What is the recommended post‑treatment surveillance schedule—including clinic visit frequency, laboratory tests, imaging studies, cardiac echocardiography, audiometry, and renal monitoring—for an adolescent who has completed curative surgery and adjuvant chemotherapy for osteosarcoma?

Post-Treatment Surveillance for Adolescent Osteosarcoma

Adolescents who have completed curative treatment for osteosarcoma should undergo surveillance every 3 months for the first 2 years, then every 4 months during year 3, every 6 months during years 4-5, and annually thereafter, with each visit including physical examination, chest imaging, plain radiographs of the primary site, and monitoring for treatment-related toxicities. 1

Surveillance Schedule and Visit Frequency

The surveillance intensity is highest during the first 2 years when recurrence risk is greatest, then gradually decreases:

• Years 1-2: Every 3 months 1
• Year 3: Every 4 months 1
• Years 4-5: Every 6 months 1
• Years 5-10: Every 6 months 1
• Beyond 10 years: Every 6-12 months 1

Important caveat: Late metastases can occur more than 10 years after diagnosis, and there is no universally accepted stopping point for tumor surveillance. 1 This necessitates lifelong vigilance, particularly in adolescent patients who have decades of life ahead.

Components of Each Surveillance Visit

Clinical Assessment

• Complete physical examination focusing on the primary tumor site 1
• Functional assessment of any reconstruction and orthopedic complications at every visit 1
• Assessment for symptoms suggesting recurrence or metastatic disease 1

Imaging Studies

Chest Surveillance

• Chest X-ray at every visit 1
• Chest CT if chest X-ray becomes abnormal 1
• Chest CT is superior to plain radiography for detecting pulmonary metastases, which are the most common site of recurrence 1

Primary Site Monitoring

• Plain radiographs of the primary tumor site every 4 months until the end of year 4 1
• This monitors for local recurrence and assesses bone healing/reconstruction integrity 1

Optional Additional Imaging

• Bone scan (category 2B) may be considered, though not routinely required 1
• For Ewing sarcoma (not osteosarcoma), isotope bone scanning is more commonly used due to higher risk of osseous metastases 1

Monitoring for Treatment-Related Toxicities

Critical consideration: Multimodal therapy with chemotherapy (doxorubicin, cisplatin, high-dose methotrexate, ifosfamide) causes permanent organ damage requiring lifelong monitoring. 1

Cardiac Monitoring

• Echocardiography to assess for anthracycline-induced cardiomyopathy 1
• Doxorubicin causes dose-dependent cardiac toxicity that may manifest years after treatment 1
• Monitoring should continue for more than 10 years after treatment 1

Renal Function Monitoring

• Serial renal function tests to detect cisplatin and high-dose methotrexate nephrotoxicity 1
• Assess glomerular filtration rate and tubular function 1

Audiometry

• Regular hearing assessments for cisplatin-induced ototoxicity 1
• High-frequency hearing loss is common and may be progressive 1

Reproductive Function Assessment

• Fertility counseling and monitoring as chemotherapy can cause gonadal dysfunction 1
• Particularly important for adolescents approaching reproductive age 1

Secondary Malignancy Surveillance

• Monitor for secondary cancers, including acute myeloid leukemia (as early as 2-5 years post-treatment) and radiation-induced sarcomas 1
• Risk persists lifelong, requiring continued vigilance 1

Laboratory Tests

While the guidelines do not specify routine laboratory tests at each visit, the following are implied by the toxicity monitoring requirements:

• Complete blood count (monitoring for secondary leukemia) 1
• Renal function tests (creatinine, BUN, electrolytes) 1
• Liver function tests (if indicated by clinical status)

Common Pitfalls to Avoid

Do not rely solely on chest X-ray for pulmonary surveillance: CT scans are more sensitive and tend to detect metastases that plain films miss. 1 However, the guidelines recommend chest X-ray at each visit with CT reserved for abnormal findings, balancing radiation exposure concerns in adolescents. 1

Do not stop surveillance at 5 years: Unlike many cancers, osteosarcoma can recur after prolonged disease-free intervals exceeding 10 years. 1 Adolescent patients require particularly long-term follow-up given their life expectancy.

Do not neglect functional and quality-of-life assessments: Functional reassessment should occur at every visit, as limb salvage procedures and chemotherapy can cause progressive orthopedic problems and functional decline. 1

Do not forget late effects monitoring: The toxicity monitoring is as important as tumor surveillance, as treatment-related morbidity significantly impacts long-term quality of life and mortality. 1