng/ml, but is also recommended with PSA between 4.0 and 10 ng/ml. Depending on age, PSA, Gleason score and characteristics of the tumour, treatment options for localised PC are active surveillance, radical prostatectomy and radiation therapy. Androgen deprivation treatment (ADT) should be added to radiotherapy for men with intermediate- or high-risk PC. ADT is the current standard first-line treatment for metastatic PC. Castration-resistant PC is a heterogeneous entity. Several treatments such as sipuleucel-T, docetaxel-based chemotherapy, radium 223, cabazitaxel or abiraterone plus prednisone, zoledronic and denosumab, are useful for this situation.

Reduction of treatment volume and radiation doses to surrounding tissues with intraprostatic gold markers in prostate cancer radiotherapy

BACKGROUND

High-precision radiotherapy with gold marker implantation is a standard technique for prostate cancer treatment. To provide insight into the beneficial effect of gold markers, the influence on treatment volume and radiation doses to healthy tissues was investigated.

PATIENTS AND METHODS

Three consecutive treatment margins were constructed, for 10 patients with localized prostate cancer, to show the reduction of planning target volume (PTV): PTV 10 mm (no markers), PTV 7 mm (markers), and PTV 7/5 mm (markers and online correction). On planning computed tomography (CT) scan, the prostate, bladder, rectal wall, and anal canal were contoured. The treatment volume and radiation doses to surrounding organs were calculated. In 65 patients, with the online protocol and gold markers, late toxicity was evaluated.

RESULTS

With gold markers a significant PTV reduction of 27% was achieved (P < .001). Subsequently, radiation dose reductions to the mean of 17% (± 4.5%) to the bladder, 19% (± 4.7%) to the anal canal, and 12% (± 3%) to the rectal wall, respectively were seen (P < .001). With 5-mm posterior margins an additional PTV reduction of 3.7% (P < .001) and total radiation dose reduction to the mean of 24% (± 4%), and 16% (± 4.5%) to anal canal and rectal wall, respectively were seen (P < .001). Late Grade 1-2 genitourinary and gastrointestinal toxicity was seen in 32%, and 33%, respectively. Grade 3 toxicity was less than 10%.

CONCLUSIONS

This study showed a significant reduction of treatment volume and radiation doses to healthy tissues with intraprostatic gold markers.

Clinician's guide to prostate IMRT plan assessment and optimisation

Intensity-modulated radiotherapy (IMRT) offers dosimetric benefit for irregularly shaped treatment volumes compared to three-dimensional conformal approaches. Some groups advocate IMRT as the standard of care for prostate radiotherapy. For clinicians, assessment of an IMRT plan can introduce new opportunities and challenges. Although a standard IMRT plan may be deemed acceptable by meeting pre-set dose constraints, further optimisation may yield a superior treatment plan by further reducing dose to critical structures or improving target volume homogeneity. The aim of this article is to present aspects of IMRT planning relevant to clinicians to aid in plan critiquing.

Impact of body mass index on outcomes after conformal radiotherapy in patients with prostate cancer

PURPOSE

Several retrospective analyses have suggested that obese men with prostate cancer treated with external beam radiotherapy (EBRT) have outcomes inferior to those of normal-weight men. However, a recently presented analysis for the first time challenged this association between body mass index (BMI) and treatment failure. It is therefore important to provide further data on this issue.

METHODS AND MATERIALS

This was a retrospective analysis of 564 men treated with risk-adapted conformal EBRT at a single institution. Low-risk patients received EBRT alone, and the other patients received EBRT plus endocrine treatment. In addition, high-risk patients were treated to higher EBRT doses (74 Gy). A rectal balloon catheter for internal immobilization, which can be identified on portal images, was used in 261 patients (46%). Thus, localization did not rely on bony landmarks alone in these cases.

RESULTS

The median BMI was 26, and 15% of patients had BMI≥30. Neither univariate nor multivariate analyses detected any significant impact of BMI on biochemical relapse, prostate cancer-specific survival, or overall survival. The 5-year biochemical relapse rate was 21% and prostate cancer-specific survival 96%.

CONCLUSIONS

The present analysis of a large cohort of consecutively treated patients suggests that efforts to reduce prostate movement and geographic miss might result in comparable outcomes in obese and normal-weight patients.