title: Chemotherapy drug dose alteration due to radiation therapy in an adjuvant situation in breast cancer.
abstract: Fifty-six patients with T1-T3 and T2-T3 N0 medial lesions of breast carcinoma were randomized after modified radical mastectomy to receive either cytoxan, methotrexate, 5-fluorouracil (5-Fu) (CMF) chemotherapy for 1 year (group A) or CMF for 1 year and postoperative radiation therapy (group B). Thirty-two patients received chemotherapy alone and 25 patients received both chemotherapy and radiation therapy. Twenty-five of 32 group A patients (median age 52) and 20/24 group B patients (median age 50) were evaluable. Leukopenia was the major cause of drug dose reduction in both groups. In group A, 4/25 patients (16%) had leukopenia at less than the 2500 level, whereas 8/20 (40%) group B patients had leukopenia at the same level. If 70% of all three drug dosages are considered as adequate chemotherapy, 21/25 (84%) patients received adequate chemotherapy in group A, and 10/20 (50%) in group B (p approximately equal to 0.029 from contingency table). It appears that radiation therapy in postmastectomy patients hinders adequate drug dose delivery in an adjuvant setting.
mesh_terms: D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage* / Q000009:adverse effects; D001943:Breast Neoplasms / Q000532:radiotherapy / Q000628:therapy*; D003131:Combined Modality Therapy; D003520:Cyclophosphamide / Q000008:administration & dosage; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage; D006801:Humans; D007970:Leukopenia / Q000139:chemically induced; D008727:Methotrexate / Q000008:administration & dosage; D008875:Middle Aged
chemical_list: D003520:Cyclophosphamide; D005472:Fluorouracil; D008727:Methotrexate