Patterns of failure after reirradiation with intensity-modulated radiation therapy and the competing risk of out-of-field recurrences

PURPOSE

To describe patterns of failure (POF) after reirradiation (reRT) with intensity modulated radiation therapy (IMRT) for recurrent/second primary squamous cell carcinoma of the head and neck.

METHODS

From 08/2004-02/2013, 75 consecutive patients received reRT with IMRT. Gross tumor was generally treated with a 5mm planning target volume (PTV) margin. For postoperative cases, a 5mm PTV was added to the clinical target volume which included the postoperative bed. Elective neck coverage was not standard. POF were characterized by correlating the recurrent tumor location on CT-imaging with the reRT IMRT plan.

RESULTS

Patients received definitive reRT (55%) or postoperative reRT (45%) to a median 60Gy (range, 59.4-70Gy). Most patients (88%) received concurrent chemotherapy including induction (16%). The median overall survival was 1.8years. Isolated local-regional recurrence (LRR) was the most common failure-type (2-year cumulative incidence [CI] 22.5% [95% C.I. 13.6-32.7%]), but concurrent LRR and distant-failure occurred frequently (2-year CI LRR+distant-failure 19.6% [95% C.I. 11.3-29.5%]); isolated distant-failure was rare (2-year CI 5.7% [95% C.I. 1.8-12.8%]). The 2-year in-field control was 65% (95% C.I. 52-81%) reflecting encouraging control within the irradiated target. Patients with gross disease were more likely to recur in-field (p=0.02), whereas postoperative patients were more likely to recur out-of-field/marginally than in-field (p=0.02).

CONCLUSIONS

POF after reRT differ when treating gross disease or postoperatively and should be considered when delineating reRT targets. Aggressive local therapy resulted in favorable in-field control, yet there remains a high competing risk of regional and distant micrometastatic disease. Better systemic agents are needed to control clinically occult local-regional and distant disease.

Sentinel node biopsy for oral and oropharyngeal squamous cell carcinoma in the previously treated neck

In patients with early stage oral or oropharyngeal squamous cell carcinoma (OSCC) sentinel node biopsy (SNB) is a reliable method to detect occult disease in the neck. However, patients with a history of surgery or radiotherapy in the neck may have aberrant lymphatic drainage caused by disruption of lymphatic channels. Therefore, treatment of the same levels at risk as in the primary setting may not be appropriate. The aim of our prospective observational study was to evaluate the clinical application of SNB in previously treated OSCC. Between 2003 and 2010 twenty-two patients were included. Lymph node mapping consisted of preoperative lymphoscintigraphy, SPECT/CT, intraoperative use of gamma-probe and patent blue. Endpoints were the sentinel node (SN) detection rate, unexpected lymphatic drainage patterns, negative predictive value and regional tumor control. 4/22 (18%) Patients were previously treated only on the contralateral site. The SN detection rate was 100% and unexpected drainage was found in 1/4 patients. The other 18 patients had ipsi- or bilateral previous neck treatment and a SN detection rate of 83%. The upstaging rate was 7% and 67% had unexpected lymphatic drainage patterns. The median follow-up was 22 months. Regional tumor control and negative predictive value were 100%. SNB in previously treated OSCC patients is feasible. SN detection is reliable and regional tumor control after staging by SNB is excellent. Moreover, SNB renders an assessment of the individual lymphatic drainage pattern, compensating for a potential variability after previous treatment of the neck.

Functional imaging of head and neck cancers

PURPOSE OF REVIEW

Functional imaging including single photon emission computed tomography, PET and MRI techniques in head and neck squamous cell cancer allows disease characterization beyond structure and morphology.

RECENT FINDINGS

In patients without clinical signs of lymph node involvement, sensitivity of fluoro-2-deoxy-D-glucose PET is only 50%. This has led to the use of sentinel lymph node scintigraphy that seems to be a valid alternative to elective stage dissection. Additionally, the use of single-photon emission computed tomography-computed tomography imaging enables a more accurate localization of the sentinel lymph node scintigraphy. The fluoro-2-deoxy-D-glucose uptake intensity of the head and neck squamous cell carcinoma sites is related to locoregional control and overall survival. In case of suspicion for residual or recurrent head and neck squamous cell carcinoma after surgery or (chemo)radiotherapy, fluoro-2-deoxy-D-glucose-PET has a high sensitivity and seems to be cost-effective in selecting patients for direct laryngoscopy. Diffusion-weighted MRI in combination with size and morphological criteria is a strong predictor of presence of malignant lymph nodes. Initial reports indicate the use of diffusion-weighted imaging for response assessment as early as 1 week after beginning of radiochemotherapy. Perfusion MRI is studied for the measurement of drug effects on tumour (micro)vascularity and capillary permeability.

SUMMARY

Functional imaging improves the initial staging and the detection of residual or recurrent disease following therapy.