The Cancer Chronicles by George Johnson

Author:George Johnson [Johnson, George]
Language: eng
Format: epub
ISBN: 978-0-385-34971-0
Publisher: Knopf Doubleday Publishing Group
Published: 2013-08-26T16:00:00+00:00

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.

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