Pelvic Lymph Node Coverage Research Articles

Sexual Function and Dosimetric Relationships to Erectile Structures among Patients Treated Definitively with Pd-103 LDR Prostate Brachytherapy

Sexual potency and erectile function are important quality of life metrics for many men and is a significant consideration when planning and treating prostate cancer. There are limited long-term data correlating post-implant dosimetry with patient-reported sexual toxicity outcomes following LDR prostate brachytherapy using Pd-103, specifically as it pertains to genital substructures. Our aim was to correlate dosimetric patterns with quality-of-life outcomes to determine if dose to the pudendal arteries and neurovascular bundles is a significant consideration when planning prostate LDR brachytherapy. We analyzed a prospectively collected IRB-approved database of men receiving LDR prostate brachytherapy between 11/2014-04/2019 at our institution. Patients received either LDR brachytherapy only, or combined with intensity-modulated radiation therapy (IMRT) to the prostate with or without pelvic lymph node coverage. Patients were given quality of life questionnaires at consultation and at subsequent follow up visits. Outcomes data related to sexual toxicity were evaluated based on the Sexual Health Inventory (SHIM) Questionnaire. The right/left pudendal arteries, and right/left neurovascular bundles (NVB) were contoured retrospectively on CT-MRI fusion sequences. Dosimetric data for each of the erectile substructures was analyzed. Statistical analyses included generalized linear mixed effects models with random intercept for patient to explore the association between dose and SHIM confidence. A total of 50 patients met criteria for inclusion in the analysis. 5 patients received combined IMRT to 45 Gy with Pd-103 (90-100 Gy) and 45 patients received Pd-103 monotherapy (125 Gy). Median follow-up was 18 months for 50 patients; 40 (80%) patients had follow-up greater than 2 years, and 15 (30%) greater than 5 years. There were 344 individual questionnaires completed. 28% of records reported low or very low confidence level (Question #1 of SHIM questionnaire). Likelihood of moderate-very high confidence increased up to 2 years after beginning of treatment (p = 0.052) and then subsequently decreased between 2- and 5 years post treatment (p = 0.042). NVB doses were not associated with SHIM confidence level. D100 greater than 150 cGy to either pudendal artery was associated with worse SHIM confidence score after treatment (p = 0.003). Sexual function is variable in the post treatment setting following definitive prostate radiation with Pd-103 LDR-brachytherapy. Avoiding pudendal artery dose may improve sexual outcomes and should be considered when planning prostate brachytherapy. Further investigation with a larger prospective, cohort may be warranted.

Prostate-specific Membrane Antigen Positron Emission Tomography/Computed Tomography–based Lymph Node Atlas for Salvage Radiotherapy in Patients with Recurrent Prostate Cancer: A Validation of the New NRG Oncology 2020 guideline

BackgroundApproximately 20–40% of patients with prostate cancer (PC) who undergo radical prostatectomy (RP) experience relapse, with the majority of these cases developing pelvic lymph node (LN) metastases. Taking new data from the prostate-specific membrane antigen (PSMA) positron emission tomography (PET) era into account, the Radiation Therapy Oncology Group (RTOG) 2009 contouring guideline for the pelvic LNs from 2009 was updated by the NRG Oncology group in 2020 (NRG 2020). ObjectiveTo evaluate and validate the updated NRG 2020 guideline with our established LN atlas. Design, setting, and participantsWe screened 1653 PSMA PET/computed tomography (CT) data sets for patients with biochemical relapse who underwent a PET scan between November 2012 and November 2017. After screening, we developed an LN atlas using data from 233 patients. Outcome measurements and statistical analysisWe evaluated LN overlap (OL) with the RTOG 2009 and NRG 2020 contouring guidelines. OL was defined as within (>90%), partly within (10–90%), or outside (<10%). Results and limitationsIn comparison to the RTOG 2009 guideline, 403 (52%), 134 (17%), and 241 (31%) of the LNs were not, were partly, or were fully covered within the overall group, respectively. By contrast, using the NRG 2020 guideline, 302 (39%), 190 (24%), and 286 (37%) of the LNs were not, were partly, or were fully covered, respectively (p < 0.001). Limitations include the retrospective design with missing data and no histopathological confirmation of the PET results. ConclusionsThe updated NRG 2020 contouring guideline improves coverage of the pelvic LNs in patients undergoing salvage radiation therapy. However, PET/CT should be considered whenever possible to ensure coverage of untypical LN spread. Patient summaryWe compared the 2009 and 2020 guidelines on the radiation area for the pelvis for patients with recurrent prostate cancer that has spread to lymph nodes. The newer guideline provides better coverage of pelvic lymph nodes than the older one and is useful in planning radiation therapy. However, a scan of the pelvis using the newest technique should be considered for individual patients to ensure coverage of untypical lymph nodes.

Impact of prostate focused alignment on planned pelvic lymph node dose.

PurposeProstate patients with positive lymph node margins receive an initial course of 45 Gy to the planning target volume (PTV) comprised of prostate, seminal vesicles, and lymph nodes with a 1‐cm margin. The prostate is localized via implanted fiducial markers before each fraction is delivered using portal‐imaging. However, the pelvic lymph nodes are affixed to the bony anatomy and are not mobile in concert with the prostate. The aim of this study was to determine whether a significant difference in pelvic lymph node coverage exists between planned and delivered external beam therapy treatments for these patients.MethodsThe recorded prostate motions were gathered for 19 patients; conjointly the pelvic lymph node motions were determined by manual registration of the bony anatomy in the kV‐images. The difference between the prostate and the bony anatomy coordinates was input into Eclipse as field shifts to represent the deviation in planned vs delivered pelvic lymph node coverage.ResultsStructure volume at V(100) was recorded for each patient for two structures: summed pelvic lymph nodes (LN CTV) and pelvic lymph nodes +1 cm margin (LN PTV) to express their contribution to the PTV. For the LN PTV, the average difference between the planned coverage and calculated delivered coverage was 3.5%, with a paired t‐test value of P = 0.005. Based upon bony anatomy registration, 26% of patients received less than 95% dose coverage using V(100) criteria for LN PTV. Dose value differences between the two plans at minimum were 6.96 ± 6.23 Gy, at mean were 0.54 ± 0.40 Gy, and at maximum were 0.10 ± 0.29 Gy. For the LN CTV, the average difference between the planned coverage and calculated delivered coverage was 1%, with a paired t‐test value of P = 0.53.ConclusionsThe results indicate a significant difference exists between the planned coverage and calculated delivered coverage for the LN PTV. There was no significant difference found for the LN CTV. We conclude that lymph node motion must be considered with the prostate motion when aligning patients before each fraction.

Impact of daily soft-tissue image guidance to prostate on pelvic lymph node (PLN) irradiation for prostate patients receiving SBRT.

PurposeTo determine the impact of using fiducial match for daily image‐guidance on pelvic lymph node (PLN) coverage for prostate cancer patients receiving stereotactic body radiation therapy (SBRT).MethodsThirty patients underwent SBRT treatment to the prostate and PLN from 2014 to 2016. Each patient received either 800cGy × 5 or 500cGy × 5 to the prostate and 500cGy × 5 to the PLN. A 5 mm clinical target volume (CTV)‐to‐planning target volume (PTV) margin around the PLN was used for planning. Two registrations with planning computed tomography (PCT) for each of the daily cone beam CTs (CBCTs) were performed: a rigid registration to fiducials and to the bony anatomy. The average translational difference between fiducial and bony match as well as percentage of fractions with differences > 5mm were calculated. Changes in bladder and rectal volume as well as center‐of‐mass (COM) position from simulation parameters, and their correlation with translational difference were also evaluated. The dosimetric impact of the translational differences was calculated by shifting the plan isocenter.ResultsThe average translational difference between fiducial and bony match was 0.06 ± 0.82, 2.1 ± 4.1, −2.8 ± 4.3, and 5.5 ± 4.2 mm for lateral, vertical, longitudinal, and vector directions. The average change in bladder and rectal volume from simulation was −67.2 ± 163.04 cc (−12 ± 52%) and −1.6 ± 18.75 (−2 ± 30%) cc. The average change in COM of bladder from the simulation position was 0.34 ± 2.49, 4.4 ± 8.1, and −3.9 ± 7.5 mm along the LR, AP, and SI directions. The corresponding COM change for the rectum was 0.17 ± 1.9, 1.34 ± 3.5, and −0.6 ± 5.2 mm.ConclusionsThe 5 mm margin covered ~75% of fractions receiving PLN irradiation with SBRT, daily CBCT and fiducial‐guided setup. The dosimetric impact on PLN coverage was significant in 19% of fractions or 25% of patients. A larger translational shift was due to variation in rectal volume and changes in COM position of the bladder and rectum. A consistent bladder positioning and/or rectum filling compared with presimulation volume were essential for adequate coverage of PLN in a hypofractionated treatment regime.

Prostate radiotherapy effects on testosterone levels: an empirical investigation

There is a paucity of clinical data to support the hypothesis that external beam radiation therapy causes iatrogenic hypogonadism in prostate cancer patients. All prostate cancer patients treated at a single institution with radiation therapy between 2002 and 2010 were retrospectively evaluated. Patients treated with brachytherapy alone received 0 Gy of external beam radiation therapy and served as the control group. Patients treated with combination external beam radiation therapy + brachytherapy, or external beam radiation therapy alone were categorized into groups who received 45–54 Gy or > 60 Gy of external beam radiation therapy, respectively. Serum testosterone levels were routinely measured with prostate-specific antigen tests. The median follow-up periods for 149 evaluable patients in the control group (0 Gy), the 45–54 Gy group, and > 60 Gy group were 57, 62, and 55 months, respectively (p = 0.43). Among patients who underwent external beam radiation therapy, 53% were treated with intensity-modulated radiation therapy, 65% with pelvic lymph node coverage, and 78% with 18 megavoltage photons. There were no differences in serum testosterone level declines over time between the 45–54 Gy group (p = 0.32) or the > 60 Gy group (p = 0.14) when compared to the control group (0 Gy). While body mass index was associated with baseline testosterone levels in univariate analysis (p < 0.0001), it was not associated with the rate of change following radiation therapy (p = 0.6). Empirical evidence does not support the hypothesis that incidental exposure of the testicular Leydig cells from scattered photons and/or daily portal imaging affects testosterone levels.

Patterns of Lymph Node Failure After Dose-Escalated Radiation Therapy in Patients Who Did Not Undergo Pelvic Lymph Node Irradiation: Implications for Extended Pelvic Lymph Node Coverage

Patterns of Lymph Node Failure After Dose-Escalated Radiation Therapy in Patients Who Did Not Undergo Pelvic Lymph Node Irradiation: Implications for Extended Pelvic Lymph Node Coverage

Patterns of Lymph Node Failure after Dose-escalated Radiotherapy: Implications for Extended Pelvic Lymph Node Coverage

BackgroundClinical trials evaluating the benefit of pelvic radiotherapy (PRT) in the radiotherapeutic management of patients with higher-risk prostate cancer have limited the superior field border to the S1/S2 or L5/S1 interspace. However, imaging and surgical series have demonstrated a high frequency of prostatic lymph node (LN) drainage beyond these landmarks. ObjectiveTo determine the patterns of radiographically defined abdominopelvic LN failures and their potential implications for PRT field design. Design, setting, and participantsDuring 1992–2008, 2694 patients with localized prostate cancer were treated with prostate/seminal vesicle–only radiotherapy without PRT. Some 156 patients had their first failure within the abdominopelvic LNs, of whom 60 had isolated failures within the pelvic LNs. Outcome measurements and statistical analysisA radiologist reviewed all imaging and mapped each LN failure to a template consisting of 34 abdominopelvic LN stations. Results and limitationsThe median follow-up was 8.9 yr. Of patients who experienced first recurrence in the pelvic LNs (n=60), the common iliac station was involved in 55% (n=33) of patients, including 10% (n=6) who had isolated common iliac failures. Use of a PRT field superior border of L5/S1 would fully cover only 42% of the first recurrences among these patients. Extending the field to cover the common iliac stations would increase coverage to 93% of recurrences. The presence of T3/T4 disease and omission of androgen-deprivation therapy both independently conferred an approximate fivefold increase in the likelihood of having a common iliac LN failure. Use of imaging as a surrogate for LN involvement is the primary study limitation. ConclusionsPelvic LN failures frequently occur superior to the commonly used L5/S1 landmark for PRT coverage, and use of ADT may be protective of more superior LN failures. The current RTOG 0924 trial is evaluating the benefit of PRT with extended superior coverage to L4/5 when possible, which, according to our data, should significantly improve the coverage of potential sites of failure. Patient summaryWe looked at lymph node recurrence patterns after external beam radiotherapy of the prostate in men who did not have their lymph nodes treated. We found that there was a high incidence of pelvic lymph node recurrences above the internal and external iliac lymph node regions. Therefore, the current field recommendation for pelvic lymph nodes that stops at the superior border of the internal and external iliac vessels provides inadequate coverage of common sites of cancer recurrence, namely the common iliac lymph nodes.

CT Simulation to Evaluate of Pelvic Lymph Node Coverage in Conventional Radiotherapy Fields Based on Bone and Vessels Landmarks in Prostate Cancer Patients.

BackgroundRadiotherapy is the gold standard for treatment of prostrate cancer as it can cover an adequate area of tissues at risk for metastasis.ObjectivesWe evaluated the Pelvic lymph node coverage of conventional radiotherapy fields based on bone and vessels landmarks using computed tomography (CT) simulation in patients with prostate cancer referred to Shohada-e-Tajrish hospital.Patients and MethodsIn this cross sectional study, 40 patients with prostate cancer at the Stage T1c to T3b were studied. Pelvic lymph nodes were contoured by using pelvic vessels as surrogate markers. The distances were measured at different points of anterior-posterior (AP) and lateral fields and distances > 5 mm or more between the contoured nodes and the field borders.ResultsMean and standard deviation of the aortic bifurcation from the superior border was 4.73 ± 1.16 cm, the distance of common iliac bifurcation from the superior border was 1.11 ± 1.25 cm, the mean (SD) distance of right external iliac from the lateral border of AP field was 2.06 ± 0.48 cm and for left external iliac artery was 1.90 ± 0.56 cm. The distance of the external iliac artery from the anterior border of the lateral field was 2.30 ± 0.74 cm. The distance of the external iliac artery from pelvic rim was 0.59 ± 0.59 cm, distance of bifurcation of iliac from sacroiliac joint was 0.82 ± 1.01 cm, the size of the pelvic rim was 12.30 ± 0.64 cm, sacral width was 8.29 ± 1.01 cm, anterior promontory symphysis distance was 12.02 ± 0.92 cm and posterior promontory symphysis distance was 10.98 ± 0.73 cm.ConclusionsWe observed that conventional radiotherapy using CT simulation based on bone and vessels landmarks provided adequate coverage of pelvic lymph nodes in our patients with prostate cancer.

Intensity-modulated radiotherapy (IMRT) to prostate and pelvic nodes-is pelvic lymph node coverage adequate with fiducial-based image-guided radiotherapy?

There remains concern regarding the use of fiducial-based image-guided radiotherapy (IGRT) in patients with high-risk prostate cancer also undergoing intensity-modulated radiotherapy (IMRT) to pelvic nodes. By a retrospective study, we aim to ascertain the impact of the use of fiducial-based IGRT on lymph node planned target volume (PTV) coverage. 30 consecutive IMRT prostate and pelvic node plans were reviewed, and dose was recalculated with 1-mm increment movements in anterior, posterior, superior, inferior, right and left directions up to 10 mm. All patients were treated with a full bladder after drinking 450-750 ml of water and empty rectum with the use of sodium citrate enemas daily. Dose-volume histogram parameters were recorded at each position, specifically nodal PTV V95%, V99% and V100%. A local IGRT database was used to identify the likelihood of a particular bony to fiducial offset in all directions. The combined data were used to calculate the percentage risk of underdosing the lymph node PTV on any given fraction. The likelihood of an offset in the left, right and anterior directions occurring and resulting in a failure to cover the PTV was <0.25%. The likelihood of a posterior offset occurring and resulting in inadequate coverage was slightly higher but remained <1%. This study confirms the safety of fiducial-based image-guided IMRT (IG-IMRT) with a strict bowel and bladder protocol, allowing a reduction of the clinical target volume to PTV margin of the prostate volume and consequent reduction in rectal toxicity. This study strengthens the evidence supporting the safe implementation of fiducial-based IG-IMRT treating the prostate and pelvic nodes in high-risk prostate cancer.

Occult Pelvic Lymph Node Involvement in Bladder Cancer: Implications for Definitive Radiation

To inform radiation treatment planning for clinically staged, node-negative bladder cancer patients by identifying clinical factors associated with the presence and location of occult pathologic pelvic lymph nodes. The records of patients with clinically staged T1-T4N0 urothelial carcinoma of the bladder undergoing radical cystectomy and pelvic lymphadenectomy at a single institution were reviewed. Logistic regression was used to evaluate associations between preoperative clinical variables and occult pathologic pelvic or common iliac lymph nodes. Percentages of patient with involved lymph node regions entirely encompassed within whole bladder (perivesicular nodal region), small pelvic (perivesicular, obturator, internal iliac, and external iliac nodal regions), and extended pelvic clinical target volume (CTV) (small pelvic CTV plus common iliac regions) were calculated. Among 315 eligible patients, 81 (26%) were found to have involved pelvic lymph nodes at the time of surgery, with 38 (12%) having involved common iliac lymph nodes. Risk of occult pathologically involved lymph nodes did not vary with clinical T stage. On multivariate analysis, the presence of lymphovascular invasion (LVI) on preoperative biopsy was significantly associated with occult pelvic nodal involvement (odds ratio 3.740, 95% confidence interval 1.865-7.499, P<.001) and marginally associated with occult common iliac nodal involvement (odds ratio 2.307, 95% confidence interval 0.978-5.441, P=.056). The percentages of patients with involved lymph node regions entirely encompassed by whole bladder, small pelvic, and extended pelvic CTVs varied with clinical risk factors, ranging from 85.4%, 95.1%, and 100% in non-muscle-invasive patients to 44.7%, 71.1%, and 94.8% in patients with muscle-invasive disease and biopsy LVI. Occult pelvic lymph node rates are substantial for all clinical subgroups, especially patients with LVI on biopsy. Extended coverage of pelvic lymph nodes up to the level of the common iliac nodes may be warranted in subsets of patients.

Coverage of pelvic lymph nodes in conventional pelvic radiation for cervical cancer

Objective To assess the coverage of pelvic lymph nodes in conventional pelvic radiation for cervical cancer. Methods Between Jan. 2005 and Mar. 2008, 56 patients with cervical cancer receiv-ing radiotherapy were enrolled in this study. The common iliac, external and internal iliac lymph nodes were delineated on the plan.ning CT images. The borders of conventional pelvic irradiation fields were copied to the sagittal and coronal images of digital reconstruction. Anterior-posterior fields (AP) :superior border was the inferior border of L 4 ;inferior border was the inferior border of the obturator foramen;and lateral borders were 15 mm lateral to The bone pelvic. Lateral fields (LAT) :anterior border was anterior to the symphysis pubis;posterior border was the posterior border of the sacrum. Distances were measured between the bifurcation of the aorta and superior border, between the bifurcation of the common iliac artery and lateral border of the AP field, and between the external iliac artery and anterior border of the LAT field. The radiation fields were de-fined as adequate, undersize and oversize when the distances were 15-20 mm, less than 15 mm and more than 20 mm, respectively. Results Superiorly, the common iliac lymph nodes were missed in 98% pa-tients, oversize fields found in 2%, and at least one side of the internal or external iliac lymph nodes missed in 14%. Laterally, the external iliac lymph nodes were missed in 41% patients, and oversize fields found in 11%. Anteriorly, the external iliac lymph nodes were missed in 43% patients, and oversize fields found in 25%. Conclusions Conventional pelvic radiation fields according to the bone markers may miss the pelvic lymph nodes, especially the internal iliac lymph nodes. The target nodes should be delineated individually based on CT or MRI to guarantee their coverage in radiotherapy. Key words: Cervical neoplasms/radiotherapy; Tomography; X-ray computed; Lymph nodes; overlay

Evaluation of pelvic lymph node coverage of conventional radiotherapy fields based on bony landmarks in Chinese cervical cancer patients using CT simulation

To evaluate the pelvic lymph node coverage of conventional pelvic fields based on bony landmarks in Chinese patients with cervical cancer by using computed tomography (CT) simulation images to contour pelvic vessels as substitutes for lymph nodes location. A retrospective review of CT simulation images and conventional pelvic radiation planning data sets was performed in 100 patients with cervical cancer at the International Federation of Gynecology and Obstetrics (FIGO) Stage IIB to IIIB in our hospital. Pelvic arteries were contoured on CT simulation images, and the outlines of conventional pelvic fields were drawn as defined by the gynecologic oncology group (GOG) after hiding the contours. The distances between the following vessel contours and field borders were measured: D(1), the superior border of the anterior/posterior (AP) field and the bifurcation of abdominal aorta; D(2), the ipsilateral border of the AP field and the distal end of external iliac artery; and D(3), the anterior border of the lateral (LAT) field and the distal end of the external iliac artery. The distances were recorded as positive values if the measuring point was within the conventional pelvic fields, or they were recorded as negative values. Lymph nodes coverage was considered adequate when D(1)(0 mm, D(2)(17 mm or D(3)(7 mm. All patients had at least 1 inadequate margin, 97 patients (97.0%) had 2, and 22 patients (22.0%) had all the 3. On the AP field, 95 patients (95%) had the measuring point, the bifurcation of the abdominal aorta, out of the field (D(1)<0 mm), and all the patients had a distance less than 17.0 mm between the distal end of the external iliac artery and ipsilateral border (D(2)<17.0 mm). On the LAT field, 24 patients (24%) had a distance less than 7.0 mm between the distal end of the external iliac artery and anterior border (D(3)<7.0 mm). We observed that conventional pelvic fields based on bony landmarks provided inadequate coverage of pelvic lymph nodes in our patients with cervical cancer. CT simulation may be a feasible technique for planning pelvic fields optimally and individually.

Effect of Pelvic Lymph Node Irradiation in Salvage Therapy for Patients with Prostate Cancer with a Biochemical Relapse Following Radical Prostatectomy

Radiation therapy (RT) as salvage treatment for a biochemical relapse following prostatectomy has been shown to be of benefit measured by serum prostate-specific antigen (PSA) control. However, identifying a target volume for RT has not been well established in this setting. In this study, the results of postoperative RT delivered to extended fields (EFs), prostatic fossa, and pelvic lymph nodes encompassing at least the obturator lymph nodes are compared with treatment of limited fields (LFs), prostatic fossa only, as salvage treatment for patients with a biochemical relapse. Between 1987 and 1999, 68 patients were referred for postprostatectomy RT. Of these patients, 46 were treated for salvage intent by RT alone without adjuvant hormones, 21 patients were treated to EFs and 25 treated to LFs. All patients were treated using 4-field plans. The mean field sizes measured 15 × 14 cm (AP/PA fields) and 12 × 14 cm LFs for the EFs and 10 × 10 cm (AP/PA fields) and 10 × 10 cm (lateral fields) for the LFs. The mean total doses for the EFs and LFs were 6300 and 6200 cGy, respectively, using 180-cGy daily increments. All patients treated to the EFs received boost doses to the prostatic fossa after 4500 cGy total dose to the pelvis. The 10-year actuarial biochemical diseasefree survival (DFS) rates for the EF and LF groups were 52% and 47%, respectively (P = 0.523). The distant metastasis-free survival (DMFS) rates were 77% and 78% (P = 0.925), and overall survival (OS) rates were 88% and 68% (P = 0.615) for the EF and LF group, respectively. A subset analysis of patients with adverse pathologic features (including tumor-involved surgical margins, lymph node involvement, seminal vesicle involvement, extracapsular extension, and/or perineural invasion) showed biochemical DFS rates of 57% and 44% (P = 0.217) for the EF and LF groups, respectively. The DMFS rates were 84% and 72% (P = 0.423), and OS rates 92% and 61% (P = 0.366) for the EF and LF groups, respectively. For patients with increasing PSA levels after a radical prostatectomy, salvage irradiation is a viable option for biochemical control. Our results suggest that EF radiation with coverage of pelvic lymph nodes shows a trend toward better PSA control in those with adverse pathologic features, although statistical significance was not achieved because of the limited number of patients who satisfied the restricted criteria excluding use of adjuvant hormones.

Do conventional field borders adequately cover pelvic lymph nodes in the treatment of advanced cervix cancer? A CT-simulation study

Since conventional pelvic fields for the radical treatment of cervix cancer are based on bony landmarks and not individual patient anatomy, it is hypothesized that pelvic artery mapping via CT-Simulation is superior to conventional simulation. The purpose of this study is to assess the adequacy of pelvic lymph node coverage of conventional fields using CT-Simulation and vessel mapping, as a surrogate for lymph node location.