Evaluation of Three-Dimensional Conformal Radiotherapy and Intensity Modulated Radiotherapy Techniques for Left Breast Post-Mastectomy Patients: Our Experience in Nigerian Sovereign Investment Authority-Lagos University Teaching Hospital Cancer Center, South-West Nigeria

Objective

This study aimed to evaluate the dosimetric properties of treatment plans obtained from three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy techniques (IMRT) plans for left chest wall breast cancer patients.

Materials and Methods

A total of 20 patients with left-sided chest wall radiotherapy were randomly selected with the dose prescriptions: 42 Gy and 45 Gy in 15 and 18 fractions, respectively. Treatment plans were obtained using 3D-CRT and IMRT for each patient. Five to seven beams were used for IMRT, while tangential beams were used for 3D-CRT. Planning target volume, D_near-max (D₂ ), D_near-min (D₉₈ ), D_mean, Homogeneity and Conformity Indices (HI and CI) were obtained. Similarly, mean doses to organs at risk (OAR), V₅, V₁₀, V₂₀, V₂₅ were generated from the dose-volume histogram and compared.

Results

IMRT showed a significant improvement in HI compared to 3D-CRT (p<0.0001). Although there was no significant difference in sparing of the left lung between both plans for high-dose volumes (V20: 18.2 vs 30.55, p<0.0001), (V25: 11.17 vs 28.12, p<0.0001). IMRT however showed supremacy to 3D-CRT with high-dose volumes for the heart, including V20 (4.44 vs 10.29, p = 0.02), V25 (2.08 vs 8.94, p = 0.002). 3D-CRT was better than IMRT in low-dose volumes for left lung (V5: 92.23 vs 56.60, p<0.001; V10: 60.98 vs 47.20, p = 0.04) and heart (V5: 57.45 vs 30.39, p = 0.004).

Conclusion

IMRT showed better homogeneity and sparing of high-dose volumes to OAR than 3D-CRT. On the other hand, 3D-CRT showed a reduction of low-dose volumes to OARs than IMRT.

Human onchocerciasis: current assessment of the disease burden in Nigeria by rapid epidemiological mapping

Rapid epidemiological mapping of onchocerciasis (REMO) was carried out in Nigeria between 1994 and 1996, to provide accurate estimates of the populations living in high-risk areas for the disease and to identify the communities to be given priority treatment with Mectizan (ivermectin, MSD). The rapid epidemiological assessment (REA) teams which carried out the survey comprised epidemiologists, geographers, and entomologists. They used topographical maps, at a scale of 1:250,000, to select sample villages at 30-km intervals along selected river courses. Several non-governmental development organizations participated in the surveys, providing support to the teams. In each study community, 50 adult males who had lived in the area for at least 10 years were randomly selected and examined for the presence of palpable, onchocercal nodules. The REA results were cross-validated by an independent REMO expert and then presented, initially as percentage prevalences in pie-chart form, using a geographical information system. The number of Nigerians living in high-risk areas (demarcated by river systems with villages that had > or = 19% prevalence) and who therefore require urgent Mectizan treatment, was estimated as 13,809,313. The national REMO map produced is allowing the African Programme for Onchocerciasis Control's technical consultative committee to prioritize the approval of proposals submitted from Nigeria in a rational and effective manner.