Cracking the Cancer Code: An interview with
Dr. Kenneth Offit, Chief of the Clinical Genetics Service
For years,
science has understood that certain cancers can be inherited, winding their
way through a family like an ominous thread. Now, thanks to recent
breakthroughs in human genetics, doctors like Kenneth Offit, chief of
Memorial Sloan-Kettering Cancer Center's Clinical Genetics Service, are
using this information to help high-risk individuals detect cancers early,
before they appear, and in some cases to prevent them altogether.
"As
we learned of the genetic basis of cancer through the late 1980s," Dr. Offit
remembers, "Suddenly cancer moved from this sort of black box -- where you
gave cancer-causing substances to animals and cancers appeared as a result
of what we thought were environmental agents -- to a
fundamental understanding of what those agents did at the level of
the genome."
Not all cancers are hereditary, but genetic defects are
at work even in non-inherited cancers. A mutation
causing uncontrolled cell growth can occur at any point in one's lifetime,
either spontaneously, when a mistake is made during cell division, or as a
result of exposure to a toxic substance.
As a result of the new
discoveries and the new information they provided, the Clinical Genetics
Service at Memorial Sloan-Kettering was created, offering genetic
counseling, testing, and education for individuals with high risks
of hereditary cancers.
The service has gone from seeing a few
dozen cases in 1993 to today's caseload of well over a thousand cases a year.
The counseling and genetic testing services provided by MSKCC's Clinical
Genetics Service are typically recommended for individuals with family
histories marked by multiple cases of cancer or cancer diagnosed at unusually
young ages.
Prevention genetics entails testing people before they
have any sign of the disease, then, if necessary, taking appropriate
measures, such as changes in diet, lifestyle and screening schedules, or
preventive surgery. Diagnostic genetics can indicate the earliest
stages of certain common cancers, when doctors can most effectively
intervene. And predictive genetics can provide valuable information
about the course a cancer will probably take, information that in turn can
help to guide potential therapies.
"It's important to note that
information about heredity and family history may or may not include genetic
testing," Dr. Offit clarifies. "You can come in and get a lot
of information without a genetic test. And in many cases a genetic test is
something we wouldn't necessarily recommend."
In the end, the service
enables individuals to understand their risk, and armed with this
understanding, make informed decisions. Naturally, questions and concerns
about the potential benefits and dangers of this powerful new
resource will be raised. Common concerns, including fear
of employment or insurance discrimination, are discussed in the counseling
session and an individual's confidentiality is always protected.
"Ultimately," Offit concludes, "we talk about what can be done
medically and surgically to prevent or detect cancers at their earliest, most
curable stages. And the part that is most exciting is that we can
actually intervene in these families and hopefully we can change the natural
history -- which is our way of saying save lives."
