Stem Cell Transplant
Autologous stem cell transplant (SCT) is the preferred type of SCT for patients with testicular cancer and involves delivery of high doses of chemotherapy followed by infusion of patient-derived myeloid stem cells. While the details of this treatment are outside the scope of this review, decades of experience has shown that this is an effective curative option for a subset of patients with poor prognosis, such as those with platinum-refractory or relapsed disease.36
Due to excellent clinical outcomes with front-line therapy, as described, and the relatively low incidence of testicular and other germ cell tumors, clinical trial options for patients with testicular cancer are limited. The TIGER trial is an ongoing international, randomized, phase 3 trial comparing conventional TIP (paclitaxel, ifosfamide, and cisplatin) chemotherapy with high-dose chemotherapy with SCT as the first salvage treatment for relapsed/refractory germ cell tumors (NCT02375204). It is enrolling at multiple centers in the United States and results are expected in 2022. At least 2 ongoing trials are evaluating the role of immunotherapy in patients with relapsed/refractory germ cell tumors (NCT03081923 and NCT03726281). Cluster of differentiation antigen-30 (CD30) has emerged as a potential target of interest in germ cell tumors, and brentuximab vedotin, an anti-CD30 monoclonal antibody, is undergoing evaluation in a phase 2 trial of CD-30–expressing germ cell tumors (NCT01851200). This trial has completed enrollment and results are expected to be available in late 2019 or early 2020.
When possible, patients with relapsed/refractory germ cell tumors should be referred to centers of excellence with access to either testicular/germ-cell tumor specific clinical trials or phase 1 clinical trials.
Adjuvant radiation to the retroperitoneum has a role in the management of stage I and IIA seminomas (Table 3). In a randomized noninferiority trial of radiation therapy versus single-dose carboplatin in stage I seminoma patients, 5-year recurrence-free survival was comparable at approximately 95% in either arm.37,38 In a retrospective database review of 2437 patients receiving either radiation therapy or multi-agent chemotherapy for stage II seminoma, the 5-year survival exceeded 90% in both treatment groups.39 Typically, a total of 30 to 36 Gy of radiation is delivered to para-aortic and ipsilateral external iliac lymph nodes (“dog-leg” field), followed by an optional boost to the involved nodal areas.40 Radiation is associated with acute side effects such as fatigue, gastrointestinal effects, myelosuppression as well as late side effects such as second cancers in the irradiated field (eg, sarcoma, bladder cancer).
Evaluation of Treatment Response
Monitoring of treatment response is fairly straightforward for patients with testicular cancer. Our practice is the following:
- Measure tumor markers on day 1 of each chemotherapy cycle and 3 to 4 weeks after completion of treatment.
- CT of the chest, abdomen, and pelvis with intravenous contrast prior to chemotherapy and upon completion of chemotherapy. Interim imaging is only needed for a small subset of patients with additional clinical indications (eg, new symptoms, lack of improvement in existing symptoms).
- For patients with stage II/III seminoma who have a residual mass ≥ 3 cm on post-treatment CT scan, a PET-CT scan is indicated 6 to 8 weeks after the completion of chemotherapy to determine the need for further treatment.
Because testicular cancer has high cure rates even when patients have disease relapse after primary therapy, and additional therapies have significant short- and long-term side effects in these generally young patients, active surveillance is a critical option used in the management of testicular cancer.41
Patients must be counseled that active surveillance is a form of treatment itself in that it involves close clinical and radiographic monitoring. Because there is a risk of disease relapse, patients opting to undergo active surveillance must fully understand the risks of disease recurrence and be willing to abide by the recommended follow-up schedule.
Surveillance is necessary for a minimum of 5 years and possibly 10 years following orchiectomy, and most relapses tend to occur within the first 2 years. Late relapses such as skeletal metastatic disease from seminoma have been reported to occur more than 15 years after orchiectomy, but are generally rare and unpredictable.
The general guidelines for active surveillance are as follows:
For patients with seminoma, history and physical exam and tumor marker assessment should be performed every 3 to 6 months for the first year, then every 6 to 12 months in years 2 and 3, and then annually. CT of the abdomen and pelvis should be done at 3, 6, and 12 months, every 6 to 12 months in years 2 and 3, and then every 12 to 24 months in years 4 and 5. A chest radiograph is performed only if clinically indicated, as the likelihood of distant metastatic recurrence is low.
For patients with nonseminoma, history and physical exam and tumor markers assessment should be performed every 2 to 3 months for first 2 years, every 4 to 6 months in years 3 and 4, and then annually. CT of the abdomen and pelvis should be obtained every 4 to 6 months in year 1, gradually decreasing to annually in year 3 or 4. Chest radiograph is indicated at 4 and 12 months and annually thereafter for stage IA disease. For those with stage IB disease, chest radiograph is indicated every 2 months during the first year and then gradually decreasing to annually beginning year 5.
These recommendations are expected to change over time, and treating physicians are recommended to exercise discretion and consider the patient and tumor characteristics to develop the optimal surveillance plan.