Skipping the clinical target volume (CTV) around the primary tumor in limited-stage small cell lung cancer

Omission of Clinical Target Volume (CTV) for Primary Tumors in Limited-Stage Small Cell Lung Cancer: A Prospective Multicenter Randomized Controlled Trial

This trial tests whether giving chest radiotherapy that skips the usual extra margin around the main tumor is as effective and causes fewer side effects for people with limited-stage small cell lung cancer who have responded to initial chemotherapy.

Quick facts

• Phase: PHASE3
• Study type: Interventional
• Enrollment: 852 (estimated)
• Ages: 18 Years to 75 Years
• Sex: All
• Sponsor: Sun Yat-sen University (other)
• Locations: 2 sites (Guangzhou, Guangdong and 1 other locations)
• Trial ID: NCT07008716 on ClinicalTrials.gov

What this trial studies

This is a randomized phase 3 non-inferiority trial comparing two radiation approaches for limited-stage small cell lung cancer after 2–4 cycles of etoposide with cisplatin or carboplatin. One arm receives radiotherapy that omits the clinical target volume (CTV) for the primary tumor, while the control arm receives standard radiotherapy including CTV; both arms may include prophylactic cranial irradiation as indicated. The trial compares local control, progression, survival outcomes, and treatment-related toxicity between the groups. The aim is to see if smaller target volumes can maintain tumor control while reducing dose to nearby organs and treatment side effects.

Who should consider this trial

Good fit: Adults aged 18–75 with histologically confirmed limited-stage small cell lung cancer, good performance status (KPS ≥ 80), measurable disease, adequate blood and organ function, and no progression after 2–4 cycles of etoposide plus cisplatin or carboplatin are ideal candidates.

Not a fit: Patients with extensive-stage disease, intrapulmonary metastases, progression after initial chemotherapy, poor performance status, or significant comorbidities are unlikely to benefit from this trial approach.

Why it matters

Potential benefit: If successful, this approach could maintain local tumor control while reducing radiation dose to nearby organs and lowering treatment side effects.

How similar studies have performed: Margin-reduction approaches have shown promise in other lung cancer settings for lowering toxicity, but high-level phase 3 evidence specifically supporting omission of CTV in limited-stage SCLC is limited and this approach is relatively novel for this disease.

Eligibility criteria

Inclusion Criteria:

1. Small cell lung cancer confirmed by histology or cytology; TNM stage IA-IIIC (AJCC 8th edition, 2017; limited-stage) without intrapulmonary metastasis;
2. Aged 18-75 years, KPS score ≥ 80, ≤ 10% weight loss within the past 6 months;
3. Have measurable lesions per RECIST 1.1 criteria;
4. Have no disease progression after 2-4 cycles of etoposide/carboplatin or etoposide/cisplatin;
5. Lung function test: FEV1 ≥ 1 L (Optional);
6. Complete blood count: neutrophil count ≥ 1.5 x 10\^9/L, hemoglobin ≥ 100 g/L, platelet count ≥ 100 x 10\^9/L;
7. Renal function: serum creatinine ≤ 1.5 x upper limit of normal (ULN);
8. Liver function: AST and ALT ≤ 2.5 x ULN, bilirubin ≤ 1.5 x ULN;
9. Fully understand the study, able to complete treatment and follow-up, and voluntarily sign the informed consent.

Exclusion Criteria:

1. Other malignant tumors (prior or concurrent), except those that have been curatively treated with disease-free survival ≥ 5 years, such as non-melanoma skin cancer, cervical carcinoma in situ, or early-stage papillary thyroid cancer;
2. Uncontrolled heart disease or myocardial infarction within the past 6 months;
3. Patients with a history of mental illness;
4. Pregnant and lactating patients;
5. Poorly controlled diabetes and hypertension;
6. Interstitial pneumonia or active pulmonary fibrosis;
7. Active infection;
8. Other conditions unsuitable for enrollment (per investigator judgment).

Where this trial is running

Guangzhou, Guangdong and 1 other locations

• Sun Yat-sen University Cancer Center — Guangzhou, Guangdong, China (RECRUITING)
• Zhejiang Provincial Cancer Hospital — Hangzhou, Zhejiang, China (RECRUITING)

Study contacts

• Study coordinator: Ming Chen

Conditions: SCLC, Limited Stage, Radiation Exposure, Radiotherapy Side Effect, Progression