Locoregional recurrence of triple-negative breast cancer: effect of type of surgery and adjuvant postoperative radiotherapy.

BACKGROUND/PURPOSE: The aim was to evaluate the prognostic significance of postoperative radiotherapy (PORT) and surgical type on local recurrence-free survival (LRFS) and overall survival (OS) in triple-negative breast cancer (TNBC) in the Egyptian population. PATIENTS AND METHODS: We evaluated 111 patients with stage I-III TNBC diagnosed at our institute during the period from 2004 to 2009. Patients were stratified according to PORT into two groups: a PORT group and a non-PORT group. The influence of PORT and surgical type on LRFS and OS were evaluated. A cross-matching was done to the non-TNBC group of patients to compare the recurrence and survival rates between them and the studied group of TNBC patients. RESULTS: The mean age of TNBC patients at diagnosis was 63±7 years. The majority of the patients had stage III disease (68.5%) and 73% had clinical or pathological positive lymph nodes. Sixty percent (67/111) of patients had modified radical mastectomy and 44/111 (40%) patients had breast-conserving treatment. PORT was given for 63% of patients, while systemic treatment was given in 89% of patients. At the time of analysis, 13 patients (11%) developed local recurrence: five of 70 (7%) in the PORT group and eight of 41 (19.5%) in the non-PORT group. Five-year LRFS for the whole group of patients was 88%±6%, which was significantly affected by PORT. The surgical type did not affect local recurrence significantly. Five-year OS for the whole group was 54%±8%. PORT and surgical type did not affect OS significantly (P-value 0.09 and 0.11, respectively). Five-year LRFS was 88%±6% and 90%±11% for TNBC and non-TNBC patients, respectively (P-value 0.8); however, OS for TNBC was significantly lower than for non-TNBC (P-value 0.04). CONCLUSION: TNBC is an aggressive entity compared with other non-TNBC, and these patients benefit from PORT significantly to decrease the risk of local recurrence in all stages. However, further large, prospective, randomized trials are warranted.

Conventional (2D) Versus Conformal (3D) Techniques in Radiotherapy for Malignant Pediatric Tumors: Dosimetric Perspectives.

OBJECTIVES: In pediatric radiotherapy, the enhanced radiosensitivity of the developing tissues combined with the high overall survival, raise the possibility of late complications. The present study aims at comparing two dimensional (2D) and three dimensional (3D) planning regarding dose homogeneity within target volume and dose to organs at risk (OARs) to demonstrate the efficacy of 3D in decreasing dose to normal tissue. MATERIAL AND METHODS: Thirty pediatric patients (18 years or less) with different pediatric tumors were planned using 2D and 3D plans. All were CT scanned after proper positioning and immobilization. Structures were contoured; including the planning target volume (PTV) and organs at risk (OARs). Conformal beams were designed and dose distribution analysis was edited to provide the best dose coverage to the PTV while sparing OARs using dose volume histograms (DVHs) of outlined structures. For the same PTVs conventional plans were created using the conventional simulator data (2-4 coplanar fields). Conventional and 3D plans coverage and distribution were compared using the term of V95% (volume of PTV receiving 95% of the prescribed dose), V107% (volume of PTV receiving 107% of the prescribed dose), and conformity index (CI) (volume receiving 90% of the prescribed dose/PTV). Doses received by OARs were compared in terms of mean dose. In children treated for brain lesions, OAR volume received 90% of the dose (V90%) and OAR score were calculated. RESULTS: The PTV coverage showed no statistical difference between 2D and 3D radiotherapy in terms of V95% or V107%. However, there was more conformity in 3D planning with CI 1.43 rather than conventional planning with CI 1.86 (p-value <0.001). Regarding OARs, 3D planning shows large gain in healthy tissue sparing. There was no statistical difference in mean dose received by each OAR. However, for brain cases, brain stem mean dose and brain V90% showed better sparing in 3D planning (brain stem mean dose was 61% in 2D and 51% in 3D (pvalue 0.0001) and Brain V90% was 17.6 in 2D and 8.6 in 3D (p-value 0.001). Similarly, there was overall significant decrease in doses receive by healthy tissues in term of OARs score which was 0.24 in 3D and 0.40 in 2D planning (p-value 0.0001). CONCLUSION: This study confirms that 3D conformal radiotherapy is more effective than 2D conventional radiotherapy in decreasing dose to normal tissue without compromising dose distribution, homogeneity and dose coverage to PTV. KEY WORDS: Conformal radiation therapy - Pediatric tumors - Dosimetry.

Palliative spleen irradiation: can we standardize its technique?

PURPOSE: To explore the pattern of practice of palliative splenic irradiation (PSI) at the National Cancer Institute (NCI), Cairo University. PATIENTS AND METHODS: The medical records of patients referred for PSI during the time period from 1990 to 2005 were retrospectively reviewed. We compared the three most common planning techniques (two parallel opposing, single direct field, anterior and lateral fields). RESULTS: Eighteen patients who received PSI were identified. Thirteen patients were diagnosed as CML and 5 as CLL. The mean age of the patients was 44 (+/-16) years and the majority were men (60%). Spleen enlargement was documented in all cases. The single direct anterior field was the most commonly used technique. The dose per fraction ranged from 25 cGy to 100 cGy. The total dose ranged from 125 cGy to 1200 cGy and the median was 200 cGy (mean 327 cGy). There was no significant difference between CML and CLL patients regarding the dose level. Three out of 5 CLL patients and only one out of 13 CML patients received re-irradiation. All patients showed subjective improvement regarding pain and swelling. There was a significant increase in the hemoglobin level and a significant decrease in the WBC count. The single direct field shows variations in the dose from 56 to 102%; however, it is the simplest and the best regarding the dose to the surrounding normal tissues especially the kidney and the liver. CONCLUSION: PSI has a significant palliative benefit. Although the most widely accepted technique is the 2 parallel opposing anterior-posterior fields, single anterior field is also considered as a suitable option. Higher doses are needed for CLL patients compared to CML patients.

Computerized treatment planning in radiation therapy of intact breast: influence of number of CT-cuts.

PURPOSE: To compare the accuracy of 2D algorithm with an established 3D algorithm, and to define the number of CT-slices needed for treatment planning of intact breast irradiation. MATERIAL AND METHODS: Twenty patients with breast cancer treated with conservative surgery were included in this study, ten of them had right breast cancer and the other 10 patients had cancer of the left breast. For each patient, 3-D calculations (HeLax-TMS) were performed using one CT-slice (central), 3 CT-slices (central, caudal, and cephalic) and full set CT-slices in addition to 2D calculations (Multidata System) on the digitized central cut. All calculations were done using 6MV-photon. RESULTS: When using 2D planning with lung correction, a large hot area of 105% was found at the medial and lateral subcutaneous (SC) regions. Comparison of 2D-treatment planning using Multidata System (2D-physics) and 2D-planning using HeLax System (3D-physics) showed that the 2D planning using Multidata System gave a large hot area of 105% compared with HeLax-2D at the subcutaneous region. The central axis dose distributions obtained from 2D and 3D calculations using HeLax system were compared. No differences were found in the two planes (central cut plane) and this was because the two planes were based on the same algorithm. The only difference was that the hot area (110%) was found at the superior or the inferior border of the field. Also, a comparison using the 3D-system for the central slice and the multiple slices showed a difference in calculating the maximum dose to the target of 2.19%, which was Statistically significant (p=0.001). For all left sided patients, the maximum dose to the heart was significantly different from one to full CT-cuts. It was 12.0+/-6.0% when using one CT-cut versus 6.6+/-1.3% when using full CT-cuts (p<0.03). We compared isodose distributions using three and full CT-cuts for both small and large breasts. For the large breast patients, larger differences in isodose distributions were observed in the cephalic and the caudal planes than for small breast patients. CONCLUSION: Dose distributions based on a single CT cut through the central axis using 2D or even 3D treatment planning system will lead, quite often, to hot volumes in 76 excess of 105%. For patients whose breast contours vary slowly within the tangential fields, a three-slice CT scan appears to be adequate for clinical decision. However, for patients with large variation of contours within the tangential fields, a full CT scan gives more accurate dose distributions than the three-slice model.