Faculty Bibliography

PURPOSE/OBJECTIVE:To report long-term outcomes of high-dose-rate (HDR) intraoperative radiotherapy (IORT) at the time of radical resection for recurrent head-and-neck cancer and determine potential prognostic factors. METHODS AND MATERIALS/METHODS:Between 7/1998 and 11/2011, 57 patients with recurrent head-and-neck cancer underwent radical resection with curative intent and single-fraction IORT to 59 sites using a Harrison-Anderson-Mick applicator with remotely after-loaded (192)Ir HDR brachytherapy. RESULTS:One- and 3-year in-field progression-free survival (IFPFS) was 67% and 57%, respectively. In a multivariate model, IORT dose >15Gy (hazard ratio [HR] = 0.11; p = 0.02), and prerecurrence disease-free interval >12 months (HR = 0.29; p = 0.04) independently predicted for superior IFPFS; nodal extracapsular extension (HR = 4.62; p = 0.003) predicted for inferior IFPFS. Three-year overall survival (OS) was 50% vs. 32% in those achieving in-field control vs. those not achieving in-field control (p = 0.04). Grade 3+ toxicity occurred in 37% and was unrelated to IORT dose. CONCLUSIONS:HDR-IORT combined with radical surgical resection is associated with durable IFPFS and long-term overall survival in select patients with acceptable treatment-related morbidity. IORT dose >15Gy should be used to increase the likelihood of disease control. The ability to achieve in-field local control in this poor prognostic cohort was associated with improved survival outcomes.

PURPOSE/OBJECTIVE:We report on quality of dose delivery to target and normal tissues from low-dose-rate prostate brachytherapy using postimplantation dosimetric evaluations from a random sample of U.S. patients. METHODS AND MATERIALS/METHODS:Nonmetastatic prostate cancer patients treated with external beam radiotherapy or brachytherapy in 2007 were randomly sampled from radiation oncology facilities nationwide. Of 414 prostate cancer cases from 45 institutions, 86 received low-dose-rate brachytherapy. We collected the 30-day postimplantation CT images of these patients and 10 test cases from two other institutions. Scans were downloaded into a treatment planning system and prostate/rectal contours were redrawn. Dosimetric outcomes were reanalyzed and compared with calculated outcomes from treating institutions. RESULTS:Median prostate volume was 33.4cm(3). Reevaluated median V(100), D(90), and V(150) were 91.1% (range, 45.5-99.8%), 101.7% (range, 59.6-145.9%), and 53.9% (range, 15.7-88.4%), respectively. Low gland coverage included 27 patients (39%) with a D(90) lower than 100% of the prescription dose (PD), 12 of whom (17% of the entire group) had a D(90) lower than 80% of PD. There was no correlation between D(90) coverage and prostate volume, number of seeds, or implanted activity. The median V(100) for the rectum was 0.3cm(3) (range, 0-4.3cm(3)). No outcome differences were observed according to the institutional strata. Concordance between reported and reevaluated D(90) values (defined as within ±10%) was observed in 44 of 69 cases. CONCLUSIONS:Central review of postimplantation CT scans to assess the quality of prostate brachytherapy is feasible. Most patients achieved excellent dosimetric outcomes, yet 17% had less than optimal target coverage by the PD. There was concordance between submitted target-coverage parameters and central dosimetric review in 64% of implants. These findings will require further validation in a larger cohort of patients.

PURPOSE/OBJECTIVE:Intraoperative radiation therapy (IORT) allows delivery of tumoricidal doses of radiation to areas of potential residual microscopic disease while minimizing doses to normal tissues. IORT using high-dose-rate (HDR) brachytherapy allows dose modulation and delivery of concomitant boosts to high-risk areas. This study describes a novel technique of HDR-IORT with dose painting (DP) (HDR-IORT-DP) and evaluates the clinical outcomes. METHODS AND MATERIALS/METHODS:Sixteen patients with recurrent cancers received HDR-IORT-DP at the time of radical resection. Of these patients, 13 had colorectal cancer, 2 had head and neck cancer, and 1 had a gynecologic malignancy. All received external beam radiation previously. Negative margin (R0) was obtained in 12 patients (75%) and microscopically positive margins (R1) in 4 patients (25%). RESULTS:The median total target and boost area were 45 and 8.5cm(2), and HDR-IORT and boost dose were 1500 and 1750cGy, respectively. Median followup was 14.9 months. The 2-year local control and overall survival were 80% and 20%, respectively. Eleven patients (69%) developed distant metastasis and were deceased at the time of the last followup. A total of 13 patients (19%) developed Grade 3 toxicity related to HDR-IORT; no grade 4+ toxicities were observed. CONCLUSIONS:HDR-IORT-DP technique is feasible, safe, and allows for dose escalation in locally advanced or recurrent previously irradiated tumors. To our knowledge, this is the first clinical report on HDR-IORT-DP. Further studies are warranted to evaluate efficacy in a larger patient cohort. Local control was encouraging in our patients.

PURPOSE/OBJECTIVE:To report prostate-specific antigen (PSA) relapse-free survival and treatment-related toxicity outcomes after combining high-dose-rate (HDR) brachytherapy with external beam radiotherapy (EBRT) for patients with clinically localized prostate cancer. METHODS AND MATERIALS/METHODS:Between 1998 and 2009, 229 patients were treated with HDR brachytherapy followed 3 weeks later by supplemental EBRT. The HDR brachytherapy boost consisted of three fractions of (192)Ir (5.5-7.5Gy per fraction), and EBRT consisted of intensity-modulated radiotherapy delivering an additional 45.0-50.4Gy directed to the prostate gland and seminal vesicles. Median follow-up was 61 months. RESULTS:Seven-year PSA relapse-free survival for low-, intermediate-, and high-risk patients were 95%, 90%, and 57%, respectively (p<0.001). Among high-risk patients treated with biological equivalent doses in excess of 190Gy, 7-year PSA relapse-free survival was 81%. In multivariate analysis, Gleason scores of ≥8 predicted for increased risk of biochemical failure, whereas the use of short-term neoadjuvant androgen deprivation therapy did not influence tumor-control outcomes even among intermediate- or high-risk patients. Seven-year incidence of distant metastases for low-, intermediate-, and high-risk patients were 5%, 3%, and 17%, respectively. Seven-year incidence of late Grade 2 and 3 genitourinary toxicities were 22.1% and 4.9%, respectively and the 7-year incidence of Grade 2 and 3 gastrointestinal toxicities were 1% and 0.4%, respectively. CONCLUSION/CONCLUSIONS:HDR prostate brachytherapy in conjunction with supplemental EBRT results in excellent biochemical relapse-free survival rates with a low incidence of severe late genitourinary or gastrointestinal toxicities. The use of short-term neoadjuvant androgen deprivation did not influence long-term biochemical tumor control in this cohort.