Medacs Healthcare

APR 26/2013

Is chemosensitivity-assay directed therapy effective?

Oncologists might find themselves caught up in the debate of assay-directed therapy and whether or not chemosensitivity testing is effective for patients. It sounds logical to try determine if a treatment is useful for inhibiting tumour growth before administering it to a patient. This prevents the patient from being given a drug that will fail to improve their survival rate. In fact, administering the wrong drug to a cancer patient can give the disease more time to grow as you wait around to see if the treatment is making an impact.

Assay-directed therapy might, in fact, be particularly relevant in the case of rare cancers, where little is known about effective treatments and how patients will respond to specific drugs. In this case, testing the tumour in vitro gives oncologists an edge when it comes to deciphering how well the treatment works on the cancer. Again, the patient is spared from the trial-and-error aspect of cancer treatment that can delay results and cause the individual to give up hope. What it is important to remember is that assay-directed therapy is not 100 per cent precise, so there could be times when it gets it wrong. The decision, therefore, seems to lie in whether or not it is worth relying on typical cancer treatments, or trying to pin-down exactly which drugs will work best.

A recent US study from the Women & Infants Hospital of Rhode Island did, however, discover that chemoresponse assays could help improve survival rates among women with ovarian cancer. The eight-year research was launched in 2004 across 283 females. Some 262 of these participants had successful biopsies which were tested in vitro. The assay tested up to 15 approved treatments on the sample tissue, identifying chemotherapy drugs that tumours might be sensitive too.

Dr Richard Moore, a gynaecologic oncologist with the Program in Women's Oncology at Women & Infants, explained that the assay detected at least one treatment that a tumour would be sensitive to in 52 per cent of study participants. That led to median survival rates standing at 37.5 months for patients with treatment-sensitive tumours, compared to 23.9 months for intermediate and resistant tumours.

"Essentially, we have demonstrated that by using a tissue sample from the patient's tumour and a chemoresponse assay, we are able to determine which treatment may or may not work for her," Dr Moore said. "This study shows that a woman with recurrent ovarian cancer could benefit from having a biopsy and chemosensitivity testing."

He added: "Learning that personal directed therapies may improve overall survival for these patients made this the first study in two decades to show a significant increase in survival in recurrent ovarian cancer."

Assay-directed therapy is a topic you can discuss with your colleagues. Think about asking them how familiar they are with this approach and whether or not they have found it effective for their patients. What are the arguments against using this type of approach? And how do patients feel about treatments being trialled before they are administered? All of these questions, and the subsequent answers, will help inform your decision if you are considering assay-directed therapy for a patient.

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