Jeffrey M. Martin

The rise and fall of prostate brachytherapy: use of brachytherapy for the treatment of localized prostate cancer in the National Cancer Data Base.

Brachytherapy has been shown to be an efficacious and cost‐effective treatment among patients with localized prostate cancer. In this study, the authors examined trends in brachytherapy use for localized prostate cancer using a large national cancer registry.

Postmastectomy radiation therapy for T3N0: A SEER analysis

There is conflicting evidence regarding the benefit of postmastectomy radiation therapy (PMRT) for pathologic stage T3N0M0 breast cancers. We analyzed data from the Surveillance, Epidemiology, and End Results (SEER) database to investigate the benefit of PMRT in this patient population.

Evaluation and Management of Head and Neck Squamous Cell Carcinoma of Unknown Primary

The diagnostic evaluation and therapeutic management of a patient with squamous cell carcinoma of an unknown primary (SCCUP) has considerably evolved over recent decades and will likely continue to change as a result of the improving ability to identify small primary tumors and better tailor the implementation of multimodality therapy. By application of the general principles of head and neck oncology, physicians and surgeons are often able to achieve satisfactory control of the disease in patients with SCCUP.

Didactic noteComparison of testicular dose delivered by intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) in patients with prostate cancer

A small decrease in testosterone level has been documented after prostate irradiation, possibly owing to the incidental dose to the testes. Testicular doses from prostate external beam radiation plans with either intensity-modulated radiation therapy (IMRT) or volumetric-modulated arc therapy (VMAT) were calculated to investigate any difference. Testicles were contoured for 16 patients being treated for localized prostate cancer. For each patient, 2 plans were created: 1 with IMRT and 1 with VMAT. No specific attempt was made to reduce testicular dose. Minimum, maximum, and mean doses to the testicles were recorded for each plan. Of the 16 patients, 4 received a total dose of 7800 cGy to the prostate alone, 7 received 8000 cGy to the prostate alone, and 5 received 8000 cGy to the prostate and pelvic lymph nodes. The mean (range) of testicular dose with an IMRT plan was 54.7 cGy (21.1 to 91.9) and 59.0 cGy (25.1 to 93.4) with a VMAT plan. In 12 cases, the mean VMAT dose was higher than the mean IMRT dose, with a mean difference of 4.3 cGy (p = 0.019). There was a small but statistically significant increase in mean testicular dose delivered by VMAT compared with IMRT. Despite this, it unlikely that there is a clinically meaningful difference in testicular doses from either modality.

Comparison of testicular dose delivered by intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) in patients with prostate cancer

A small decrease in testosterone level has been documented after prostate irradiation, possibly owing to the incidental dose to the testes. Testicular doses from prostate external beam radiation plans with either intensity-modulated radiation therapy (IMRT) or volumetric-modulated arc therapy (VMAT) were calculated to investigate any difference. Testicles were contoured for 16 patients being treated for localized prostate cancer. For each patient, 2 plans were created: 1 with IMRT and 1 with VMAT. No specific attempt was made to reduce testicular dose. Minimum, maximum, and mean doses to the testicles were recorded for each plan. Of the 16 patients, 4 received a total dose of 7800 cGy to the prostate alone, 7 received 8000 cGy to the prostate alone, and 5 received 8000 cGy to the prostate and pelvic lymph nodes. The mean (range) of testicular dose with an IMRT plan was 54.7 cGy (21.1 to 91.9) and 59.0 cGy (25.1 to 93.4) with a VMAT plan. In 12 cases, the mean VMAT dose was higher than the mean IMRT dose, with a mean difference of 4.3 cGy (p = 0.019). There was a small but statistically significant increase in mean testicular dose delivered by VMAT compared with IMRT. Despite this, it unlikely that there is a clinically meaningful difference in testicular doses from either modality.

Use of Postprostatectomy Radiation Therapy at an NCI-Designated Comprehensive Cancer Center

PURPOSE Characterize use of postprostatectomy radiation (PPRT) for patients with prostate cancer at an NCI-designated comprehensive cancer center. METHODS We queried our prospective prostate cancer database for patients treated with 60 to 68 Gy of radiation therapy (RT) to the prostate bed after prostatectomy from 2003 to 2011. Prostatectomy cases were obtained from billing records. Patients with an intact prostate treated with definitive RT served as a control for the change in volume of patients with prostate cancer treated in the department. Chi-square analysis assessed differences between adjuvant and salvage RT cohorts. Spearman correlation assessed yearly trends in prostate-specific antigen (PSA) level at the time of referral for RT. Linear regression models tested trends for number of PPRT cases, prostatectomies, and patients with intact prostate receiving radiation across years. RESULTS PPRT was used to treat 475 men at Fox Chase Cancer Center from 2003 to 2011 (83 adjuvant and 392 salvage). Over time, an increased proportion of patients receiving RT to the prostate were treated with PPRT. No increase was seen in the proportion of patients treated with adjuvant RT compared with salvage RT (P=.5). Patients receiving adjuvant RT were younger, had higher pathologic Gleason score, pathologic T stage, and rates of positive margins than those receiving salvage RT. Pre-RT PSA values were inversely correlated with year (P=.005). The number of patients referred for salvage RT with a PSA of 0.5 ng/mL or less increased significantly from 7.9% in 2003 to 26.6% in 2011 (P=.002). CONCLUSIONS A larger proportion of patients treated with RT for localized prostate cancer are now receiving PPRT. No increase was seen in the proportion of patients treated with adjuvant RT. Over time, patients with lower PSAs were referred for salvage RT.

SU-E-T-424: Dosimetric Verification of Modulated Electron Radiation Therapy Delivered Using An Electron Specific Multileaf Collimator for Treatment of Scalp Cases

PURPOSE Modulated electron radiotherapy (MERT) has the potential to achieve better treatment outcome for shallow tumors such as those of breast and scalp. In a separate study with scalp lesions, MERT was compared to volumetric modulated arc therapy. Our results showed a reduction in the dose reaching the brain with MERT. However dose calculation accuracy and delivery efficiency challenges remain. Thus in the current study we proceed to add more cases to demonstrate MERT beneficial outcome and its delivery accuracy using an electron specific multileaf collimator (eMLC). METHODS We have used the MCBEAM code for treatment head simulation and for generating phase space files to be used as radiation source input for our Monte Carlo based treatment planning system (MC TPS). MCPLAN code is used for calculation of patient specific dose deposition coefficient and for final MERT plan dose calculation. An in-house developed optimization code is used for the optimization process. MERT plans were generated for real patients and head and neck phantom. Film was used for dosimetric verification. The film was cut following the contour of the curved phantom surface and then sealed with black masking tape. In the measurement, the sealed film packet was sandwiched between two adjacent slabs of the head and neck phantom. The measured 2D dose distribution was then compared with calculations. RESULTS The eMLC allows effective treatment of scalps with multi-lesions spreading around the patient head, which was usually difficult to plan or very time consuming with conventional applicators. MERT continues to show better reduction in the brain dose. The dosimetric measurements showed slight discrepancy, which was attributed to the film setup. CONCLUSION MERT can improve treatment plan quality for patients with scalp cancers. Our in-house MC TPS is capable of performing treatment planning and accurate dose calculation for MERT using the eMLC.

MO‐H‐19A‐02: Investigation of Modulated Electron Arc (MeArc) Therapy for the Treatment of Scalp Tumors

PURPOSE Electron arc therapy has long been proposed as the most suitable technique for the treatment of superficial tumors that follow circularly curved surfaces. However it was challenged by unsuitability of the conventional applicators and the lack of adequate 3-D dose calculation tools for arc electron beams in the treatment planning systems (TPS). Now with the availability of an electron specific multi-leaf collimator (eMLC) and an in-house Monte Carlo (MC) based TPS, we were motivated to investigate more advanced modulated electron arc (MeARC) therapy and its beneficial outcome. METHODS We initiated the study by a film measurement conducted in a head and neck phantom, where we delivered electron arcs in a step and shoot manner using the light field as a guide to avoid fields abutments. This step was done to insure enough clearance for the arcs with eMLC. MCBEAM and MCPLAN MC codes were used for the treatment head simulation and phantom dose calculation, respectively. Treatment plans were generated for targets drawn in real patient CTs and head and neck phantom. We utilized beams eye view available from a commercial planning system to create beamlets having same isocenter and adjoined at the scalp surface. Then dose-deposition coefficients from those beamlets were calculated for all electron energies using MCPLAN. An in-house optimization code was then used to find the optimum weights needed from individual beamlets. RESULTS MeARC showed a nicely tailored dose distribution around the circular curved target on the scalp. Some hot spots were noticed and could be attributed to fields abutment problem owing to the bulging nature of electron profiles. Brain dose was shown to be at lower levels compared to photon treatment. CONCLUSION MeARC was shown to be a promising modality for treating scalp cases and could be beneficial to all superficial tumors with a circular curvature.