Moving the Needle for Maintenance Cancer Treatment

Successful management of cancer requires treatment planning based on
the best science available.

Our growing knowledge of the biology of cancer has led to many refinements and innovations to surgery, radiation and medical treatments. Carefully designed, conducted and interpreted results from clinical trials testing each of the therapeutic components and modifications are needed to prove better outcomes — either a long-term cure, extension of survival or at least some control of the cancer and/or enhanced quality of life.

It is not uncommon to extend part of a patient’s medical therapy to address the possibility of cancer that we cannot see or even test for — microscopic cancer cells that in some cases lay dormant for many years (even when the patient may live a full life free of recurrence). This approach is called “maintenance therapy” and is addressed in more detail in this issue of CURE®, focusing on its application in ovarian cancer.

In many cases, maintenance therapy includes less-intense components of
the initial treatment.

For most malignancies, we currently do not have good ways to detect and measure microscopic cancer cells that could lead to recurrence and death. That is changing with newer technology, particularly the ability to assess and quantify tumor DNA circulating in the bloodstream.

Therefore, we still need to test types and durations of maintenance therapy in controlled clinical trials that can take a long time to complete before a new therapy can be adopted. The notion of additional treatment after the patient is technically free of cancer can be daunting for some patients who may be sapped of energy and still have side effects from their long journey.

There is particular interest in using biological therapies that home in on unique drivers of a patient’s cancer, as is explained with the use of poly (ADP ribose) polymerase inhibitors, commonly known as PARP inhibitors, for ovarian cancer.

This class of therapies is clearly active in ovarian and other cancers that carry an inherited BRCA1 or BRCA2 mutation or other characteristics seen with this aberration. It is critical that the side effects of maintenance treatments be such that patients can have some normalcy and move beyond the typical in-treatment phase.

We expect there will be more maintenance strategies adopted for a range of cancer types over time, particularly with more focused and less toxic protocols.
It may become easier to conduct these notoriously difficult-to-complete clinical trials to prove and quantify their long-term effects.

Not only are more targeted and immunologically-focused drugs becoming available, but imaging and blood-based technologies are advancing to provide us “surrogate” measures that can complement, or even some day replace, the gold standard of following patients over the long term for recur- rence and survival.

As the case with ovarian cancer proves, we can incrementally “move the needle” as maintenance therapy continues to evolve.