External beam radiotherapy for stage I and nonbulky stage II disease
Refer patients with stage I and nonbulky stage II seminomas for external beam radiotherapy. Over a 3-week period, administer 2500 cGy in a hockey-stick field, including the para-aortic, paracaval, bilateral common iliac, and external iliac nodal regions. Recent protocols are reducing the radiation field to the para-aortic area only.
A 2005 randomized trial from the Medical Research Council compared adjuvant radiotherapy at 30 Gy versus 20 Gy for stage I seminoma. The lower dose resulted in equivalent associated relapse rates and reduced morbidity, especially regarding fatigue. Further follow-up was recommended to determine if associated long-term secondary malignancies develop.[23]
Mediastinal radiation was commonly administered but is currently avoided because chemotherapy is more effective. Mediastinal radiation may also diminish the ability to provide salvage chemotherapy later, if needed.
Only 3% of patients relapse after radiation therapy. Relapses are usually located outside the radiation field.
Short-term adverse effects include fatigue, nausea, vomiting, and GI upset.
Long-term adverse effects have become of more concern over the last several years. Zagars and colleagues (2004) published a review of all patients who underwent radiotherapy postorchiectomy for seminoma between 1951 and 1999. They then computed standardized mortality ratios based on the person-years method. They found an increased risk after 15 years for cardiovascular and secondary cancer mortalities and recommended investigating new therapies that do not confer these long-term effects.[24] Gamulin et al recommend cytogenetic screening as a way to detect high-risk individuals and thereby regularly monitor seminoma patients after the successful therapy.[25]
As an alternative to radiotherapy, single-agent carboplatin protocols are being studied. The Medical Research Council compared adjuvant carboplatin with radiotherapy and found equivalent relapse rates after a median follow-up period of 4 years. Long-term success of carboplatin therapy is unknown so should be considered experimental at this time.[26]
Chemotherapy for stage II bulky or stage III disease
After radical orchiectomy (see Surgical Care) and metastatic workup, administer 4 cycles of chemotherapy without radiotherapy in patients with advanced seminoma (stage IIB bulky or stage III).[27]
Clinical trials have evaluated numerous chemotherapeutic regimens. While the optimal regimen is debatable, 4 cycles of bleomycin, etoposide, and cisplatin (BEP) is standard.
Ongoing clinical trials are evaluating the omission of the fourth cycle, or bleomycin, in low-risk patients.
For poor-risk and salvage cases, physicians may use alternative regimens using ifosfamide and vinblastine with dose escalation.
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