Lymphomas such as that which struck Sheriff Sherman Block are generally among the most curable forms of cancer, according to the American Cancer Society. The cure rate can be as high as 80%, depending on the stage at which the cancer is detected.
Overall, half of all lymphoma patients are considered cured, meaning no further evidence of the disease is found for five years or longer. "It's not the best thing in the world to get cancer, but if you have to get something, lymphoma is the way to go," said Dr. Alexandra Levine of USC's Kenneth Norris Jr. Comprehensive Cancer Center, where Block is being treated.
Lymphoma is a cancer of the immune system, specifically the lymph nodes and the lymphocytes, cells that provide protection against invading bacteria. Health experts expect 43,000 cases to be diagnosed in the United States this year and 20,500 deaths to be caused by the disease.
The incidence has been climbing over the past decade because lymphoma is relatively common in AIDS patients and in other people whose immune systems have been suppressed, such as organ transplant recipients.
The incidence is also rising among people over age 65 for reasons that are unclear. Lymphoma is somewhat more common in men than in women.
The most common signs of lymphoma are enlarged lymph nodes, anemia, weight loss and fever. The cancer is diagnosed by removing the swollen lymph node and examining it for cancerous lymphocytes.
Lymphoma can be caused by exposure to radiation or toxic chemicals, particularly herbicides and industrial solvents. It is also caused by viruses, such as the AIDS virus and the human T-cell leukemia/lymphoma virus.
"But for any individual case, we generally don't know the exact cause," said Dr. Cary Presant, an oncologist who is president-elect of the California section of the American Cancer Society.
When the disease is localized--a so-called low-grade lymphoma--the treatment of choice is radiation. Low-grade lymphomas are generally not highly curable, Levine said, but patients often survive for decades because the cancer is slow-growing.
But when the disease has spread to lymph nodes in several areas of the body and is rapidly growing--the high-grade type of lymphoma that Block has--it is generally treated with four to eight anti-cancer drugs given over several days once a month for up to six months.
"High-grade lymphomas can be the most aggressive, but they are also the most curable," said Dr. Robert Figlin of UCLA's Jonsson Comprehensive Cancer Center.
In the most severe cases, especially in younger patients who are better able to tolerate the procedure, bone marrow transplants are performed.
Treatment is generally least effective in patients who have a tremendous mass of cancer cells and in those already debilitated and weak from other ailments.
"Hopefully, those factors should not be true in Block's case," Levine said.
Physicians have also begun using a series of new drugs, most available only within the last year, that minimize the side effects of chemotherapy.
"In the old days, five to 10 years ago, patients would have to stay out of work or in bed" because of the side effects, which range from nausea and vomiting to weakness and an increased susceptibility to infections, Presant said.
"But with improved medicines that control side effects, patients now remain fully active," he said.
The one side effect that physicians cannot yet block, he added, is loss of hair.