Deviations from Standard Chemoradiation among Early Stage Anal Cancer Patients

Publication date: Available online 16 December 2017
Source:International Journal of Radiation Oncology*Biology*Physics
Author(s): Thomas M. Churilla, Lyudmila DeMora, Elizabeth Handorf, Nicholas G. Zaorsky, Yanqun Dong, Crystal S. Denlinger, Elin Sigurdson, Joshua E. Meyer
PurposeWe sought to evaluate factors associated with non-standard chemoradiation treatment for early stage anal cancer.MethodsWe queried the National Cancer Database for patients with squamous cell carcinoma of the anal canal, T1-T2N0M0, treated with non-palliative radiation therapy (>35Gy) from 2004- 2013. We defined "standard" radiation doses as 45-54Gy for T1 primaries and 45-59.4Gy for T2 primaries. We used multivariable logistic regression with generalized estimating equations (GEE) to test for associations with receipt of higher than standard (high dose) radiation and use of concurrent chemotherapy. The Cochran-Armitage test was used to analyze trends over time.ResultsA total of 7,800 patients met inclusion criteria. Among all patients, 82.4% received standard dose radiation, 5.2% received low dose radiation, and 12.4% received high dose radiation. The vast majority (93.5%) of patients received concurrent chemotherapy (single or multi-agent). Receipt of high dose radiation was associated with lack of single or multi-agent chemotherapy (HR [95%CI] = 2.82 [2.23-3.56]) and tumor size < 2 cm (1.89 [1.56-2.30] compared to 2-2.9 cm. Multi-agent chemotherapy administration was more frequent among patients with increasing tumor size (compared to < 2 cm): 2-2.9cm (1.38[1.17-1.64]), 3-3.9cm [1.38[1.15-1.66], and 4-5cm (1.40[1.12-1.75]). Use of multi-agent chemotherapy was less frequent among the elderly (age > 70) (0.43 [0.36-0.52]) and males (0.76 [0.66-0.86]). There was a linear trend towards increased use of standard dose radiation with time (p < 0.001) and increased use of concurrent chemotherapy with time (p < 0.001).ConclusionsOver 10% of patients with early stage anal cancer received radiation doses in excess of 54 Gy (cT1N0M0) - 59.4 Gy (cT2N0M0) and this practice varied by time, chemotherapy administration, and tumor size. Although this analysis is limited by lack of data on tumor response, wide variation in treatment practices suggest further prospective study is warranted to define the optimal radiotherapy dose for patients with early stage anal cancer.

Teaser

The optimal chemoradiation regimen for early stage (T1-T2N0M0) anal cancer patients is not well established. We sought to evaluate treatment practice patterns for early stage anal cancer patients using the National Cancer Database. Over 10% of patients with early stage anal cancer received high dose external beam radiation with concurrent chemotherapy (including 20.7% of T1 and 6.9% of T2 primary tumors), suggesting possible overtreatment of these early stage cancers.


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