Outcomes of surveillance versus adjuvant treatment for patients with stage-I seminoma: a single-center experience.

INTRODUCTION: Testicular germ cell tumors (seminoma/non-seminoma) are the most common carcinomas in young males, comprising approximately 1% of all carcinomas. In stage-I disease, orchiectomy can cure approximately 85% of patients. Post-surgical options are adjuvant therapy and active surveillance. Our study examined the effects of management options on stage-I seminoma patients followed in our center. METHODS: We evaluated the patients with stage-I testicular seminoma who underwent radical orchiectomy and followed up in the oncology center between 2001 and 2022. The outcomes of management options, survivals were retrospectively analyzed. The prognostic significance of risk factors for relapse on survival was evaluated. RESULTS: Of the 140 patients with stage-I seminoma, 49 (35%) were treated with adjuvant therapy, and 91 (65%) underwent surveillance. The median follow-up duration was 37 months. During the follow-up period, nine patients in the active surveillance group and four in the adjuvant therapy group had a recurrence. There was no statistically significant difference between the two groups (p = 0.67). In the surveillance group, the univariate and multivariate analyzes identified the presence of lymphovascular invasion (p = 0.005, HR: 0.13) as significant prognostic factor for disease-free survival (DFS). In the surveillance cohort, the 5-year DFS rate was 60% for patients with lymphovascular invasion and 93% for those without. There was statistical significance between the two groups (p = 0.003). CONCLUSION: Our study shows that adjuvant therapy does not significantly improve DFS compared to surveillance in patients. In addition, it has been shown that lymphovascular invasion is an important prognostic indicator for DFS in determining the treatment strategy.

Relationship between dose and stopping power values for electrons in skin and muscle tissues.

Absorbed dose and stopping power of the target material are two important parameters for determining the radiation effects. In this work, the relationship between these two parameters has been investigated for electron beams incident on skin and muscle tissue. Absorbed dose was obtained by using the EGSnrc code and the stopping power values were calculated by considering the velocity-depended effective charge and mean excitation values. To obtain the relationship between absorbed dose and stopping power values, these parameters were graphed together and simple fitting functions have been obtained. The results obtained show that these parameters are linearly correlated with each other.