The influence of computer tomography on treatment strategies and follow-up in tumors of the nasopharynx and the paranasal sinuses. A retrospective study on 104 patients.
BACKGROUND
The high value of computer tomography (CT) for detailed imaging of nasopharyngeal and paranasal sinus tumors is known. Less known is the influence of such diagnostic findings on decisions of the therapist. An analysis of this influence might help to compare the value of CT and MRT.


METHODS
We performed a retrospective study on 104 treated patients with malignant tumors of the nasopharynx (n = 54) and the paranasal sinuses (n = 50). The study analyzed the influence of CT on primary tumor diagnosis, tumor staging, treatment decision, therapy planning, detection and time of recurrences and retreatment of relapses.


RESULTS
Tumors of the nasopharynx: The value of CT for tumor staging was 76% but there was no influence on treatment decision. Radiotherapy planning was influenced in 37% of cases. CT for follow-up was done in 22% of cases. Most relapses occurred within the first 2 years. Paranasal sinus tumors: There was no influence of CT on primary diagnosis of the tumor. Tumor staging was influenced by CT in 94%, treatment decision in 44% and radiotherapy planning in 60%. CT control immediately after therapy was of value in 40%. Most relapses were found within 3 years but some in the 4th and 5th year. Some patients survived 3 to 9 years after retreatment.


CONCLUSIONS
In tumors of the nasopharynx there is less influence of CT on therapy strategies than diagnostic radiologists might think. No CT is needed for treatment decision since radiotherapy is the only choice of treatment. CT influenced radiotherapy planning however, in about 1/3 of our cases answering sufficiently the 2 main questions: tumor spread into the anterior half of the facial skull or involvement of the base of skull. The retreatment of recurrences detected by CT showed poor results. Late recurrences seem to have better prognosis. We recommend therefore routinely 1 basic CT 6 months after primary treatment followed by 1 CT yearly from the 3rd to 5th year. MRT might offer more diagnostic details than CT. However, at present therapy is not influenced much by this. Since CT is cheaper and faster, MRT could be discussed as additional procedure when CT presents equivocal findings and this fact could be decisive for therapy planning. Paranasal sinus tumors: The influence of CT on tumor-staging and treatment decision is high and convincing. CT helps also at radiotherapy planning and control of tumor response after therapy. CT has high value in detecting recurrences. Retreatment could control disease in some of our patients for 3 to 9 years. Better results could be achieved possibly with earlier diagnosis of recurrence. We propose therefore a basic-CT 6 months after first treatment and 1 CT routinely from the 2nd to 5th year. From the therapist's point of view we recommend CT as first imaging procedure in sinonasal tumors. MRT, more time- and cost consuming, should be applied when CT is equivocal and treatment decision could be influenced.
Reisner
K
K
Radiologische Klinik, St. Vincentius-Krankenhäuser, Karlsruhe.
Uhlig
U
U
D005500:Follow-Up Studies; D006801:Humans; D009303:Nasopharyngeal Neoplasms / Q000000981:diagnostic imaging* / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy; D009367:Neoplasm Staging; D010255:Paranasal Sinus Neoplasms / Q000000981:diagnostic imaging* / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D010315:Particle Accelerators; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods