Purpose: To compare the incidence and severity of acute and chronic hematologic toxicity (HT) in patients treated with three-dimensional conformal radiotherapy (3DCRT) and intensity modulated radiotherapy (IMRT) for curative treatment of cervical cancer and to ascertain the dosimetric parameters of two techniques associated with acute and chronic HT.
Materials and methods: A total of 127 patients with cervical cancer receiving concomitant pelvic radiotherapy (RT) and cisplatin were evaluated. Pelvic bone marrow (BM) was contoured for each patient and divided into five sub-regions: lumbosacrum (LS), ilium (IL), lower pelvis (LP), pelvis (P), and whole pelvis (WP). The volume of each BM region receiving 10, 20, 30, and 40 Gy was calculated (V10, -V20, -V30, and -V40). The lowest level of hemoglobin, leukocyte, neutrophil, and platelet counts were obtained during chemoradiotherapy and six months after RT. The nadir values were graded according to Common Terminology Criteria for Adverse Events (version 3.0).
Results: Grade 2 or greater acute anemia, leukopenia, neutropenia, thrombocytopenia was observed in 2%, 41.5%, 12% ,and 0% in 3DCRT group and in 27%, 53%, 24.5%, and 4.5% in IMRT group, respectively. Grade 2 or greater chronic anemia, leukopenia, neutropenia, and thrombocytopenia was observed in 11%, 10%, 6%, and 0% in 3DCRT group and in 11%, 9%, 4.5%, and 0% in IMRT group, respectively. LS-V30, 40; IL-V10, 20, 30, 40; LP-V10, 20 ,40; P-V10, 20, 30, 40, and TP-V10, 20, 30, 40 were significantly reduced with IMRT planning compared to 3DCRT planning. Logistic regression analysis of potential predictors showed that none of the dosimetric parameters were significant for predicting acute and chronic HT.
Conclusion: The present findings showed that IMRT planning reduced irradiated BM volumes compared to 3DCRT planning. However, no difference between the two techniques was observed in terms of acute and chronic HT. Further studies are needed to confirm these results.