Following a cancer diagnosis, patients are typically offered two categories of treatment: local and systemic. Local treatments include surgery and radiation, both of which might be used after an initial diagnosis or if the tumor has spread to other parts of the body. Systemic treatments include chemotherapy, hormonal therapy, targeted therapy, and now, for some cancers, immunotherapy.
But there is an increasing amount of evidence that suggests it may well be time to reevaluate this way of thinking. This evidence comes from studies that suggest surgery and radiation tag cancer cells in other parts of the body in a way that alerts the immune system that these cells need to be killed. This suggests these local treatments may have farther-reaching effects than previously believed.
Two recent examples relate surgery and radiation therapy to the immune reaction. Of growing interest in the anesthesia community are the studies suggesting surgery itself may wake up dormant cells elsewhere in the body. Michael Baum has written about the original studies showing an increase in recurrence of breast cancer in the first few years after surgery and newer studies have shown that giving ketorolac (a non-steroidal analgesia) along with the regular anesthesia during surgery can reduce the chance of a cancer recurrence. Although this is clearly an area that needs further study, it is intriguing and makes sense.
With radiation therapy, the situation is the reverse. Although directed at one spot such as metastases in the liver, radiation may well have effects throughout the body. The current thinking is that the radiation therapy causes the immune system to see cancer cells both in the targeted area as well as in certain other parts of the body. Now studies have shown that in some cancers giving an immunotherapy drug along with radiation has a better effect than either of the two treatments alone.
Obviously these are early days, but they certainly point out that treatments are not just local or systemic, as we had previously believed, but are actually wholistic.
I keep thinking of a terrorist analogy, which might not be politically correct but works as explanation. Radiation has this impact: you capture some terrorists and imprison them in one part of the world and it affects a terrorist cell somewhere else because the online communication and coaching has ended. Likewise, with surgery, your attack on a terrorist cell may cause them to get mad and ratchet up their messages to those in other countries, causing things to get worse. We need to stop thinking about the different approaches in isolation and think of them as having effects that both enhance and inhibit when used together.
Before you panic that the surgery you underwent has or will make your cancer spread, it is important to emphasize that surgery plays a key role in treating breast cancer. None the less, more recent approaches, such as giving chemotherapy prior to surgery (neoadjuvant treatment) and doing less surgery in the breast and or /axilla and following that surgery by radiation probably counteracts much of the stimulation surgery may cause. I don’t want to panic anyone. But it is important to take the time to look at the ways new knowledge about how cancer and the immune system interact changes our thinking, which, in turn, opens up new avenues for improving cancer treatments.