Radiation in the Elderly: ‘Excellent Alternative’ for Some Tumor Types

TAMPA, Florida-Radiation therapy is an "excellent alternative" to surgery and systemic chemotherapy in older cancer patients, according to Babu Zachariah, MD. Although there is only limited information on the effectiveness and tolerability of radiation therapy in theelderly, some studies do show that radiation is a reasonable therapeutic choice in this patient population, according to Dr. Zachariah, associate professor of radiation oncology withthe H. Lee Moffitt Cancer Center, University of South Florida, Tampa. "Mortality from radiotherapy is rare, and organ function and preservation is very good," said Dr. Zachariah, who reviewed current literature and described several combination chemoradiation trials now enrolling older patients. Clinical Benefit Similar Elderly patients do not appear to be at risk of increased toxicity to normal tissue, such as fibrosis, telangiectasia or arm edema, several clinical studies suggest. Likewise, clinical benefit appears similar to what is achieved in younger patients. For example, Dr. Zachariah said, data show that older women with stage I to II breast cancer who undergo breast-conservation surgery and radiotherapy have similarrates of overall survival, relapse-free survival, and freedom from local failure or distant metastasis vs younger patients. Radiation as Alternative to Surgery In lung cancer, the available data suggest that radiation therapy can be an alternative for patients more than 70 years of age who have resectable lung cancer lesions of 4 cm or less, with a 5-year survival rate of close to 17% (Cancer 45:698-702, 1980; Radiother Oncol 13:83-89, 1988). In one study, which included 40 patients more than 70 years of age with a Karnofsky performance status greater than 70, the complete response rate was 50%, while the 2-year survival rate was 56%; the 5-year survival rate of 16% achieved in the study was comparableto that achieved in surgical patients at the same institution. Toxicity was comparable to what might be expected in younger patients (Radiother Oncol 13:83-89, 1988). Radiation might also be used when radical surgery for prostate cancer is indicated. Dr. Zachariah and colleagues have reported that, in men more than 70 years of age with prostate cancer, 85% had a complete clinical response to radiotherapy, while 77% achieved biochemical control, with side effects comparable to what is seen in younger patients. A 4-year survival rate of 96% was reported (Ann Oncol 9(suppl 3) 84, 1998). Combined Chemoradiotherapy In bladder cancer, older patients with good performance status might be candidates for concurrent chemoradiotherapy. One study included 54 bladder-cancer patients (mean age, 66 years) who received fluorouracil(Drug information on fluorouracil) (5-FU)/cisplatin chemotherapy with concomitant bifractionated radiation therapy. The treatment was well tolerated, and at 3 years, the disease-free survival rate was 62% (J Clin Oncol 11:2150-2157, 1993). In another study, of MVAC (methotrexate, vinblastine(Drug information on vinblastine), doxorubicin(Drug information on doxorubicin), and cisplatin(Drug information on cisplatin)) chemotherapy, and radiation in patients more than 70 years of age, the 3-year survival rate was 34% (Cancer 80:115-120, 1997). Combined chemoradiotherapy is also well tolerated by elderly patients who have upper aerodigestive tract cancers. Likewise, it has also proven feasible in "well selected" older patients with anorectal carcinoma; Dr. Zachariah said trial results suggest "acceptable"acute toxicity and no severe late toxicity. "Very few clinical trials are currently open for older patients," Dr. Zachariah said, describing the one lung cancer study, one breast cancer study, and five active lymphoma trials currently recruiting patients. Lung Cancer Study The lung cancer study, sponsored by CALGB (Cancer and Leukemia Group B), is a phase I dose-escalationinvestigation of accelerated 3-D conformal radiation therapy for patients at least 18 years of age with early non- small-cell lung cancer and poor pulmonary function. Breast Cancer and Lymphoma Studies The breast cancer study, available for patients 60 years or older with stage I or II disease, is a phase III randomized clinical trial of surgery with or without axillary node dissection, followed by tamoxifen(Drug information on tamoxifen). Radiation therapy is offered optionally in patients who underwent conservative surgery. This trial is sponsored by the International Breast Cancer Study Group. Two of the five open lymphoma trials are sponsored by Memorial Sloan-Kettering Cancer Center. Oneis a phase II study of rituximab (Rituxan)/ CHOP (cyclophosphamide [Cytoxan, Neosar]/doxorubicin HCl/vincristine [Oncovin]/prednisone) plus the radiolabeled monoclonal antibody yttrium Y90 ibritumomab tiuxetan (Zevalin). Patients must be 60 years of age or older and have previously untreated diffuse large B-cell lymphoma. The EORTC (European Organization for Research and Treatment of Cancer) Lymphoma Cooperative Group is sponsoring two more lymphoma trials open to the elderly, including a phase II study of cyclophosphamide(Drug information on cyclophosphamide) (Cytoxan, Neosar), vincristine (Oncovin), and prednisone(Drug information on prednisone), for elderly patients with diffuse large B-cell lymphoma or peripheral T-cell non-Hodgkin's lymphoma; patients who respond get consolidative radiotherapy. At the same time, an EORTC phase II to III trial includes older patients with non-Hodgkin's lymphoma who receive CHOP with or without etoposide(Drug information on etoposide), with involvedfield radiotherapy for some responsive patients. The fifth lymphoma investigation is a randomized phase III trial of older patients who receive cyclophosphamide, doxorubicin, vincristine, and prednisone, with or without rituximab(Drug information on rituximab); following chemotherapy, they receive radiotherapy to the initial bulky disease. "It is encouraging to see a few studies are active for older patients with cancer," Dr. Zachariah said, "but more prospective trials combining chemotherapy and radiation are needed to improve the current therapy."