Kent, it’s natural to jump to the worst conclusion when there is a resurgence of previous symptoms or the start of new ones. The info in this new publication, (March 2018) should calm you down a bit. I include the abstract below:
Temporal Dynamics of Pseudoprogression After Gamma Knife Radiosurgery for Vestibular Schwannomas-A Retrospective Volumetric Study.
Breshears JD1, Chang J2, Molinaro AM1,3, Sneed PK4, McDermott MW1, Tward A2, Theodosopoulos PV1.
Author information
Abstract
BACKGROUND:
The optimal observation interval after the radiosurgical treatment of a sporadic vestibular schwannoma, prior to salvage intervention, is unknown.
OBJECTIVE:
To determine an optimal postradiosurgical treatment interval for differentiating between pseudoprogression and true tumor growth by analyzing serial volumetric data.
METHODS:
This single-institution retrospective study included all sporadic vestibular schwannomas treated with Gamma Knife radiosurgery (Eketa AB, Stockholm, Sweden; 12-13 Gy) from 2002 to 2014. Volumetric analysis was performed on all available pre- and posttreatment magnetic resonance imaging scans. Tumors were classified as "stable/decreasing," "transient enlargement", or "persistent growth" after treatment, based on incrementally increasing follow-up durations.
RESULTS:
A total of 118 patients included in the study had a median treatment tumor volume of 0.74 cm3 (interquartile range [IQR] = 0.34-1.77 cm3) and a median follow-up of 4.1 yr (IQR = 2.6-6.0 yr). Transient tumor enlargement was observed in 44% of patients, beginning at a median of 1 yr (IQR = 0.6-1.4 yr) posttreatment, with 90% reaching peak volume within 3.5 yr, posttreatment. Volumetric enlargement resolved at a median of 2.4 yr (IQR 1.9-3.6 yr), with 90% of cases resolved at 6.9 yr. Increasing follow-up revealed that many of the tumors initially enlarging 1 to 3 yr after stereotactic radiosurgery ultimately begin to shrink on longer follow-up (45% by 4 yr, 77% by 6 yr).
CONCLUSION:
Tumor enlargement within ∼3.5 yr of treatment should not be used as a sole criterion for salvage treatment. Patient symptoms and tumor size must be considered, and giving tumors a chance to regress before opting for salvage treatment may be worthwhile.
Basically it says tumor can still be enlarged up to 3.5 years of treatment. In fact, peak volume within 3.5 years post treatment. So you fall into this timeframe of peak enlargement. Good news is, after that it starts shrinking. So do your best not to panic just yet.