by Elyse M. Rogers
CHEMOTHERAPY, CANCER AND INFECTION
I had the privilege of attending the 14th International Congress of Chemotherapy (ICC) in Kyoto last June. The Kyoto Conference Center is a super convention site with its multiple halls, many meeting rooms, restaurants and adjacent exhibition center And, if the scientific meetings wear down your brain a bit, you can step outside, sit on a bench overlooking tranquil Lake Takanaika or stroll through the lavish gardens, complete with a Tea House.
The hall contains lots of open space to serve the 6,000 participants who attended the ICC and, perhaps best of all, lots of couches or benches along (he long halls or in small nooks and crannies for a stimulating discussion on what’s new in the science of chemotherapy, or just a relaxing chat with friends and colleagues from around the world.
Just to prove that the world is indeed a small place, and that medical writers have their share of coincidences just like normal folk, I bumped into a good Stateside friend at the congress, Jean McCann. Jean has her own company, Medical News Inc., and they put out the Oncology Times and cover medical congresses for the Physicians Radio Network, among other things.
Although I was surprised to see Jean, I shouldn’t have been —she travels more than most travel writers! At any rate, it was a grand reunion and we had too few, but still delightful, moments to sit in the comfortable chairs, watch the people in action and chat.
There are many exciting formalities all any big congress and international medical meetings are no exception. The opening ceremony is impressive in any country, but in Japan it was spectacular. (Our Japanese friends have a special touch with such ceremonies, don’t they?) And to share the special flavor of Japan, there were banquets with tempura and sushi, kimono-clad women playing the koto in the exhibition hall, and even sensu (fans) for sale as souvenirs in the conference center’s gift shop.
In addition, of course, there were the less formal aspects that give delightful cultural insight. I loved the large English sign in the lobby that pointed the way to “Coffee — free charge.”
But, nice as the formalities may be, what brings everyone to the congress is the science. And that it most exciting. Although there were not any “major new breakthroughs” this year at the congress, there were many new drugs and techniques being refined. I asked some of my physician friends to point out the more significant seminars, workshops and presentations, as I’m not expert enough in that field to be on the “inside.” Armed with that information, I would often be in “standing room only” presentations.
Take my word for it, hearing first-line information about new drugs or treatments that might cure thousands of people with lung cancer, or fight infections that are still claiming young heart disease victims can give you chills down th spine. And you just hope and pray that, after all the refinement and testing, it turns out to be as promising as it sounds.
Chemotherapy is probably best known in relationship to cancer treatment, but it means much more than that. It’s easier to understand if the word is broken down into it’s two parts—chemo and therapy. Chemo means chemical, and therapy refers to treatment. So, any treatment of disease by chemical agents is considered chemotherapy.
Generally in medicine it is restricted to therapy with those drugs that work directly on the disease-causing organism without hurting the patient.
Two major categories: The two major categories of chemotherapeutic drugs are antimicrobials and cancer drug (“Antibiotic” is the term more commonly known but “antimicrobial” is actually the more correct term as it includes both the natural and synthetic compound “which either kill or stop the growth of micro-organisms.”)
To get a feel for the interest in the two categories, of the 141 scientific sessions. 42 dealt with cancer drugs and the remainder with antibiotics. It might seem surprising that antibiotics are still so much in the limelight, since curing infections such as pneumonia is taken for granted in this jet age. However, antibiotics remain important because infections are still a major problem.
Antibiotics have come a long way since Sir Alexander Fleming discovered in 1929 that bacteria were destroyed by penicillin. It was an accidental discovery. On a forgotten plate of laboratory nutrient that was almost discarded. Fleming noticed that mold had developed and that the mold had created a bacteria-free ring around itself.
However, although antibiotics were (and continue to be) a “miracle” breakthrough in medicine, there are problems. As scientists develop more and better antibiotics, the disease micro-organisms modify or change to resist those antibiotics. Bacteria are amazingly tricky and determined to stay alive. For instance, some bacteria give off toxins which repel the antibiotic, and some gram-negative disease organisms produce beta-lactamase enzymes that destroy the beta-lactam linkage of the antibiotic (which is the way in which many antibiotics ultimately kill bacteria).
New and stronger beta-lactam antibiotics have been developed and are being researched. And other ways of destroying disease bacteria are under investigation.
Currently, many new refinements have been or are being made on old antibiotics and the search is on for new and better compounds. I think it’s fascinating that the cephalosporins (one of the newer categories of antibiotics) were discovered in soil near a sewer outlet in Sardinia, and more recently, Squibb Corporation scientists discovered a new antibiotic they now call Aztreonam, in mud on the banks of the Wading River in New Jersey.
New screening techniques are allowing scientists to sift through numerous samples of soil from all over the globe to determine if they contain bacteria with antibiotic potential.
Cancer drugs: Probably the anti-cancer drugs are of the most interest to the general population because somehow cancer is more “dreaded” than even a stubborn infection. And cancer strikes many of us and our families — one out of four people will get some type of cancer.
The problems of designing effective chemotherapy agents for cancer are many, but the two main goals are clear: To make drugs that are more selective and have fewer side effects.
1. Selectivity. Making the anti-cancer drug more cell selective is the ultimate goal. For example, a drug that would only kill ovarian cancer cells and not any other cell of the body would obviously be ideal for treating patients with cancer of the ovaries since it could be administered safely and cure completely. Unfortunately, such ideal selectivity is still an unreached goal.
However, scientists have been successful in making drugs more selective, or in combining two or more anti-tumor agents in order to kill the most cancer cells without injuring normal healthy tissues.
Other ways to improve the specific effectiveness of antitumor drugs arc also under investigation. For example, in breast cancer, by combining a cancer drug with a hormone that has an affinity for breast cancer tumors, the potency and selectivity are enhanced and the cure rale increased. Or in some cancers, by lowering the blood pressure inside the tumor, better drug penetration into the tumor is possible which leads to a more complete destruction of the cancer cells.
2. Reducing side effects. Unfortunately, until we find drugs with ultimate selectivity there will be side effects. For instance, some normal body cells are especially susceptible to the drugs that are potent enough to kill cancer cells — particularly the hair roots and the GI gastric-intestinal epithelia. That’s why so many people who undergo chemotherapy treatment for cancer lose their hair and often have persistent nausea and/or vomiting.
Cyclic drug therapy (giving the drug for a short time and then having a rest period) used to be the only way side effects could be reduced; however, new research is showing that drugs can be refined to deliver fewer side effects to normal cells while still killing or retarding the growth of cancer cells. Or, by a combination of drugs, side effects can be reduced or almost eliminated so that the patient “feels better” during therapy — which as anyone who has undergone cancer chemotherapy knows, is a significant contribution.
It’s reassuring to know that medical science marches onward. Perhaps by the time the ICC meets in Istanbul in 1987 there’ll be even more exciting news to report.