Several months ago, I was introduced to a 58-year-old gentleman with a very bad diagnosis — a bout of gastrointestinal bleeding that had lead to an upper GI endoscopy. It wasn’t an ulcer, or even gastric cancer, but a very rare form of cancer arising in the duodenum. Adenocarcinoma of the duodenum is very uncommon.
This patient was in trouble.
In addition to the bleeding, he had lost a substantial amount of weight, was in pain and had a very large tumor that was nearly obstructing his upper GI tract. After getting the patient stabilized in September 2010, he was referred to a surgeon who conducted an aggressive surgical resection. The recovery was difficult, prolonged and accompanied by additional GI bleeding. By the time the patient had recovered adequately enough to consider additional therapy, his PET scan revealed extensive re-growth.
If you were to ask medical oncologists in the United States what to give such a duodenum cancer patient, 99 percent would recommend FOLFOX or some variation thereof. But, FOLFOX wasn’t the right treatment for this patient. Instead, based on our EVA-PCD functional profiling assay, he had a strong signal for Irinotecan, which was further enhanced by the addition of an EGFR inhibitor.
Based on this, I elected to treat the patient with Erbitux + Irinotecan. Before starting therapy, his CA 19-9 was 354. Although his signal for the EGFr inhibitor was very favorable in our analysis, I screened him for K-ras mutation. It seemed evident from his dose response curves and clear synergy between Irinotecan and the EGFR inhibitors that he would be K-ras wild type, but in this era of evidenced-based medicine one must be politically correct.
Indeed, he was K-ras wild type and we started treatment with Erbitux + Irinotecan. Other than the rash associated with the Erbitux, the tolerance was good. The bleeding stopped immediately, the CA plummeted with the first dose to 71 and the patient then returned every other week for therapy.
On February 11, 2011, three cycles later, we repeated the PET/CT. The phrase “marked interval regression” of measurable disease caught my eye. I also noted the normalization of his CA 19-9. The patient had gained weight and returned to normal activities. With the exception of a small and diminishing rash, he looks quite normal. In fact, with the rather modest dose of Irinotecan used in his schedule, he hasn’t even suffered any hair loss.
What I find most interesting about this duodenum cancer patient is that FOLFOX, the most widely used regimen in this setting, wasn’t anywhere on the radar screen. It wasn’t active, it wasn’t recommended and I feel confident it wouldn’t have worked. However popular FOLFOX may have come to be in patients like this, it doesn’t fit everyone.