Oncologists report that cancer patients with brain tumors who receive a combination of chemotherapy and radiation treatment do only as well, on average, as those patients who receive radiation treatment alone. Yet the oncologists state that chemotherapy is a necessary part of the treatment of all patients who receive them for tumors.
Which of the following, if true, most helps to reconcile the oncologists’ two claims?
A. Oncologists treat all cancer patients who have tumors with either radiation treatment alone or a combination of radiation and chemotherapy.
B. Oncologists who prescribe these treatments make accurate determinations about which patients need both radiation and chemotherapy and which need radiation alone.
C. Some tumors have been completely healed by a combination of radiation and chemotherapy.
D. Some tumors that have been exacerbated by improper attempts at chemotherapy have been successfully treated with radiation.
E. Patients with tumors in other areas of the body show more improvement when treated with both radiation and chemotherapy than when treated with radiation alone.