Ali El-Gayed

Planning target volume margins for prostate radiotherapy using daily electronic portal imaging and implanted fiducial markers

BackgroundFiducial markers and daily electronic portal imaging (EPI) can reduce the risk of geographic miss in prostate cancer radiotherapy. The purpose of this study was to estimate CTV to PTV margin requirements, without and with the use of this image guidance strategy.Methods46 patients underwent placement of 3 radio-opaque fiducial markers prior to prostate RT. Daily pre-treatment EPIs were taken, and isocenter placement errors were corrected if they were ≥ 3 mm along the left-right or superior-inferior axes, and/or ≥ 2 mm along the anterior-posterior axis. During-treatment EPIs were then obtained to estimate intra-fraction motion.ResultsWithout image guidance, margins of 0.57 cm, 0.79 cm and 0.77 cm, along the left-right, superior-inferior and anterior-posterior axes respectively, are required to give 95% probability of complete CTV coverage each day. With the above image guidance strategy, these margins can be reduced to 0.36 cm, 0.37 cm and 0.37 cm respectively. Correction of all isocenter placement errors, regardless of size, would permit minimal additional reduction in margins.ConclusionsImage guidance, using implanted fiducial markers and daily EPI, permits the use of narrower PTV margins without compromising coverage of the target, in the radiotherapy of prostate cancer.

Combined radiation therapy and dendritic cell vaccine for treating solid tumors with liver micro‐metastasis

Tumor metastasis and relapse are major obstacles in combating human malignant diseases. Neither radiotherapy alone nor injection of dendritic cells (DCs) can successfully overcome this problem. Radiation induces tumor cell apoptosis and necrosis, resulting in the release of tumor antigen and danger signals, which are favorable for DC capturing antigens and maturation. Hence, the strategy of combined irradiation and DC vaccine may be a novel approach for treating human malignancies and early metastasis.

Dose–volume analysis of locoregional recurrences in head and neck IMRT, as determined by deformable registration: A prospective multi-institutional trial

BACKGROUND AND PURPOSE Although IMRT for head and neck cancer is widely accepted, the implications of sparing normal tissue immediately adjacent to target volumes are not well known. MATERIALS AND METHODS Between 2002 and 2007, 124 patients with head and neck cancer were treated with surgery and postoperative IMRT (n=79) or definitive RT (n=45). Locoregional recurrences were analyzed for location relative to target volumes, and dosimetry. RESULTS With a median follow-up of 26.1months, a total of 16 locoregional recurrences were observed. The five-year actuarial locoregional disease-free survival was 82% [95% CI, 72-90%]. Analysis of 18 distinct sites of locoregional failure revealed that five of these failures were within the high dose clinical target volume (CTV), nine failures were at the margin of the CTV, and four recurrences were outside the CTV. The mean dose delivered to these recurrent volumes was 63.1 Gy [range: 57-68 Gy], while the mean dose to the coolest 1cc within each recurrence was 60.0 Gy [range: 51-67 Gy]. There were two periparotid recurrences observed. CONCLUSIONS We observed excellent locoregional control rates overall. The majority of recurrences occur within high dose regions of the neck and not near the spared parotid glands.

Phase II study of hypofractionated image-guided radiotherapy for localized prostate cancer: Outcomes of 55 Gy in 16 fractions at 3.4 Gy per fraction ☆

PURPOSE To estimate the late morbidity of a novel, hypofractionated external beam radiotherapy schedule of 55 Gy in 16 fractions (4 fractions/week, 3.4 Gy per fraction) for localized prostate cancer. METHODS AND MATERIALS A multi-center phase 2 study enrolled seventy-three patients between September 2004 and June 2006. After insertion of fiducial gold markers, they were treated with image-guidance (IGRT) using conformal techniques with intensity-modulation, if necessary, and then followed every 6 months for toxicity rating and PSA. Patient reported outcomes were collected yearly. Median follow up was 4.6 years. RESULTS At 4 years post-radiotherapy, the cumulative incidence of combined urinary and bowel grade 3 toxicity was 7% (95% CI 3-16%) and grade 2+ was 33% (95% CI 24-46%). All except two patients recovered from their grade 3 events. Patient-reported reduction of function was most pronounced at year two for urinary function (mean -7, SD 16), and at year one for bowel function (mean -7, SD 21). The cumulative incidence of biochemical (PSA nadir+2) or biopsy-proven relapse at 4 years was 9% (95% CI 4-18%). CONCLUSIONS Hypofractionated radiotherapy is clinically feasible and more convenient than conventional schedules for patients with localized prostate cancer. Phase 3 multicenter studies are on-going (NCT00126165).

Long-term outcome of breast cancer patients with one to two nodes involved-application of nodal ratio

Abstract:  Nodal ratio (NR) is defined as the number of involved nodes to the number of nodes examined. There is limited information on the application of NR on population data. Previous reports in breast cancer generally analyzed one to three positive axillary nodes as a single group. This study investigates whether one to three positive axillary nodes is a homogeneous group in prognosis by comparing one to two positive nodes to three positive nodes. The population‐based registry of a Canadian province from 1981 through 1995 was searched. As the reliability of nodal assessment depends on the number of nodes sampled, we also studied the subgroup of patients with greater than or equal to eight nodes dissected. Of a total of 5,996 breast cancer patients, 1187 had one to three positive axillary nodes. The 263 patients with three positive nodes compared to the 924 patients with one to two nodes fared worse with a significantly reduced cause‐specific survival (CSS) and overall survival (OS). Patients with one to two positive nodes had similar CSS (p = 0.31) and OS (p = 0.63). Among those with greater than or equal to eight nodes dissected, there were 677 patients with one to two positive nodes. CSS and OS were not significantly different between one versus two positive nodes (p = 0.16 and 0.34, respectively), but with NR, the corresponding p values were 0.0068 and 0.08, respectively. The cutoff value of NR 0.15 was found to be most useful and confirmed by the validation dataset. NR is able to segregate patients better than the absolute number of positive nodes used in the current staging system. NR should be incorporated into the staging system.