Lung Cancer & Diving

[AllenG]

In one of the other areas, the issue of lung cancer came up. While the thread was about refusing a potential student who presents with proper medical clearance, one component of the discussion was that a diving doc reportedly felt that lung cancer was an absolute contra-indication to diving, or as Drew the Sailbum from the Cayman Islands (everybody heave that sigh of envy for Drew being in the Caymans!) more aptly put it, "When I ran this idea past our local dive physician (who is a scuba instructor, hyperbaric physician, and an ENT specialist) he said, 'No <expletive deleted> way!'"

I would appreciate hearing from our venerable docs here on ScubaBoard re what are the clinical considerations to be addressed when evaluating the risks associated with diving with lung cancer (not "can you dive with lung cancer - yes or no?" but rather what are the factors to be addressed in order to arrive at an informed opinion).

Those interested in the broader issue of refusing a physician's medical clearance may find the issue discussed at
http://www.scubaboard.com/showthread.php?s=&postid=114851#post114851

 

[sunfish]

Effects of therapy: There are three main approaches to treating lung cancer. That's not to say that only one is used on any given patient, on the contrary, a combination of two or more are often used .

1. Surgery. You open up the chest and cut out the bad stuff, duh. The problem this might cause with diving would be
A. Along with the "bad stuff" (i.e. the cancer), some "good stuff" (normal lung" would have to be cut out with it to provide a "safety margin". That means less normal healthy lung, which means less respiratory capacity. How much lung is cut out (and hence how much respiratory capacity will be decreased) will depend upon the size and spread of the tumor.
B. If a chest is opened and closed, sometimes there will be "dead air", or air closed inside the chest cavity left inside, which can't be decompressed with normal breathing the way air in the lungs can. Most of the time, this air is absorbed by the body over time, but sometimes it is not. And when it is left, it is difficult to predict how this air will behave at depths and also during ascent and descent.

2. Chemotherapy. Anti-cancer drugs, which are toxic to the tumor, duh, but are also slightly toxic to the rest of the body as well.
A. depending upon the drug, everything from the liver to the kidneys to the heart can be injured, sometimes in a permanent manner. The injury might be subtle enough that someone leading a sedentary lifestyle might not notice it in day-to-day live, but diving can be a strenuous activity.
B. Hematopoetic stem cells, or blood-cell-producing-cells, are particularly vulnerable to anti-cancer drugs. Someone on anti-cancer drugs is in a state of artificially induced anemia. They may also become prone to infection (due to a deficit of white blood cells) or bleeding (due to a deficit of platelets).
C. Powerful drugs like anti-cancer drugs can alter the blood's ability to clot when it is supposed to. Small cuts that would be ignored by most might turn into major blood loss for someone on the drugs. At the same time, it becomes easier for blood to clot when it's not supposed to. This means these people may be at increased risk for getting bent.

3. Radiotherapy. You've hacked at it, poisoned it, now it's time to zap it. Ionizing radiation is aimed at the tumor (while avoiding as much normal tissue as possible) and administered in doses and periods adjusted in a very deliberate manner.
A. I said you avoid as much normal tissue as possible. You can't avoid it all. This means some normal lung is going to be involved no matter what. That means there may be some injured lung, suseptible to infection and impaired function. Sometimes it does not become clear just how much adjacent lung has been injured just how badly until many many months after radiotherapy.
B. (unlikely to become an issue in potential divers, but) a much-feared side-effect of radiotherapy is damage to the spinal cord. That's why the doses of radiation are carefully planned.

Hoping those more knowlegeable will correct and add.

 

[AllenG]

Sunfish - Thanks for the information. While, like the person who started the original post re refusing a medical clearance, I might be surprised to see a lung cancer survivor receiving medical clearance, I was interested in seeing the medical issues laid out.

It makes me think that what DAN or other diving medicine groups ought to develop is not the usual thumbs up/thumbs down list of diagnoses, but rather diagnosis-specific assessment protocols which would guide or assist physicians that face the task of issuing medical clearance. Let's face it, docs that are knowledgeable in the area of diving medicine are few and far between, and the thousands of physicians who have to issue medical clearances can't possibly know all the issues relevant to diving.

I see it as analogous to, in our practice, family physicians that are asked to opine on an individual's ability or inability to work based on a given diagnosis (e.g., in a workers comp claim, a disability insurance claim, an ADA claim, or a person in medical/vocational rehabilitation). If, in the example of a worker comp claim, a physician has opined without reviewing essential job functions and the environment in which those functions are performed, one may reasonably wish to question that physician's recommendation and engage that physician in further discussion to ensure that his/her assessment gives appropriate consideration as to the tasks and job setting. Having specific information about the job and the work environment establishes a conceptual framework into which the physician can then offer his/her clinical impressions. I would think that a diving assessment is no different, in that a physician needs to know what clinical/anatomical and physics/science-based aspects of diving are germane to a person's illness.

Perhaps some of the respected physicians that frequent ScubaBoard could encourage their DAN colleagues to consider this valuable pursuit?

 

[BillP]

Howdy Allen:

Sunfish has done a superb job of discussing some of the possible effects of lung cancer treatment as they relate to diving. Lung cancer and lung cancer treatment can affect/obstruct airways. I would imagine that one of the primary concerns of Drew's hyperbaric physician friend would be air-trapping and a possible over-expansion lung barotrauma injury. I don't know of a test that you could do to prove whether a lung cancer patient has sufficient air trapping to injure them on any particular dive. You don't have to dive on vacation. If the potential risk is significantly increased, the natural reaction is to advise, "Don't dive."

I would say that doctors tend to answer questions as they relate to their area of expertise. For example, it's not at all uncommon for a patient to ask me, "You just did abdominal surgery on me, and I'm scheduled for eye surgery next week. Is that OK?" And my answer will be, "Sure it's OK. There's no way that eye surgery will affect your healing from the abdominal surgery- the abdominal surgery will be fine." But that's not what the patient was really asking, so I'll add, "But I'm not an eye surgery specialist. You need to ask your eye surgeon if your recent procedure will affect what he's going to do. That's his area of expertise." I have no way of knowing, but it's possible that the lung cancer patient's oncologist was saying, "No problem- diving won't affect your cancer." That's not the complete answer to the question.

The idea of having "decision trees" available for doctors not familiar with dive medicine problems to follow is an excellent one. Getting the "experts" to agree on trees that are complete without being overly burdensome would be tough, but would be helpful if it could be worked out.

HTH,

Bill