Treatment of Multiple Lung Tumors

Transcription

1 VUmc SABR Symposium 2017 Treatment of Multiple Lung Tumors Indications and Dosimetric Considerations Dr. David Palma, MD, MSc, PhD Radiation Oncologist, London Health Sciences Centre Clinician-Scientist, Ontario Institute for Cancer Research London, Canada

2 Before We Start Two things are needed to contour: Image dataset Folder with DICOM files Contouring program ITK SNAP

3 Contouring Session Tonight Go to: goo.gl/ui1v4c Click and choose download goo.gl/ui1v4c

4 Triple Trouble 85 year-old man with prior history of a T3N2c squamous cell carcinoma of the supraglottis treated with chemoradiation in Presented in May 2017 with a cough. CXR showed nodules in right lung and CT scan ordered. goo.gl/ui1v4c

5 Triple Trouble None were present in Left-sided lesion arising within a previous cyst. goo.gl/ui1v4c

6 Triple Trouble Medical History: Type 2 diabetes (not on insulin), GERD, HTN, angina, hypothyroidism, depression, mild cognitive impairment Social History: 80 pack-year history of smoking, quit 30 years ago

7 Triple Trouble Referred to Thoracic Surgery PFTs: mild airflow obstruction Offered observation or referral to Radiation Oncology

8 Triple Trouble Repeat CT September 2017 showed increase in size in all 3 lesions RUL 0.8 to 1.3 cm RML 1.2 to 1.7 cm LLL 1.4 to 1.7 cm There are 3 separate lung lesions which have been slowly growing, none of which were present in September, They all look concerning for synchronous bronchogenic carcinomas.

9 PET/CT All 3 lesions are hot on PET: SUVmax Underlying primary lung neoplastic process versus metastatic lesions cannot be distinguished

10 What is going on?? 3 metastases from laryngeal cancer 3 lung primaries 2 lung primaries with 1 metastasis (from lung or larynx) 1 lung primary with 2 metastasis Summary: Oligometastatic disease or 3 primary lung cancers

11 Martini and Melamed Criteria J Thorac Cardiovasc Surg 1975

12 Genomic Profiling Genomic profiles analyzed from 15 lung adenocarcinomas in 6 patients All suggested independent primary tumors (not metastases) Lung tumours of the same individuals are no more similar to each other than are lung adenocarcinomas of different patients from TCGA cohort matched for tumour size and smoking status. Nature Communications 2016

13 Genomic Profiling

14 IASLC It is easier to determine that two tumors are different than that they are the same; finding similarities does not establish that they are the same. Few features are definitive; many commonly used characteristics are suggestive but associated with a substantial rate of misclassification.

15 IASLC Clinical Criteria

16 Back to the Case It was decided at our multidisciplinary tumor board that the most likely scenario is that these lesions represent 3 primary lung tumors Herder risk calculator: each nodule >95% doesn t even take into account synchronicity or growth In light of the high PET avidity and Herder score, treatment without biopsy was considered reasonable

17 Multiple Targets: Dose Constraints? Hanna et al, Clin Oncol 2017

18 Data: Multiple Lung Targets 101 patients, 39 synchronous, 62 metachronous (>6 months apart). First lesion: 29 SABR, 25 conventional RT, 42 surgery, 5 surgery + PORT Second lesion: 101 SABR Treated with 50 Gy in 4 fractions (or 70 Gy in 10 fractions if dose constraints not met)

19 Outcomes 4 year in-field local control 95.7%

20 Outcomes: Toxicity

21 SABR for Synchronous Lesions 84 patients with 188 lesions treated with multiple isocentres, from 2 institutions Most patients (97%) with 2-3 lesions. Median total PTV size: 52 cc Fractionations: 34/1, 54/3, 55/5, 60/8 Acta Oncologica 2016

22 SABR for Synchronous Lesions

23 Dosimetry: EQD2

24 SABR for Synchronous Lesions Toxicity 20% Grade 2+ RP (11%), chest wall (6%) 2% Grade 3 1 patient with possible Grade 5: bilateral pneumonia

25 Prediction of Toxicity EQD 2 35 Gy = BED Gy 3 fractions: V19 < 6.5% 5 fractions: V23 < 6.5% 8 fractions: V27 < 6.5%

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27 Critical Volume Concept Rough rule of thumb: For a parallel organ, keep a certain amount of the organ (approximately 1/3) preserved NRG protocols, and others, define threshold doses for 1500 cc and 1000 cc of lung

28 Critical Volume Concept

29 Critical Volume Concept CV12.5 = volume receiving 12.5 Gy or less 5 fractions: 1.5 L receiving <12.5 Gy

30 Our Case: PTVs in Red

31 Our Case: Dose

32 Our Plan Goal: 1500 cc with a critical volume threshold of 14.3 Gy (8 fractions) Each PTV optimized separately. There was some contribution across plans, so each PTV was optimized to be under-covered; good coverage on composite plan

33 Multiple Lung Targets: A Hot Topic

34 Expert Opinions Bilateral VATS vs. sternotomy is the surgical dilemma. This case is not in the gray zone. The patient has incurable metastatic disease and should not have further meddlesome local therapy, unless symptomatic.

35 Expert Opinions Our preference would be to recommend initial systemic chemotherapy if SABR is chosen as initial therapy we would recommend 60 Gy in 8 fractions to the left and 54 Gy in 3 fractions to the right

36 What Really Happened

37 TROG 13.01

38 What Really Happened

39 Take Home Messages When histology is the same, it is difficult to determine if multiple lung lesions are primary tumors or metastases. Early genomic data suggests that multiple primaries are common. SABR of multiple lesions is feasible. Dose constraints not well-determined Early studies suggest toxicity is reasonable

40 Contouring Session Tonight Go to: goo.gl/ui1v4c Click and choose download