Drs. Oz & Roizen: Should I have a liquid biopsy? Indoor allergies

My doctor suggested that I get a liquid biopsy to determine what therapy will be most effective for treating my prostate cancer, even though my insurance won’t pay for it. Is it more accurate, less risky? What’s the deal? — Jack H., Orlando, Florida


The concept of a liquid biopsy is a great one: It uses a simple blood draw to see what DNA mutations related to prostate cancer are present in your circulation. No incisions, no risk of infection nor complications from the biopsy itself. Identifying those mutations is supposed to help doctors predict a patient’s response to immunotherapy, and if it turns out that the DNA mutations are not responsive, then the doctor can select another therapy that may be more effective.

Sounds perfect. And one day it might be, but not now. A new Johns Hopkins study took blood draws to obtain DNA samples from 40 study participants, and then divided each one so that identical samples could be sent to two separate, well-accredited labs for analysis. Unfortunately, the lab results matched only 7.5 percent of the time (that’s three of the 40 participants), and only 15 percent of the time did the two companies’ results match for at least one mutation.

These results come on the heels of an earlier study published this year in JAMA Oncology that found that mutations identified in tumor tissue samples and in liquid biopsy results from the same patients had what Johns Hopkins calls “a similar lack of congruence.” That means doctors looking at differing results may come to different conclusions about which treatments will be most effective for you.

Ask your doctor about the Johns Hopkins findings, and offer this quote from the researchers: “Liquid biopsy is a promising technology, with an exceptional potential to impact our ability to treat patients, but it is a new technology that may need more time and experience to improve.”

I have seasonal allergies, but here it is the middle of winter — no leaves, no pollen — and my eyes sting and my sinuses still bother me. Am I allergic to something in my house (no pets)? — Lewis B., Pittsburgh

A: Chances are good there’s something in your home that’s causing your symptoms. It may just be irritants that trigger your symptoms and not an allergic reaction, but don’t rule out allergies. According to the largest indoor-allergy study ever done in the U.S., the 2005-2006 National Health and Nutrition Examination Survey, over 90 percent of homes had three or more detectable allergens present. The most common allergens:

• two types of dust mites

• cockroach

• mouse and rat (dander or poop)

• mold

• cat and dog (dander)

There are a couple of ways to find out what you’re reacting to, and if it’s an allergy: You can go to an allergist for a skin-prick test, or you can systematically eliminate what could be the source of your reaction.

• For dust mites, start by vacuuming not just floors, but upholstered furniture too; wash sheets, blankets and pillows in non-allergic soap and hot water every week; use new allergen-impermeable covers for box springs, pillows and mattresses.

• If that doesn’t ease your sneeze, change up your laundry detergent and the rest of your cleaning supplies. There’s a good chance that’s where your irritant is hiding.

• For cockroach- or rodent-related allergies, hire exterminators.

• Pets? Keep them outdoors (as much as possible) and out of the bedroom.

• Still no relief? Check for leaks in the walls (that can stimulate mold growth) and mold growth in bathroom corners and basements. If it’s superficial, using a mask, you can clean it with bleach. For black mold, you need professional help.

Talk to your doc about the possibility that it’s something in your diet instead, and about relieving symptoms with medications such as oral antihistamines like loratadine (Claritin) and fexofenadine (Allegra), decongestants and corticosteroid nasal sprays like triamcinolone (Nasacort) and fluticasone propionate (Flonase).

Mehmet Oz, M.D., is host of “The Dr. Oz Show,” and Mike Roizen, M.D., is chief wellness officer andchairoftheWellnessInstitute at the Cleveland Clinic.