Keywords: Invasive ductal carcinoma; lung adenocarcinoma; multiple primary cancer; targeted therapies
Currently, survival of cancer patients is increasing
due to both improvements in treatment modalities and availability of early diagnosis; thus, there will be
an increasing need for management of multiple tumors
in future. The mechanisms that cause MPMTs are still
unclear. While genetic predisposition can play an important
role in these cases, such as with hereditary non
polyposis coli syndrome, which increases risk for ovarian,
endometrial and small intestine cancers as well as
colon carcinoma, intensive use of chemotherapy and
radiotherapy (RT) might be also associated with certain
types of primary cancers.[
In the last quarter of the 20th century, improvements
in hybridoma and recombinant DNA technologies
led to use of monoclonal antibodies (mAb) for
diagnosis in vitro and ex vivo, and subsequently they
have been included in clinical use as a treatment option.
Within 30 years, mAb therapy has become part
of standard treatment for certain types of cancer.[
Targeted cancer therapies are drugs designed to
interfere with specific molecules necessary for tumor growth and progression. Traditional cytotoxic chemotherapies
usually kill rapidly dividing cells in the body
by interfering with cell division. A primary goal of targeted
therapies is to fight cancer cells with more precision
and potentially fewer side effects.[
Many different targeted therapies have been approved
for use in cancer treatment. These include hormone
therapies, signal transduction inhibitors, gene
expression modulators, apoptosis inducers, angiogenesis
inhibitors, immunotherapies, and toxin delivery
molecules.[
In terms of studies observing treatment of MPMTs,
Zeng et al. investigated hepatocellular carcinoma
(HCC) tumors accompanied by non-HCC primary tumors
and reported that it was important to treat both
the synchrone and metachrone tumors, while also
pointing out need for additional studies to support
their observations.[
Search of literature revealed no reports in which
more than one targeted therapy was administered for
multiple primary tumors. Described in the present case
is multiple primary carcinoma – primary lung cancer
and ductal invasive breast carcinoma – along with liver
metastasis for which targeted therapies for both lung
and breast cancer were administered.
Immunohistochemically estrogen and progesterone
receptors were found to be >%90 positive, and c-erb-
B2 (HER2/neu) was found to be strongly positive. As
the patient was evaluated as multiple primary, biopsies
of liver metastasis to determine primary was planned;
however, approval of the patient could not be obtained
for biopsy. Before announcement of results of immunohistochemical
and genetic testing, 4 cycles of chemotherapy
with paclitaxel 250 mg, carboplatin 600 mg
and zoledronat 4 mg were administered every 3 weeks.
After chemotherapy, a partial metabolic regression in
lesion located in lower lobe - posterobasal segment of
left lung - a complete regression in lymphadenopathies
located in right lower paratracheal site, and complete
regression of mass in right breast was obtained. Furthermore,
metastatic mass lesion observed initially in
segment 7 of liver was not reported. Since EGFR was
positive in lung adenocarcinoma and c-erb was positive
in breast adenocarcinoma immunohistochemically,
maintenance treatment was as follows: erlotinib
150 mg/day, letrozole 2.5 mg/day, trastuzumab 520 mg
loading dose followed by 420 mg was continued for 12
cycles every 3 weeks. At ninth month of treatment, patient
was still in follow-up, with assessment of stable
disease according to the Response Evaluation Criteria
In Solid Tumors (RECIST) version 1.1.[
In a study investigating outcomes of synchrone
non-small cell lung cancers, it was shown that best
outcomes can be obtained with more than 1 targeted
therapy if tumor is resectable; however, these synchrone
tumors were only tumors originating in the
lung.[
In literature, outcomes of multiple primary cancers that were accompanied by lung cancer have been investigated.[
Most side effects of targeted therapies are directly
related to the specific molecular target in normal tissue
inhibited or modulated by the specific drug. As present
case involves administration of 2 targeted therapies,
potential side effects of both were considered. The most
commonly observed side effect with EGFR inhibitors
is an acneiform eruption, also called acne-like rash or
folliculitis, which occurs in 50% to 100% of patients.
[
Post-chemotherapy diarrhea is the result of extensive
crypt damage in the small bowel and colon,
resulting in excess fluid in the bowel lumen. Exact
pathophysiology of anti-EGFR agent–related diarrhea
remains unclear. EGF is involved in the maintenance
of mucosal integrity and is also a potent mitogen of the
gastric epithelium; it stimulates mucin production and
enhances prostaglandin synthesis.[
Trastuzumab was humanized from the original
mAb, thereby allowing chronic administration in humans
without development of human anti-mouse antibodies
response, which is characterized by anaphylactic
response or other immune reactions and rapid drug
clearance.[
In the present case, echocardiogram was performed
at initiation of therapy. LVEF was initially 60% and
there was no decrease seen during or after treatment.
It is clear that resectability and adverse effects can
create difficulties in treatment of multiple primary tumors.
However, targeted therapies are developing rapidly
and there are promising reports that these modalities
will be widely used in the near future. Since there
is no definitive modality for treating patients with
multiple primary tumors at this time, it is the suggestion
of the authors that treatments targeting the same
pathways to hit the tumor could be a promising choice
of treatment. In the present case, we obtained a better
survival than expected with 2 targeted therapies. The
result must definitely be supported by further studies
in terms of drug interactions and side effects.
Conflict of interest: None declared.