# Clinical Cases: Radiation Oncology

## Case 1: Adjuvant Radiation for Breast Cancer

### Patient Presentation
**Demographics:** 52-year-old female marketing executive

**Chief Complaint:** "I had my lumpectomy for breast cancer and my surgeon says I need radiation to reduce the chance of it coming back."

**History of Present Illness:**
A 52-year-old postmenopausal woman presents to the radiation oncology department for consultation regarding adjuvant radiation therapy following breast-conserving surgery (lumpectomy) for early-stage breast cancer. She was diagnosed 6 weeks ago after a screening mammogram revealed a 1.8 cm spiculated mass in the upper outer quadrant of her left breast. Ultrasound-guided core needle biopsy confirmed invasive ductal carcinoma, grade 2, ER+/PR+, HER2-negative, Ki-67 18%.

She underwent lumpectomy with sentinel lymph node biopsy 3 weeks ago. Surgical pathology confirmed a 2.1 cm invasive ductal carcinoma with negative margins (closest margin 4 mm), no lymphovascular invasion, and 0/3 sentinel lymph nodes positive for metastatic disease. Final pathologic stage: pT2N0M0, Stage IIA. Oncotype DX recurrence score was 16 (low-intermediate), supporting endocrine therapy alone without adjuvant chemotherapy.

She has been referred for adjuvant whole-breast radiation therapy with consideration of boost to the tumor bed. She is anxious about potential side effects, particularly cardiac toxicity given that the left breast is being treated.

**Past Medical History:**
- Breast cancer (newly diagnosed, as above)
- Hypertension, well-controlled
- Gastroesophageal reflux disease
- No prior radiation exposure
- Menopausal since age 49

**Medications:**
- Amlodipine 5 mg daily
- Omeprazole 20 mg daily
- Recently started anastrozole 1 mg daily (aromatase inhibitor)

**Social History:**
- Marketing executive, works full-time
- Non-smoker
- Social wine drinker (1-2 glasses per week)
- Divorced, two adult children
- Exercises regularly (yoga, walking)

**Family History:**
- Mother: breast cancer at age 68 (ER+, treated with mastectomy)
- Father: hypertension
- Genetic testing: BRCA1/2 negative

### Physical Examination
- **Vital Signs:** BP 128/76 mmHg, HR 72 bpm, RR 14/min, Temp 36.8°C, SpO2 99% on room air
- **General:** Well-appearing female in no acute distress
- **Left breast:** Well-healed lumpectomy incision in UOQ, mild residual ecchymosis, no seroma, no skin changes; breast cosmesis good
- **Right breast:** Normal, no masses
- **Lymph nodes:** No palpable axillary, supraclavicular, or cervical lymphadenopathy bilaterally
- **Cardiovascular:** Regular rate and rhythm, no murmurs
- **Lungs:** Clear bilaterally
- **Chest wall:** Normal, no tenderness

### Workup and Results

**Laboratory Studies:**
| Test | Result | Reference Range |
|------|--------|-----------------|
| CBC | Normal | - |
| CMP | Normal | - |
| Vitamin D | 32 ng/mL | 30-100 ng/mL |
| CA 15-3 | 12 U/mL | <30 U/mL |

**Surgical Pathology Summary:**
| Feature | Result |
|---|---|
| Tumor size | 2.1 cm |
| Histology | Invasive ductal carcinoma, grade 2 |
| Margins | Negative (closest 4 mm) |
| ER/PR | Positive (95%/80%) |
| HER2 | Negative (IHC 1+) |
| Ki-67 | 18% |
| LVI | Absent |
| Sentinel nodes | 0/3 positive |
| Stage | pT2N0M0, Stage IIA |
| Oncotype DX RS | 16 |

**Radiation Treatment Planning:**
- **CT simulation:** Patient positioned supine on wing board with left arm abducted; 3 mm CT slices through thorax; respiratory assessment performed
- **Target volumes:**
  - Clinical Target Volume (CTV): Entire left breast tissue (whole breast CTV)
  - Boost CTV: Tumor bed with 1.5 cm expansion (guided by surgical clips)
  - Planning Target Volume (PTV): CTV + 5 mm expansion for setup uncertainty
- **Organs at risk (OAR) dose constraints:**
  - Heart: Mean dose <4 Gy (QUANTEC); V25Gy <10%
  - Left anterior descending artery (LAD): Mean dose <10 Gy
  - Ipsilateral lung: V20Gy <30%; mean lung dose <15 Gy
  - Contralateral breast: Mean dose <3 Gy

### Clinical Image

![Breast RT Treatment Planning](case_01_image.jpg)

*Diagram showing radiation treatment planning for left breast cancer, illustrating tangential beam arrangement, dose distribution with color wash, and critical organ-at-risk structures (heart, LAD artery, ipsilateral lung) with deep inspiration breath hold (DIBH) technique. Source: Educational illustration.*

### Diagnosis
**Left Breast Invasive Ductal Carcinoma, pT2N0M0, Stage IIA, ER+/PR+/HER2-, Status Post Breast-Conserving Surgery, Requiring Adjuvant Whole-Breast Radiation Therapy**

**Key Diagnostic Criteria:**
- Invasive ductal carcinoma confirmed on surgical pathology
- Breast-conserving surgery with negative margins
- Node-negative disease (0/3 sentinel nodes)
- Adjuvant radiation therapy is standard of care after lumpectomy, reducing ipsilateral breast recurrence from ~30% to ~10% at 10 years
- Left-sided breast cancer requiring cardiac-sparing techniques

### Treatment Plan
1. **Whole-breast radiation:** Hypofractionated regimen -- 40 Gy in 15 fractions (2.67 Gy/fraction) over 3 weeks to the whole breast (per UK FAST-Forward trial and ASTRO guidelines for hypofractionation)
2. **Tumor bed boost:** 10 Gy in 4 fractions (2.5 Gy/fraction) to the lumpectomy cavity (age 52 with grade 2 tumor; boost reduces local recurrence by an additional 50% relative risk reduction)
3. **Cardiac-sparing technique:** Deep inspiration breath hold (DIBH) for all fractions -- patient holds breath during treatment, displacing heart away from treatment field; target mean heart dose <2 Gy
4. **Treatment technique:** Tangential field-in-field IMRT (forward-planned) to improve dose homogeneity across the breast; daily image guidance with surface-guided radiation therapy (SGRT) for setup verification
5. **Side effect management:**
   - Skin care: Aquaphor or aloe-based moisturizer to treatment area starting week 1; avoid irritants
   - Fatigue: Expected mild-moderate; continue exercise as tolerated
   - Monitor for radiation dermatitis (expected peak 1-2 weeks after completion)
6. **Continue anastrozole:** 1 mg daily for planned 5-10 years of adjuvant endocrine therapy
7. **Follow-up:** Post-treatment evaluation at 4-6 weeks; mammography at 6 months post-RT (new baseline); annual surveillance mammography thereafter

### Key Learning Points
- Adjuvant whole-breast radiation after breast-conserving surgery reduces the 10-year ipsilateral breast recurrence rate by approximately two-thirds and provides a modest overall survival benefit
- Hypofractionated whole-breast radiation (40 Gy/15 fractions or 42.5 Gy/16 fractions) is now the standard of care for most patients, with equivalent efficacy and comparable or improved toxicity compared to conventional fractionation (50 Gy/25 fractions)
- Deep inspiration breath hold (DIBH) is a critical cardiac-sparing technique for left-sided breast radiation, reducing mean heart dose by 40-60% compared to free-breathing treatment
- The tumor bed boost provides an additional absolute local recurrence benefit of 3-4% at 20 years, with the greatest benefit in younger patients (<50 years)
- Radiation planning for breast cancer requires careful attention to organs at risk, particularly the heart (long-term cardiovascular risk), LAD artery, and ipsilateral lung

---

## Case 2: Definitive Chemoradiation for Head and Neck Cancer

### Patient Presentation
**Demographics:** 57-year-old male truck driver

**Chief Complaint:** "I've had a sore throat for 3 months and found a lump in my neck."

**History of Present Illness:**
A 57-year-old male presents with a 3-month history of progressive sore throat, initially on the left side, now bilateral. He reports difficulty swallowing solid foods and has lost 7 kg over 3 months. Two weeks ago, he noticed a firm, non-tender lump in his left neck. He also reports referred pain to his left ear (otalgia) and a change in voice quality (muffled, "hot potato" voice). He denies hemoptysis, stridor, or trismus.

He was evaluated by his primary care physician, who referred him to an otolaryngologist. Flexible nasopharyngolaryngoscopy revealed a 3 cm exophytic mass arising from the left base of tongue extending to the left tonsillar fossa. Biopsy confirmed squamous cell carcinoma, p16-positive (HPV-associated). CT neck with contrast and PET/CT were performed for staging.

Given the stage and HPV-positive status, the multidisciplinary tumor board recommended definitive concurrent chemoradiation therapy with organ preservation, rather than primary surgery.

**Past Medical History:**
- Hypertension
- Gastroesophageal reflux disease
- No prior head and neck cancer
- No prior radiation exposure

**Medications:**
- Losartan 50 mg daily
- Omeprazole 40 mg daily

**Social History:**
- Truck driver (long-haul)
- Former smoker: 15 pack-years, quit 10 years ago
- Social alcohol: 4-6 beers per week
- Divorced, lives alone
- No illicit drug use

**Family History:**
- Father: lung cancer at age 72
- No family history of head and neck cancer

### Physical Examination
- **Vital Signs:** BP 136/82 mmHg, HR 78 bpm, RR 14/min, Temp 37.0°C, SpO2 98% on room air, Weight 82 kg (down from 89 kg), Height 180 cm
- **General:** Thin male, appears fatigued, mild odynophagia when speaking
- **HEENT:**
  - Oral cavity: Normal dentition (dental clearance obtained pre-RT), no trismus (interincisal distance 42 mm)
  - Oropharynx: 3 cm exophytic, ulcerated mass arising from left base of tongue, crossing midline, extending to left tonsillar fossa; right tonsil appears normal
  - Indirect laryngoscopy: Bilateral true vocal cord mobility normal
- **Neck:**
  - Left level II: 3.5 cm firm, fixed, non-tender lymph node
  - Left level III: 2.0 cm firm node
  - Right neck: no palpable lymphadenopathy
- **Cardiovascular:** Regular rate and rhythm
- **Lungs:** Clear bilaterally
- **Neurological:** Cranial nerves II-XII intact, no hypoglossal weakness

### Workup and Results

**Laboratory Studies:**
| Test | Result | Reference Range |
|------|--------|-----------------|
| CBC | Normal | - |
| CMP | Normal | - |
| Creatinine | 0.9 mg/dL | 0.7-1.3 mg/dL |
| eGFR | 88 mL/min | >60 mL/min |
| Albumin | 3.4 g/dL | 3.5-5.0 g/dL |
| TSH | 2.1 mIU/L | 0.4-4.0 mIU/L |
| Audiometry | Normal bilateral hearing | Baseline pre-cisplatin |

**Pathology:**
- Squamous cell carcinoma, non-keratinizing
- p16-positive by IHC (block positivity >70%)
- HPV-16 detected by in situ hybridization

**Imaging/Additional Studies:**
- **CT Neck with contrast:** 3.2 cm enhancing mass in left base of tongue crossing midline; left level II node 3.8 cm with central necrosis; left level III node 2.2 cm; no retropharyngeal nodes
- **F-18 FDG PET/CT:** Intensely FDG-avid primary tumor (SUVmax 18.2); FDG-avid left level II (SUVmax 12.4) and level III (SUVmax 8.8) nodes; no distant metastases; no FDG-avid contralateral nodes
- **MRI Neck:** Better soft tissue delineation; tumor extends to left glossotonsillar sulcus; no skull base invasion; no prevertebral fascia involvement
- **Staging:** T3N1M0 (AJCC 8th edition, p16-positive oropharyngeal), Stage I (p16+ staging)

### Clinical Image

![Head and Neck IMRT Planning](case_02_image.jpg)

*Diagram showing intensity-modulated radiation therapy (IMRT) treatment plan for oropharyngeal cancer with dose color wash demonstrating high-dose volume encompassing primary tumor and involved nodes, intermediate-dose volume covering at-risk nodal regions, and parotid gland sparing to reduce xerostomia. Source: Educational illustration.*

### Diagnosis
**HPV-Positive (p16+) Squamous Cell Carcinoma of the Left Base of Tongue, T3N1M0, AJCC 8th Edition Stage I, Planned for Definitive Concurrent Chemoradiation**

**Key Diagnostic Criteria:**
- Biopsy-confirmed squamous cell carcinoma with p16 positivity (HPV-associated)
- Primary tumor >4 cm (T3) involving left base of tongue crossing midline
- Ipsilateral single lymph node metastasis <6 cm (N1)
- No distant metastases on PET/CT
- p16-positive oropharyngeal SCC has a significantly better prognosis than HPV-negative disease (3-year OS >80%)

### Treatment Plan
1. **Radiation therapy prescription:**
   - **High-risk CTV (primary tumor + involved nodes):** 70 Gy in 35 fractions (2 Gy/fraction) over 7 weeks
   - **Intermediate-risk CTV (at-risk bilateral nodal levels II-IV, retropharyngeal nodes):** 56 Gy in 35 fractions (1.6 Gy/fraction) simultaneously
   - **Low-risk CTV (bilateral level V, level IB):** 54 Gy in 35 fractions (if indicated)
2. **Technique:** Volumetric modulated arc therapy (VMAT) with simultaneous integrated boost (SIB); daily CBCT for image guidance
3. **Concurrent chemotherapy:** Cisplatin 100 mg/m² IV on days 1, 22, and 43 of radiation (standard high-dose cisplatin regimen)
4. **Pre-treatment preparation:**
   - Dental extraction of carious teeth (completed)
   - Custom fluoride trays fabricated for daily fluoride application (lifelong for radiation caries prevention)
   - Prophylactic PEG tube placement given tumor size and anticipated severe mucositis/dysphagia
   - Baseline swallowing evaluation with speech-language pathology
   - Begin prophylactic swallowing exercises (Mendelsohn maneuver, tongue base retraction)
5. **OAR dose constraints:**
   - Parotid glands: Mean dose <26 Gy to at least one parotid (sparing to reduce xerostomia)
   - Spinal cord: Max dose <45 Gy
   - Brainstem: Max dose <54 Gy
   - Mandible: Max dose <70 Gy
   - Pharyngeal constrictors: Mean dose <50 Gy (reduce dysphagia)
   - Larynx: Mean dose <40 Gy
6. **Supportive care during treatment:**
   - Weekly oncology clinic visit for toxicity assessment and weight monitoring
   - Aggressive oral care (salt/baking soda rinses, nystatin for candidiasis prophylaxis)
   - Pain management escalation (viscous lidocaine to opioid analgesics as needed)
   - IV hydration with cisplatin; monitor renal function, electrolytes, audiometry
   - Nutritional support via PEG tube if oral intake <60% of caloric needs
7. **Post-treatment response assessment:** PET/CT at 12 weeks post-treatment completion; if complete metabolic response, surveillance; if residual PET-avid disease, consider neck dissection for nodal disease

### Key Learning Points
- HPV-positive oropharyngeal squamous cell carcinoma is a distinct disease entity with significantly better prognosis than HPV-negative disease, leading to de-escalation trials aimed at reducing treatment toxicity while maintaining cure rates
- Intensity-modulated radiation therapy (IMRT) or VMAT enables precise dose sculpting that spares parotid glands, significantly reducing the incidence and severity of chronic xerostomia compared to older 3D-conformal techniques
- Concurrent cisplatin-based chemoradiation is the standard of care for locally advanced oropharyngeal cancer, with cisplatin providing a 6-8% absolute survival benefit as a radiosensitizer
- Acute toxicities of head and neck chemoradiation include mucositis (grade 3 in ~50% of patients), dysphagia, dermatitis, and myelosuppression; proactive supportive care and nutritional support are essential
- Prophylactic swallowing exercises during and after radiation reduce the risk of chronic dysphagia and pharyngeal stricture, a major quality-of-life concern for long-term survivors

---

## Case 3: Stereotactic Body Radiation for Lung Cancer

### Patient Presentation
**Demographics:** 76-year-old female retired librarian

**Chief Complaint:** "They found a spot on my lung on a screening CT scan."

**History of Present Illness:**
A 76-year-old female presents to the radiation oncology department following diagnosis of an early-stage non-small cell lung cancer (NSCLC). She was enrolled in a low-dose CT lung cancer screening program due to her 45 pack-year smoking history (quit 8 years ago). Her annual screening LDCT revealed a new 2.2 cm solid, spiculated nodule in the right upper lobe that was not present on prior year's scan. PET/CT demonstrated the nodule to be intensely FDG-avid (SUVmax 8.4) with no mediastinal or hilar lymphadenopathy and no distant metastases. CT-guided percutaneous core needle biopsy confirmed adenocarcinoma (NSCLC), and staging was T1cN0M0, Stage IA3.

She was evaluated by thoracic surgery for consideration of lobectomy (standard of care for operable early-stage NSCLC). However, pulmonary function testing revealed severe COPD with an FEV1 of 0.82 L (38% predicted) and DLCO of 34% predicted. Her predicted post-operative FEV1 was calculated at 28% predicted, placing her at prohibitive surgical risk. The thoracic surgery team deemed her medically inoperable.

She was referred for stereotactic body radiation therapy (SBRT), which achieves local control rates of 90-95% for early-stage NSCLC and is the standard of care for medically inoperable patients.

**Past Medical History:**
- Severe COPD (GOLD Stage III, FEV1 38% predicted)
- Coronary artery disease (PCI with DES to RCA 4 years ago)
- Hypertension
- Osteoporosis
- Peripheral arterial disease
- Former smoker (45 pack-years, quit 8 years ago)

**Medications:**
- Tiotropium/olodaterol inhaler daily
- Albuterol inhaler PRN
- Aspirin 81 mg daily
- Clopidogrel 75 mg daily (continued post-PCI per cardiology)
- Atorvastatin 80 mg daily
- Metoprolol succinate 25 mg daily
- Alendronate 70 mg weekly
- Home oxygen 2L NC with exertion

**Social History:**
- Retired librarian
- Lives alone in single-story home
- Former smoker: 45 pack-years (1 pack/day for 45 years), quit 8 years ago
- No alcohol
- Uses home oxygen with exertion; walks with walker for longer distances
- ECOG Performance Status: 2

**Family History:**
- Mother: COPD, died at age 70
- Father: colon cancer at age 74
- Brother: lung cancer at age 68 (smoker)

### Physical Examination
- **Vital Signs:** BP 132/78 mmHg, HR 72 bpm, RR 20/min, Temp 36.7°C, SpO2 92% on room air (96% on 2L NC), Weight 54 kg, BMI 21.2
- **General:** Thin, elderly female, mildly dyspneic at rest, barrel chest
- **Lungs:** Decreased breath sounds bilaterally, prolonged expiratory phase, scattered expiratory wheezes, no crackles; increased AP diameter
- **Cardiovascular:** Regular rate and rhythm, no murmurs
- **Extremities:** No clubbing, no edema, ABI 0.76 bilaterally
- **Neurological:** Alert, oriented, no focal deficits

### Workup and Results

**Laboratory Studies:**
| Test | Result | Reference Range |
|------|--------|-----------------|
| CBC | Normal | - |
| Hemoglobin | 13.8 g/dL | 12.0-16.0 g/dL |
| Creatinine | 0.9 mg/dL | 0.6-1.2 mg/dL |
| Albumin | 3.6 g/dL | 3.5-5.0 g/dL |
| CEA | 4.2 ng/mL | <5.0 ng/mL |

**Pulmonary Function Tests:**
| Parameter | Result | % Predicted |
|---|---|---|
| FEV1 | 0.82 L | 38% |
| FVC | 1.86 L | 62% |
| FEV1/FVC | 0.44 | - |
| DLCO | 6.8 mL/min/mmHg | 34% |
| Predicted post-op FEV1 | 0.58 L | 28% |

**Imaging/Additional Studies:**
- **Low-dose CT chest:** 2.2 cm solid, spiculated nodule in right upper lobe (segment 1, apical); no other pulmonary nodules; severe emphysematous changes bilaterally
- **PET/CT:** FDG-avid RUL nodule, SUVmax 8.4; no FDG-avid mediastinal, hilar, or supraclavicular lymphadenopathy; no distant metastases
- **CT-guided biopsy:** Adenocarcinoma (NSCLC); TTF-1 positive; PD-L1 TPS 45%; EGFR/ALK/ROS1 negative (molecular testing for potential future systemic therapy)
- **Brain MRI:** No intracranial metastases
- **EBUS (endobronchial ultrasound):** Stations 4R and 7 sampled; no malignant cells (confirms N0 status)

**SBRT Treatment Planning:**
- **CT simulation:** 4D-CT acquired with abdominal compression to reduce respiratory motion; ITV (internal target volume) generated from all respiratory phases
- **Tumor motion:** 6 mm craniocaudal motion with free breathing, reduced to 3 mm with abdominal compression
- **Target volumes:**
  - GTV: 2.2 cm visible tumor on CT
  - ITV: GTV expanded to encompass tumor motion on 4D-CT
  - PTV: ITV + 5 mm isotropic expansion
- **Prescription:** 54 Gy in 3 fractions (18 Gy/fraction), delivered every other day over 1 week
- **OAR constraints (3-fraction regimen):**
  - Spinal cord: Max <18 Gy (single fraction equivalent)
  - Chest wall: V30Gy <30 cc
  - Esophagus: Max <27 Gy
  - Heart: Max <30 Gy
  - Proximal bronchial tree: Max <30 Gy (tumor is peripheral, >2 cm from proximal bronchial tree)
  - Ipsilateral lung (minus GTV): V20Gy <10%
- **Plan quality:** PTV V100% = 95%; R50% (50% isodose volume/PTV volume) = 4.2 (within RTOG constraints); maximum dose 130% of prescription (within PTV)

### Clinical Image

![SBRT Lung Treatment Plan](case_03_image.jpg)

*Diagram showing stereotactic body radiation therapy (SBRT) treatment plan for early-stage lung cancer with multiple non-coplanar beam arrangements, highly conformal dose distribution around the tumor, and steep dose falloff protecting surrounding normal lung tissue. Source: Educational illustration.*

### Diagnosis
**Right Upper Lobe Adenocarcinoma (NSCLC), T1cN0M0, Stage IA3, Medically Inoperable Due to Severe COPD, Treated with Stereotactic Body Radiation Therapy (SBRT)**

**Key Diagnostic Criteria:**
- Biopsy-confirmed adenocarcinoma of the lung
- Peripheral RUL location, 2.2 cm, spiculated, FDG-avid (SUVmax 8.4)
- Pathologic N0 status confirmed by EBUS
- No distant metastases on PET/CT and brain MRI
- Medically inoperable: FEV1 38% predicted, DLCO 34% predicted, predicted post-op FEV1 28% predicted (prohibitive risk per thoracic surgery)

### Treatment Plan
1. **SBRT delivery:** 54 Gy in 3 fractions (18 Gy/fraction), BED₁₀ = 151.2 Gy (BED >100 Gy associated with >90% local control); treatments on Monday, Wednesday, Friday of a single week
2. **Image guidance:** Cone-beam CT (CBCT) before each fraction with online match to ITV; respiratory monitoring with abdominal compression device
3. **Treatment delivery:** VMAT with 6-10 MV photons, multiple non-coplanar arcs; total treatment time approximately 15-20 minutes per fraction
4. **Monitoring during treatment:** Pulse oximetry before and after each fraction; supplemental oxygen available
5. **Acute toxicity management:**
   - Expected: mild fatigue, possible transient cough exacerbation
   - Radiation pneumonitis risk: ~5-10% (Grade ≥2); prednisone taper if symptomatic (dyspnea, cough, fever at 2-6 months post-treatment)
   - Chest wall pain: possible if tumor adjacent to ribs (this case: apical, low risk)
6. **Follow-up imaging:** CT chest at 3 months, then every 6 months for 2 years, then annually; expected post-SBRT changes include consolidation at treatment site (peak at 6-12 months, then slow regression)
7. **Distinguish recurrence from fibrosis:** If growing or newly FDG-avid mass at treatment site >12 months post-SBRT, consider PET/CT and possible biopsy; the "high-risk CT features" (bulging margins, loss of air bronchograms, enlargement after 12 months) suggest recurrence

### Key Learning Points
- SBRT delivers ablative doses of radiation in 3-5 fractions using highly conformal treatment plans with steep dose gradients, achieving local control rates of 90-95% for early-stage peripheral NSCLC
- Biologically effective dose (BED) is the key metric for SBRT efficacy: BED₁₀ >100 Gy is associated with optimal local control (54 Gy in 3 fractions = BED₁₀ 151.2 Gy)
- 4D-CT simulation is essential for lung SBRT to account for respiratory tumor motion; the internal target volume (ITV) encompasses the tumor position throughout the breathing cycle
- SBRT is the standard of care for medically inoperable early-stage NSCLC; prospective data suggest outcomes comparable to surgery for operable patients, with the STARS and ROSEL trials and VALOR/SABRTooth trials ongoing
- Post-SBRT imaging interpretation requires expertise: benite consolidation and fibrotic changes at the treatment site are expected and can mimic recurrence on CT; PET/CT and serial imaging are needed to distinguish the two