Sunday, June 14, 2009

Adjuvant chemo

Medical oncologists in sarcoma still disagree over the value of adjuvant chemo for many subtypes, and that was apparent in a discussion at ASCO last month. The ASCO Daily News reported on it, but I'll add in some of my own notes.

Dr. George Demetri of the Dana-Farber Cancer Institute in Boston talked specifically about GIST, and if you're interested, I encourage you to click on the Daily News link above. The other two doctors in the session talked about chemo in general for other subtypes.
Session Chair Ian Robert Judson, MD, of the Royal Marsden Hospital, United Kingdom, noted that questions arise about the appropriateness of adjuvant therapies because of several factors. Soft tissue sarcomas are rare diseases, he explained, and there are conflicting data on the efficacy of chemotherapy as well as variations in clinical practice regarding the standard treatment for these diseases. ...

“We know that there are variations in response to these treatments among individuals, and unless we learn more about how to identify who is likely to benefit, we run the risk of administering a lot of unnecessary treatments with accompanying toxicity,” said Dr. Judson in an interview with ASCO Daily News.

He noted that the physician must take into account the individual patient’s level of risk tolerance, along with the best available evidence regarding the likelihood of benefit when deciding whether to initiate adjuvant therapy for these malignancies.

Robert S. Benjamin, MD, of M. D. Anderson Cancer Center, reviewed recent literature regarding adjuvant chemotherapy for soft tissue sarcomas. He noted that the Sarcoma Meta-analysis Collaboration in 1997 found that doxorubicin-based chemotherapy improved time to local and distant recurrence and overall recurrence-free survival; however, there was not a significant improvement in overall survival.
After the 1997 study, ifosfamide was added to doxorubicin, and that improved survival a little, he noted. Since then, other drugs have been developed or tried with sarcoma. He criticized a 2007 study by the EORTC, saying it was not representative of a global, random population.

He recommends neoadjuvant chemo, if possible, because it lets the oncologist judge whether the tumor is reacting to the chemo. In regard to adjuvant chemo, he would like to see doctors give more of it for a longer period of time.
“I don’t put much stock in the argument that chemotherapy doesn’t work,” he said. “We know that, yes, it works and no, it doesn’t work nearly well enough. So we need to give more of it, not less. Stage III sarcomas are such a bad group of tumors that, even though we know the treatment is going to be awful for the patient, not treating them is ethically unacceptable.”

Dr. Benjamin suggested that clinicians should not approach adjuvant therapy for soft tissue sarcomas using the same rules for breast cancer therapies because of broad differences between the diseases.

He noted that breast cancer is more common and more homogeneous than sarcoma and therefore results in larger studies and more numerous therapies, whereas there are limited options for sarcoma.
An abstract from the French Sarcoma Group, presented at last month's ASCO, found little benefit for grade 2 patients, but improved survival for those with grade 3.
-- Suzie Siegel

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