Impact of Maximum Point Dose Within the Planning Target Volume on Local Control of Nonsmall Cell Lung Cancer Treated With Stereotactic Body Radiotherapy

BACKGROUND

No consensus exists on the maximum dose delivered to the planning target volume (PTV) in the delivery of stereotactic body radiotherapy (SBRT) for primary lung cancer. We investigated whether higher biologically effective doses (BED) within the PTV were associated with improved tumor control.

METHODS

We reviewed patients with early-stage, node-negative nonsmall cell lung cancer who received curative-intent SBRT between 2005 and 2018. We calculated the maximum BED (maxBED) within the PTV for all patients, analyzing outcomes using the cumulative incidence method and Fine-Gray test statistics to assess prognostic impact.

RESULTS

We analyzed 171 patients (median age, 70.2; range, 43 to 90 y) with 181 lung nodules. Median follow-up was 2.7 years (range, 0.1 to 12 y) for all patients and 4.2 years (range, 0.2 to 8.4 y) for living patients. Median maximum tumor diameter was 1.9 cm (range, 0.7 to 5.6 cm). Patients received a prescription of 48 or 50 Gy in 4 or 5 fractions, respectively, except for one who received 60 Gy in 5 fractions. Median maxBED was 120 Gy (range, 101 to 171 Gy). There was no difference in the 3-year local control (LC) rate among patients treated with a maxBED<120 Gy versus ≥120 Gy ( P =0.83).

CONCLUSIONS

No significant differences in LC were observed between patients with early-stage nonsmall cell lung cancer treated with SBRT in 4 or 5 fractions with a maxBED≥120 Gy. However, a higher maxBED trended toward improved LC rates, suggesting a maxBED threshold greater than 120 Gy may be needed to improve LC rates.

Lessons in clinical reasoning - pitfalls, myths, and pearls: a case of crushing, substernal chest pain

OBJECTIVES

Diagnostic error is not uncommon and diagnostic accuracy can be improved with the use of problem representation, pre-test probability, and Bayesian analysis for improved clinical reasoning.

CASE PRESENTATION

A 48-year-old female presented as a transfer from another Emergency Department (ED) to our ED with crushing, substernal pain associated with dyspnea, diaphoresis, nausea, and a tingling sensation down both arms with radiation to the back and neck. Troponins were elevated along with an abnormal electrocardiogram. A negative myocardial perfusion scan led to the patient's discharge. The patient presented to the ED 10 days later with an anterior ST-elevation myocardial infarction.

CONCLUSIONS

An overemphasis on a single testing modality led to diagnostic error and a severe event. The use of pre-test probabilities guided by history-taking can lead to improved interpretation of test results, ultimately improving diagnostic accuracy and preventing serious medical errors.

Reirradiation in Conservative Salvage of Recurrent Soft-tissue Sarcoma: An Analysis of Treatment Efficacy and Toxicities

OBJECTIVE

Compared with radical resection alone, perioperative radiation therapy (RT) combined with neurovascular preserving surgery is the standard for the management of virgin soft-tissue sarcomas. Yet, the optimal management of a local recurrence remains unclear. We report outcomes of patients with locally recurrent soft-tissue sarcoma treated with resection and reirradiation at the University of Florida.

MATERIALS AND METHODS

We reviewed the records of patients treated with primary conservative surgery and radiation for soft-tissue sarcoma followed by salvage resection and reirradiation for a local recurrence at our institution.

RESULTS

We analyzed 23 patients treated between 1976 and 2014 (median follow-up, 46 mo). Tumor sites included: proximal extremity, 11 patients; trunk, 6; distal extremity, 5; and head and neck, 1. All patients had conservative gross total resection of their recurrent tumor, without amputation. For reirradiation, 16 patients received external-beam RT alone, 6 received external-beam RT and brachytherapy, and 1 received brachytherapy alone. Two patients received chemotherapy. After retreatment, the 5-year overall survival, cause-specific survival, local control, and distant control rates were 39%, 42%, 46%, and 60%, respectively. Ten patients experienced local recurrences, 1 experienced regional recurrence, and 9 developed distant metastases. Retreatment-related complications ranged from delayed wound healing to limb amputation; 8 patients required amputation. Only 3 patients remained disease-free at last follow-up. No statistically significant associations were found between treatment factors (eg, RT dose) and local control.

CONCLUSIONS

Achieving local control of recurrent soft-tissue sarcoma is challenging. Treatment with reoperation and reirradiation can lead to debilitating complications affecting function and quality of life.