Mathematical formulas tell physician about cancer
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COMPUTING THE
ODDS — Dr. Edwin B.
Cox uses some old
formulas and some
new calculations of his
own to predict when
some cancer patients
will be cured. (Photo by
William Erwin)
(Continued from page 7)
through a blood vessel, causing internal
bleeding.
Like tumor growth, the action of many
anticancer drugs is also predictable, Cox
said. So called "alkylating agents" such as
nitrogen mustard kill the same
percentage of cancer cells per dose.
"If we treat a myeloma patient with a
typical dose of Alkeran (a drug) for four
days," he said, "we would kill about 50 per
cent of his cancer cells."
Each subsequent four-dose treatment
would likewise kill half the cancer cells
left, he added.
The hardest part
The hardest part of predicting time
until cure, Cox said, is measuring the
extent of cancer in a patient;
Doctors can measure a tumor's size
directly. Calipers can be used to measure
surface tumors. For deeper-lying tumors,
size can be judged on conventional X-ray
pictures, on ultrasound pictures made by
bouncing sound waves off body
structures, or on "CAT" scans producing
cross-sectional X-rays of the body.
Many tumors, however, don't look
regular on such pictures. A doctor often
has trouble, seeing where the tumor ends
and normal tissue begins.
Looking for 'markers'
A more accurate measurement
technique looks for cancer "markers" in
the patient's body fluids, such as blood
and urine. These markers are substances
Radiologists gather to improve diagnoses
Sixty radiologists from throughout the
United States and Canada came to
Durham this week to improve their
ability to diagnose cancer.
They have been participating in an
intensive five-day tutorial course
sponsored by the Department of
Radiology, being held at the downtown
Ramada Inn and ending today.
Dr. Robert McLelland, associate
professor of radiology, said 12 members
of the department and three guest faculty
have offered individualized instruction
that goes far beyond the traditional
lecture format.
Two new tools
In addition to conventional X ray
diagnosis, the course has covered
computerized tomography (CT) and
ultrasound scanning, two of the newest
tools in the radiologist's arsenal,
McLelland said.
"The two techniques are complimenta
ry methods of locating tumors," the
physician said. "It's important to know
the advantages and disadvantages of
each, and when they should be used."
Computerized tomography scanners
are devices that take multiple X rays of
the head or the body and then
electronically feed the information
received into a computer, he explained.
The computer converts the information
into clear, composite pictures that show
the size and location of certain tumors.
Sound waves produce images
Mci.elland said ultrasound scanning
works on the same basic principle as
sonar, the apparatus that allows ships to
find submarines under water.
"High frequency sound waves pass
through the body, and the patterns of
sound form images of organs and
tumors," he said.
CT scanners can be operated by
technicians, but they cost over a half
million dollars each, and hospitals have to
charge significantly more for these tests.
Ultrasound machines cost only about a
tenth as much as CT scanners and are
believed to have none of the harmful
effects of repeated exposure to X rays.
Compared with CT, however, ultrasound
requires more technical expertise to
obtain diagnostic images.
Course faculty
McLelland said Dr. Charles E. Putman,
professor and chairman of radiology at
Duke, is heading the course. Guest
faculty are Drs. Gerald D. Dodd, director
of diagnostic radiology at M.D. Anderson
Hospital in Houston; Kenneth R.
Maraville, chief of computerized
tomography at Southwestern Medical
School in Dallas; and Guy D. Potter,
professor of radiology at Columbia
University in New York.
Medical center faculty, in addition to
Putman and McLelland, are Drs. John A.
Gehweiler, Richard Daffner, Salutario
Martinez, Herman Grossman, Frederick
M. Kelvin, Reed P. Rice, Terrence A.
Oddson, William Thompson, Robert A.
Older and James C. Reed.
secreted by cancer cells. The more
markers a person has, the more cancer.
"The development of new tumor
markers will be the keystone for this
formula," Cox said. Such markers already
exist for medullary cancer of the thyroid,
choriocarcinoma (a cancer beginning in
the uterus) and recurrent breast cancer.
The marker for recurrent breast cancer
was rejwrted only last year by another
Duke cancer researcher. Dr. Darrow E.
Haagensen Jr. and colleagues.
One quirk of cancer could limit the
method's usefulness, Cox said. A type of
cancer cell that initially succumbs to
treatment can change into a more
aggressive form that resists the same
type of treatment. If this happens, it
would throw off a doctor's predictions
based on the formulas.
Thompson named
service chief
Dr. Ervin M. Thompson, an associate in
the Department of Psychiatry, has been
named chief of the hospital's Psychiatric
Inpatient Service, effective July 1.
His appointment was announced by Dr.
H. Keith H. Brodie, chairman of the
Department of Psychiatry, and Dr.
Frederick R. Hine, head of the Division of
Inpatient Psychiatry.
Thompson, 32, will have overall
responsibility for operation of the service
and for developing new programs.
He is a native of Mobile, Ala., and a
graduate of Yale University and
Vanderbilt Medical School. He completed
an internship at Presbyterian-St. Lukes
Hospital in Chicago in 1973 and his
residency in psychiatry at Duke in 1977.
Before being named to the Duke
faculty last year, he was chief resident in
psychiatry.
On tour today
Eighteen high school seniors from
Person County High School in Roxboro
are touring the medical center today. The
students are members of a health
occupations class and are accompanied by
their teacher, Brenda Long.
Intercom
is published weekly by the Office of Public
Relations, Duke University Medical
Center, Box 3354, Durham, N.C. 27710.
Ice Sigler
Director
John Becton
Editor
Primary contributors; William Erwin,
Comprehensive Cancer Center medical
writer; Ina Fried, staff writer; Parker
Herring, public relations assistant; Edith
Roberts, staff writer; David Williamson,
medical writer.
Circulation: Ann Kittrell.
Med show has
$acred theme
The event which is reputed in some
circles to be "the highlight of the
medical center social calendar" has
been scheduled for April 22.
The house lights will be dimmed and
the stage lights will come up at 8 p.m.,
as the annual MedicalStudent-Faculty
Show fills Card Gym with the sounds
of music and the taste of cold
beverages. The doors will open about
an hour before show time.
This year's production is entitled
"What We Hold Most Sacred."
Tickets, good for admission and
unlimited quantities of beer (and
possibly Coca Cola, too), will be on sale
starting next week outside the hospital
cafeteria and in the House Staff
Office.
It has been announced that inside
knowledge of the internal structure of
the medical center is not a prerequisite
to enjoying the show.
. • • \
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LAST YEAR'S Medical Student-Faculty Show wa» a knock-out. This year's production will be
presented April 22 in Card Gym. (Photo by John Becton)