Biomedical subjects

S L Hancock

Publications and source records attributed to S L Hancock.

39 records · Page 3Linked to original sources

PubMed1986

Anterior eye protection with orbital neoplasia.

The administration of adequate doses of radiation to tumors involving the orbit and surrounding facial structures and sinuses is often complicated by the need to protect the sensitive ocular components, the lens and cornea. A technique has been devised that uses four photon beam fields and an optional electron field to treat the contents of both orbits and adjacent sinuses with effective, reproducible protection of cornea and lens. Essential features include: alignment of the corneal surfaces with the central plane of rotation of the treatment machine, use of a narrow eye block across the entire beam to shield a strip equal to the width of the cornea, positioned symmetrically across the central plane of rotation, fine alignment of the eye block with both corneal surfaces by altering pedestal angle, treatment with paired, wedged, anterior oblique fields to encompass desired orbital and sinus volumes with additional blocking placed as needed, and complementary, lateral strip fields using collimators set to eye block thickness to equalize dose in the posterior orbit shielded by the strip eye block. A similar anterior electron beam strip field may be added to boost the medial orbit and ethmoid regions covered by the eye block. Bite block head immobilization and easy, direct daily visualization of block position assures eye protection for each treatment and provides substantial reduction in dose to the cornea, lens and iris. Additional blocking may be incorporated to provide partial lacrimal and parotid sparing.

Cornea↗

PubMed1984

Radiation therapy of esophageal cancer.

Radiation therapy has been used extensively in the management of patients with cancer of the esophagus. It has demonstrated an ability to cure a small minority of patients. Cure is likely to be limited to patients who have lesions less than 5 cm in length and have minimal, if any, involvement of lymph nodes. Esophagectomy is likely to cure a similar, small percentage of patients with the same presentation of minimal disease but has a substantial acute postoperative mortality rate and greater morbidity than irradiation. Combining surgery and either preoperative or postoperative irradiation may cure a small percentage of patients beyond the number cured with either modality alone. Radiation has demonstrated benefit as an adjuvant to surgery following the resection of minimal disease. However, radiation alone has never been compared directly with surgery for the highly select, minimal lesions managed by surgery. Radiation provides good palliation of dysphagia in the majority of patients, and roughly one third may have adequate swallowing for the duration of their illness when "radical" doses have been employed. Surgical bypass procedures have greater acute morbidity but appear to provide more reliable, prolonged palliation of dysphagia. They constitute the best approach for patients with persistent or recurrent dysphagia following esophageal irradiation. Several approaches to improving the efficacy of irradiation are currently under investigation. Fewer large fractions appear to be equivalent to conventionally fractionated radiotherapy in terms of local control and survival but produce more prompt palliation and shorten courses of palliative therapy. Multiple-daily-fractionation schedules and hyperfractionation have theoretical appeal and clear basis for investigation from the early suggestions of improved response rates in advanced squamous-cell cancer of the head and neck. Hypoxic-cell radiosensitizers, neutron-beam, and helium-ion therapy results have not been overly encouraging in esophageal cancer, thus far. However, the new generation of particle beams and the new radiation-sensitizer drugs require further evaluation. Better means of dealing with the high incidence of disseminated disease are clearly needed. It is clear that combined-modality approaches using both local and systemic therapy will ultimately be desirable in esophageal-cancer treatment.(ABSTRACT TRUNCATED AT 400 WORDS)

Brachytherapy↗

PubMedDate not supplied

The Janeway lecture. Hodgkin's disease--finding the balance between cure and late effects.

PURPOSE: The purpose of this review is to summarize the Stanford experience in Hodgkin's disease, the late effects of treatment, and strategies to improve management to maximize cure and decrease late effects in these patients. PATIENTS AND METHODS: Between 1960 and 1999, 2617 consecutive patients with Hodgkin's disease have been seen, treated, and rigorously followed at Stanford. This population includes patients of all ages and stages of disease. The database summarizing this experience serves as the source of survival and mortality data over 4 decades. Two thousand two hundred thirty-two of the population comprise the group evaluated for secondary cardiac disease. Two thousand one hundred sixty-two patients have been evaluated for risk of secondary leukemia, non-Hodgkin's lymphoma, and solid tumors. Eight hundred eighty-five women were evaluated for secondary breast cancer, prompting a subsequent analysis of risk of secondary cancer among 694 pediatric patients. RESULTS: The probability of cure of Hodgkin's disease has dramatically improved over the past 40 years. Today, 94% of patients are expected to survive. Among those who do not survive, approximately half die of Hodgkin's disease, 20% of new cancers, and 14% of cardiovascular complications. Modifications in patient management and treatment have greatly reduced the serious late effects observed from prior therapy. With current combined-modality therapy using moderate doses of involved field of radiation and limited cycles of multiagent, risk adapted chemotherapy, serious cardiac complications and development of secondary cancers are expected to be greatly reduced. The Stanford 25-year pediatric Hodgkin's disease experience reveals that survival in favorable early-stage disease exceeds 95%. Newer protocols for children with advanced-stage disease continue to show these excellent survival rates and promise less late morbidity. Adult protocols using the risk-adapted Stanford V combined-modality program now parallel the pediatric experience, with greater than 90% survival in these patients. DISCUSSION: Thus today the likelihood of cure of Hodgkin's disease greatly exceeds the risk of late effects, a goal both Dr. Henry Janeway and Madame Marie Curie emphasized and taught from first-hand experience.

Breast Neoplasms↗