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Sharon Spencer

Publications and source records attributed to Sharon Spencer.

7 recordsLinked to original sources
PubMed2006

Disadvantage of men living alone participating in Radiation Therapy Oncology Group head and neck trials.

PURPOSE: This study evaluated whether males without partners were disadvantaged for survival in Radiation Therapy Oncology Group (RTOG) head and neck cancer clinical trials. METHODS: Patients treated on three RTOG trials were studied. The Cox proportional hazards model was used to determine if sex and the interaction between sex and marital/partner status were independent prognostic variables for overall survival controlling for Karnofsky performance status, tumor stage, nodal stage, primary site, and protocol treatment. RESULTS: A total of 1,901 patients (1,509 men) were entered onto the three RTOG trials, with 1,822 (1,438 men) analyzable patients. Prognostic variables independent of disease-related variables for survival in multivariate analyses restricted to men were age, marital/partner status, and income. CONCLUSION: The apparent disadvantage of unpartnered men is striking, even after controlling for disease and other demographic variables. Possible explanations could easily be tested in observational studies, leading to evaluation of simple interventions to improve their outcome.

Aged↗
PubMed2005

Is there disparity in the care of minority patients with upper aerodigestive tract malignancy?

The data presently available indicate that there is unequal (disparate) care in patients with head and neck cancer. The reasons for this are likely multifactorial and require further study. Complicating such work is the need for subgroup analysis. For example, Hispanics are not a homogeneous ethnic group; hence, differences in social perception, cultural mores, and available medical resources can be demonstrated that can directly impact care and outcome. Appropriate epidemiologic studies are needed with more underserved minority patients to analyze these differences further and to address such differences.

Black or African American↗
PubMed2005

Monte Carlo techniques for scattering foil design and dosimetry in total skin electron irradiations.

Total skin electron irradiation (TSEI) with single fields requires large electron beams having good dose uniformity, dmax at the skin surface, and low bremsstrahlung contamination. To satisfy these requirements, energy degraders and scattering foils have to be specially designed for the given accelerator and treatment room. We used Monte Carlo (MC) techniques based on EGS4 user codes (BEAM, DOSXYZ, and DOSRZ) as a guide in the beam modifier design of our TSEI system. The dosimetric characteristics at the treatment distance of 382 cm source-to-surface distance (SSD) were verified experimentally using a linear array of 47 ion chambers, a parallel plate chamber, and radiochromic film. By matching MC simulations to standard beam measurements at 100 cm SSD, the parameters of the electron beam incident on the vacuum window were determined. Best match was achieved assuming that electrons were monoenergetic at 6.72 MeV, parallel, and distributed in a circular pattern having a Gaussian radial distribution with full width at half maximum = 0.13 cm. These parameters were then used to simulate our TSEI unit with various scattering foils. Two of the foils were fabricated and experimentally evaluated by measuring off-axis dose uniformity and depth doses. A scattering foil, consisting of a 12 x 12 cm2 aluminum plate of 0.6 cm thickness and placed at isocenter perpendicular to the beam direction, was considered optimal. It produced a beam that was flat within +/-3% up to 60 cm off-axis distance, dropped by not more than 8% at a distance of 90 cm, and had an x-ray contamination of <3%. For stationary beams, MC-computed dmax, Rp, and R50 agreed with measurements within 0.5 mm. The MC-predicted surface dose of the rotating phantom was 41% of the dose rate at dmax of the stationary phantom, whereas our calculations based on a semiempirical formula in the literature yielded a drop to 42%. The MC simulations provided the guideline of beam modifier design for TSEI and estimated the dosimetric performance for stationary and rotational irradiations.

Calibration↗
PubMed2003

Phase 1 trial of combined chemotherapy and reirradiation for recurrent unresectable head and neck cancer.

BACKGROUND: The management of recurrent unresectable head and neck cancer remains a challenging problem. Based on the circadian rhythm concept, we sought to determine the maximum tolerated dose (MTD) of infusional 5-flourouracil (5-FU), hydroxyurea (HU), and reirradiation (RT). METHOD: Bolus 5-FU was escalated from 300 mg/m(2)/d to a 10-hour infusion beginning at midnight, increased at 150 mg/m(2)/d increments. HU, 1.5 g, remained constant. Chemotherapy was given on weeks 1 and 4. RT was given daily, 2.0 Gy per fraction on weeks 1 and 2 followed by a 1-week break, then hyperfractionated weeks 4 and 5, total dose 50 Gy. The goal was to deliver a continuous course of RT to 60 Gy after the MTD was determined with an additional week of chemotherapy. RESULTS: Six cohorts were treated to establish the 5-FU MTD of 900 mg/m(2)/d. The seventh cohort received continuous RT and 5-FU, 750 mg/m(2)/d, one dose level below the MTD. Two hematologic, three skin, and six mucosal >or= grade 3 toxicities were noted in 7 of 16 patients. The median survival was 10.2 months and the 1-year survival was 41%. The median survival for the entire group was 9.4 months, with a 1- and 2-year survival of 39% and 15%, respectively. CONCLUSION: RT can be given in a continuous fashion with concurrent 5-FU and HU. Because radiation sensitization should be achievable at nontoxic doses of 5-FU, we recommend 600 mg/m(2)/d in phase a II setting.

Adult↗
PubMed2003

Docetaxel with concurrent radiotherapy in head and neck cancer.

Recent studies in the treatment of head and neck cancer suggest that combined chemoradiation is superior to radiation alone with regard to local-regional control. Agents that have shown activity as radiosensitizers include platinum agents and taxanes. Docetaxel is a semisynthetic taxane that affects polymerized tubulin both to promote microtubule formation and to inhibit its disassembly. As a single agent, docetaxel shows significant antitumor activity in head and neck cancer in the neoadjuvant setting. Docetaxel also exhibits potent radiosensitizing capability. Because docetaxel is a phase-specific agent, frequent administration of docetaxel offers the potential for enhancement of radiosensitization. Current trials are exploring the optimal dose and schedule of administration of docetaxel with concurrent radiotherapy in patients with head and neck cancer.

Antineoplastic Agents↗
PubMedDate not supplied

Low-dose-rate vs. high-dose-rate intracavitary brachytherapy for carcinoma of the cervix: The University of Alabama at Birmingham (UAB) experience.

PURPOSE: To review the clinical outcome retrospectively of cervical cancer patients treated definitively with either high-dose-rate (HDR) or low-dose-rate (LDR) brachytherapy. METHODS AND MATERIALS: One hundred sixty patients (44 Stage I, 83 Stage II, and 33 Stage III) were treated from 1990 to 2000 with curative intent for carcinoma of the cervix. One hundred three LDR patients were compared to 57 HDR patients. Two groups were treated during the same period. An external beam dose of 45 Gy to the entire pelvis was delivered at 1.8 Gy per fraction to most patients before the first intracavitary insertion in both groups. Brachytherapy was delivered in one to two LDR implants or four to five HDR implants at 6 Gy per fraction. The prescribed dose to Point A for LDR was at least 80-85 Gy. Patient characteristics were similar for each cohort. Point A doses were similar for each stage. The primary endpoints assessed were survivals and failure sites. Endpoints were estimated using the Kaplan-Meier method and comparisons between treatment groups were performed using the log-rank test. RESULTS: The median followup was 48 months for the LDR group and 59 months for the HDR group. For all stages combined and stage for stage in both groups, there was no statistically significant difference in locoregional control, cause-specific survival, and overall survival for LDR compared with HDR. Locoregional control and overall survival were 78% and 60% for LDR compared to 76% and 55% for HDR at 3 years, respectively (p = 0.96 and p = 0.48). Median cause-specific survival values for LDR vs. HDR were 71 and 81 months, respectively (p = 0.62). The cause-specific survival for LDR patients was 62% compared with 59% for HDR patients at 3 years. For Stage IB2, II, and III LDR patients, cause-specific survival rates were 62%, 67%, and 45%, compared to 67%, 57%, and 33% for HDR at 3 years, respectively (p = 0.75, p = 0.95, and p = 0.48). For patients with a recorded site of first failure, the most common site was locoregional (56%) and then distant metastases (26%). Eight patients who were cancer free developed late complications requiring surgical intervention. Two patients were in the HDR group (3.5%) and 5 in the LDR group (4.8%). CONCLUSIONS: Similar outcome was observed for LDR compared with HDR intracavitary brachytherapy for the entire cohort. In this review, HDR group was not inferior to LDR group in advanced stages. This is likely because our patients were treated with brachytherapy after a high dose of external pelvic radiotherapy in both LDR and HDR patients.

Alabama↗