FDG uptake after intraarterial chemotherapy in head and neck cancer

The intraarterial chemotherapy (i.a.CHT) using high dose cisplatin combined with systemic neutralization in patients with head and neck cancer (HNSCC) is used to reduce the tumor volume preoperatively. Aim of the study is the evaluation of the influence of i.a.CHT on the metabolism of fluor-18-deoxyglucose (FDG) in the primary and lymph nodes (LN). The value of FDG positron emission tomography (PET) preoperative and as follow-up method after i.a.CHT is examined.

Altogether 16 patients with HNSCC underwent two preoperative FDG PET examinations: the baseline examination one week before and the follow-up three weeks after i.a.CHT. The SUVmax values of the primary and the LN and LN metastases were evaluated and compared with each other and the histopathology.

The SUVmax value of the primary decreased after i.a.CHT significantly from a median (25 (th) percentile/75 (th) percentile) of 6.4 (4.1/7.8) to 3.6 (2.4/6.7) (p = 0.01). In 11 out of 16 patients cervical LN metastases were detected. The cervical LN metastases showed a decrease of the SUVmax value from 3.6 (2.3/4.8) in the pretreatment examination to 2.3 (1.7/3.6) after i.a.CHT (p = 0.008). Only in one patient with LN metastases the SUVmax of the nodes increased. The histopathologically measured size of the LN metastases ranged from 2 to 30 mm. Non malignant LN did not reveal a significant SUVmax decrease after i.a.CHT (p = 0.13).

As expected, primaries of HNSCC showed a significant reduction of SUV after i.a.CHT. Compared to the primary the SUVmax decrease in LN metastases was less, but also significant. Since cytotoxic levels of cisplatin do not occur systemic, postinflammatory reactions of the LN or a lymphatic drainage of the chemotherapeutic drug into the LN could be an explanation. PET for staging of HNSCC must thus be performed prior to i.a.CHT.