Stereotactic radiotherapy for lung oligometastases from colorectal cancer
PO-1189
Abstract
Stereotactic radiotherapy for lung oligometastases from colorectal cancer
Authors: Andrei Fodor1, Chiara Lucrezia Deantoni1, Roberta Tummineri1, Claudio Fiorino2,3, Italo Dell'Oca1, Martina Mori2, Sara Broggi2, Marcella Pasetti1, Lucia Perna2, Stefano Lorenzo Villa1, Giuseppina Mandurino1, Ariadna Sanchez Galvan1, Simone Baroni1, Pietro Pacifico1, Antonella Del Vecchio2, Nadia Gisella Di Muzio1,3
1IRCCS San Raffaele Scientific Institute, Department of Radiation Oncology, Milan, Italy; 2IRCCS San Raffaele Scientific Institute, Medical Physics, Milan, Italy; 3Vita-Salute San Raffaele University, Radiotherapy, Milan, Italy
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Purpose or Objective
Lung oligometastases (LOM) from
colorectal cancer (CRC) have a higher radioresistance than those from other
cancers. The objective of this retrospective analysis is to evaluate toxicity and local control (LC) of stereotactic
radiotherapy in the management of LOM from CRC performed in our institution.
Material and Methods
From 01/2006 to 07/2020, 70 metastases (mts) of
38 LOM patients from CRC were treated with SRT (37 with 4D helical/VMAT IG-IMRT
and 32 with real time-tracking robotic radiosurgery). Median age was 65.0 (48.7-84.0) years. Median interval between primary
treatment and LOM was 14 (1-117) months. A single LM was treated in 19 pts, two in 11
pts, three in five pts, four in one patient, and five in two patient
(one with 2 lesions treated in one PTV for a total of four PTVs), respectively. Median gross tumor volume
(GTV) was 5 (0.16-88.6) cc, and median planning treatment volume (PTV) was
21.35 (1.97-180) cc. Median prescribed
dose 54 (36-60) Gy, in a median number of 6 (2-8) fractions. Fifty-eight
lesions were peripheral and 11 centrally located. The Biologically Effective
Dose (BED), considering an alpha/beta ratio of 10 was 102.6 (72-180) Gy. Acute
and late toxicities were graded according to the National Cancer Institute
Common Terminology Criteria (CTCAE) v. 5.
Results
Median follow up was 15.2 (3-86.4)
months. The treatment was well tolerated and no grade (G) ≥ 2 acute toxicity was reported: two pts presented G1 cough (the patient treated on four
lesions) and another patient G1 dyspnea. Five patients presented late toxicity: a late
G3 pulmonary toxicity was observed in one patient treated on five LOM (total
PTV = 82.71 cc). The patient treated on four lesions registered
with G1 acute cough presented G1 fibrosis during the follow up. Three pts (treated on two, two and three lesions
respectively) presented G1 dyspnea. Fifteen pts (39.5%) were dead at the last
follow up, one for brain metastases, one for bacterial pneumonia, one for a
second (urothelial) tumor progression and all others for systemic progression
(none for local progression). Median overall survival (OS), cancer specific
survival (CSS) and Local progression free survival (LPFS) were 38.2 months,
38.7 months and 15.2 months, respectively. Kaplan Meyer estimates of OS were
87% at 12 months and 72% at 24 months, CSS 88.8% at 12 months and 73.5% at 24
months, while LPFS 72% at 12 months and 42% at 24 months. Of the relapsed
lesions 4 were treated with surgery, four with a second course of SRT, 9 with
chemotherapy and one with immunotherapy.
Conclusion
SRT in lung oligometastases
from colorectal cancer have a low toxicity profile at a median BED of 102 Gy,
but a better patient selection, avoiding important volumes of disease treated
concomitantly, is necessary to prevent any toxicity. A higher BED is necessary
to improve local control.