When the Air Hits Your Brain: Tales from Neurosurgery (21 page)

In any society, certain individuals choose to ignore the societal constraints and march to their own drummers. Likewise, in our own bodies, rogue cells arise which do not respond to the laws regulating their growth. These aberrant cells divide endlessly, creating dysfunctional masses of tissue which compress
other organs and commandeer nutrients. The cells escape their normal habitats and metastasize to other parts of the body. Like human miscreants, misbehaving cells have little regard for the society in which they live and will destroy it if given the chance. Indeed, cancer evolved for precisely this reason—to destroy the host.

Cells which grow beyond their normally defined limits are neoplastic; neoplastic cells which invade and destroy tissue, or which detach and spread to other parts of the body, are cancerous. While all cancers are neoplasia, not all neoplasias are cancerous. For example, common warts are neoplastic, but not cancerous.

Most of the scourges of aging arise from neoplasia. In addition to cancers, male prostatism, eye cataracts, degenerative arthritis, and atherosclerosis (hardening of the arteries) result from unchecked proliferation of normal tissues. Even dementing brain illnesses, such as Alzheimer’s disease, stem from neoplastic overgrowth of brain cells called astrocytes. As our cellular society grows senescent, neoplastic behavior becomes rampant until our bodies fall, like ancient Rome, into anarchy and ruin. Ubiquitous in the elderly, neoplasia is more a form of planned obsolescence than a disease.

To understand cancer’s role in evolution, we must remember that we are built to die. Just as automobiles roll off the assembly line with a predetermined lifespan, the fertilized ovum programs us to decay and perish in an immutable sequence.

The long-term viability of multicellular creatures on this planet demands that each generation enjoy its finite day in the sun and then be thrown from life’s stage to make way for a new cast of players. A continuous turnover of organisms, with mixing and mutations of genes occurring in each new generation, gives life flexibility to survive a wide range of climate shifts. There is
no biological reason why we could not be immortal. Indeed, we form the tail end of an unbroken chain of protoplasm, five billion years long. However, immortal species would have to stop replicating, else they would smother themselves.

Nature chose not to populate the earth with static, immortal species. To do so would place all of life’s genetic eggs in one basket, running the very real risk that some drastic geological event could wipe out all life on earth. To prevent this, the gene pool must be in constant flux, changing at a rate fast enough to keep pace with any environmental perturbations that might arise. Thus, all things must die. Death is not a flaw, a failure of biology, but an essential design feature for constant existence on an inconstant earth. Our downward spiral from youth to old age, like the upward spiral from fertilized ovum to developed infant, is stamped into our genetic code.

The wheel of life: one generation rises like summer wheat, then withers and falls to seed. The wheel turns—birth, youth, adulthood, parenthood, senescence, death—driven by genetic machinery set in motion so many eons ago. For all its subtleties and infinite beauty, life has but one purpose: to keep the wheel turning. Turning without the least regard for individuals, species, or ecosystems. The destination of the living wheel as it travels through geological time is unknown, perhaps not even important to us. Yes, each generation grows infinitesimally better than the one before it, but better at just a single thing: keeping the wheel moving. The vibrant colors of a bird’s plumage, the complexity of a spider’s web, the grace of a hunting lioness—all are variations on the single theme of birth, procreation, and death. Adapt, be ready, survive.

For those lucky enough to escape death by predators or accidents, neoplasia in one of its many forms—cancer, dementia, heart attack—will come, a message that all individuals, no
matter how worthy they may seem, must give way to the next generation. Regardless of how cautiously we live, our arteries will eventually clog with hardened tissue, our minds grow weak from excessive brain astrocytes, our eyes dim from corneal overgrowths, our organs fill with malignant growths. This is as it should be. Biology doesn’t consider these diseases enemies, just as General Motors does not consider rust a flaw. Decay is a necessary process for any business dealing in renewable goods.

We cannot accept our personal dispensability in this scheme. Cancer may be a threat to us individually, but poses no threat to our species. The vast majority of those afflicted by neoplasia are far beyond child-bearing, or even child-rearing, age. Moreover, cancer is a uniquely human affliction. Animals in the wild rarely survive long enough to suffer the neoplastic illnesses of senescence. The same was true of
homo sapiens
prior to the advent of civilization. A death at eighty from colon cancer would have been a worthy goal for cavemen daily pitted against mammoths and saber-toothed tigers.

Scientists and spiritualists who insist that our bodies harbor some hidden potential to conquer all cancers ignore the trivial effect cancer exerts on our species. Nature does not care if I get cancer, since the wheel of humanity will turn just fine without me. Biology could have easily endowed me with a foolproof method of defeating cancer. And a tire company could make a tire that lasts for a million miles. The awful truth is that neither nature nor a tire company has any motivation to provide unreasonable longevity.

So Sakren, in essence, was right. Whatever entity, divine or earthly, deposits malignant brain tumors into our heads does so not to test our resolve, to challenge our faith, or to prove our strength, but to make us die. This does not mean that we should not use our intellects to prevent this fate when we can.
Such is the very business of the medical arts. Nature discards individuals; surgeons do not. Let nature worry about the species; we must care for individuals one at a time.

At this moment, the individual in question (individual plus one-quarter?) was Sarah Clarke. Her biopsy confirmed the presence of a malignant mixed glioma, a small lump of cancerous cells that were to become grains of sand binding up the gears of Sarah’s reason. Over time, her mind’s clockwork would slowly grind to a halt. Would she let us throw our backs into her wheel of life and push it further along? Would she let us try to extend her life?

“No way.”
Linda, the university’s chief radiation physicist, shook her head vehemently. We were discussing Sarah. “I’ve done some preliminary calculations and, even with the most coned-down fields and maximal shielding, the scattered dose to the fetus is unacceptable. Third trimester, maybe, but even then there is the liability issue. There is no way we can deliver any meaningful amount of radiotherapy to this tumor unless the pregnancy is terminated. Period.”

“What liability problem is there in treating her in the third trimester?” I asked. “I would think that a fully formed child should be able to tolerate the small amount of radiation that would leak through the abdominal shielding.”

“Medically, none. There really isn’t even that substantial a risk in the first trimester, either, but try and tell that to a jury. There have been some goofy cases which have produced milliondollar malpractice awards. In Texas, a child is born without a leg and the mother’s lawyer successfully argues that an inadvertent occupational exposure to radiation in the ninth month was responsible. You don’t have to be too sophisticated in embryology to know that the legs are fully formed in the ninth month
of pregnancy and that whatever caused this child to be born with only one leg must have occurred in the first trimester or in the fertilized ovum itself. Yet they bring this little crippled child into the courtroom, sit her in the arms of her crying mother while some expert waves his arms and says that magic word ‘radiation,’ and the jury gives the kid seven million dollars. Add in the fact that the statute of limitations in children doesn’t run out until they are over eighteen, and our department will assume responsibility for the baby Clarke forever if we treat this woman. If the baby doesn’t get accepted into the college of its choice, it can come back and sue us for brain damage. No thanks. If the patient aborts, we’ll do it. Otherwise, forget it.”

Sakren ran his fingers through his thinning hair. “Goddamned lawyers.” A phrase repeated almost daily by neurosurgeons across the country. Lawyers have pretty much determined when we should scan people, when we should operate upon them, and how much better we should make them. To believe that legal issues don’t alter the practice of medicine is to know nothing about the practice of medicine in the late twentieth century.

The radiation risk to Sarah’s fetus derived as much from the fear of litigation as from tumor biology. Because a fetus is a blank slate, almost any jury award can be conjured up for a pregnancy gone bad. Sarah’s unborn child represented a financial burden that no one wished to bear.

Sakren approached the Clarkes about the refusal of the radiation oncologists to give Sarah radiotherapy. “With radiation therapy, you have maybe a one in ten chance of living five years or longer. Not great, but people waste hundreds of dollars a year on much longer odds in the state lottery. Without it, on the other hand, the median survival is only about three to five months, which means you have a ‘50 percent or greater chance
of not carrying the baby to term. I recommend a therapeutic abortion be performed and radiation therapy commenced immediately thereafter.”

Sarah’s face became serene granite. “I am not a statistic, doctor. I’m not interested in odds. I will not abort my baby.”

Sakren’s irritation grew. The surgeon turned to her husband. “For God’s sake, man, talk to her. If she was my wife, I know what decision I would urge her to make. I wouldn’t want to lose her.”

James Clarke was unmoved. “Don’t talk to us about what we should do or not do ‘for God’s sake.’ My wife has made her decision. She’s in the Savior’s hands, not yours.”

“The Savior’s hands didn’t do this”—Sakren laid his finger on the small wound on Sarah’s left temple—“mine did. And I’m telling you that she needs to have some therapy if she is to have any chance at all of surviving the next six months! I’ve been in this business for twelve years, and I haven’t seen Jesus come and lift one of these things out of a head yet.”

“Doctor,” Sarah said calmly, “we’re telling you that I will not have an abortion. What Jesus does to my head is not important, but what I do to my child is. So you might as well send me home now. I’ll have no further therapy.”

Sakren frowned. “Frank, get a serum phenobarbital level on Mrs. Clarke today and discharge her on a Decadron taper. If she’s forgoing therapy and wants to save her baby, we might as well get her off the steroids, too. Have her come back in one week to have her sutures removed. To residents’ clinic.”

“Residents’ clinic?” I asked.

“Yes, residents’ clinic. There is nothing more I can offer her now.” Residents’ clinic was the dumping ground of patients the staff surgeons no longer wished to follow in their private offices. Although technically overseen by the attendings, the care was relegated to residents.

“But…”

“Residents’ clinic is fine with us,” James said.

Sakren hustled from the room. I cast an embarrassed look at the Clarkes. “He’s a little high-strung, I guess.”

“Don’t make excuses for the man, son,” James admonished me. “He has his views, we have ours.”

“Do you want to die, Mrs. Clarke?”

“No, I want to have this child.” The tears welled in her eyes, the first I had seen. “When you first came in,” she continued after a pause, “you said these tumors could be either pretty good or very, very bad. Where does a malignant mixed glioma fit in?”

“Somewhere in between.”

“How much in between?”

“Well…drop one ‘very’ in the ‘very, very bad’ category.”

“Fair enough. Fair enough.”

Two days after her biopsy, Sarah went home. The race was on. Which would grow faster, fetus or glioma?

Cancers and embryos
are kindred spirits, both composed of highly mobile cells dividing at full throttle. A fertilized ovum changes from a single cell to a miniature human body in a matter of weeks. During this period of high-speed construction, cells migrate freely from one region of the embryo to another as complex organs are assembled from amorphous cell clusters. The ability of cancerous cells to metastasize to distant sites is a throwback to the migratory properties of embryonic cells.

The similarity of cancer cells to embryonic cells goes deeper than a simple capacity to migrate. Proteins and hormones produced in fetal tissues suddenly reappear in cancerous tissues of adults. Carcinoembryonic antigen, a protein normally present only in fetal colons, resurfaces in adult colon cancers; a serum test for this protein allows early detection of the disease. Mechanistically,
cancer results not from the degeneration of adult tissues into decrepit forms but from their regression into juvenile forms.

Cancer cells relive the heyday of their fetal youths, chucking the staid responsibilities of mature tissues and reverting to the time when they could grow and travel as they pleased. In this way, cancer reflects a symmetry of life. From dust we came and to dust we shall return. The cancer patient ends life as she began it: an amorphous mass of nomadic cells.

While adult tumors arise from differentiated cells lapsing retrograde into prenatal behavior, pediatric tumors arise from islands of embryonic tissue which never matured in the first place. These ‘“Peter Pan” cells won’t grow up, acting like embryonic tissue even after birth. Rebecca’s PNET was one example of a Peter Pan tumor. Composed of refractory fetal-nerve cells, the PNET endlessly tries to build a new cerebellum—ignorant of the fact that the job has already been completed. The child with a PNET is literally born with brain cancer. The fetal nature of these tumors explains why they are so refractory to treatment. Fetal cells have a mission: to create a child. Their drive to complete this mission is so strong that only killing the patient will stop them. The wheel must turn.