Dear Doctor: I recently read that a modified Pap smear has the potential to show early warning signs of ovarian and endometrial cancers, as well as cervical cancer. How accurate is this test, and when might it be available?

Dear Reader: An almost all-purpose test is a tantalizing prospect. Already, the Pap smear and HPV testing are crucial screenings in the diagnosis of cervical cancer and have led to a significant decline in death rate from the disease. Yet thus far, screening tests for endometrial (uterine) cancer and ovarian cancer have not been promising. Endometrial cancer and ovarian cancer combined still claim the lives of about 25,000 women in the United States per year because such cancers are often found only after they have spread to other portions of the body. A screening test to find these cancers could dramatically reduce those numbers.

Such a test could be available in the relatively near future. A greater understanding of the gene mutations involved in these two cancers have spurred some scientists to propose a simple technique to find these mutations using DNA testing of the fluid obtained through the Pap smear. A study published in March assessed the technique's ability to detect such mutations in 382 women diagnosed with endometrial cancer, 245 women with ovarian cancer and 714 women without cancer.

Researchers looked for mutations within 18 genes and also for an abnormal number of chromosomes. The technique, called "PapSEEK," positively identified 81 percent of women with endometrial cancer, including 78 percent of those with early-stage endometrial cancer. However, it identified only 33 percent of women with ovarian cancer, including only 34 percent with early-stage disease.

In an attempt to improve these numbers, researchers took samples from farther within the uterus in a subset of patients. The test then positively identified 93 percent of women with endometrial cancer, and 45 percent of those with ovarian cancer.

The researchers also tested a subset of patients with ovarian cancer using PapSEEK and a blood test to detect circulating tumor-specific DNA. The positive rate then increased to 63 percent for ovarian cancer, including 54 percent with early-stage ovarian cancer. It's an improvement, but a lot of ovarian cancers would still be missed.

On the plus side, the rates of false positives were low with these tests. In the women without cancer, the rate of false positives was between zero and 1 percent.

Note that this was a retrospective study, meaning that the test was conducted among women who had already been diagnosed with cancer. It's unclear how well the test would work as a screening that could affect the course of the disease. A large screening study is needed to help us understand the true potential benefits of the test.

No doubt about it, however, the results are encouraging, especially as a way to detect endometrial cancer when used on samples taken from farther within the cervix and to detect ovarian cancer when used with a blood test.

Due to the need for more assessment, the test may not be available for several years, but it's good to know that our increased ability to conduct DNA testing is likely to help us, ultimately, catch these cancers early enough to save more lives.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: Just how risky are sinus infections? I read about a teenager who died recently after a sinus infection spread to his brain. Is this common? How do you prevent a sinus infection?

Dear Reader: We hadn't heard about this before we received your letter, but we did a search and found the incident you're referring to.

A 13-year-old boy in Michigan who had been diagnosed with a sinus infection went on to develop migrainelike headaches. The severe headaches worsened over the course of several weeks and an MRI was performed. It was discovered that a viral infection had spread to his brain and caused blood clots, which led to a series of strokes, according to his family members. Despite emergency surgery, the boy passed away. It's a tragic story and, considering that sinus infections are common -- an estimated 31 million are diagnosed in the United States every year -- it's an alarming one. However, the fact is that these types of complications are rare.

The sinuses are pairs of air-filled cavities located behind the lower forehead, behind the nose, on either side of the bridge of the nose, and within the bony structures of the cheeks. In a heathy sinus, a thin layer of mucus catches dust, dirt or debris and, with the aid of tiny hairlike structures, clears it away. That mucus then drains into the nasal passage and winds up in the nasopharynx, which is where the very back of the nose and the throat converge. At that point, the mucus continues its journey down the esophagus and into the stomach.

A sinus infection occurs when a virus, bacterium or fungus causes the tissues that line these cavities to become inflamed. When this happens, the flow of mucus is blocked and it begins to collect in the sinus cavity. This can cause symptoms like congestion, postnasal drip, excess and sometimes discolored (usually greenish) mucus, tooth pain, a feeling of pressure, frontal headache, fatigue and even bad breath. In rare cases, the pathogens causing a sinus infection can cross the blood brain barrier, which is a filtering mechanism that protects brain tissues, and cause an abscess.

Conditions with similar symptoms, like colds or allergies, can be mistaken for a sinus infection. An accurate diagnosis requires an examination of the throat, nose and sinuses. This can include a physical examination with an endoscope, X-rays or a CT scan, and a mucus culture to pinpoint the cause of infection. Antibiotics may be used when the infection is bacterial but will not help with a viral infection. Symptoms can be eased with over-the-counter antihistamines, nasal decongestant sprays and nasal saline washes. Patients are often counseled to drink plenty of fluids to help thin the mucus.

Prevention consists of the same steps you take to avoid catching a cold or the flu. The Centers for Disease Control and Prevention suggest:

-- Practice good hand hygiene.

-- Keep the family up-to-date with immunizations.

-- Steer clear of individuals with upper respiratory infections.

-- Avoid exposure to tobacco smoke.

-- Use a humidifier -- and be sure to keep it clean.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I understand that poking cotton swabs into the ear is dangerous. But how is one supposed to clean the ears otherwise? I don't want to see goopy yellow wax in anyone's ear canal or to have it in my own.

Dear Reader: This is a very good question -- and one that poses another question: Why clean your ears?

Let's assess the potential health benefits (or lack thereof) of doing so. This so-called wax, called cerumen, is a necessary product for the ear canal. Produced by glands under the skin, cerumen is composed of many different chemicals that mix with the skin cells that slough off within the ear canal. Cerumen moistens, cleans and lubricates the ear canal. It also acts as a barrier to dust, water and particles from the outside world. Further, cerumen creates an acidic environment within the ear canal that works against invading bacteria, even as its antibacterial enzymes and antibodies further protect the ear from bacteria.

I know that it may be unsightly and seem unhygienic to have yellowish material coming out of the ear, but letting cerumen come out on its own is actually the more hygienic course. First, removing the cerumen dries out the canal, which can lead to skin irritation within the canal. Often, this causes the ear canal to feel itchy, leading to more use of cotton swabs and even greater irritation of the canal. Second, the cotton swabs can make cerumen itself drier, reducing its ability to come out on its own. Swabs also can push wax further into the canal toward the eardrum.

In some instances, the tips of the cotton swabs or the cotton fibers themselves can dislodge and remain within the ear canal. The fibers then can mix with the cerumen, leading to closure of the ear canal and loss of hearing. Finally, putting a cotton swab in the ear canal can perforate the eardrum.

In short: Cotton swabs should not be used within the ear.

Nonetheless, the belief that the ear canals should be cleaned is widespread. Two surveys have found that 90 percent of people think that they should clean their ear canals, with many people cleaning their ears on a regular basis. This practice appears to be passed from parents to their children as a part of normal hygiene.

That said, even without the use of cotton swabs, cerumen can harden and remain lodged within the ear canal. This is especially likely to occur in people with ear infections, psoriasis or eczema, or in those who use hearing aids, ear plugs or ear phones. In such cases, ear drops can help soften the wax, so that it comes out on its own. Irrigating the canal with water -- at home or within a doctor's office -- can provide additional relief. If such hardening is a recurrent problem, the answer is to more regularly use ear drops.

To sum it up, cerumen (ear wax) is necessary to lubricate and protect the ear canal from infection. Cotton swabs can be used to clean the outer ear, but -- please -- don't put them inside the ear.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)