Long-Term Toxicity in Patients Receiving Radiotherapy for Ultracentral Stage I Non-Small Cell Lung Cancer - A Secondary Analysis of the LUSTRE Randomized Trial

PURPOSE/OBJECTIVE(S)

Hypofractionated and stereotactic body radiotherapy (SBRT) are increasingly used in the treatment of centrally located, early-stage non-small cell lung cancer (NSCLC), though there are concerns of increased morbidity and mortality in patients with ultracentral tumors (UC). We report on the long-term toxicity of patients with UC lung cancer treated on a prospective randomized clinical trial of SBRT versus conventionally hypofractionated radiotherapy (CRT) for stage I NSCLC (NCT01968941).

MATERIALS/METHODS

Patients with UC tumors, defined as those where the planning target volume directly overlaps with the proximal bronchial tree (PBT), were identified from the larger cohort of patients treated on the trial. These patients received either SBRT with 60 Gy in 8 fractions or CRT with 60 Gy in 15 fractions. The primary endpoint of this secondary analysis was development of any grade 3 or higher toxicity defined using CTCAE version 3.0. Secondary endpoints included local control, as well as dosimetric analysis of the PBT, using EQD2 with α/β ratio of 3 to assess the relationship between dose to the PBT and toxicity.

RESULTS

Twenty-nine patients were identified with UC tumors; 21 received SBRT and 8 received CRT. Median age was 72 years (range 55-88 years) and 59% were female. Median FEV1 was 1.46L (range 0.64-2.37L). Patients had either T1 (59%) or T2 (41%) lesions, with median tumor size 2.5cm (range 1.1-4.9cm). Most patients had histologically confirmed disease (squamous cell, n = 10; adenocarcinoma, n = 8; radiographically suspicious, n = 11). The median follow-up was 2.9 years (range 0.7-5.2 years). The 3-year local control rate of all patients was 88.3% (95% confidence interval: 75.7-100%). There were 3 patients with late (>3 months) grade 3 toxicity (bronchial stricture, chest pain, and atelectasis) and 1 patient with late grade 5 toxicity (bleeding/hemorrhage), all treated in the SBRT arm. Median EQD2 dose to PBT in patients with grade ≥3 late toxicity compared to the rest of the cohort was: Dmax, 132 vs 129 Gy; D0.1cc, 129 vs 119 Gy; D1cc, 124 vs 80 Gy; and D5cc, 83 vs 41 Gy. Median EQD2 volumetric doses in grade ≥3 patients (compared to the rest) to PBT were: V65 Gy, 9.7 vs 2.2cc; V80 Gy, 7.9 vs 1.1cc; V90 Gy, 6.2 vs 0.4cc; and V100 Gy, 4.8 vs 0.3cc. The single patient with grade 5 toxicity had the highest D5cc (116 Gy) and V100 Gy (7cc) among all patients.

CONCLUSION

Stereotactic radiation with 60 Gy in 8 fractions for UC lung cancer provides good local control but carries an approximately 15-20% rate of late grade ≥3 toxicity. There appears to be a dosimetric association between toxicity and dose to the PBT. It may be more important to minimize volumetric PBT dose rather than maximum point dose to reduce risk of severe late toxicity.

Outcomes of Hypofractionated Stereotactic Radiotherapy for Small and Moderate-Sized Brain Metastases: A Single-Institution Analysis

Background

Stereotactic radiosurgery (SRS) is the standard treatment for limited intracranial metastases. With the advent of frameless treatment delivery, fractionated stereotactic radiotherapy (FSRT) has become more commonly implemented given superior control and toxicity rates for larger lesions. We reviewed our institutional experience of FSRT to brain metastases without size restriction.

Methods

We performed a retrospective review of our institutional database of patients treated with FSRT for brain metastases. Clinical and dosimetric details were abstracted. All patients were treated in 3 or 5 fractions using LINAC-based FSRT, did not receive prior cranial radiotherapy, and had at least 6 months of MRI follow-up. Overall survival was estimated using the Kaplan–Meier method. Local failure and radionecrosis cumulative incidence rates were estimated using a competing risks model with death as the competing risk. Univariable and multivariable analyses using Fine and Gray’s proportional subdistribution hazards regression model were performed to determine covariates predictive of local failure and radionecrosis.

Results

We identified 60 patients and 133 brain metastases treated at our institution from 2016 to 2020. The most common histologies were lung (53%) and melanoma (25%). Most lesions were >1 cm in diameter (84.2%) and did not have previous surgical resection (88%). The median duration of imaging follow-up was 9.8 months. The median survival for the whole cohort was 20.5 months. The local failure at 12 months was 17.8% for all lesions, 22.1% for lesions >1 cm, and 13.7% for lesions ≤1 cm (p = 0.36). The risk of radionecrosis at 12 months was 7.1% for all lesions, 13.2% for lesions >1 cm, and 3.2% for lesions ≤1 cm (p = 0.15).

Conclusions

FSRT is safe and effective in the treatment of brain metastases of any size with excellent local control and toxicity outcomes. Prospective evaluation against single-fraction SRS is warranted for all lesion sizes.

Quality of life and swallowing with standard chemoradiotherapy versus accelerated radiotherapy and panitumumab in locoregionally advanced carcinoma of the head and neck: A phase III randomised trial from the Canadian Cancer Trials Group (HN.6)

AIM

To compare quality of life (QOL) between standard (SFX) chemoradiotherapy (arm A) and altered fractionation radiotherapy (AFX) with panitumumab (PMab; arm B).

METHODS

Patients with T any N + M0 or T3-4N0M0 squamous cell head-neck carcinoma were randomised to SFX (70 Gy/35/7 wks) plus cisplatin (100 mg/m² IV × 3) versus AFX (70 Gy/35/6 wks) plus PMab (9 mg/kg IV × 3). QOL was collected at baseline, end of radiation therapy (RT) and 2, 4, 6, 12, 24 and 36 months post-RT using the Functional Assessment of Cancer Therapy Head and Neck (FACT-H&N), MD Anderson Dysphagia Index (MDADI) and SWAL-QOL. We hypothesised a 6-point more favourable change in FACT-H&N score from baseline to 1 year in arm B over arm A.

RESULTS

Among 320 patients, median follow-up was 46 (range: 0.1-64.3) months, median age 56, 84% male, Eastern Cooperative Oncology Group PS 0 (71%), 1 (29%). Primary site was oropharynx in 81% (p16+ 68%, p16- 16%, missing 16%). Baseline scores did not differ by arm (A/B): FACT-H&N 116.5/115, MDADI Global 83/77, SWAL-QOL General 67/68. At 1 year, no difference was seen between arms in FACT-H&N change from baseline: A -1.70, B -4.81, p = 0.194. Subscale change scores by arm were (A/B): last week RT, FACT-Physical (-11.6, -10, p = 0.049), MDADI Physical (-40.4, -33.9, p = 0.045), and SWAL-QOL Eating Duration (-61.2, -51.2, p = 0.02), Eating Desire (-53.3, -43.9, p = 0.031) and Mental Health (-42, -32.6, p = 0.009); 4 months, HN subscale (-7.7, -10, p = 0.014). No clinically important differences by arm were seen post-treatment.

CONCLUSIONS

PMab with AFX did not durably improve QOL or swallowing as compared with SFX with cisplatin.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00820248.