Source: MedScape Today News

Reirradiation plus hyperthermia is an effective treatment for radiation-associated sarcoma (RAS) and could even cure some of these rare tumors, a small new study suggests.

“The reirradiation plus hyperthermia as we used it appears to be quite successful with a very high response rate and reasonable local control rate,” Dr. Geertjan van Tienhoven of the Academic Medical Center in Amsterdam, one of the study’s authors, told Reuters Health.

RAS develops in areas previously reirradiated with 25 to 80 Gray, usually with a latency period of three years or more, and with a different histology from the original tumor, according to a June 28th online paper in Cancer.

Dr. van Tienhoven predicts that “radiation-associated sarcomas are going to be more frequent in the future, because of an increasing prevalence of breast cancer survivors who are at risk, be it a low risk, for RAS.”

These tumors are usually resected with radical surgery and sometimes adjuvant chemotherapy. To date, according the paper, there haven’t been any randomized trials or other prospective studies of reirradiation for RAS.

“Many papers and textbooks state that radiation shouldn’t be done in these tumors because they are caused by radiation. Indeed it sounds counterintuitive to irradiate again,” Dr. van Tienhoven said in an interview.

But using hyperthermia with reirradiation allows for a lower radiation dose, he and his coauthors explain. The Academic Medical Center and the Institute Verbeeten have “extensive experience” with this approach, for example in breast cancer recurrence in previously irradiated areas.

To assess the value of radiation plus hyperthermia (RT-HT) for RAS, the researchers studied 16 patients treated between 1979 and 2009, all of whom had RAS in the thoracic region. The median latency was 86 months, and 11 patients had angiosarcoma. Thirteen patients had unresectable disease, while three of the patients received RT-HT as adjuvant therapy after surgery.

Treated patients survived for up to 204 months, with a median of 15.5 months. Four patients could not be evaluated for response. Of the remaining 12, seven had a complete response, two had a partial response, and three had stable disease.

Six patients remained free of recurrent disease until death (one patient at five months, one at seven months) or last follow-up (eight months, 11 months, 39 months, and 68 months).

“The response and local control rates are promising and appear to contradict the common assumption that reirradiation is not useful in patients with RAS,” the authors write.

“I think that treating these radiation-associated sarcomas, particularly the angiosarcomas, with a combination of attempted radical surgery and reirradiation plus hyperthermia has the possibility of a cure,” Dr. van Tienhoven told Reuters Health. “I think these tumors are very much more radiosensitive than is often thought.”

He added, “We must be very cautious of course because this is a very small series and there are various types of tumors and several aspects of this series are heterogeneous.”

Nevertheless, the researcher concluded, “it gives us the suggestion that reirradiation helps.”

This news story was resourced by the Oral Cancer Foundation, and vetted for appropriateness and accuracy.