I go to many meetings in which cases are presented and medical oncologists provide their repsonses about how they’d be inclined to treat a patient. Although we bemoan the lack of much progress in managing small cell lung cancer, one of the effects of that is that there is pretty strong uniformity in how we manage it, since the standards are quite well established.
Although several years ago there was a small Japanese trial that showed a significant survival benefit for the combination of cisplatin/irinotecan compared with cisplatin/etoposide, which led to growing use of irinotecan instead of etoposide outside of the US as well, North American trials over the last few years have not shown a similar benefit (summarized in prior post here). This difference in outcomes by geography is likely real and related to relevant genetic differences in how Japanese and Caucasian patients process and respond to irinotecan vs. etoposide. The North American studies have shown that the different regimens are comparable in activity, but that irintecan is associated with significant diarrhea, while etoposide is associated with more significant drops in blood counts.
These days, the vast majority of US-based oncologists give a platinum with etoposide, fairly split between cisplatin and carboplatin. My preference has generally been to use carboplatin in a setting in which we can’t cure the cancer, and for which there is a little evidence that they produce comparable results (see prior post). In fact, historically most of the studies of ED-SCLC have used cisplatin/etoposide as the standard treatment, but one recent trial used carboplatin/etoposide and produced results every bit as good as what we see with cisplatin (see prior post). This corroborated the more limited avidence that carboplatin was a less challenging but very comparable alternative to cisplatin.
Patients with SCLC very often have a nice response to chemo, so much so that we can often tell by how a person is doing clinically that they’re responding. They may start gaining weight after weeks of weight loss, have improvement in their breathing, better energy, etc., so I don’t always scan patients after two cycles and sometimes go to three, just because there’s so little question that you;ll see a good response and want to continue. Our standard is 4 to 6 cycles, and this is dictated for me primarily by how a patient is tolerating the treatment.
The only significant change in our practice of SCLC over the last few years is that we now routinely give prophylactic cranial irradiation (PCI) to patients with ED-SCLC who respond to first line chemo. This is based on a study from Europe that showed a very significant reduction in the risk of brain metastases, otherwise a very common complication with SCLC, as well as as significant improvement in overall survival after PCI (see prior post). I don’t believe that this has become common practice yet, but I consider the results to be impressive enough that this is now my practice. Importantly, not every patient with SCLC is healthy enough after chemo to pursue PCI, but for the ones who still have a good performance status, had meaningful tumor shrinkage, and are inclined to pursue it, I do refer my patients to a radiation oncologist to discuss this.
At some point, we need to also deal with the treatment options for patients with relapsed SCLC, but that’s the subject for a separate post.