Portada Simposios - Supplements - Haematologica

XLII Reunión Nacional de la AEHH y XVI Congreso de la SETH. Foros de debate
305
as a common finding in both HD and NHL, more
and more frequently a computed tomography (CT)
scan tends to replace the combination of chest radiogram
and abdomen ultrasonography (US).
Among non-invasive procedures both gallium-67-
citrate single photon emission ( 67 GaSPECT) 2,3 and
positron emission tomography (PET) 4,5 have come
into their own, with important consequences on the
management of lymphoma patients, whereas two
invasive procedures proven very compelling are core-needle
biopsy of the mediastinal 6 and abdominal
7 .lymph nodes.
Here we are going to summarize our personal and
institutional experience with respect to all the above
mentioned novel staging and monitoring procedures.
Gallium-67-citrate single photon emission
Residual masses in the mediastinum following
lymphoma therapy are as common as troubling for
both patients and physicians, to such an extent that,
when in doubt concerning the real nature of the residue,
both of them generally feel obliged to think that,
therapy-wise, “more is better” or at least “safer”.
CT scan and nuclear magnetic resonance (NMR) often
prove not adequate in order to discriminate beyond
a reasonable doubt between active tumour and
fibrotic tissue and the use of the former, definitely
more widespread in Italy than the latter, often does
not allow to perfectly monitor during the follow-up
patients who were diagnosed with a bulky lesion in
the mediastinum.
This is the reason for we started in 1992 a study 8
associating and comparing CT scan and 67 GaSPECT
in patients with either HD or aggressive NHL presenting
mediastinal involvement (64 % with bulky
mass). The study design was essentially based on
this double evaluation being performed at the end of
standard combined modality treatments (chemoand
radio-therapy) all patients had undergone.
Once this specific response analysis was completed,
each and every patient was allotted to one of
the following four categories: CT negative/ 67 GaS-
PECT positive, CT negative/ 67 GaSPECT negative, CT
positive/ 67 GaSPECT positive and CT positive/ 67 GaS-
PECT negative.
All the three patients who resulted CT negative
and 67 GaSPECT positive at the time of restaging
following the completion of both chemo and radio-therapy
relapsed within 15 months. Among the
18 patients who were CT negative and 67 GaSPECT
negative, seventeen have maintained their clinical
complete response (CCR), whereas one patient relapsed
18 months later with lung and neck localizations
of HD. As many as ten of the 13 (77 %) patients
being CT positive and 67 GaSPECT positive relapsed,
in nine cases within 5 months and in one
case after 10 months. Finally, only 5 of 41 (12 %) patients
who ended up as CT positive and 67 GaSPECT
negative relapsed. However, the most astounding
difference emerged from the comparison in terms
of 4-year actuarial relapse-free survival (RFS) rate
between CT positive/ 67 GaSPECT negative and CT
positive/ 67 GaSPECT positive patients (90 % vs 23 %;
p < 0.000000).
We conclude that 67 GaSPECT should become somehow
mandatory among the restaging procedures
for lymphoma, at least with respect to patients with
mediastinal involvement at diagnosis and CT scan
positivity at the end of the treatment. Then, in case
of 67 GaSPECT positivity, a local biopsy might be warranted.
Positron emission tomography
If the 67 GaSPECT has proven extremely useful in
order to discriminate between fibrosis and neoplasia
in the residual masses of the mediastinum, the same
cannot be said when the same dilemma refers to residual
masses in the abdomen. As a matter of fact,
mainly due to hepatic uptake and bowel excretion of
the radionuclide, 67 GaSPECT yields too many false
positives below the diaphragm to be somehow considered
as reliable as it is above.
Inasmuch as a number of reports had recently
shown a possible role for fluorine-18 fluorodeoxyglucose
PET in the context of lymphoma imaging, we
started our own study on it in 1996 9 and over the
next two years enrolled 44 patients with either HD or
aggressive NHL, in both cases with at least an abdominal
localization larger than 5 centimetres (41 % of
the patients had a bulky mass). All patients received
the appropriate chemo- and/or radio-therapy and
their restaging included PET 1 month after completion
of chemotherapy or two months after the end
of radiotherapy, when given.
Once the response analysis was completed, each
and every patient was allotted to one of the following
three categories: CT negative/PET negative, CT
positive/PET positive and CT positive/PET negative.
No patients were ever CT negative and PET positive
at the same time.
All 7 patients who were negative with respect to
both procedures at the completion of their therapy
have maintained their CCR. On the contrary, no patients
with double positivity were able to avoid relapsing,
in 11 cases within 8 months. Of the 24 patients
who were CT positive and PET negative, all but
one have also maintained their CCR, with a current
median follow-up of 18 months. Once again, an extremely
significative data is represented by the difference
in terms of 2-year actuarial RFS between CT
positive patients who were respectively PET negative
or positive (95 % vs 0 %; p < 0.000000).
Similarly to what concluded with respect to the
67 GaSPECT in lymphoma imaging above the diaphragm,
we think that PET should be used mandatorily
at the time of lymphoma restaging in all of the patients
diagnosed with abdominal masses that are
still CT positive at the end of treatment.