Prostate Cancer, Version 3.2024

The NCCN Guidelines for Prostate Cancer include recommendations for staging and risk assessment after a prostate cancer diagnosis and for the care of patients with localized, regional, recurrent, and metastatic disease. These NCCN Guidelines Insights summarize the panel's discussions for the 2024 update to the guidelines with regard to initial risk stratification, initial management of very-low-risk disease, and the treatment of nonmetastatic recurrence.

Prospective Correlation of Magnetic Resonance Tumor Regression Grade With Pathologic Outcomes in Total Neoadjuvant Therapy for Rectal Adenocarcinoma

PURPOSE

Total neoadjuvant therapy (TNT) is a newly established standard treatment for rectal adenocarcinoma. Current methods to communicate magnitudes of regression during TNT are subjective and imprecise. Magnetic resonance tumor regression grade (MR-TRG) is an existing, but rarely used, regression grading system. Prospective validation of MR-TRG correlation with pathologic response in patients undergoing TNT is lacking. Utility of adding diffusion-weighted imaging to MR-TRG is also unknown.

METHODS

We conducted a multi-institutional prospective imaging substudy within NRG-GI002 (ClinicalTrials.gov identifier: NCT02921256) examining the ability of MR-based imaging to predict pathologic complete response (pCR) and correlate MR-TRG with the pathologic neoadjuvant response score (NAR). Serial MRIs were needed from 110 patients. Three radiologists independently, then collectively, reviewed each MRI for complete response (mriCR), which was tested for positive predictive value (PPV), negative predictive value (NPV), sensitivity, and specificity with pCR. MR-TRG was examined for association with the pathologic NAR score. All team members were blinded to pathologic data.

RESULTS

A total of 121 patients from 71 institutions met criteria: 28% were female (n = 34), 84% White (n = 101), and median age was 55 (24-78 years). Kappa scores for T- and N-stage after TNT were 0.38 and 0.88, reflecting fair agreement and near-perfect agreement, respectively. Calling an mriCR resulted in a kappa score of 0.82 after chemotherapy and 0.56 after TNT reflected near-perfect agreement and moderate agreement, respectively. MR-TRG scores were associated with pCR (P < .01) and NAR (P < .0001), PPV for pCR was 40% (95% CI, 26 to 53), and NPV was 84% (95% CI, 75 to 94).

CONCLUSION

MRI alone is a poor tool to distinguish pCR in rectal adenocarcinoma undergoing TNT. However, the MR-TRG score presents a now validated method, correlated with pathologic NAR, which can objectively measure regression magnitude during TNT.

Prostate Cancer, Version 4.2023, NCCN Clinical Practice Guidelines in Oncology

The NCCN Guidelines for Prostate Cancer provide a framework on which to base decisions regarding the workup of patients with prostate cancer, risk stratification and management of localized disease, post-treatment monitoring, and treatment of recurrence and advanced disease. The Guidelines sections included in this article focus on the management of metastatic castration-sensitive disease, nonmetastatic castration-resistant prostate cancer (CRPC), and metastatic CRPC (mCRPC). Androgen deprivation therapy (ADT) with treatment intensification is strongly recommended for patients with metastatic castration-sensitive prostate cancer. For patients with nonmetastatic CRPC, ADT is continued with or without the addition of certain secondary hormone therapies depending on prostate-specific antigen doubling time. In the mCRPC setting, ADT is continued with the sequential addition of certain secondary hormone therapies, chemotherapies, immunotherapies, radiopharmaceuticals, and/or targeted therapies. The NCCN Prostate Cancer Panel emphasizes a shared decision-making approach in all disease settings based on patient preferences, prior treatment exposures, the presence or absence of visceral disease, symptoms, and potential side effects.

NCCN Guidelines® Insights: Prostate Cancer, Version 1.2023

The NCCN Guidelines for Prostate Cancer address staging and risk assessment after a prostate cancer diagnosis and include management options for localized, regional, recurrent, and metastatic disease. The NCCN Prostate Cancer Panel meets annually to reevaluate and update their recommendations based on new clinical data and input from within NCCN Member Institutions and from external entities. These NCCN Guidelines Insights summarizes much of the panel's discussions for the 4.2022 and 1.2023 updates to the guidelines regarding systemic therapy for metastatic prostate cancer.

VA-Radiation Oncology Quality Surveillance Program

PURPOSE

We sought to develop a quality surveillance program for approximately 15,000 US veterans treated at the 40 radiation oncology facilities at the Veterans Affairs (VA) hospitals each year.

METHODS AND MATERIALS

State-of-the-art technologies were used with the goal to improve clinical outcomes while providing the best possible care to veterans. To measure quality of care and service rendered to veterans, the Veterans Health Administration established the VA Radiation Oncology Quality Surveillance program. The program carries forward the American College of Radiology Quality Research in Radiation Oncology project methodology of assessing the wide variation in practice pattern and quality of care in radiation therapy by developing clinical quality measures (QM) used as quality indices. These QM data provide feedback to physicians by identifying areas for improvement in the process of care and identifying the adoption of evidence-based recommendations for radiation therapy.

RESULTS

Disease-site expert panels organized by the American Society for Radiation Oncology (ASTRO) defined quality measures and established scoring criteria for prostate cancer (intermediate and high risk), non-small cell lung cancer (IIIA/B stage), and small cell lung cancer (limited stage) case presentations. Data elements for 1567 patients from the 40 VA radiation oncology practices were abstracted from the electronic medical records and treatment management and planning systems. Overall, the 1567 assessed cases passed 82.4% of all QM. Pass rates for QM for the 773 lung and 794 prostate cases were 78.0% and 87.2%, respectively. Marked variations, however, were noted in the pass rates for QM when tumor site, clinical pathway, or performing centers were separately examined.

CONCLUSIONS

The peer-review protected VA-Radiation Oncology Surveillance program based on clinical quality measures allows providers to compare their clinical practice to peers and to make meaningful adjustments in their personal patterns of care unobtrusively.

Smoking Decreases Survival in Locally Advanced Cervical Cancer Treated With Radiation

PURPOSE

To study the prevalence and effect of smoking on cervical cancer recurrence and mortality in patients undergoing definitive treatment with radiation.

MATERIALS AND METHODS

Between July 2007 and September 2013, 96 locally advanced cervical cancer patients received definitive radiation or chemoradiation followed by brachytherapy. Smoking status was obtained from prospective intake questionnaires and quantified by pack-years. Pelvic control (PC), disease-free survival (DFS), and overall survival (OS) were analyzed by multivariable Cox proportional hazards models.

RESULTS

Smoking history included 51 (53.1%) nonsmokers, 45 active smokers, and former smokers: 20 (20.8%) with 1 to 20 pack-years and 25 (26%) with 21+ pack-years. With a median follow-up of 2 years on univariate analysis, the impact of 1 to 20 pack-years on PC, DFS, and OS relative to nonsmokers was hazard ratio (HR) 4.29 (95% confidence interval [CI], 1.36-14.1; P=0.014), 4.99 (95% CI, 1.21-22.4; P=0.027), and 4.77 (95% CI, 1.34-17.8; P=0.017), respectively. For patients with 21+ pack-years, the impact on PC, DFS, and OS was HR=6.13 (95% CI, 2.29-18.6; P<0.001), 7.24 (95% CI, 2.28-29.1; P=0.001), and 4.21 (95% CI, 1.26-15.4; P=0.02). On multivariate analysis, there remained a significant difference of 1 to 20 pack-years smoking history on OS relative to nonsmokers, HR=4.68 (95% CI, 1.02-29; P=0.047). For patients with 21+ pack-years smoking history, there continued to be a negative impact on PC and DFS, HR=5.66 (95% CI, 1.7-22.18; P=0.004) and HR=6.89 (95% CI, 1.54-42; P=0.011), respectively.

CONCLUSIONS

Former and active tobacco smoking during radiation therapy for cervical cancer is associated with unfavorable PC, DFS, and OS outcomes. The increased number of smoking pack-years conferred a worse outcome effect in those treated with radiation.

Underutilization of brachytherapy and disparities in survival for patients with cervical cancer in California

PURPOSE

The treatment for locally advanced cervical cancer is external beam radiation (EBRT), concurrent chemotherapy, and brachytherapy (BT). We investigated demographic and socioeconomic factors that influence trends in BT utilization and disparities in survival.

METHODS

Using the California Cancer Registry, cervical cancer patients FIGO IB2-IVA from 2004 to 2014 were identified. We collected tumor, demographic and socioeconomic (SES) factors. We used multivariable logistic regression analysis to determine predictors of use of BT. Using Cox proportional hazards, we examined the impact of BT vs EBRT boost on cause specific (CSS) and overall survival (OS).

RESULTS

We identified 4783 patients with FIGO stage 11% IB2; 32% II, 54% III, 3% IVA. Nearly half (45%) of patients were treated with BT, 18% were treated with a EBRT boost, and 37% had no boost. Stage II and III were more likely to be treated with BT (p = 0.002 and p = 0.0168) vs Stage IB2. As patients aged, the use of BT decreased. Using multivariate analysis, BT impacted CCS (HR 1.16, p = 0.0330) and OS (HR 1.14, p = 0.0333). Worse CSS was observed for black patients (p = 0.0002), low SES (p = 0.0263), stage III and IVA (p < 0.0001. Black patients, low and middle SES had worse OS, (p = 0.0003).

CONCLUSIONS

The utilization of BT in locally advanced cervical cancer was low at 45%, with a decrease in CSS and OS. Black patients and those in low SES had worse CSS. As we strive for outcome improvement in cervical cancer, we need to target increasing access and disparities for quality and value.

Radiomics for Response and Outcome Assessment for Non-Small Cell Lung Cancer

Routine follow-up visits and radiographic imaging are required for outcome evaluation and tumor recurrence monitoring. Yet more personalized surveillance is required in order to sufficiently address the nature of heterogeneity in nonsmall cell lung cancer and possible recurrences upon completion of treatment. Radiomics, an emerging noninvasive technology using medical imaging analysis and data mining methodology, has been adopted to the area of cancer diagnostics in recent years. Its potential application in response assessment for cancer treatment has also drawn considerable attention. Radiomics seeks to extract a large amount of valuable information from patients' medical images (both pretreatment and follow-up images) and quantitatively correlate image features with diagnostic and therapeutic outcomes. Radiomics relies on computers to identify and analyze vast amounts of quantitative image features that were previously overlooked, unmanageable, or failed to be identified (and recorded) by human eyes. The research area has been focusing on the predictive accuracy of pretreatment features for outcome and response and the early discovery of signs of tumor response, recurrence, distant metastasis, radiation-induced lung injury, death, and other outcomes, respectively. This review summarized the application of radiomics in response assessments in radiotherapy and chemotherapy for non-small cell lung cancer, including image acquisition/reconstruction, region of interest definition/segmentation, feature extraction, and feature selection and classification. The literature search for references of this article includes PubMed peer-reviewed publications over the last 10 years on the topics of radiomics, textural features, radiotherapy, chemotherapy, lung cancer, and response assessment. Summary tables of radiomics in response assessment and treatment outcome prediction in radiation oncology have been developed based on the comprehensive review of the literature.

Secondary analysis of RTOG 9508, a phase 3 randomized trial of whole-brain radiation therapy versus WBRT plus stereotactic radiosurgery in patients with 1-3 brain metastases; poststratified by the graded prognostic assessment (GPA)

PURPOSE

Radiation Therapy Oncology Group (RTOG) 9508 showed a survival advantage for patients with 1 but not 2 or 3 brain metastasis (BM) treated with whole-brain radiation therapy (WBRT) and stereotactic radiosurgery (SRS) versus WBRT alone. An improved prognostic index, the graded prognostic assessment (GPA) has been developed. Our hypothesis was that if the data from RTOG 9508 were poststratified by the GPA, the conclusions may vary.

METHODS AND MATERIALS

In this analysis, 252 of the 331 patients were evaluable by GPA. Of those, 211 had lung cancer. Breast cancer patients were excluded because the components of the breast GPA are not in the RTOG database. Multiple Cox regression was used to compare survival between treatment groups, adjusting for GPA. Treatment comparisons within subgroups were performed with the log-rank test. A free online tool (brainmetgpa.com) simplified GPA use.

RESULTS

The fundamental conclusions of the primary analysis were confirmed in that there was no survival benefit overall for patients with 1 to 3 metastases; however, there was a benefit for the subset of patients with GPA 3.5 to 4.0 (median survival time [MST] for WBRT + SRS vs WBRT alone was 21.0 versus 10.3 months, P=.05) regardless of the number of metastases. Among patients with GPA 3.5 to 4.0 treated with WBRT and SRS, the MST for patients with 1 versus 2 to 3 metastases was 21 and 14.1 months, respectively.

CONCLUSIONS

This secondary analysis of predominantly lung cancer patients, consistent with the original analysis, shows no survival advantage for the group overall when treated with WBRT and SRS; however, in patients with high GPA (3.5-4), there is a survival advantage regardless of whether they have 1, 2, or 3 BM. This benefit did not extend to patients with lower GPA. Prospective validation of this survival benefit for patients with multiple BM and high GPA when treated with WBRT and SRS is warranted.

Clinical response of pelvic and para-aortic lymphadenopathy to a radiation boost in the definitive management of locally advanced cervical cancer

PURPOSE

Optimal treatment with radiation for metastatic lymphadenopathy in locally advanced cervical cancer remains controversial. We investigated the clinical dose response threshold for pelvic and para-aortic lymph node boost using radiographic imaging and clinical outcomes.

METHODS AND MATERIALS

Between 2007 and 2011, 68 patients were treated for locally advanced cervical cancer; 40 patients had clinically involved pelvic and/or para-aortic lymph nodes. Computed tomography (CT) or 18F-labeled fluorodeoxyglucose-positron emission tomography scans obtained pre- and postchemoradiation for 18 patients were reviewed to assess therapeutic radiographic response of individual lymph nodes. External beam boost doses to involved nodes were compared to treatment response, assessed by change in size of lymph nodes by short axis and change in standard uptake value (SUV). Patterns of failure, time to recurrence, overall survival (OS), and disease-free survival (DFS) were determined.

RESULTS

Sixty-four lymph nodes suspicious for metastatic involvement were identified. Radiation boost doses ranged from 0 to 15 Gy, with a mean total dose of 52.3 Gy. Pelvic lymph nodes were treated with a slightly higher dose than para-aortic lymph nodes: mean 55.3 Gy versus 51.7 Gy, respectively. There was no correlation between dose delivered and change in size of lymph nodes along the short axis. All lymph nodes underwent a decrease in SUV with a complete resolution of abnormal uptake observed in 68%. Decrease in SUV was significantly greater for lymph nodes treated with ≥54 Gy compared to those treated with <54 Gy (P=.006). Median follow-up was 18.7 months. At 2 years, OS and DFS for the entire cohort were 78% and 50%, respectively. Locoregional control at 2 years was 84%.

CONCLUSIONS

A biologic response, as measured by the change in SUV for metastatic lymph nodes, was observed at a dose threshold of 54 Gy. We recommend that involved lymph nodes be treated to this minimum dose.

The impact of body mass index on rectal dose in locally advanced cervical cancer treated with high-dose-rate brachytherapy

PURPOSE

The impact of body mass index (BMI) on rectal dose in brachytherapy for cervical cancer is unknown. We assessed the association of BMI on rectal dose and lower gastrointestinal (GI) toxicity.

METHODS AND MATERIALS

Between 2007 and 2010, 51 patients with 97 brachytherapy planning images were reviewed. Volumetric measurements of the maximum percentage, mean percentage, dose to 2cc (D2cc), and dose to 1cc (D1cc) of the rectum, and the Internal Commission on Radiation Units and Measurement (ICRU) rectal point were recorded. Linear mixed effect models, analysis of variance, and regression analyses were used to determine the correlation between multiple observations or to detect a difference in the mean. The GI acute and late toxicity were prospectively recorded and retrospectively analyzed.

RESULTS

The average BMI (kg/m(2)) was 27.7 with a range of 17.4-46.6. Among the patients, 8% were morbidly obese, 25% obese, 25% overweight, 40% normal weight, and 2% underweight. The mean D1cc, D2cc, mean rectal dose (%), maximum rectal dose (%), and ICRU rectum was 3.03 Gy, 2.78 Gy, 20%, 60%, and 2.99 Gy, respectively. On multivariate analysis, there was a significant decrease in the D1cc and D2cc rectal dose (p=0.016), ICRU rectal point dose (p=0.022), and mean rectal dose percentage (p=0.021) with an increase in BMI. There was, however, no statistically significant relationship between BMI and GI toxicity.

CONCLUSIONS

Obesity decreases the rectal dose given in high-dose-rate brachytherapy for locally advanced cervical cancer because of an increase in fatty tissue in the recto-uterine space. There is no significant correlation between BMI and acute or late GI toxicity.

Down-regulation of microRNA 106b is involved in p21-mediated cell cycle arrest in response to radiation in prostate cancer cells

BACKGROUND

microRNAs (miRNAs) are endogenous short non-coding RNAs, and play a pivotal role in regulating of a variety of cellular processes, including proliferation and apoptosis, both of which are cellular responses to radiation treatment. The purpose of this study is to identify candidate miRNAs whose levels are altered in response to radiation in prostate cancer cells and to investigate the molecular pathway of such miRNAs in the regulation of radiation-induced cellular response.

METHODS

Using a miRNA microarray assay, we screened 132 cancerous miRNAs in LNCaP cells in response to radiation treatment. The function of one candidate miRNA was investigated for checkpoint protein expression, cell cycle arrest, cell proliferation, and cell survival in cells transfected with precursor or antisense miRNA.

RESULTS

In response to radiation, multiple miRNAs, including mi-106b, showed altered expression. Cells transfected with precursor miR-106b were able to suppress radiation-induced p21 activation. Functionally, exogenous addition of precursor miR-106b overrode the G2/M arrest in response to radiation and resulted in a transient diminishment of radiation-induced growth inhibition.

CONCLUSION

We have shown a novel role of miR-106b, in the setting of radiation treatment, in regulating the p21-activated cell cycle arrest. Our finding that miR-106b is able to override radiation-induced cell cycle arrest and cell growth inhibition points to a potential therapeutic target in certain prostate cancer cells whose radiation resistance is likely due to consistently elevated level of miR-106b.

Variation in the definition of clinical target volumes for pelvic nodal conformal radiation therapy for prostate cancer

PURPOSE

We conducted a comparative study of clinical target volume (CTV) definition of pelvic lymph nodes by multiple genitourinary (GU) radiation oncologists looking at the levels of discrepancies amongst this group.

METHODS AND MATERIALS

Pelvic computed tomography (CT) scans from 2 men were distributed to 14 Radiation Therapy Oncology Group GU radiation oncologists with instructions to define CTVs for the iliac and presacral lymph nodes. The CT data with contours were then returned for analysis. In addition, a questionnaire was completed that described the physicians' method for target volume definition.

RESULTS

Significant variation in the definition of the iliac and presacral CTVs was seen among the physicians. The minimum, maximum, mean (SD) iliac volumes (mL) were 81.8, 876.6, 337.6 +/- 203 for case 1 and 60.3, 627.7, 251.8 +/- 159.3 for case 2. The volume of 100% agreement was 30.6 and 17.4 for case 1 and 2 and the volume of the union of all contours was 1,012.0 and 807.4 for case 1 and 2, respectively. The overall agreement was judged to be moderate in both cases (kappa = 0.53 (p < 0.0001) and kappa = 0.48 (p < 0.0001). There was no volume of 100% agreement for either of the two presacral volumes. These variations were confirmed in the responses to the associated questionnaire.

CONCLUSIONS

Significant disagreement exists in the definition of the CTV for pelvic nodal radiation therapy among GU radiation oncology specialists. A consensus needs to be developed so as to accurately assess the merit and safety of such treatment.

Short-Term Neoadjuvant Androgen Deprivation Therapy and External-Beam Radiotherapy for Locally Advanced Prostate Cancer: Long-Term Results of RTOG 8610

Purpose

Radiation Therapy Oncology Group (RTOG) 8610 was the first phase III randomized trial to evaluate neoadjuvant androgen deprivation therapy (ADT) in combination with external-beam radiotherapy (EBRT) in men with locally advanced prostate cancer. This report summarizes long-term follow-up results.

Materials and Methods

Between 1987 and 1991, 456 assessable patients (median age, 70 years) were enrolled. Eligible patients had bulky (5 × 5 cm) tumors (T2-4) with or without pelvic lymph node involvement according to the 1988 American Joint Committee on Cancer TNM staging system. Patients received combined ADT that consisted of goserelin 3.6 mg every 4 weeks and flutamide 250 mg tid for 2 months before and concurrent with EBRT, or they received EBRT alone. Study end points included overall survival (OS), disease-specific mortality (DSM), distant metastasis (DM), disease-free survival (DFS), and biochemical failure (BF).

Results

Ten-year OS estimates (43% v 34%) and median survival times (8.7 v 7.3 years) favored ADT and EBRT, respectively; however, these differences did not reach statistical significance (P = .12). There was a statistically significant improvement in 10-year DSM (23% v 36%; P = .01), DM (35% v 47%; P = .006), DFS (11% v 3%; P < .0001), and BF (65% v 80%; P < .0001) with the addition of ADT, but no differences were observed in the risk of fatal cardiac events.

Conclusion

The addition of 4 months of ADT to EBRT appears to have a dramatic impact on clinically meaningful end points in men with locally advanced disease with no statistically significant impact on the risk of fatal cardiac events.

An update of the phase III trial comparing whole pelvic to prostate only radiotherapy and neoadjuvant to adjuvant total androgen suppression: updated analysis of RTOG 94-13, with emphasis on unexpected hormone/radiation interactions

PURPOSE

This trial was designed to test the hypothesis that total androgen suppression and whole pelvic radiotherapy (WPRT) followed by a prostate boost improves progression-free survival (PFS) by > or =10% compared with total androgen suppression and prostate only RT (PORT). This trial was also designed to test the hypothesis that neoadjuvant hormonal therapy (NHT) followed by concurrent total androgen suppression and RT improves PFS compared with RT followed by adjuvant hormonal therapy (AHT) by > or =10%.

METHODS AND MATERIALS

Patients eligible for the study included those with clinically localized adenocarcinoma of the prostate and an elevated prostate-specific antigen level of <100 ng/mL. Patients were stratified by T stage, prostate-specific antigen level, and Gleason score and were required to have an estimated risk of lymph node involvement of >15%.

RESULTS

The difference in overall survival for the four arms was statistically significant (p = 0.027). However, no statistically significant differences were found in PFS or overall survival between NHT vs. AHT and WPRT compared with PORT. A trend towards a difference was found in PFS (p = 0.065) in favor of the WPRT + NHT arm compared with the PORT + NHT and WPRT + AHT arms.

CONCLUSIONS

Unexpected interactions appear to exist between the timing of hormonal therapy and radiation field size for this patient population. Four Phase III trials have demonstrated better outcomes when NHT was combined with RT compared with RT alone. The Radiation Therapy Oncology Group 9413 trial results have demonstrated that when NHT is used in conjunction with RT, WPRT yields a better PFS than does PORT. It also showed that when NHT + WPRT results in better overall survival than does WPRT + short-term AHT. Additional studies are warranted to determine whether the failure to demonstrate an advantage for NHT + WPRT compared with PORT + AHT is chance or, more likely, reflects a previously unrecognized biologic phenomenon.

Whole-pelvis, “mini-pelvis,” or prostate-only external beam radiotherapy after neoadjuvant and concurrent hormonal therapy in patients treated in the Radiation Therapy Oncology Group 9413 trial

PURPOSE

The Radiation Therapy Oncology Group (RTOG) 9413 trial demonstrated a better progression-free survival (PFS) with whole-pelvis (WP) radiotherapy (RT) compared with prostate-only (PO) RT. This secondary analysis was undertaken to determine whether "mini-pelvis" (MP; defined as > or = 10 x 11 cm but < 11 x 11 cm) RT resulted in progression-free survival (PFS) comparable to that of WP RT. To avoid a timing bias, this analysis was limited to patients receiving neoadjuvant and concurrent hormonal therapy (N&CHT) in Arms 1 and 2 of the study.

METHODS AND MATERIALS

Eligible patients had a risk of lymph node (LN) involvement > 15%. Neoadjuvant and concurrent hormonal therapy (N&CHT) was administered 2 months before and during RT for 4 months. From April 1, 1995, to June 1, 1999, a group of 325 patients were randomized to WP RT + N&CHT and another group of 324 patients were randomized to receive PO RT + N&CHT. Patients randomized to PO RT were dichotomized by median field size (10 x 11 cm), with the larger field considered an "MP" field and the smaller a PO field.

RESULTS

The median PFS was 5.2, 3.7, and 2.9 years for WP, MP, and PO fields, respectively (p = 0.02). The 7-year PFS was 40%, 35%, and 27% for patients treated to WP, MP, and PO fields, respectively. There was no association between field size and late Grade 3+ genitourinary toxicity but late Grade 3+ gastrointestinal RT complications correlated with increasing field size.

CONCLUSIONS

This subset analysis demonstrates that RT field size has a major impact on PFS, and the findings support comprehensive nodal treatment in patients with a risk of LN involvement of > 15%.

Radiation dose delivered to the proximal penis as a predictor of the risk of erectile dysfunction after three-dimensional conformal radiotherapy for localized prostate cancer

PURPOSE/OBJECTIVE

In this study, we evaluated in a serial manner whether radiation dose to the bulb of the penis is predictive of erectile dysfunction, ejaculatory difficulty (EJ), and overall satisfaction with sex life (quality of life) by using serial validated self-administered questionnaires.

METHODS AND MATERIALS

Twenty-nine potent men with AJCC Stage II prostate cancer treated with three-dimensional conformal radiation therapy alone to a median dose 72.0 Gy (range: 66.6-79.2 Gy) were evaluated by determining the doses received by the penile bulb. The penile bulb was delineated volumetrically, and the dose-volume histogram was obtained on each patient.

RESULTS

The median follow-up time was 35 months (range, 16-43 months). We found that for D(30), D(45), D(60), and D(75) (doses to a percent volume of PB: 30%, 45%, 60%, and 75%), higher than the corresponding median dose (defined as high-dose group) correlated with an increased risk of impotence (erectile dysfunction firmness score = 0) (odds ratio [OR] = 7.5, p = 0.02; OR = 7.5, p = 0.02; OR = 8.6, p = 0.008; and OR = 6.9, p = 0.015, respectively). Similarly, for EJD D(30), D(45), D(60), and D(75), doses higher than the corresponding median ones correlated with worsening ejaculatory function score (EJ = 0 or 1) (OR = 8, p = 0.013; OR = 8, p = 0.013; OR = 9.2, p = 0.015; and OR = 8, p = 0.026, respectively). For quality of life, low (< or =median dose) dose groups of patients improve over time, whereas high-dose groups of patients worsen.

CONCLUSIONS

This study supports the existence of a penile bulb dose-volume relationship underlying the development of radiation-induced erectile dysfunction. Our data may guide the use of inverse treatment planning to maximize the probability of maintaining sexual potency after radiation therapy.

An optimized forward-planning technique for intensity modulated radiation therapy

Intensity modulated radiation therapy (IMRT) has stirred considerable excitement in the radiation oncology community. Its objective is to make the dose conform to the tumor and spare other organs. Instead of resorting to the rather complex inverse-planning, the technique described here is an extension of the conventional treatment planning technique. The beam orientation and wedge angles are chosen in the conventional rule-based manner. However, within each conformal beam's eye view (BEV) field including margin, a number of sub-field openings are added. The smaller field openings are designed to irradiate the tumor, while sparing the normal tissue of the organs at risk (OARs) that intrude into the target region in the BEV. As the number of intrusions into the target BEV increases, the number of sub-fields for each beam increases. The Cimmino simultaneous projection method was employed to obtain the optimized weighting for each field of each beam. In cases where the dose constraints for the tumor and for the OARs are reasonable, it is possible to obtain a plan with a fairly small number of beams that satisfies the specified dose objectives. This is illustrated for the treatment of prostate cancer, where the rectum creates a concavity in the planning target volume. An advantage of this technique is that the quality assurance for the delivery of these plans does not require extensive special efforts.

Survival advantage from higher-dose radiation therapy for clinically localized prostate cancer treated on the Radiation Therapy Oncology Group trials

PURPOSE

We evaluated the effect of external-beam radiation therapy on disease-specific survival (death from causes related to prostate cancer) and overall survival in men with clinically localized prostate cancer.

METHODS

From 1975 to 1992, 1,465 men with clinically localized prostate cancer received radiation therapy on four Radiation Therapy Oncology Group phase III randomized trials and were pooled for this analysis. No one received androgen-deprivation therapy with his initial treatment. All original histology had central pathologic review for grading using the Gleason classification system. Total delivered radiation dose ranged from 60 to 78 Gy (median, 68.4 Gy). The median follow-up time was 8 years.

RESULTS

A Cox regression model revealed that Gleason score was an independent predictor of disease-specific survival and overall survival. The 10-year disease-specific survival rates by Gleason score were as follows: score of 2 through 5, 85%; score of 6, 79%; score of 7, 62%; and score of 8 through 10, 43%. Stratifying outcome by this important prognostic factor revealed that higher radiation dose was a significant predictor for improved disease-specific survival and overall survival only for those patients whose cancers had Gleason scores of 8 through 10 (P <.05). After adjusting for clinical T stage, nodal status, and age, treating with a higher radiation dose was associated with a 29% lower relative risk of death from prostate cancer and 27% reduced mortality rate (P <.05).

CONCLUSION

These data demonstrate that higher-dose radiation therapy can significantly reduce the risk of dying from prostate cancer in men with clinically localized disease. This survival benefit is restricted to men with poorly differentiated cancers.