The Cancer Chronicles (23 page)

Some critics thought that extrapolating from miners to suburban neighborhoods was too big a leap. But in recent years the estimates have been supported by more extensive research on households.
The most ambitious study was carried out in
Iowa. The state has the highest average radon levels in the country. Women were chosen as subjects because they were more likely to spend time at home. To qualify they had to have occupied the same house for at least the past two decades. Radon detectors were placed in several locations
in each house and readings were taken over the course of a year. Through questionnaires the researchers estimated the percentage of time the women spent in various rooms or other buildings—or outdoors, where average radon levels were also measured. When the women had been on vacations or business trips it was assumed that they received the average
exposure for the United States. Allowances were made for occupational exposure, smoking (passive included), and other factors. In the end, it was concluded that someone living for fifteen years in a house with an average radon level of 4 picocuries per liter might have an “excess risk” of about 0.5. The age-adjusted
incidence of lung cancer (for smokers and nonsmokers combined) is
about 62 cases per 100,000 men and women per year. All things being equal, that would increase by half to 93 cases—31 more people suffering the horror of what is almost always a fatal condition.

No single study can draw firm conclusions. The sample size is too small. But statisticians have gone on to amalgamate the data, producing what is called a
pooled analysis. It’s tricky work. Research is conducted on different populations according to different methodologies. In combining the numbers these discrepancies must be accounted for.
Three of the analyses—in Europe, North America, and China—found similar results to those derived from the experience with the miners, and most radon researchers now
consider the matter clinched.

But epidemiology is never a closed book. As I was anxiously poring over the radon literature I learned about a controversial hypothesis called
hormesis, which holds that small doses
of radiation are not just harmless but beneficial. We evolved in a world bathed in radiation, the argument goes, and have adapted to all but the most egregious assaults.
A Johns Hopkins researcher recently concluded that levels of radon as high as 6.8 picocuries per liter may actually lower lung cancer risk. While the
alpha particles are causing potentially carcinogenic mutations,
low-level x-ray,
gamma, and
beta radiation may be activating
epigenetic circuitry involved with DNA
repair and
apoptosis and enhancing the
immune response. If that is true then
reducing exposure to the EPA’s recommended action level might actually increase lung
cancer risk. But that remains a maverick view. Considering the evidence on balance, I decided to start keeping a window cracked open when I work downstairs, even on cold days in winter. Just in case it matters.

Not even the radiation from
nuclear blasts, accidental or deliberate, has caused nearly as much cancer as most people think. Fifty workers were killed almost immediately by the estimated 100 million curies unleashed by the calamity at
the
Chernobyl
nuclear power plant in 1986. A huge wave of cancer was expected to follow. But almost two decades later a United Nations study group lowered its estimate of the excess: 4,000 deaths among the 600,000 people (workers, evacuees, and nearby residents) who received the highest exposures, or less than 1 percent. There was
an increase in
thyroid cancer among people exposed as
children, but the
biggest public health problem, the report concluded, has been psychological. “People have developed
a paralyzing fatalism because they think they are at much higher risk than they are, so that leads to things like drug and
alcohol use, and unprotected sex and unemployment,” a researcher told
The New
York Times.
The government of Ukraine
recently opened the Chernobyl site to tourism, and ecologists have found that the absence of humans has turned the area into
a mecca for wildlife.

The nuclear warheads dropped on
Hiroshima and
Nagasaki in 1945
killed at least 150,000 people—either immediately from the impact or within months from injuries and radiation poisoning. Since then scientists have been monitoring the health of approximately 90,000 survivors. They estimate that radiation from the explosions has led to
527 excess deaths from solid cancers
and 103 from
leukemias.

Tsutomu
Yamaguchi survived both blasts. Visiting Hiroshima on a business trip, he was close enough to ground zero to suffer severe burns and a ruptured eardrum. After spending a night in a shelter, he returned home to Nagasaki in time for the second blast. He
died in 2010 at age ninety-three. The cause was
stomach
cancer. It’s impossible to know how big a factor radiation played in the death of the old man, who had outlived so many others. Maybe the crowning blow was a diet of
salted fish.

It was leukemia that killed
Marie
Curie, the discoverer of
radium (radon’s mother), at age sixty-six—“
cancer in a molten, liquid form,” as
Siddhartha Mukherjee memorably called it in
The
Emperor of All Maladies
. When she was exhumed in 1995 for the honor of being
reburied with Pierre in the Panthéon, French officials
worried that her body would be dangerously radioactive. The three black notebooks describing her celebrated experiments are
kept in a lead box at the Bibliothèque Nationale in Paris, and people who want to read them must sign a waiver acknowledging the risk. When her grave was opened her remains were found enclosed in a wooden coffin inside a lead coffin, which was inside another wooden coffin. Emanating from inside was 9.7 picocuries—almost twenty times less than the maximum considered safe for the public by the French government. Madame Curie was only half as hot as the air on that winter day in my
office.

With a half-life measured in centuries, the radium she had absorbed during her career would not have appreciably diminished since her death. France’s
Office de Protection Contre les Rayonnements Ionisants
therefore concluded that it probably wasn’t radium that killed her. A more likely cause of her cancer, they suggested, was the x-ray equipment she and her daughter,
Irène Joliot-Curie, operated as medical volunteers in World War I. Irène, who won a
Nobel Prize for her own work on radioactive elements, also died from leukemia. She was fifty-eight.

For Pierre, death came early, at age forty-six, when he was run over on a Paris street by a horse-drawn carriage. We don’t know what kind of damage radium might have done to his cells. He and Marie had both been
too ill to travel to Stockholm to accept their
Nobel Prize. Whether it was from radiation poisoning or physical exhaustion—extracting a gram of radium from a ton of
pitchblende was like factory work—is unknown. Two years later they made the journey. In his Nobel lecture (also delivered on Marie’s behalf),
Pierre described an experiment he had done on himself: “If one leaves a wooden or cardboard box containing a small glass ampulla with several centigrams of a radium salt in one’s pocket for a few hours, one will feel absolutely nothing. But fifteen days afterwards a redness will appear on the epidermis, and then a sore which will be very difficult to heal. A more prolonged action could lead to paralysis and death.” This destructiveness, he noted, had its uses. Radium was already being used to burn away tumors. So were x-rays, since just after their discovery in 1895. Long before it was established as a cause of
cancer, radiation was used as a cure.

Before
Nancy’s chemo had ended her doctors began discussing the next stage of her
treatment and what kind of particles they should use to irradiate her.
Alpha particles are too massive and damaging to beam directly at the body.
Beta rays, consisting of streams of electrons, are a gentler radiation. The lightweight particles penetrate a little deeper than alphas—it takes a sheet of aluminum to stop them—but they deliver less punch. They are often chosen to treat skin cancers, sparing what lies below. X-rays and
gamma rays have the long reach needed for deeper cancers. Their wavelengths are so tiny that they can pass through many layers of tissue before striking their target. But their fuzzy edges make it harder to avoid harming nearby cells.
Protons, which are 1,800 times heavier than electrons but smaller than alpha particles, can deliver large amounts of energy with less mess.

Instead of beaming rays from outside, oncologists might decide instead on
brachytherapy: small capsules of radioactive isotopes inserted in or near a tumor. For some cancers,
radioisotopes are injected into the bloodstream.
Radioactive iodine, for example, will
concentrate in the thyroid and attack malignancies there.
A
targeted drug called
Alpharadin delivers radium directly to metastatic
bone
cancer cells. Whatever the method, the rationale is the same as with chemotherapy: Rapidly dividing cancer cells will succumb more quickly to the poison than healthy cells, and they will be less able to repair themselves.

Both Nancy’s
surgeon and
oncologist agreed that her left and right groin, where the lymph nodes had bulged with carcinoma, should be treated with beta radiation. In the right groin, the cancer had encroached into the epidermal layers, and beams of electrons would impinge just deep enough to reach any cells that the chemo had missed. The doctors disagreed, however, on whether they should also irradiate her entire pelvis with x-rays. The surgeon thought the risks were unwarranted. Radiation can leave internal scars that cause bowel obstructions and it can hurt other organs. Damage to the
lymphatic system can bring on
lymphedema, an accumulation of lymphatic fluid that can cause chronic swelling of the torso and limbs. Very rarely the mutations induced by radiation will trigger another cancer decades later. There were so many trade-offs to consider.

Certain that he had excised every bit of compromised tissue, the surgeon thought pelvic radiation would be dangerously redundant—that the weeks of chemo followed by superficial beta rays should be insurance enough against escaping metastases. Using more radiation now, when it might not be absolutely necessary, would limit the options if there was a recurrence later on. Both chemo and radiation destroy
bone marrow, weakening the body’s ability to withstand further therapeutic assaults. “Save your bone marrow for future battles,” another doctor advised. Nancy’s oncologist was having none of this. He thought that hubris was clouding the surgeon’s judgment. So aggressive a cancer in so young and healthy a woman called for an extreme counterattack. Forgoing pelvic radiation, he told Nancy, would be gambling with her life. There was no right answer. The experts at MD
Anderson also recommended whole pelvic and that is the course we chose.

Firing rays at cancer cells sounds like a shotgun attack. But the planning and precision is impressive. Medical scanners—
CT,
MRI,
PET—map the tumor and surrounding organs in three dimensions. In aiming the beam, pathways and angles are chosen that avoid the most vulnerable organs. Dosages are calculated meticulously—some organs are more sensitive to
radiation than others and so are some tumors. Treatments are scheduled so smaller doses can be spread over days and weeks, gradually enough for the healthy cells to repair or replace themselves but not so gradually that the cancer regains the upper hand. Computer-guided robot arms can deliver graded doses to different parts of a tumor. To reduce the amount of radiation passing through healthy tissue, beams can be pointed from several directions, each weak in itself, converging to deliver the maximum jolt.

For all the care and calculation, damage is unavoidable—the fatigue, the burning skin, the tingling nerves, the diarrhea. Radiation shines through the bowel, creating a sunburn inside. Bulky food worsens the condition, and Nancy was advised to follow a low-residue diet, avoiding high-fiber foods: whole grain breads, coarse-grained cereals, fresh fruits, raw vegetables, wild or brown rice. Also to be avoided were strongly flavored vegetables—broccoli, brussels sprouts, cauliflower—all these things that under other circumstances are supposed to be good for you. All these foods she loved. Chile and other spicy fare, popcorn—all were forbidden. She grew accustomed instead to the taste of Imodium.

Looking back years later through the big ring binder where she kept the papers from this horrible time, I was struck by a couple of absurdities. Among the research papers weighing the dangers and advantages of pelvic radiation and the waivers acknowledging the near- and long-term side effects was a disclaimer: In preparing the patient for treatment ink marks might be made on the body. Nancy had to sign a release recognizing that the ink might rub off on her clothes. She was also advised to avoid getting pregnant.

During the chemo sessions I could sit with her in the light-filled
lounge with those beautiful mountain views. For the radiation she was taken into a lead-lined room. Alone with the robot deftly swinging its arm and zapping its preprogrammed targets, she felt like she was in sickbay on the Starship
Enterprise
. She would try to visualize the rays killing the
cancer cells and sparing the rest. My strongest memory from that time is the day I drove her to her first treatment. As we approached, she fought back tears. She had been through so much already and I rarely saw her cry. “I can’t believe what they’re doing to my poor body,” she said. And, like so many times, I had to suppress the guilt. I told myself again that her cancer was not known to be estrogen related, that my not wanting to have children was unlikely to be the cause. But who could really know? And what about the stress I had caused her—the blasts of cortisol skewing insulin skewing the metabolic balance? Was there some slight chance—yet to be enshrined in the literature—that radon was a factor? I imagined the gas seeping into pores and orifices. It is part of the curse of being human: this idea that you get cancer because you did something wrong or someone—something—did it to you. For
Nancy no cause was ever identified. The best that could be said was that she was a victim of
randomness. But randomness can be complexity too deep to understand.