The role of adjuvant radiation therapy in older patients with node-positive vulvar cancer: A national cancer database analysis.

OBJECTIVE: We sought to evaluate whether the survival benefit of adjuvant radiotherapy in patients with node-positive vulvar cancer is maintained in older patients, who comprise a large subgroup of patients with vulvar cancer. METHODS: The National Cancer Database (NCDB) was queried for patients aged 65 years or older, who were diagnosed with vulvar squamous cell carcinoma from 2004 to 2017 and underwent surgery with confirmed node-positive disease. Statistical analysis was performed with propensity-score matching, chi-square test, log-rank test, Kaplan-Meier, and multivariable Cox proportional regression. RESULTS: A total of 2396 patients were analyzed, and 1517 (63.3%) received adjuvant radiotherapy. Median follow-up was 73 months. Median age at diagnosis was 77 years (range 65-90). In the propensity score-matched cohort, five-year overall survival (OS) was 29%. Five-year OS was 33% in patients who received surgery followed by adjuvant radiotherapy and 26% in patients who received surgery alone (p < 0.0001). Multivariable analysis continued to demonstrate a survival benefit associated with the addition of adjuvant radiotherapy (OR 0.77 [95% CI 0.69-00.87], p < 0.001). Adjuvant radiotherapy was associated with improved OS among patients aged 65-84 (5-year OS 35% vs 29%, p = 0.0004), but not in patients aged 85 years and older (5-year OS 20% vs 19%, p = 0.32). CONCLUSION: This NCDB study suggests that in older patients with node-positive vulvar cancer, radiotherapy continues to be a vital component of multimodality therapy. However, a comprehensive and geriatrics-specific approach is crucial for treating older adults with node-positive vulvar cancer, as the benefit of adjuvant radiotherapy may be compromised by treatment-related morbidity/toxicity.

Adjuvant radiation followed by chemotherapy is associated with improved overall survival in endometrial cancer.

OBJECTIVE: Although multimodality therapy has been shown to improve outcomes for patients with high-risk endometrial carcinoma, optimal type and timing of adjuvant therapies is unknown. METHODS: Patients with stage I-IVA endometrial carcinoma diagnosed from 2004 to 2015, and treated with surgery, chemotherapy, and radiation were identified in the National Cancer Database. Adjuvant treatment was categorized as sequential radiation followed by chemotherapy (RT-CT), concurrent chemoradiation (CCRT, RT and CT started within 7 days), or sequential chemotherapy followed by radiation (CT-RT). Analysis for propensity score matched (PSM) cohorts comparing RT-CT to CCRT and CT-RT groups was additionally performed. RESULTS: A total of 17,070 patients were identified, including 12,402 (72.7%) treated with RT-CT, 2,153 (12.6%) with CCRT, and 2,515 (14.7%) with CT-RT. Median follow-up was 44.3 months. Five-year overall-survival (OS) by adjuvant treatment regimen was 77.3% (95% CI 76.4%-78.2%), 74.3% (95% CI 72.0%-76.3%), and 74.4% (95% CI 72.5%-76.3%), respectively (p < .001). When unmatched cohorts were stratified by stage, adjuvant RT-CT was associated with improved OS in stage I and III patients. A similar survival advantage associated with RT-CT was observed in PSM cohorts comparing RT-CT group to CCRT/CT-RT group (5-year OS 77.4% vs 74.2%, p = .001). However, the difference in OS was significant only among stage III patients (RT-CT 73.9% compared to CCRT/CT-RT 69.7%, p =.002). CONCLUSION: Our findings suggest survival benefit with adjuvant RT-CT compared to CT-RT or CCRT in patients undergoing trimodality therapy for endometrial cancer. This survival benefit may be limited to stage III patients.

Sentinel lymph node imaging guided IMRT for prostate cancer: Individualized pelvic radiation therapy versus RTOG guidelines.

PURPOSE/OBJECTIVES: Current Radiation Therapy Oncology Group (RTOG) guidelines for pelvic radiation therapy are based on general anatomic boundaries. Sentinel lymph node (SLN) imaging can identify potential sites of lymph node involvement. We sought to determine how tailored radiation therapy fields for prostate cancer would compare to standard RTOG-based fields. Such individualized radiation therapy could prioritize the most important areas to irradiate while potentially avoiding coverage in areas where critical structures would be overdosed. Individualized radiation therapy could therefore increase the therapeutic index of pelvic radiation therapy. METHODS AND MATERIALS: Ten intermediate or high-risk prostate cancer patients received androgen deprivation therapy with definitive radiation therapy, including an SLN imaging-tailored elective nodal volume (ENV). For dosimetric analyses, the ENV was recontoured using RTOG guidelines (RTOG_ENV) and on SLNs alone (SLN_ENV). Separate intensity modulated radiation therapy (IMRT) plans were optimized using RTOG_ENV and SLN_ENV for each patient. Dosimetric comparisons for these IMRT plans were performed for each patient. Dose differences to targets and critical structures among the different IMRT plans were calculated. Distributions of dose parameters were analyzed using non-parametric methods. RESULTS: Sixty percent of patients had SLNs outside of the RTOG_ENV. The larger volume IMRT plans covering SLN imaging-tailored elective nodal volume exhibited no significant dose differences versus plans covering RTOG_ENV. IMRT plans covering only the SLNs had significantly lower doses to bowel and femoral heads. CONCLUSIONS: SLN-guided pelvic radiation therapy can be used to either treat the most critical nodes only or as an addition to RTOG guided pelvic radiation therapy to ensure that the most important nodes are included.

Postoperative radiation therapy for patients at high-risk of recurrence after radical prostatectomy: does timing matter?

OBJECTIVE: To evaluate among radical prostatectomy (RP) patients at high-risk of recurrence whether the timing of postoperative radiation therapy (RT) (adjuvant, early salvage with detectable post-RP prostate-specific antigen [PSA], or 'late' salvage with a PSA level of >1.0 ng/mL) is significantly associated with overall survival (OS), prostate-cancer specific survival or metastasis-free survival, in a longitudinal cohort. PATIENTS AND METHODS: Of 6 176 RP patients in the Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE), 305 patients with high-risk pathological features (margin positivity, Gleason score 8-10, or pT3-4) who underwent postoperative RT were examined, either in the adjuvant (≤6 months after RP with undetectable PSA levels, 76 patients) or salvage setting (>6 months after RP or pre-RT PSA level of >0.1 ng/mL, 229 patients). Early (PSA level of ≤1.0 ng/mL, 180 patients) or late salvage RT (PSA level >1.0 ng/mL, 49 patients) was based on post-RP, pre-RT PSA level. Multivariable Cox regression examined associations with all-cause mortality and prostate cancer-specific mortality and/or metastases (PCSMM). RESULTS: After a median of 74 months after RP, 65 men had died (with 37 events of PCSMM). Adjuvant and salvage RT patients had comparable high-risk features. Compared with adjuvant, salvage RT (early or late) had an increased association with all-cause mortality (hazard ratio [HR] 2.7, P = 0.018) and with PCSMM (HR 4.0, P = 0.015). PCSMM-free survival differed by further stratification of timing, with 10-year estimates of 88%, 84%, and 71% for adjuvant, early salvage, and late salvage RT, respectively (P = 0.026). For PCSMM-free survival and OS, compared with adjuvant RT, late salvage RT had statistically significantly increased risk; however, early salvage RT did not. CONCLUSION: This analysis suggests that patients who underwent early salvage RT with PSA levels of <1.0 ng/mL may have comparable metastasis-free survival and OS compared with adjuvant RT; however, late salvage RT with a PSA level of >1.0 ng/mL is associated with worse clinical outcomes.

Quality improvement of International Classification of Diseases, 9th revision, diagnosis coding in radiation oncology: single-institution prospective study at University of California, San Francisco.

PURPOSE: Accurate International Classification of Diseases (ICD) diagnosis coding is critical for patient care, billing purposes, and research endeavors. In this single-institution study, we evaluated our baseline ICD-9 (9th revision) diagnosis coding accuracy, identified the most common errors contributing to inaccurate coding, and implemented a multimodality strategy to improve radiation oncology coding. METHODS AND MATERIALS: We prospectively studied ICD-9 coding accuracy in our radiation therapy--specific electronic medical record system. Baseline ICD-9 coding accuracy was obtained from chart review targeting ICD-9 coding accuracy of all patients treated at our institution between March and June of 2010. To improve performance an educational session highlighted common coding errors, and a user-friendly software tool, RadOnc ICD Search, version 1.0, for coding radiation oncology specific diagnoses was implemented. We then prospectively analyzed ICD-9 coding accuracy for all patients treated from July 2010 to June 2011, with the goal of maintaining 80% or higher coding accuracy. Data on coding accuracy were analyzed and fed back monthly to individual providers. RESULTS: Baseline coding accuracy for physicians was 463 of 661 (70%) cases. Only 46% of physicians had coding accuracy above 80%. The most common errors involved metastatic cases, whereby primary or secondary site ICD-9 codes were either incorrect or missing, and special procedures such as stereotactic radiosurgery cases. After implementing our project, overall coding accuracy rose to 92% (range, 86%-96%). The median accuracy for all physicians was 93% (range, 77%-100%) with only 1 attending having accuracy below 80%. Incorrect primary and secondary ICD-9 codes in metastatic cases showed the most significant improvement (10% vs 2% after intervention). CONCLUSIONS: Identifying common coding errors and implementing both education and systems changes led to significantly improved coding accuracy. This quality assurance project highlights the potential problem of ICD-9 coding accuracy by physicians and offers an approach to effectively address this shortcoming.

American Society for Radiation Oncology (ASTRO) and American College of Radiology (ACR) practice guideline for the performance of high-dose-rate brachytherapy.

High-Dose-Rate (HDR) brachytherapy is a safe and efficacious treatment option for patients with a variety of different malignancies. Careful adherence to established standards has been shown to improve the likelihood of procedural success and reduce the incidence of treatment-related morbidity. A collaborative effort of the American College of Radiology (ACR) and American Society for Therapeutic Radiation Oncology (ASTRO) has produced a practice guideline for HDR brachytherapy. The guideline defines the qualifications and responsibilities of all the involved personnel, including the radiation oncologist, physicist and dosimetrists. Review of the leading indications for HDR brachytherapy in the management of gynecologic, thoracic, gastrointestinal, breast, urologic, head and neck, and soft tissue tumors is presented. Logistics with respect to the brachytherapy implant procedures and attention to radiation safety procedures and documentation are presented. Adherence to these practice guidelines can be part of ensuring quality and safety in a successful HDR brachytherapy program.

Class solution in inverse planned HDR prostate brachytherapy for dose escalation of DIL defined by combined MRI/MRSI.

PURPOSE: To establish an inverse planning set of parameters (class solution) to boost dominant intra-prostatic lesion (DIL) defined by MRI/MRSI. METHODS: For 15 patients, DIL were contoured on CT or MR images and a class solution was developed to boost the DIL under the dosimetric requirements of the RTOG-0321 protocol. To determine the maximum attainable level of boost for each patient, 5 different levels were considered, at least 110%, 120%, 130%, 140% and 150% of the prescribed dose. The maximum attainable level was compared to the plan without boost using cumulative dose volume histogram (DVH). RESULTS: DIL dose escalation was feasible for 11/15 patients under the requirements. The planning target volume (PTV) dose was slightly increased, while the DIL dose was significantly increased without any violation of requirements. With slight adjustments of the dose constraint parameters, the dose escalation was feasible for 13/15 patients under requirements. CONCLUSION: Using a class solution, a dose escalation of the MRI/MRSI defined DIL up to 150% while complying with RTOG dosimetric requirements is feasible. This HDR brachytherapy approach to dose escalation allows a significant dose increase to the tumor while maintaining an acceptable risk of complications.

Measurement of craniocaudal catheter displacement between fractions in computed tomography-based high dose rate brachytherapy of prostate cancer.

The objective of this work is to measure the cranio-caudal displacement of catheters occurring between consecutive fractions of transrectal ultrasound (TRUS) guided high dose rate (HDR) prostate brachytherapy. Ten consecutive patients were treated with 2 fractions of 9.5 Gy TRUS guided HDR brachytherapy using dental putty for the fixation of catheters. For each patient, a CT scan with 3 mm slice thickness was acquired before each of the two fractions. Two different references were employed to measure the catheter displacement between fractions: the ischial bone as a bony marker (BM) and the center of two gold markers (COGM) implanted in the prostate. The catheter displacement was calculated by multiplying the thickness of CT slice with the difference in number of CT slices between the reference slice and the slice containing the tip of a catheter. The average (range) magnitude of caudal catheter displacement was 2.7 mm (-6.0 to 13.5 mm) for BM method and 5.4 mm (-3.75 to 18.0 mm) for COGM method, respectively. The measurement data obtained from BM and COGM methods verified that both prostate movement and catheter displacement occurred independently between fractions. The most anterior and medial two catheters (catheter position 8 and 12) had the greatest tendency to be displaced in the caudal direction because they were located at the most distant position from the fulcrum, susceptible to the rotation of the dental putty in lateral plane due to the movement of patient legs between fractions. In conclusion, the use of both BM and COGM methods can demonstrate the prostate and catheter movement relative to the BM between fractions. We found a pattern of catheter displacement using our technique. Based on our finding further improvement of our results may be possible by modification of our current technique.

Optimization of dose distribution for HDR brachytherapy of the prostate using Attraction-Repulsion Model.

PURPOSE: To optimize dose distribution for high-dose-rate brachytherapy for prostate cancer, we have developed a new algorithm named Attraction-Repulsion Model (ARM). In this study, we compared the ARM with geometric optimization (GO). METHODS AND MATERIALS: The ARM was used to optimize the dose distribution by finding the best dwell time combination. ARM requires grids inside the clinical target volume (CTV) and critical organs. These grids generate attraction or repulsion based on specific dose constraints. After calculations were performed repeatedly until the attraction and repulsion forces reached equilibrium, the optimal dwell time distribution was established. We compared the ARM with GO for 10 patients using dose-volume histograms. RESULTS: The CTV ranged from 23 to 48 cc, and the CTV V150 ranged from 52% to 79%, and 23% to 44% for GO and ARM, respectively. This indicates that the dose homogeneity indices, as well as the conformal indices, were higher for ARM than for GO. The urethra V150 was 0-99% and 0-1% for GO and ARM, respectively. CONCLUSION: The ARM proved to be superior to GO in minimizing the dose to normal structures and in improving dose homogeneity for the target while reducing the dose to normal tissues.

Combined modality treatment with high-dose-rate brachytherapy boost for locally advanced prostate cancer.

PURPOSE: This is a retrospective review of our experience using high-dose-rate (HDR) brachytherapy boost for prostate cancer. METHODS AND MATERIALS: During the study period, we recommended external beam radiotherapy (45 Gy) and HDR boost (18 Gy in three fractions) combined with hormonal therapy (HT) for 2 months before and during radiotherapy to patients with at least one of the following risk features: pretreatment prostate-specific antigen>10, Gleason score (GS)>or=7, and clinical T3 disease. Additional HT for 2 years after radiotherapy was recommended for patients with GS>7. To patients whose risk of positive nodes exceeded 15%, we recommended whole pelvic radiotherapy. We administered HDR via single implant, and all fractions were given within 24h. RESULTS: This report is based on our initial 64 patients treated with HDR boost. The median follow-up was 50 months (range 25-68 months). The 4-year estimates of overall and disease-free survival were 98% and 92%, respectively. One patient experienced late grade 4 gastrointestinal toxicity. CONCLUSIONS: HDR brachytherapy is an effective means of delivering conformal prostate radiotherapy, and may be used with whole pelvic radiotherapy and HT.

Expandable and rigid endorectal coils for prostate MRI: impact on prostate distortion and rigid image registration.

Endorectal coils (ERCs) are used for acquiring high spatial resolution magnetic resonance (MR) images of the human prostate. The goal of this study is to determine the impact of an expandable versus a rigid ERC on changes in the location and deformation of the prostate gland and subsequently on registering prostate images acquired with and without an ERC. Sagittal and axial T2 weighted MR images were acquired from 25 patients receiving a combined MR imaging/MR spectroscopic imaging staging exam for prostate cancer. Within the same exam, images were acquired using an external pelvic phased array coil both alone and in combination with either an expandable ERC (MedRad, Pittsburgh, PA) or a rigid ERC (USA Instruments, Aurora, OH). Rotations, translations and deformations caused by the ERC were measured and compared. The ability to register images acquired with and without the ERC using a manual rigid-body registration was assessed using a similarity index (SI). Both ERCs caused the prostate to tilt anteriorly with an average tilt of 18.5 degrees (17.4 +/- 9.9 and 19.5 +/- 11.3 degrees, mean +/- standard deviation, for expandable and rigid ERC, respectively). However, the expandable coil caused a significantly larger distortion of the prostate as compared to the rigid coil; compressing the prostate in the anterior/posterior direction by 4.1 +/- 3.0 mm vs 1.2 +/- 2.2 mm (14.5% vs 4.8%) (p < 0.0001), and widening the prostate in the right/left direction by 3.8 +/- 3.7 mm vs 1.5 +/- 3.1 mm (8.3% vs 3.4%) (p = 0.004). Additionally, the ability to manually align prostate images acquired with and without ERC was significantly (p < 0.0001) better for the rigid coil (SI = 0.941 +/- 0.008 vs 0.899 +/- 0.033, for the rigid and expandable coils, respectively). In conclusion, the manual rigid-body alignment of prostate MR images acquired with and without the ERC can be improved through the use of a rigid ERC.

Comparison of inverse planning simulated annealing and geometrical optimization for prostate high-dose-rate brachytherapy.

PURPOSE: An inverse planning simulated annealing (IPSA) algorithm for optimization of high-dose-rate (HDR) brachytherapy has been previously described. In this study, IPSA is compared with geometrical optimization (GO) for prostate brachytherapy. METHODS AND MATERIALS: Using CT data collected from 10 patients, treatment plans were prepared using GO and IPSA. The clinical target volume (CTV) and critical organs (CO) including bladder, rectum, and urethra were contoured using Plato Version 14.2.1 (Nucletron Corp., Veenendaal, The Netherlands). Implant catheters were digitized using the CT planning system. All dwell positions outside of the CTV were turned off. Two optimized plans were generated for each implant using GO and IPSA. The same set of dose constraints were used for all inverse planning calculations and no manual adjustment of the dwell weight was used. Two prescription methods were used. Using the first method, coverage was prioritized: the prescription dose was normalized to the isodose volume that covers 98% of the CTV (V100 = 98% of CTV). The dose volume histograms (DVH) of CO were generated for comparison. Using the second method, sparing was prioritized: the prescription dose was normalized such that no urethra volume received 150% of the prescription dose (V150-urethra = 0 cc). The DVH of CTV and CO were generated, and the homogeneity index (HI) and conformal index (COIN) were calculated for comparison and compared using the Wilcoxon matched-pairs test. RESULTS: Using the coverage-prioritized method, the difference in V80-bladder dose was not statistically significant (p = 0.09; median: IPSA = 0.62 cc, GO = 1.05 cc). The V80-rectum ranged from 0.20-4.8 cc, and 0.05-1.4 cc using GO and IPSA, respectively. IPSA's V80-rectum was significantly lower (p = 0.005; median: IPSA=0.38 cc, GO = 1.31 cc). V150-urethra ranged from 0.02-0.75 cc and 0.0-0.01 cc using GO and IPSA, respectively. The V150-urethra was significantly lower using IPSA (p = 0.005; median: IPSA = 0.00 cc, GO = 0.33 cc). Using the sparing prioritized method, the V100-prostate ranged from 30-97% and 95-100% using GO and IPSA, respectively. This difference was statistically significant (p = 0.008). The HI and COIN were statistically higher using IPSA (p = 0.005). CONCLUSION: Anatomy-based inverse optimization using IPSA is superior to dwell-position-based optimization using GO as it: (1) Improves target coverage and conformality while sparing normal structures, (2) Improves dose homogeneity within the target, and (3) Minimizes volume of non-contoured normal tissue irradiated. Routine application of three-dimensional brachytherapy planning and anatomy-based inverse dwell time optimization is recommended.

Analysis of interaction between number of implant catheters and dose-volume histograms in prostate high- dose-rate brachytherapy using a computer model.

PURPOSE: In prostate high-dose-rate brachytherapy, to determine before implant, using the standard geometric optimization algorithm, whether there is an optimal number of catheters. MATERIALS AND METHODS: Transrectal ultrasound images of the prostate from 24 patients were transferred into the brachytherapy planning system. Urethra and prostate contours were digitized onto each axial slice of a CT scan, as well as hypothetical locations of the catheters (2/3 of the catheters along the prostate contour, 1/3 around the urethra). Each prostate was implanted with 9, 12, 15, 18, and 21 catheters. Dosimetry was optimized using a geometric optimization algorithm; prescription isodose was chosen so that 95% of planning target volume was covered by the 100% isodose. RESULTS: A significant increase in mean volume of prostate receiving 150% of the dose (V150) when the number of catheters decreased (p < 0.0001). The 9-catheter group significantly differed from each of the other groups; no difference was seen in V150 among the 21-, 18-, and 15-catheter groups. Parallel results were observed for urethra V150 and homogeneity index; there was no difference in conformity index by catheter group. CONCLUSION: V150 increased when fewer catheters were used. There was no significant difference among the 21-, 18-, and 15-catheter groups: the geometric optimization routine probably compensated for the larger distance between dwell positions. Based on the technique described in our study, we conclude that 15 to 21 catheters seem to cover the prostate adequately without creating excess hot spots.

A comparison between tandem and ovoids and interstitial gynecologic template brachytherapy dosimetry using a hypothetical computer model.

PURPOSE: To evaluate the dose distribution within the clinical target volume between two gynecologic brachytherapy systems---the tandem and ovoids and the Syed-Neblett gynecologic template---using a hypothetical computer model. METHODS AND MATERIALS: Source positions of an intracavitary system (tandem and ovoids) and an interstitial system (GYN template) were digitized into the Nucletron Brachytherapy Planning System. The GYN template is composed of a 13-catheter implant (12 catheters plus a tandem) based on the Syed-Neblett gynecologic template. For the tandem and ovoids, the dwell times of all sources were evenly weighted to produce a pear-shaped isodose distribution. For the GYN template, the dwell times were determined using volume optimization. The prescribed dose was then normalized to point A in the intracavitary system and to a selected isodose line in the interstitial system. The treated volume in the two systems was kept approximately the same, and a cumulative dose-volume histogram of the treated volume was then generated with the Nucletron Brachytherapy Planning System to use for comparison. To evaluate the dose to a hypothetical target, in this case the cervix, a 2-cm-long, 3-cm-diameter cylinder centered along the tandem was digitized as the clinical target volume. The location of this hypothetical cervix was based on the optimal application of the brachytherapy system. A visual comparison of clinical target coverage by the treated volume on three different orthogonal planes through the treated volume was performed. The percentage dose-volume histograms of the target were generated for comparison. Multiple midline points were also placed at 5-mm intervals away from the tandem in the plane of the cervix to simulate the location of potential bladder and rectal dose points. Doses to these normal structures were calculated for comparison. RESULTS: Although both systems covered the hypothetical cervix adequately, the interstitial system had a better coverage of the region lateral to the cervix. Smaller volumes of the vagina and uterine fundus received the full dose from the interstitial implant. The cumulative dose-volume histograms revealed larger high-dose regions within the treatment volume for the intracavitary system. The volumes receiving > or = 180% of the prescription dose were 31 cc and 17 cc for the intracavitary system and interstitial system, respectively. The isodose lines showed that most of this difference results from the high-dose region around the tandem. The percentage dose-volume histograms showed that a larger percentage of cervix received a higher dose in the intracavitary system. Fifty-two percent of the target volume received 200% or higher of the prescription dose with tandem and ovoids, compared with only 20% with the template system. Analysis of dose points outside of the 100% isodose lines showed a slightly more rapid dose drop-off with the interstitial system compared to the intracavitary system. Point doses at 20, 25, and 30 mm from the tandem in the interstitial system were 100%, 69%, and 51% of prescribed dose, and from the intracavitary system were 101%, 76%, and 58%, respectively. CONCLUSIONS: Our dosimetric analysis revealed a better coverage in the parametrial regions, but underdosage of the central cervical region, for the interstitial system. On the other hand, because of the increased distance of source to dose point, there is a more rapid dose drop-off outside the treated volume with the interstitial system, which has the potential to improve tissue sparing. Based on this analysis, we caution against using a radiotherapy system with a homogeneous central dose distribution when treating cervical cancer with an intact uterus. We recommend differential loading of the implant catheters with the majority of dose delivered from the tandem when using an interstitial GYN template with remote afterloader.

Managing nasopharyngeal carcinoma with intracavitary brachytherapy: one institution's 45-year experience.

PURPOSE: At our institution, we have been using intracavitary brachytherapy as a boost in selected cases of both primary and recurrent nasopharyngeal carcinoma. The local control, distant metastasis-free rate, overall survival, and morbidity are presented. METHODS AND MATERIALS: Between January 1, 1955, and August 2000, 576 patients with a diagnosis of nasopharyngeal carcinoma were seen at the department of radiation oncology, University of California-San Francisco, and 55 patients received intracavitary brachytherapy as one part of their treatment. All patients were treated with megavoltage external beam radiation, including 43 patients treated for initial disease and 12 for recurrence. Brachytherapy was routinely used for early cases of T1 and T2 lesions and selected cases of more advanced lesions, as well as recurrent lesions. The median age was 48 years (range 22-85 years); there were 17 women and 38 men, and 39 patients were ethnic Chinese, 13 were white, and 3 were other races. Stage at treatment (primary and recurrent) was I (n=13), II (n=18), III (n=19), and IV (n=5); 18 patients had concurrent chemotherapy. The brachytherapy applicators used were Rotterdam (n=24), balloon (n=16), ovoid (n=14), and ribbon (n=1). The dose rate was high (n=24), low (n=29), or pulsed (n=2). External beam doses ranged from 54 to 72 Gy for primary disease and 30 to 42 Gy for recurrent disease. Brachytherapy doses ranged from 5 to 7 Gy for high dose rate and 10 to 54 Gy for low dose rate. RESULTS: With a median follow-up of 36 months in those who were treated for primary carcinoma, the 5-year estimate of local control was 89%, the distant metastasis-free rate was 75%, and the overall survival estimate was 86%. Recurrent patients had a median follow-up of 50 months; the 5-year estimate of local control was 64%, the distant metastasis-free rate was 100%, and the overall survival estimate was 91%. Patients with Stage I or II disease had a longer overall survival compared with those with Stage III or IV (p=0.05). There was a significant difference in the rate of distant metastases due to nodal status (N0 vs. N1-N3, p=0.02) or to overall stage (I/II vs. III/IV, p=0.005). CONCLUSIONS: Intracavitary boost brachytherapy was found to be effective and well tolerated in selected cases of both primary and recurrent nasopharyngeal carcinoma.