External beam radiotherapy in the management of locally invasive carcinoma of the thyroid

External beam radiotherapy in the management of locally invasive carcinoma of the thyroid

rad/hr. It has been suggested increasing dose-rate the biological I suggest that mental and artefacts. IOW-LET dose-rate, Cf-252, nent, becau...

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rad/hr.

It has been suggested

increasing

dose-rate

the biological

I suggest that mental and

artefacts.

IOW-LET

dose-rate, Cf-252, nent,

because

effect

increases

OER values In addition,

radiations,

or (ii) or (iii)

that

OER of Cf-252

the contribution with

for Cf-252,

both at their

of the neutron

respective

component

neutrons

behave

of about

1.6,

than

of the gamma-ray which

of Cf-252

interaction

component

with

of Cf-252

to

dose-rates,

fission

spectrum

1.7,

relative

to 1.8

high-

independent

and gamma-rays

to its gamma-ray

of of

compo-

1 0 I also suggest that the OER

which

neutrons, neutrons

1.7

neutrons

may be less than

may be about

are experi-

based on OER of mixed

is about

betieen

of Cf-252

cyclotron-produced like

increasing

are too far from 1.7 to 1.8,

of OER of Cf-252,

component

of Cf-252

more like

rather

(i) OER

is a synergistic

RBE of the neutron

dependent,

dose-rate.

an analysis

indicates:

there

is dose-rate

which

would

indicate

supposedly

for which

that

Cf-252

have an OER

the OER is supposedly

beiween 1.3 and l-5. Each of the possibilities, biology

(215)

which

my analysis

suggests,

has great

significance

in radio-

and radiotherapy.

EXTERNAL BEAM RADIOTHERAPY IN THE MANAGEMENT OF LOCALLY INVASIVE CARCINOMA OF THE THYROID John R. McDay, M.D. and Barbara F. Danoff, M.D. Department of Radiation Therapy, Thomas Jefferson University Hospital, Philadelphia, PA 19107

Between 1956 and 1976 36 patients completed a course of external beam radiotherapy for carcinoma of the thyroid. All patients had either incomplete surgical resection or biopsy proven recurrence without evidence of distant metastatic disease. Eight patients were treated post-operatively for microscopic residual disease and ten patients were treated for macroscopic residual. Eight patients received radiotherapy for inoperable disease and ten Histologically, 23 patients were patients were treated for local recurrence. found to have differentiated carcinoma (papillary, follicular, medullary), while 13 had anaplastic carcinoma. All patients received radiotherapy to the thyroid region, cervical Thirty-five patients received supervoltage lymph nodes and upper mediastinum. and one patient was treated with orthovoltage therapy. Tumor doses ranged from 4300-6700 rads (median, 5800 rads) to the thyroid region. Radioactive I-131 was administered for thyroid ablation before external beam therapy in four patients with microscopic residual disease and one patient Four patients with recurrent disease had with macroscopic residual disease. ablation with I-131 as either part of their initial post-surgical management or as a diagnostic/ablative procedure prior to external beam. Patients with differentiated tumors and microscopic residual had a fiveyear survival of 100% and a lo-year survival of 66%. Local control was achieved in all. Patients with differentiated tumors and macroscopic residual or inoperable disease had a five-year survival of 50% and a ten-year survival of 43%. There was 60% local control achieved in this group. Patients with

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recurrent disease had a five and ten year survival of 50% with a 43% local control rate. Only one of 13 patients with anaplastic carcinoma survived Five patients experienced local control. five years. In cases of differentiated thyroid carcinoma with incomplete surgery or recurrence, radiotherapy can produce long-term survival and local control.

(216) EXTRANODAL

RADIATION THERAPY TREATMENT OF NON-HODGKIN'S LYMPHOMA OF THE HEAD AND NECK

W. B. Mill, M.D.*, F. A. Lee, M.D.*, K. 0. Franssila, M.D.** *Division of Radiation Oncology, Mallinckrodt Institute of Radiology Washington University, School of Medicine, St. Louis, Missouri 63108 **Department of Pathology, University of Helsinki, Finland

This study is based on a retrospective review of the records of 91 patients referred for radiation treatment. The histologic specimens have been reviewed in the 78 cases in which they were available. The cell type was

changed on review in five cases. One case was initially diagnosed as Hodgkin's disease. Seventy-five of the patients presented with stage I or II These are analyzed in regard to size disease (Ann Arbor Classification). of primary lesion , influence of regional lymph node involvement, value of lymphangiography in staging, sites of presentation, dose-response, and sites of failure. There were 33 failures in the 75 patients presenting with stages I and

II.

Twenty-four

of these (72%) occurred in distant sites.

Four

of the five patients presenting with localized brain involvement failed in the primary site. There were 20 failures in 42 patients presenting with involvement of Waldeyer's ring with or without regional node involvement. Seventeen of these (85%) were in distant sites. We have concluded that the addi-

tion of chemotherapy to radiation treatment should be studied in stages I and II.

(217)

LOCALIZED CURRENT FIELD HEATING AS AN ADJUNCT TO RADIATION THERAPY R.C. Miller, M.D., W.G. Connor, Ph.D.,D.H. McKelvie, D.V.M., Ph.D. and H.B. Roth, M.S. Department of Radiology University of Arizona Health Sciences Center, Tucson, Arizona

Localized current fields (LCF) have been used to produce localized hyperthermia for treating spontaneously occurring tumors in domestic animals. A pilot study was initiated in order to refine LCF techniques for producing local hyperthermia and to establish a reasonable dose regime for testing hyperthermia as an adjunct to radiation therapy in a randomized trial. To date, over thirty cats, dogs and horses have been treated. There have been

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