0:00

In this short video, we are going to discuss the role

0:04

of FDG in immunotherapy

0:08

and we're gonna cover two main things.

0:12

One would be general concepts of immunotherapy

0:15

and then we will discuss immune related adverse effects.

0:19

So for general concepts, what is immunotherapy?

0:24

This is the activation of the patient's own immune system

0:29

to recognize and kill cancer cells.

0:32

And there are three pathways that are used

0:36

and modulated to obtain that response.

0:40

Immunotherapy is commonly given in patients with melanoma,

0:45

non-small cell lung cancer and renal cell carcinoma.

0:49

But more and more so is being used

0:52

with many other tumors.

0:56

Something that was seen with immunotherapy that was not seen

1:00

with other therapies is these two patterns of response that

1:05

are different from chemotherapy or other targeted agents.

1:09

The first one is pseudo-progression in which we see a

1:13

response after an initial progression.

1:15

And so this is not common, this is happens less than 10%

1:20

of the cases, and this is better assessed retrospectively,

1:25

prospectively it looks like from the baseline to

1:29

after initiating therapy the patient has progressed.

1:34

But if you did a shortterm follow up,

1:37

you would call pseudo progression if all those areas

1:40

of presumed progression start responding.

1:45

And this was first reported in melanoma

1:48

treated with immunotherapy.

1:50

The second response is hyper progression.

1:53

That happens between nine to 29% of the cases.

1:58

And this is essentially a very rapid progression after it.

2:03

But this one, if you do a follow up,

2:06

it is a true progression.

2:09

This is a case of, uh, pseudo progression.

2:12

You can see that on the first column we have the baseline.

2:17

This is a patient with metastatic melanoma

2:20

that was being treated with pembrolizumab.

2:23

The baseline PET CT shows metastatic left external

2:28

and inguinal lymph nodes.

2:31

And on the follow-up exam, the left

2:35

external iliac lymph node has responded

2:38

and has improved to complete resolution almost whereas the

2:44

left inguinal lymph node is larger

2:47

and more FDG Avid.

2:50

So this patient had a biopsy of this lymph node

2:54

'cause they wanted to prove if this was in

2:57

indeed progression

2:58

And the biopsy came back as chronic inflammation

3:02

and no evidence of melanoma on the subsequent scan,

3:07

this lymph node had improved.

3:10

So even though these look like progression,

3:13

if you continue following these patients, these become areas

3:18

of improvement and

3:20

therefore, retrospectively you can call these a SDO

3:24

progression.

Role of FDG PET/CT Imaging in Immunotherapy: Basic Concepts

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Interactive Transcript

Pro Tip: Click on a word in the transcript to jump to that point in the video

0:00

In this short video, we are going to discuss the role

0:04

of FDG in immunotherapy

0:08

and we're gonna cover two main things.

0:12

One would be general concepts of immunotherapy

0:15

and then we will discuss immune related adverse effects.

0:19

So for general concepts, what is immunotherapy?

0:24

This is the activation of the patient's own immune system

0:29

to recognize and kill cancer cells.

0:32

And there are three pathways that are used

0:36

and modulated to obtain that response.

0:40

Immunotherapy is commonly given in patients with melanoma,

0:45

non-small cell lung cancer and renal cell carcinoma.

0:49

But more and more so is being used

0:52

with many other tumors.

0:56

Something that was seen with immunotherapy that was not seen

1:00

with other therapies is these two patterns of response that

1:05

are different from chemotherapy or other targeted agents.

1:09

The first one is pseudo-progression in which we see a

1:13

response after an initial progression.

1:15

And so this is not common, this is happens less than 10%

1:20

of the cases, and this is better assessed retrospectively,

1:25

prospectively it looks like from the baseline to

1:29

after initiating therapy the patient has progressed.

1:34

But if you did a shortterm follow up,

1:37

you would call pseudo progression if all those areas

1:40

of presumed progression start responding.

1:45

And this was first reported in melanoma

1:48

treated with immunotherapy.

1:50

The second response is hyper progression.

1:53

That happens between nine to 29% of the cases.

1:58

And this is essentially a very rapid progression after it.

2:03

But this one, if you do a follow up,

2:06

it is a true progression.

2:09

This is a case of, uh, pseudo progression.

2:12

You can see that on the first column we have the baseline.

2:17

This is a patient with metastatic melanoma

2:20

that was being treated with pembrolizumab.

2:23

The baseline PET CT shows metastatic left external

2:28

and inguinal lymph nodes.

2:31

And on the follow-up exam, the left

2:35

external iliac lymph node has responded

2:38

and has improved to complete resolution almost whereas the

2:44

left inguinal lymph node is larger

2:47

and more FDG Avid.

2:50

So this patient had a biopsy of this lymph node

2:54

'cause they wanted to prove if this was in

2:57

indeed progression

2:58

And the biopsy came back as chronic inflammation

3:02

and no evidence of melanoma on the subsequent scan,

3:07

this lymph node had improved.

3:10

So even though these look like progression,

3:13

if you continue following these patients, these become areas

3:18

of improvement and

3:20

therefore, retrospectively you can call these a SDO

3:24

progression.

Report

Faculty

Elisa Franquet Elia, MD

Assistant Professor of Radiology

UMass Chan Medical School

Lesson

Introduction to PET/CT Imaging

Lesson

FDG Use in PET/CT

Lesson

FDG: Common Pitfalls and Benign Lesions

Lesson

FDG Use in Hematologic Malignancies

Lesson

FDG Use in Lung Cancer

Lesson

FDG Use in Head & Neck Cancer

Lesson

FDG Use in Breast Cancer

Lesson

FDG Use in Immunotherapy

Lesson

DOTATATE Use in PET/CT

Lesson

DOTATATE and FDG Use in Neuroendocrine Tumors

Lesson

PSMA Use in PET/CT

Lesson

PSMA Use in Prostate Cancer

Role of FDG PET/CT Imaging in Immunotherapy: Basic Concepts