Influence of the breast prosthesis volume in dose distribution in radiotherapy planning

Introduction: The challenge of modern radiotherapy (RT) in breast cancer is to maintain its satisfactory oncological results, adapting to oncoplastic surgery and avoiding possible cosmetic damage. Considering that the breast prosthesis is not a target volume in RT planning, this study sought to analyze the effect of this volume on the coverage of the clinical target volume (CTV) of the breast. Methods: We performed a retrospective analysis of plans in 48 patients who submitted to RT in the first half of 2014. Two volumes were measured, such as breast CTV (breast tissue with the prosthesis) and real CTV (breast tissue excluding the prosthesis). The D95% values (dose that covers 95% of the volume) for each of them were verified and related to the volume of each one as well as the volume of breast prosthesis. Results: The analysis of the CTVs showed a significant difference between the mean volumes for the real CTV and breast CTV. While performing the CTV coverage, including the prosthesis, there is a perception that the dose covered 95% of the volume. Nevertheless, the analysis of the same plan after prosthesis volume exclusion revealed a difficulty in covering 95% of the breast tissue volume, indicating the interference of the prosthesis in therapy planning. Considering the dosimetric aspects, there were patients with real CTV values below the ideal dose of 47.5 Gy, after exclusion of implant volume. Conclusions: Our data reflected the volume of the prosthesis as an important variable that should be considered when planning adjuvant RT.

Antibody reactivity against potato apyrase, a protein that shares epitopes with Schistosoma mansoni ATP diphosphohydrolase isoforms, in acute and chronically infected mice, after chemotherapy and reinfection

Schistosoma mansoni ATP diphosphohydrolase isoforms and potato apyrase share conserved epitopes. By enzyme-linked immunosorbent assays, elevated levels of IgM, IgG2a and IgG1 antibody reactivity against potato apyrase were observed in S. mansoni-infected BALB/c mice during the acute phase of infection, while only IgM and IgG1 antibody reactivity levels maintained elevated during the chronic phase of infection. Antibody reactivity against potato apyrase was monitored over an 11-month period in chronically-infected mice treated with oxamniquine. Eleven months later, the level of seropositive IgM decreased significantly (~30 percent) compared to the level found in untreated, infected mice. The level of seropositive IgG1 decreased significantly four months after treatment (MAT) (61 percent) and remained at this level even after 11 months. The IgG2a reactivity against potato apyrase, although unchanged during chronic phase to 11 MAT, appeared elevated again in re-infected mice suggesting a response similar to that found during the acute phase. BALB/c mouse polyclonal anti-potato apyrase IgG reacted with soluble egg antigens probably due to the recognition of parasite ATP diphosphohydrolase. This study, for the first time, showed that the IgG2a antibody from S. mansoni-infected BALB mice cross-reacts with potato apyrase and the level of IgG2a in infected mice differentiates disease phases. The results also suggest that different conserved-epitopes contribute to the immune response in schistosomiasis.

Radioterapia externa conformada 3D para o carcinoma de próstata: experiência do Instituto do Radium de Campinas com 285 pacientes / 3D conformal external beam radiation therapy for prostate carcinoma: an experiment of Instituto do Radium de Campinas with 285 patients

OBJETIVO: Reportar resultados de tratamentos do câncer de próstata com radioterapia conformada 3D realizadosem uma única instituição. MATERIAIS E MÉTODOS: De julho de 1997 a janeiro de 2002, 285 pacientes consecutivos com câncer de próstata foram submetidos a radioterapia conformada 3D com dose mediana de 7.920 cGy na próstata e analisados retrospectivamente. A distribuição segundo o grupo de risco foi a seguinte: baixo risco ù 95 (33,7%); risco intermediário ù 66 (23,4%); alto risco ù 121 (42,9%) pacientes. RESULTADOS: Em seguimento mediano de 53,6 meses (3,6û95,3 meses), sobrevidas atuariais global, causa específica, livre de metástases a distância e livre de recidiva bioquímica em cinco anos foram de 85,1%, 97,0%, 94,2% e 75,8%, respectivamente. Sobrevidas atuariais livre de toxicidade retal e urinária tardias em cinco anos foram de 96,4% e 91,1%, respectivamente. Ressecção transuretral pré-radioterapia conformada 3D e doses > 70 Gy em 30% do volume da bexiga implicaram maior toxicidade urinária tardia grau 2-3 em cinco anos (p = 0,0002 e p = 0,0264, respectivamente). CONCLUSÃO: A primeira experiência relatada de radioterapia conformada 3D no Brasil permitiu altas doses de radiação, com toxicidades retal e urinária aceitáveis. A existência de ressecção transuretral de próstata pré-radioterapia conformada 3D pode sinalizar maior risco de toxicidade urinária tardia grau 2-3 após irradiação. Restrição da dose ≤ 70 Gy em 30% do volume da bexiga à tomografia de planejamento pode reduzir complicações urinárias tardias.

OBJECTIVE: To report the outcomes of 3D conformal radiation therapy for prostate cancer in a single institution.MATERIALS AND METHODS: From July 1997 to January 2002, 285 consecutive patients with prostate cancer were submitted to 3D conformal radiation therapy receiving a median dose of 7,920 cGy to the prostate, and were retrospectively evaluated. The patients distribution according to the level of risk was the following: low risk û 95 (33.7%); intermediate risk û 66 (23.4%); high risk û 121 (42.9%) patients. RESULTS: Median follow-up of 53.6 months (3.6û95.3 months) demonstrated 85.1% actuarial five-year overall survival, 97.0% specific cause survival, 94.2% five-year distant metastasis-free survival, and 75.8% five-year biochemical recurrence-free survival. Rates of five-year actuarial survival free from late rectal and urinary toxicity were 96.4% and 91.1% respectively. Pre-3D conformal radiation therapy transurethral resection of the prostate and doses > 70 Gy in 30% of the bladder volume implied a higher grade 2-3 late urinary toxicity in five years (p = 0.0002 and p = 0.0264, respectively). CONCLUSION: The first experiment with 3D conformalradiation therapy reported in Brazil allowed high radiation doses with acceptable levels of urinary and rectaltoxicity. Pre-3D conformal radiation therapy transurethral resection of prostate may determine a higher riskfor post-irradiation grade 2-3 late urinary toxicity. At the tomography planning, the reduction of the radiationdose to ≤ 70 Gy in 30% of the bladder volume may reduce the risk for late urinary complications.

Biochemical Relapse for Prostate Cancer Following Radical Prostatectomy: Salvage Radiotherapy Without HormonalTherapy

Objectives: This paper aims to study biochemical control, hormonal therapy-free survival, and prognostic factors related tosalvage radiation for prostate cancer patients submitted to radical prostatectomy (RP) without hormonal therapy (HT) before orduring radiation. Materials and Methods: from August 2002 to July 2004, 39 prostate cancer patients submitted to RPpresented biochemical failure after achieving PSA nadir (<0.2ng/ml). All patients were submitted to three-dimensional conformalexternal beam radiation therapy (3DC-EBRT) and no patients had received HT. Median age was 62 years, median preoperativePSA was 9.4ng/ml, median Gleason Score was 7. We defined PSA rise above 0.2 as biochemical failure after surgery. Median3DC-EBRT dose was 70Gy, and biochemical failure after EBRT was defined as three consecutive rises in PSA or a single risesufficient to trigger HT. Results: Biochemical non-evidence of disease (BNED) in 3 years was 72%. PSA doubling time (PSADT)lower than 4 months (p=0.04), and delay to salvage EBRT (p=0.05) were associated to worse chance of successful salvagetherapy. Late morbidity was acceptable. Conclusion: Expressive PSA control (72% BNED / 3years) could be achieved withsalvage radiotherapy in well-selected patients. The importance of PSADT was confirmed, and radiotherapy should be started asearly as possible. Follow-up is somewhat short, but it is possible to conclude that it is possible to achieve a long interval freefrom hormonal therapy with low rate of toxicity, avoiding or at least delaying morbidity related to hormonal treatment.radiotherapy